The present invention provides a cationic resin composition capable of forming a cationically electrodepositable coating film which is excellent in corrosion resistance, an aptitude for the cationic electrodepositable coating of a rust preventive steel plate and in adhesion to substrate, which cationic resin composition is characterized by comprising the following components:

The present invention relates to a cationic resin composition, more specifically to a cationic resin composition capable of forming a cured coating film which is excellent in both corrosion resistance and an aptitude for the cationic electrodepositable coating of a rust preventive steel plate.
A cationic resin composition is used mainly as a cationic electrodepositable coating composition for wide-ranged uses including an undercoating composition for car bodies, and those having various characteristics have so far been developed. Proposed as a conventional cationic resin composition is, for example, a coating composition having excellent corrosion resistance and improved in an electrodepositable coating aptitude and an adhesive property toward a rust preventive steel plate, in which used as a vehicle component is a modified epoxy resin obtained by internally plasticizing an epoxy resin having an amino group and/or a quaternary ammonium salt group as a hydrophilic group with a plasticizer such as polyamide, polyester and polyether and blended is a rust preventive pigment, for example, a lead compound or a chromium compound such as lead chromate, basic lead silicate and strontium chromate. In recent years, however, hazardous compounds such as lead compounds and chromium compounds are restricted in use thereof from a viewpoint of pollution problems, and techniques which can improve a corrosion resistance of the coating film without blending such hazardous compounds are expected to be developed.
On the other hand, an epoxy resin which is internally plasticized with a plasticizer such as polyamide, polyester and polyether tends to reduce a corrosion resistance of the coating film, and therefore it is considered to use an epoxy resin containing no plasticizing modifier to thereby elevate the corrosion resistance. However, this provides the problem that the electrodepositable coating aptitude against a rust preventive steel plate is reduced. In order to solve such problems, it is proposed that added as a plasticizer for an epoxy resin are, for example, polyol resins such as polyesterpolyols, polyetherpolyols, polyurethanepolyols and acrylpolyols; and polymers including polyolefins such as polybutadiene and polyethylene. Involved therein, however, is the problem that these materials not only do not have a sufficiently high compatibility with epoxy resins and are not effective so much for elevating a rust preventive steel plate aptitude but also reduce a corrosion resistance of the coating film by adding in a large amount.
A main object of the present invention is to provide a cationic resin composition useful in particular as a cationic electrodepositable coating, comprising an epoxy resin as a base material and capable of forming a coating film which is excellent both in a corrosion resistance and a rust preventive steel plate aptitude without using hazardous compounds such as lead compounds and chromium compounds.
Intensive researches repeated by the present inventors have resulted in finding that the object described above can be achieved by combining, as a vehicle component in a cationic resin composition, a certain kind of amino group-containing epoxy resin with a specific polyol-modified amino group-containing epoxy resin and a blocked polyisocyanate curing agent.
Thus, the present invention provides a cationic resin composition comprising the following components:
(A) an amino group-containing epoxy resin which is prepared by adding an amino group-containing compound (a-2) to an epoxy resin (a-1) having an epoxy equivalent of 400 to 3000,
(B) a polyol-modified amino group-containing epoxy resin which is prepared by making an epoxy resin (b-1) having an epoxy equivalent of 180 to 2500 react with an amino group-containing compound (b-2) and with a polyol compound (b-3) obtained by adding caprolactone to a compound having plural active hydrogen groups, and
(C) a blocked polyisocyanate curing agent, component (A) being 40 to 70% by weight, component (B) being 4 to 40% by weight, and component (C) being 10 to 40% by weight, based on the total solid contents of (A), (B) and (C).
The cationic resin composition of the present invention shall be explained below in further details.
Amino group-containing epoxy resin which is used as component (A) in the cationic resin composition of the present invention is prepared by adding an amino group-containing compound (a-2) to an epoxy resin (a-1). Said epoxy resin (a-1) can have an epoxy equivalent falling in a range of 400 to 3000, preferably 450 to 2500, and more desirably 500 to 2200. Further, it has suitably a number average molecular weight falling in a range of usually 500 to 5000, particularly 600 to 4500, and more particularly 800 to 4000. An epoxy resin obtained by the reaction of a polyphenol compound with epihalohydrin, for example epichlorohydrin, is particularly suited as an epoxy resin (a-1) from the viewpoint of corrosion resistance of coating film.
Polyphenol compounds which can be used for producing the above epoxy resin include, for example, bis(4-hydroxyphenyl)-2,2-propane (bisphenol A), 4,4-dihydroxybenzophenone, bis(4-hydroxyphenyl)methane (bisphenol F), bis(4-hydroxyphenyl)-1,1 -ethane, bis(4-hydroxyphenyl)-1,1-isobutane, bis(4-hydroxy-tert-butyl-phenyl)-2,2-propane, bis(2-hydroxynaphthyl)methane, tetra(4-hydroxyphenyl)-1,1,2,2-ethane, 4,4-dihydroxy-diphenylsulfone (bisphenol S), phenol novolak and cresol novolak.
Particularly suited as an epoxy resin obtained by the reaction of a polyphenol compound with epichlorohydrin is a compound which is derived from bisphenol A, and which is represented by the following formula:
wherein n is 1 to 10.
Commercially available products of such epoxy resin include, for example, products which are marketed from Japan Epoxy Resin Co., Ltd. in the trade names of Epikote 828EL, ditto 1002, ditto 1004 and ditto 1007.
For the amino group-containing compound (a-2) as a cationic property-providing component with which to introduce an amino group into the above-mentioned epoxy resin (a-1) and to thereby cationize said epoxy resin, there are suitably used amine compounds having at least one active hydrogen which performs an addition reaction with an epoxy group of epoxy resin (a-1), for instance amine compounds which have at least one primary or secondary amino group in molecule. Concrete examples of such compounds include mono- or di-alkylamines such as monomethylamine, dimethylamine, monoethylamine, diethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, monobutylamine and dibutylamine; alkanolamines such as monoethanolamine, diethanolamine, mono(2-hydroxypropyl)amine, di(2-hydroxypropyl)amine, tri(2-hydroxypropyl)amine, monomethylaminoethanol and monoethylaminoethanol; alkylenepolyamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, tetraethylenepentamine, pentaethylenehexamine, diethylaminopropylamine, diethyelenetriamine and triethylenetetramine, and ketimine-reduced compounds of these polyamines; alkyleneimines such as ethyleneimine and propyleneimine; and cyclic amines such as piperazine, morpholine and pyrazine.
The above-mentioned addition reaction between epoxy resin (a-1) and amino group-containing compound (a-2) may be conducted by a known method. For instance, epoxy resin (a-1) and amino group-containing compound (a-2) are allowed to react with each other in an organic solvent like hydrocarbon type solvent such as heptane, toluene, xylene, octane and mineral spirits; ester type solvent such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethyleneglycol monomethylether acetate and ethyleneglycol monobutylether acetate; ketone type solvent such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone and cyclohexane; alcohols such as methanol, ethanol, iso-propanol, n-butanol, sec-butanol and isobutanol; and ether type solvent such as n-butylether, dioxane, ethyleneglycol monomethylether and ethyleneglycol monoethylether, at a temperature of about 80 to about 130xc2x0 C. The proportion of epoxy resin (a-1) to amino group-containing compound (a-2) used in the addition reaction is not strictly restricted, but can suitably be changed according to the species of starting materials used and special properties which products are desired to have. Usually, however, the weight ratio of (a-1)/(a-2) is preferably within a range of 90/10 to 60/40, in particular 85/15 to 70/30.
Thus obtained amino group-containing epoxy resin (A) can have an amine value within a range of 30 to 100, preferably 40 to 80.
Polyol-modified amino group-containing epoxy resin which is used as component (B) in the cationic resin composition of the present invention is prepared by making an epoxy resin (b-1) react with an amino group-containing compound (b-2) and with a polyol compound (b-3) obtained by adding caprolactone to a compound having plural active hydrogen groups. The above-mentioned epoxy resin (b-1) can have an epoxy equivalent within a range of 180 to 2500, preferably 200 to 2000, much desirably 400 to 1500, and suitably has a number average molecular weight within a range of at least 200, in particular 400 to 4000, especially 800 to 2000.
Like the above-mentioned epoxy resin, also epoxy resin (b-1) is preferably obtained by a reaction between a polyphenol compound and epichlorohydrin, and, thus, may be appropriately chosen from those which are recited above with respect to epoxy resin (a-1).
For amino group-containing compound (b-2) which is used for the purpose of introducing amino group, as a cationizable group, into the above-mentioned epoxy resin (b-1), there may also be employed those which are recited above as amino group-containing compound (a-2) with which to introduce amino group into epoxy resin (a-1).
In the present invention, furthermore, a polyol compound (b-3) is made to react for the purpose of internally plasticizing (modifying) the epoxy resin (b-1). For this polyol compound (b-3), there are employed those which are produced by adding caprolactone to a compound (hereinafter referred to as xe2x80x9cactive hydrogen-compoundxe2x80x9d) having plural active hydrogen groups.
An active hydrogen group means an atomic group containing at least one active hydrogen and includes, for example, an alcoholic hydroxyl group, a primary amino group and a secondary amino group. The compound having plural groups of such active hydrogen group in a molecule, i.e., active hydrogen-compound, includes, for example:
(i) low molecular weight polyols,
(ii) linear or branched polyetherpolyols,
(iii) linear or branched polyesterpolyols,
(iv) amine compounds having a primary amino group and/or a secondary amino group or hydroxylamine compounds having a primary amino group and/or a secondary amino group in combination with a hydroxyl group.
These active hydrogen group-containing compounds can have a number average molecular weight falling in a range of usually 62 to 5,000, preferably 62 to 4,000 and more preferably 62 to 1,500. The active hydrogen-compound is suitably a compound having at least two groups and less than 30 groups, particularly 2 to 10 groups of the active hydrogen groups per molecule on the average.
The low molecular weight polyol (i) described above is a compound having at least two alcoholic hydroxyl groups in a molecule, and to be specific, it includes, for example, diols such as ethylene glycol, propylene glycol, 1,3-butylene glycol 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, cyclohexane-1,4-dimethylol, neopentyl glycol, triethylene glycol and hydrogenated bisphenol A; triols such as glycerin, trimethylolethane and trimethylolpropane; tetrols such as pentaerythritol and xcex1-methylglycoside; hexols such as sorbitol and dipentaerythritol; and octols such as sucrose.
The linear or branched polyetherpolyol (ii) described above can have a number average molecular weight falling in a range of usually 62 to 10,000, preferably 62 to 2,000, and to be specific, it includes, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly(ethylenexe2x80xa2propylene) glycol, bisphenol A ethylene glycol ether and bisphenol A propylene glycol ether which are produced by ring-opening reaction of alkylene oxides (e. g., ethylene oxide, propylene oxide, butylene oxide and tetrahydrofuran).
The linear or branched polyesterpolyol (iii) described above can have a number average molecular weight falling in a range of usually 200 to 10,000, preferably 200 to 3,000, and to be specific, it includes, for example, compounds obtained by polycondensation reaction of organic dicarboxylic acids or anhydrides thereof with organic diols on the condition of organic diol excess. The organic dicarboxylic acid used in this case includes aliphatic, alicyclic or aromatic organic dicarboxylic acids having 2 to 44 carbon atoms, particularly 4 to 36 carbon atoms, for example, succinic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, glutaric acid, hexachloroheptane-dicarboxylic acid, cyclohexanedicarboxylic acid, o-phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid and tetrachlorophthalic acid. Further, in addition to these carboxylic acids, capable of being used in combination in small amounts are anhydrides of polycarboxylic acids having 3 or more carboxyl groups and adducts of unsaturated fatty acids.
The organic diol component includes, for example, alkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol, and dimethylolcyclohexane. They may be used, if necessary, in combination with a small amount of polyol such as trimethylolpropane, glycerin and pentaerythritol.
The preceding amine compound having a primary amino group and/or a secondary amino group or amine compound (iv) having a primary amino group and/or a secondary amino group in combination with a hydroxyl group includes, for example, alkylamines such as butylenediamine, hexamethylenediamine, tetraethylene-pentamine and pentaethylenehexamine; alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, mono(2-hydroxypropyl)amine and di(2-hydroxypropyl)amine; alicyclic polyamines such as 1,3-bisaminomethyl-cyclohexane and isophoronediamine; aromatic polyamines such as xylylenediamine, metaxylenediamine, diaminodiphenylmethane and phenylenediamine; alkylenepolyamines such as ethylenediamine, propylenediamine, diethylene-triamine and triethylenetetramine; and other amine compounds such as polyamides and polyamideamines which are derived from piperizine and these polyamines, amine adducts with epoxy compounds, ketimines and aldimines.
Among the compounds having plural active hydrogen groups described above, suited are the compounds of (i), (ii), (iii) and (iv), particularly compounds selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, hydrogenated bisphenol A, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol dipentaecrythritol, polyethylene glycol polypropylene glycol, polytetramethylene glycol, poly(ethylenexe2x80xa2propylene) glycol, bisphenol A ethylene glycol ether, bisphenol A propylene glycol ether, butylenediamine, hexamethylenediamine, monoethanolamine, diethanolamine, triethanol-amine, isophoronediamine, ethylenediamine, propylene-diamine, diethylene-triamine and triethylenetetramine.
On the other hand, caprolactone which can be added to these active hydrogen-compounds include xcex3-caprolactone, xcex5-caprolactone and xcex4-caprolactone, among which xcex5-caprolactone is particularly suited.
The addition reaction between the above active hydrogen-compounds and caprolactone can be carried out by conventionally known methods. To be specific, it can be carried out, for example, by heating an active hydrogen-compound and caprolactone at a temperature of about 100 to about 250xc2x0 C. for about one to about 15 hours in the presence of a catalyst including titanium compounds such as tetrabutoxytitanium and tetrapropoxytitanium, organic tin compounds such as tin octylate, dibutyltin oxide and dibutyltin laurate, and metal compounds such as stannous chloride.
In general, the catalyst described above can be used in an amount of 0.5 to 1,000 ppm based on the total amount of active hydrogen-compound and caprolactone. Caprolactone can be used in an amount falling in a range of usually 1 to 30 moles, preferably 1 to 20 moles and more desirably 1 to 15 moles per equivalent of active hydrogen group (that is, per active hydrogen) of active hydrogen-compound.
The polyol compound (b-3) thus obtained has together a high plasticizing performance based on the active hydrogen-compound, a high compatibility with an epoxy resin based on (poly)caprolactone and a high reactivity attributable to a terminal hydroxyl group, and therefore is very useful as an internal plasticizer for an epoxy resin for a coating composition.
The polyol compound (b-3) can contain caprolactone-originated units in a proportion falling in a range of usually 20 to 95% by weight, preferably 25 to 90% by weight, and can have a number average molecular weight falling in a range of usually 300 to 10,000, preferably 400 to 5,000.
The polyol-modified amino group-containing epoxy resin used as component (B) in the resin composition of the present invention can be produced by subjecting the epoxy resin (b-1) described above, by a known method, to an addition reaction with the amino group-containing compound (b-2) and the polyol compound (b-3) having a terminal hydroxyl group originating in caprolactone. The reaction of the polyol compound (b-3) and the amino group-containing compound (b-2) with the epoxy resin (b-1) can be carried out in an optional order. In general, however, the polyol compound (b-3) and the amino group-containing compound (b-2) are suitably made to react with the epoxy resin (b-1) at the same time. A single terminal of the polyol compound (b-2) is preferably added to the skeleton of the epoxy resin (b-1).
The above-mentioned addition reaction can be carried out usually in a suitable solvent at a temperature of about 90 to about 170xc2x0 C., preferably about 100 to about 150xc2x0 C. for one to 5 hours, preferably 2 to 4 hours. Said solvent includes, for example, hydrocarbons such as toluene, xylene and n-hexane; esters such as methyl acetate, ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and methyl amyl ketone; amides such as dimethylformamide and dimethylacetamide; alcohols such as methanol, ethanol n-propanol and iso-propanol; and mixtures thereof.
The proportion of reaction components in the addition reaction described above is not strictly restricted, and can suitably be changed according to uses of the resin composition. The ratio of epoxy resin (b-1), the amino group-containing compound (b-2) and the polyol compound (b-3) falls suitably in the following ranges based on the total solid matter weight of the three components described above:
Epoxy resin (b-1):
Usually 60 to 90% by weight, preferably 62 to 85% by weight and more desirably 62 to 80% by weight
Amino group-containing compound (b-2):
Usually 5 to 25% by weight, preferably 6 to 19% by weight and more preferably 6 to 18% by weight
Polyol compound (b-3):
Usually 5 to 30% by weight, preferably 5 to 20% by weight and more preferably 5 to 18% by weight
The blocked polyisocyanate curing agent which is used as component (C) in the cationic resin composition of the present invention is an addition reaction product of a polyisocyanate compound with an isocyanate blocking agent in almost stoichiometric amounts. The polyisocyanate compound used includes, for example, aromatic, aliphatic or alicyclic polyisocyanate compounds such as tolylenediisocyanate, xylilenediisocyanate, phenylenediisocyanate, bis(isocyanatemethyl)cyclohexane, tetramethylenediisocyanate, hexamethylenediisocyanate, methylenediisocyanate and isophoronediisocyanate, and terminal isocyanate group-containing compounds obtained by reacting excess amounts of these polyisocyanate compounds with low molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, trimethylolpropane, hexanetriol and castor oil.
On the other hand, the isocyanate blocking agents described above are added to, and block, isocyanate groups of the polyisocyanate compounds, and the blocked polyisocyanate compounds formed by the addition are stable at a room temperature. However, when they are heated at a baking temperature (usually, about 100 to about 200xc2x0 C.) of the coating film, the blocking agent is preferably dissociated to regenerate free isocyanate groups. Examples of blocking agent satisfying such requisite include lactam compounds such as xcex5-caprolactam and xcex3-butyrolactam; oxime compounds such as methyl ethyl ketoxime and cyclohexanoneoxime; phenol compounds such as phenol, p-t-butylphenol and cresol; aliphatic alcohols such as n-butanol and 2-ethylhexanol; aromatic alkylalcohols such as phenylcarbinol and methylphenylcarbinol; and ether alcohol base compounds such as ethylene glycol monobutyl ether.
The cationic resin composition provided by the present invention comprises amino group-containing epoxy resin (A), polyolmodified amino group-containing epoxy resin (B) and blocked polyisocyanate curing agent (C) as mentioned above.
The proportion of the above-mentioned components (A), (B) and (C) in the resin composition of the present invention is as follows, based on the total solid matter weight of these components:
Component (A): 40 to 70% by weight, preferably 43 to 67% by weight, more desirably 45 to 65% by weight;
Component (B): 5 to 40% by weight, preferably 7 to 37% by weight, more desirably 8 to 35% by weight;
Component (C): 10 to 40% by weight, preferably 15 to 40% by weight, more desirably 17 to 35% by weight.
The cationic resin composition of the present invention can be prepared, for example, by sufficiently mixing amino group-containing epoxy resin (A), polyol-modified amino group-containing epoxy resin (B) and blocked polyisocyanate curing agent (C), and then neutralizing the resultant mixture, usually in an aqueous medium, with acidic neutralizer such as formic acid, acetic acid, lactic acid, propionic acid, citric acid, malic acid and sulfamic acid by which to reduce the above-mentioned components water-soluble or water-dispersible. Thus, there are obtained a resin composition suitable as an emulsion for cationic electrodepositable coating.
As a neutralizer, acetic acid, formic acid or a mixture thereof is particularly suited, and the use of these acids elevates a finishing property, a throwing property and a low temperature-curing property of the coating composition formed as well as the stability of paint.
When used as a coating composition, the resin composition of the present invention may contain a bismuth compound as a rust preventive. The kind of the bismuth compound to be blended is not specifically restricted, and includes, for example, inorganic bismuth compounds such as bismuth oxide, bismuth hydroxide, basic bismuth carbonate, bismuth nitrate and bismuth silicate. Among them, bismuth hydroxide is particularly preferred.
Also usable as the above-mentioned bismuth compound are organic acid bismuth salts which are produced by a reaction between two or more organic acids and a bismuth compounds described above, and in which at least one of said organic acids is aliphatic hydroxycarboxylic acid. The organic acids which can be used for producing the above organic acid bismuth salts include, for example, glycolic acid, glyceric acid, lactic acid, dimethylolpropionic acid, dimethylolbutyric acid, dimethylolvaleric acid, tartaric acid, malic acid, hydroxymalonic acid, dihydroxysuccinic acid, trihydroxysuccinic acid, methylmalonic acid, benzoic acid and citric acid.
The inorganic bismuth compounds and the organic acid bismuth salts described above each can be used alone or may be used in combination of two or more kinds thereof.
The content of these bismuth compounds in the resin composition of the present invention is not strictly restricted, and can be changed over a wide range according to performances required of the resin composition. Usually, it falls suitably in a range of 0.01 to 10% by weight, preferably 0.05 to 5% by weight based on the resinous solid contents in the resin composition of the present invention.
Further, the cationic resin composition of the present invention can contain, if necessary, a tin compound as a curing catalyst. Said tin compound includes, for example, organic tin compounds such as dibutyltin oxide and dioctyltin oxide; and aliphatic or aromatic carboxylic acid salts of dialkyltin such as dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, dioctyltin benzoateoxy, dibutyltin benzoateoxy, dioctyltin dibenzoate and dibutyltin dibenzoate. Among them, dialkyltin aromatic carboxylic acid salts are suitable from a viewpoint of a low temperature curability.
The content of these tin compounds in the resin composition of the present invention is not strictly restricted, and can be changed over a wide range according to performances required of the resin composition. Usually, the tin content falls suitably in a range of 0.01 to 8 parts by weight, preferably 0.05 to 5 parts by weight per 100 parts by weight of the resinous solid contents in the coating composition.
Further, if necessary, the cationic resin composition of the present invention can contain, blended therein, coating material additives such as a color pigment, an extender pigment, a rust preventive pigment, an organic solvent, a pigment dispersant and a surface-controlling agent.
The cationic resin composition of the present invention can be applied on the surface of desired substrate by cationically electrodepositable coating, In general, electrodepositable coating can be carried out on the condition of a loaded voltage of 100 to 400 V in an electrodeposition bath which is controlled usually to a bath temperature of about 15 to about 35xc2x0 C., and which comprises the coating composition of the present invention diluted with deionized water so that the solid matter concentration becomes about 5 to about 40% by weight, preferably 15 to 25% by weight, and controlled to a pH falling in a range of 5.5 to 9.
A film thickness of an electrodeposited coating film which is formed using the resin composition of the present invention is not specifically restricted, and falls preferably in a range of usually 10 to 40 xcexcm, particularly 15 to 35 xcexcm in terms of a cured coating film. A baking temperature of the coating film is suitably a temperature falling in a range of usually about 120 to about 200xc2x0 C., preferably about 140 to about 180xc2x0 C. on the surface of substrate, and the baking time is 5 to 60 minutes, preferably 10 to 30 minutes.
The cationic resin composition of the present invention is suitably used as a cationically electrodepositable coating composition, which use is however not restrictive. The cationic resin composition of the present invention can also be used as a solvent type coating material for a corrosion resistant primer of a steel plate for coating by a method such as electrostatic coating and roll coating.
Further, the resin composition of the present invention can be used as a two-liquid type room temperature-drying coating composition or as an adhesive using, as a cross-linking agent, a polyisocyanate compound and a melamine resin in place of blocked polyisocyanate curing agent.
The cationic resin composition of the present invention forms a cured coating film which is excellent in corrosion resistance, an electrodepositable coating aptitude against a corrosion-resistant steel plate and an adhesive property to a base material, and is useful as an undercoating material for car bodies, car parts and construction and building fields.

Abstract: (A) an amino group-containing epoxy resin which is prepared by adding an amino group-containing compound to an epoxy resin having an epoxy equivalent of 400 to 3000,

Abstract: (B) a polyol-modified amino group-containing epoxy resin which is prepared by making an epoxy resin having an epoxy equivalent of 180 to 2500 react with an amino group-containing compound and with a polyol compound obtained by adding caprolactone to a compound having plural active hydrogen groups, and


The invention is a method and device for measuring the inclination of a roadway using highly precise digital inclinometer and a frame for holding and suspending the digital inclinometer over the width of a lane of traffic. The device and method require a single, and only a single, human operator. The device is lightweight and highly portable.

Typically, a roadway course will have a slope or a crown extending downwards from the center of the road towards the sides of the road. In the field of roadway construction, the slope of a roadway course perpendicular to the side of the road is of great importance as it allows water, debris, and other hindrances to roadway traffic to exit the road. Too much slope, however, can also pose a roadway hazard. Such hazards are amplified when the subject roadway receives heavy and/or fast traffic such as a United States Interstate Highway. As a result, Engineers have determined very precise slope mandates which determine best practice in roadway design and installation. Both construction codes and paving contracts include these roadway inclination design mandates and it is incumbent upon contractors to insure that their roads meet the precise specified slopes. Likewise, it is incumbent upon roadway owners, such as states and local governments, to insure that they are receiving the precision engineered, sloped roadways for which they are paying.
Typically, slope has been measured and checked using traditional surveying methods. These methods include using several humans to hold and position levels and poles and then to calculate the slope based on observed readings. These methods are labor intensive and take time to perform calculations respective of the slope. Other methods include using imprecise inclinometers mounted on the rear of a roadway paving or screeding machines to capture a reading as the road is constructed.
The present invention provides a method and device for measuring the slope of the roadway with a high degree of precision. The device and method also reduces requisite labor to a single human and eliminates the need for complex calculations. The device is thus an apparatus which may easily be operated and maneuvered by a single person whereby the reading of the slope to a high degree of precision is easily accomplished.
It is a further object of the present invention to provide a device that may be easily transported from jobsite to jobsite. It is still a further object of the present invention to optionally, and alternatively, provide a device that will measure a full lane of traffic but also measure a smaller portion of a lane.
To this end, the present invention contemplates a digital inclinometer that precisely measures slope across a roadway with an error of less than 2.0 arcminutes. This digital inclinometer is fixed in a lightweight, rigid frame designed to span at least the width of a lane of traffic. The frame can be easily moved by a single person and can be disassembled and transported. It may also be, optionally and alternatively, shortened as necessary to span smaller distances.

Method and device for measuring the inclination of a roadway


A dispenser for scents and aromas is disclosed. The scent dispenser includes a hollow central body that contains a rotating shaft. A wick is wound around the shaft and extends through an opening in the top of the central body. A sealable cap is included to allow scent material to be added to the wick inside the central body. Finally, a suspension mechanism in included to allow the dispense to be suspended from a separate structure.

1. Field of the Invention
The invention relates generally to hunting equipment. More specifically, the present invention relates to a dispenser for scents and aromas.
2. Background Art
The use of scented formulations to attract game or fur bearing animals by hunters and trappers is a time-honored technique that has been in use for at least 100 years. A variety of natural and synthetic formulations are utilized to appeal in a variety of ways to the olfactory senses of the animals, whether to arouse the animals' curiosity or to otherwise attract such animals to the location of the hunter's blind or the trapper's trap. Quite often, such materials, usually in liquid form, have been derived from the urine or glandular secretions of such animals, and are, in many cases, quite odorous and foul-smelling. Other types of scents designed to mask or conceal the odor or scent trail of a hunter or trapper are also in common, widespread use, including such fragrances as cedar, pine, and fresh earth.
In the mid-to-late twentieth century, the use of deer urine-based scents, in particular, became popularized by individuals and companies who began bottling and selling such animal fluids as an effective way to attract game animals, in particular, whitetail deer. Such scents were most commonly used by pouring them onto the ground in the area where the hunter had chosen to hunt, which technique commonly resulted in spills and leakage of the foul-smelling scents onto the hands and clothes of the user. Likewise, in pouring the scents onto the ground, much of the scent ended up being absorbed into the ground, which resulted in inefficient evaporation and dispersal, and excessive expense inasmuch as once the expensive scent was poured out, it could not be re-used.
Devices for storage and dispersal or propagation of scented materials are widely known in the art. A variety of containers housing and selectively exposing an absorbent material upon which a scented material is placed, to permit passive evaporation of such scents, is known. Such devices generally do not satisfy the need for a clean, convenient, compact, and leak-free way to handle, store, and disperse scents, and in the vast majority of cases, they do not provide optimum scent dispersal due to the limited surface area of the scent-absorbent material or scent-containing medium, some of which constitute no more than a small piece of cotton, felt or sponge material. Likewise, many of the scent containers and scent dispersal devices known in the art do not provide for adequate sealing of the containers, resulting in frequent leaks and spills of very malodorous materials. Furthermore, such devices often tend to be large and bulky, and frequently involve complicated, often failure-prone mechanisms. Finally, in most cases no adequate provision is made for loading the scent, deploying the device, and storing the scent without the user ever having to touch or come into contact with the often foul-smelling scented materials. The present invention is directed at providing just such an improved device and method for storing and efficiently dispersing hunting, trapping, and other scented materials.


At least one detected natural language phrase in audio describes at least one expected future object activity in a definable physical or geographic region. For each of one or more potential video analytic rules that are derivable from the at least one natural language phrase, whether compatibility with corresponding workflow requirements of an entity exists may be determined, such that one, some or all of the one or more potential video analytic rules are confirmed as one or more workflow-compatible video analytic rules. The one or more workflow-compatible video analytic rules are implemented within a video security system for respective one or more periods of time. For each of the implemented video analytic rules, a notification may be generated: when a rule violation of the respective video analytic rule triggers an event; or following expiry of the respective period of time of the one or more periods of time.

Managing multiple devices within a security ecosystem can be a time-consuming and challenging task. This task typically requires an in-depth knowledge of each type of device within the security ecosystem in order to produce a desired workflow when a security event is detected. For example, consider a school system that employs a security ecosystem comprising a radio communication system, a video security system, and a door access control system. Assume that some operator wishes to implement a first workflow that notifies particular radios if a door breach is detected. Assume that the operator also wishes to implement a second workflow that also notifies the particular radios when a security camera detects loitering. In order to implement these two workflows, the access control system will have to be configured to provide the notifications to the radios and the video security system will have to be configured to provide the notifications to the radios. Thus, both the access control system and the video security system will need to be configured separately in order to implement the two workflows. As is evident, this requires the operator to have an in-depth knowledge of both the video security system and the access control system. Thus, the lack of continuity across systems is a burden to operators since an in-depth knowledge of all systems within the ecosystem will be needed in order to properly configure workflows within the ecosystem.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required.

Dynamic video analytics rules based on human conversation


The present invention has the object of offering a semiconductor production method which simplifies the fabrication of gate electrodes for MOS-type semiconductor elements and allows a high yield to be maintained. For this purpose, it has steps of forming a field-shield gate insulation film on a semiconductor substrate, forming polycrystalline silicon films having an etching rate which is greater at an upper side than a lower side thereon, and etching the polycrystalline silicon films under conditions which allow for side etching with the silicon oxide film as a mask, so as to make gradually tapered inclines on side walls of field-shield gate electrode.

1. Technical Field of the Invention
The present invention relates to semiconductor device production methods, especially production methods for semiconductor devices having field-shield isolation structures.
2. Background Art
For semiconductor devices which use silicon as semiconductor substrates, LOCOS (Local Oxidation of Silicon) methods have conventionally been used as isolation methods for selectively forming thick thermal oxidation films on the substrates. However, with the LOCOS method, the oxide film regions which grow horizontally from the periphery of the thick thermal oxide film to the active region form obstacles to scaling down known as bird's beaks, so that attention has recently been turned to other techniques, such as field-shield isolation methods.
The field-shield isolation method is a method wherein a MOS structure (hereinafter referred to as a field-shield isolation structure) composed of a field-shield insulation film and a field-shield electrode is provided between the active regions forming the semiconductor element and the field-shield electrode is held at a standard electrical potential (for example, GND or 0 V), whereby parasitic channels are prevented from being formed in the substrate surface in order to isolate the active regions.
An example of a production method for semiconductor devices having field-shield isolation structures is disclosed in Japanese Patent Application, First Publication No. 2-211651. The production method described in this publication shall be explained below as a reference. FIG. 3 is a plan view showing a DRAM memory cell having a field-shield isolation structure, and FIGS. 4A.about.4L are process flow diagrams showing the DRAM memory cell production steps in order.
First, as shown in FIG. 4A, a silicon oxide film 2, a phosphorus-doped polycrystalline silicon film 3 and a silicon oxide film 4 are sequentially formed on the surface of a wafer W formed from a P-type silicon substrate 1. Next, as shown in FIG. 4B, the three films 2, 3 and 4 are patterned into a designated shape so as to form a field-shield gate oxide film 5, a field-shield gate electrode 6 and a field-shield gate cap insulation film 7.
Then, as shown in FIG. 4C, a silicon oxide film 8 is formed on the entire surface of the wafer W, after which side wall spacers 9 are formed by anisotropic etching as shown in FIG. 4D. Next, as shown in FIG. 4E, a silicon oxide film 10 is formed on the surface of the p-type silicon substrate 1, after which a phosphorus-doped polycrystalline silicon film 11 and silicon oxide film 12 are sequentially formed on the entire surface of the wafer W.
Thereafter, as shown in FIG. 4F, a gate oxide film 13, a gate electrode 14 and a gate cap insulation film 15 for a MOS transistor are formed by patterning the films 10, 11 and 12 into a designated shape. Next, as shown in FIG. 4G, an ion implantation of phosphorus is conducted while using these parts 13, 14 and 15 as a mask to form an n-type impurity diffusion layer 16, after which a silicon oxide film 17 is formed over the entire surface of the wafer W as shown in FIG. 4H.
Subsequently, as shown in FIG. 4I, side wall spacers 18 are formed at the side walls of the gate electrode 14 of the MOS transistor by anisotropic etching. Then, as shown in FIG. 4J, after forming a phosphorus-doped polycrystalline silicon film 19 over the entire surface of the wafer W, the bottom electrode 20 of a capacitor is formed by patterning this into a designated shape.
Then, as shown in FIG. 4K, a dielectric film 21 composed of a silicon nitride film is formed on the bottom electrode 20 of the capacitor, and a phosphorus-doped polycrystalline silicon film 22 is formed on the top surface thereof. This is then patterned into a designated shape to form the top electrode 23 of the capacitor as shown in FIG. 4L. Then, after forming an interlayer insulation film 24, contact holes 25 are opened at designated locations, and a wiring layer 28 is formed. A DRAM memory cell having a field-shield isolation structure is formed through the above-given steps.
In semiconductor devices such as the above-mentioned DRAM memory cell shown in FIG. 3, the active regions 26 which form the MOS-type semiconductor element (a MOS transistor in the above example) are defined to be the regions surrounded by the field-shield gate electrode 6. Additionally, with conventional production methods, the side walls of the field-shield gate electrodes 6 stand perpendicular with respect to the surface of the silicon substrate 1 as shown in FIGS. 4B.about.4L.
However, if these side walls are perpendicular, it is difficult to fabricate the gate electrodes 14 of the MOS transistor which extend from within the active regions 26 to the field-shield gate electrode 6 as shown in FIG. 3. That is, a step is formed on the gate electrodes 14 of the MOS transistor at the side wall portions of the field-shield gate electrode 6. However, these steps must be roughly perpendicular because the side walls of the field-shield gate electrodes 6 are roughly perpendicular, making the gate electrodes 14 of the MOS transistor extremely difficult to etch. Additionally, since etching residues can remain between the gate electrodes 14 (the portions indicated by the thick line and labelled with reference numeral 27 in FIG. 3), short circuits can often occur. While this problem can be somewhat relieved by forming a side wall spacer 9 on the side walls 6 of the field-shield gate electrodes 6, this is not sufficient. Additionally, this problem will get even worse as the active regions get smaller due to higher integration of elements, which could cause reduced yields.
Therefore, two methods have been proposed as means for solving this problem. The first method is described in Japanese Patent Application, First Publication No. 2-161753. With this method, the side walls of the field-shield gate electrodes are given an inclination by isotropically etching a conductive film having a single impurity concentration to form the field-shield gate electrodes. Additionally, the second method is described in Japanese Patent Application, First Publication No. 6-238599. With this method, the side walls of the field-shield gate electrodes are made into gradually tapered shapes by etching under conditions wherein the etching rate changes over time when the conductive film is etched.
However, the two above-mentioned methods also have problems. That is, while the side walls of the field-shield gate electrodes are inclined by means of isotropic etching with the first method, isotropic etching usually results in etched surfaces which are curved into concave shapes, so that the upper portions of the side walls become close to perpendicular and the problem is not fully solved. Additionally, since the etching rate is changed over time by changing the concentration of etchant with respect to a conductive film with a uniform impurity concentration according to the second method, the etchant concentration must be changed for each semiconductor wafer when etching, thus presenting problems such as reduced product throughput and poor etch controllability.

Production method for semiconductor device having field-shield isolation structure


A process for applying silver-graphite dispersion electrodeposits from an electrolyte with a conducting salt that is free of free cyanide. The process facilitates working at relatively high current densities to achieve high speed plating.

DE 25 43 082 C3 discloses a process of this type. In this known process for applying dispersion electrodeposits, potassium cyanide as a free cyanide is used as a supporting electrolyte. Suited as wetting agents for the known process are, inter alia, Turkey-red oil, sulphonated oleate ester, and fatty alcohol sulphonate. The known process is used to galvanize metal objects such as frames at current densities from to 1 to 5 A/dm.sup.2.

Process for applying silver-graphite dispersion electrodeposits


A method for transmitting a multiplexed uplink control channel and localized sounding reference symbol (localized SRS) by a terminal comprises a step of dividing the uplink control channel into a plurality of uplink control channel sub-blocks in a frequency domain and then transmitting the divided uplink control channel, when a frequency bandwidth of the localized SRS is smaller than or equal to a coherent bandwidth, wherein the divided uplink control channel sub-blocks may be frequency-division-multiplexed together with at least one localized SRS and then transmitted in one symbol.

With the introduction of a new Radio Access Technology (RAT) system, a number of communication devices have required higher communication capacity, and thus the necessity of mobile broadband communication much improved than the conventional RAT has increased. In addition, massive Machine Type Communications (MTC) capable of providing various services at anytime and anywhere by connecting a number of devices or things to each other has been considered as an important issue to be discussed in the next generation communication system. Moreover, a communication system design capable of supporting services/UEs sensitive to reliability and latency has been discussed. That is, the new RAT system is expected to provide services by considering enhanced Mobile Broadband Communication (eMBB), massive MTC (mMTC), Ultra-reliable and low-latency communication (URLLC), and the like.

Method for transmitting and receiving multiplexed uplink control channel and localized sounding reference symbol and device therefor


Radiation stable glass for space applications, especially glass in the form of thin sheet for cladding of spacecraft, is produced by including at least 5% by weight of barium oxide in a borosilicate glass composition. Because barium has a low absorption in the ultra violet, its use enables radiation stable glasses of low ultra violet absorption to be produced, alleviating problems of overheating when the glasses are used for cladding space craft. The glass is useful in the production of solar cell cover slips and second surface mirrors for cladding purposes, and space applications generally.

1. Field of the Invention
This invention relates to glasses having good stability to radiation useful as cladding glasses in space and terrestrial applications, and to cladding panes composed of such glasses.
On irradiation with high energy radiation typically encountered in space, glass tends to discolour, reducing the transmission of the glass and increasing its solar absorptance. Thus, radiation stability is a particular requirement of glasses used as cladding glasses in space applications, for example, as solar cell cover slips or as the glass substrates of second surface mirrors used as cladding to protect spacecraft from overheating.
2. Description of the Prior Art
It is known, for example from EP 0 261 885A1 and EP 0 505 061A2, to use borosilicate glasses, stabilised against the effects of irradiation by the incorporation of cerium (typically in amounts of 2% to 5% by weight), for production of solar cell cover slips having a high transmission in the visible and infra-red regions of the spectrum. Cerium has very broad absorption bands in the ultra-violet region of the spectrum at 240 nm and 315 nm. This absorption in the ultra-violet may be beneficial when the glasses are to be used in solar cell cover slips, for example, in protecting the adhesive used to bond the cover slips to the cells from ultra-violet radiation which would otherwise tend to degrade the adhesive. However, when the same base glasses are used, with a reflective coating on the back surface, as second surface mirrors to clad the exterior surface of a space craft and reflect unwanted solar radiation incident upon it, the absorption in the ultra-violet leads to an undesirable build-up of heat in the glass.
Thus there is a need for a method of stabilising a high transmission borosilicate glass to radiation especially radiation encountered in space, which does not rely on the use of cerium (or any other element which absorbs significantly in the spectral region from 250 nm wavelength to 2500 nm wavelength). It has now been found, and the discovery forms the basis of the present invention, that borosilicate glasses may be stabilised against radiation by inclusion of barium.

Borosilicate glasses and second surface mirrors thereof


A blow molded container comprises a transfer ring open to the container body and characterized by a plurality of arcuate recesses in the sidewall thereof disposed to reduce deformation at the junction of the top transfer ring surface and container neck resulting from compressive forces acting on the neck along the longitudinal axis of the container. Advantageously an elongated dome protrudes outwardly from each sidewall recess, each dome being open to the interior of the container. A blow mold assembly for extrusion blow molding of a container according to the invention comprises first and second mating mold components, each mating mold component comprising molding surfaces open to a mating face of the mold component. Advantageously each mating mold component comprises a removable insert comprising the molding surfaces defining the neck and transfer ring of the container.

1. Field of the Invention
This invention relates generally to blow molded containers. In particular, this invention relates to such of those containers wherein the so called bumper roll or transfer ring is formed in the blow molding process and mold assemblies for such containers.
2. Description of Related Art
Blow molding is a cyclic process wherein a hollow tubular preform of material in a moldable condition is centered on the parting plane of a mold assembly, the mold assembly is closed around the preform, the preform is expanded so the exterior of the preform abuts molding surfaces defined by the closed mold assembly, the blow molded article is conditioned to be sufficiently rigid to retain its size and shape while unsupported, the mold assembly is opened and the blow molded article is removed. In general, the moldable condition of the preform is achieved when the material of the preform is at an elevated temperature, and the rigid condition of the blow molded article is achieved when the temperature of the material has been reduced. A blow molding machine comprises a press for opening and closing the mold assembly and blowing means for introducing a pressurized fluid (typically air) to expand the preform in the mold assembly. One type of blow molding equipment produces blow molded containers from tubular extrusions produced by extruding equipment arranged relative a molding assembly to position one or more extrusions in the parting plane of the mold assembly. Additionally, blow molding machines may comprise means for handling the molded article upon removal from the mold assembly and means for trimming waste from the molded article (single-stage machines only). Hence, it is known to produce containers having features for facilitating manipulation thereof for removal from mold assemblies and conveyance for subsequent operations.
Blow molding is commonly used for production of containers for transporting, storing and dispensing liquids wherein the blow molded article comprises a body portion comprising a closed end and a neck connecting the container body with a mouth opening for filling the container and dispensing the contents therefrom. Advantageously, the neck portion of the container comprises an exterior surface having a feature, such as a thread, referred to herein as the "neck finish", for engaging a separable closure for covering the mouth. In addition, the neck portion further comprises an element referred to herein as a "transfer ring" or "bumper roll" for facilitating manipulation of the blow molded article. Mold assemblies for blow molding containers comprise mating mold components wherein molding surfaces open to the mating faces of the mold components define the exterior of the container. Advantageously, mold assemblies comprise replaceable inserts for forming the neck portion, the inserts defining the exterior surface of both the neck finish and the transfer ring. Replacement of such inserts permits production of containers having a different neck finish or to refurbish inserts that are degraded through use.
To broaden the range of containers for which a particular grasping device is suitable, it is desirable to provide transfer rings of large diameter relative to the container body. To insure complete conformance of the preform with the molding surfaces defining the outside diameter of such transfer rings, the height of the transfer rings must be relatively large. Consequently, there is an increased potential for unacceptable deformation at the junction of the transfer ring and neck portion when the container is subjected to compressive loads, as may occur in stacking of filled containers.


To measure the weight of an excavated object, with a simple configuration at low cost, a scraper vehicle includes a coupler having a first portion to be coupled to a driving vehicle and a first detection device provided at at least one of the first portion of the coupler and a first supporting member that supports the first portion. The first detection device is configured to detect a variation in a physical quantity of the first portion.

A known scraper vehicle including a scraper for excavating, for example, the ground surface has been used in a construction site. Such a scraper vehicle is provided with a bowl for storing an excavated object excavated by the scraper. JP Patent Publication No. H02-80720 A describes measuring the weight of the excavated object house in the bowl.


A versatile data handling apparatus providing multiple alternatives for inputting data is disclosed. The apparatus includes an array of depressible keys, a screen-based input system that is located distinctly from the depressible keys, an optical information sensing component and a visual display to present visual information to a user. The data input activities are coordinated by a computerized data handling system communicatively coupled with the various components.

Hand-held data terminals or computers are commercially available for use in a variety of applications, including the distribution and control of products distributed by a route sales person. These hand-held data terminals provide the route sales person with the latest product and customer information as well as information regarding the inventory of the products being distributed. As products are distributed to the customer and other products picked up for return, this information is entered into the terminal together with payment or pricing information. Thus, these hand-held data terminals are useful in many application for order entry, inventory control and route accounting in any industry where a product is being distributed.
Although these hand-held data terminals as a part of a distribution system have greatly increased the accuracy and efficiency of product distribution, there are situations where it is desirable to allow the capture and recording of handwritten data rather than data that is entered by keystrokes. One such use would be to provide for the recording of signatures and for verification of the signatures recorded. In some applications, digitized pads are available to permit the entry of handwritten data, usually in situations where the data is entered by marking a predetermined location on a form that overlies the pad. However, to date there does not appear to be available any means for combining a handwritten data entry module with a portable data terminal in such a way that the handwritten data can be directly entered or read and entered by a scanner.

Data capture apparatus with handwritten data receiving component


A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for making high resolution objects utilizing low resolution materials which are limited by their inability to reliably form coatings of a desired thickness. The formation of coatings of such materials is limited to a Minimum Recoating Depth (MRD), when formed over entirely solidified laminae, which is thicker than the desired layer thickness or object resolution. Data manipulation techniques result in layers of material (and laminae) of the object being categorized as non-consecutive primary layers (laminae) and secondary layers (laminae) positioned intermediate to the primary layers (laminae). Substantially, all portions of primary laminae are exposed in association with primary layers and portions of the secondary laminae are formed in association with their respective secondary layers while other portions of the secondary laminae are formed in association with primary layers so as to form the object with a higher resolution than that dictated by the spacing between the primary layers. Recoating techniques are described which can be used when the thickness between consecutive layers is less than a leading edge bulge phenomena that results from the use of a particular recoating device such that direction of sweeping and/or order of sweeping of the recoating device is varied between consecutive primary layers.

1. Related Art
Rapid Prototypying and Manufacturing (RP&M) is the name given to a field of technologies that can be used to form three-dimensional objects rapidly and automatically from three-dimensional computer data representing the objects. RP&M can be considered to include three classes of technologies: (1) Stereolithography, (2) Selective Deposition Modeling, and (3) Laminated Object Manufacturing.
The stereolithography class of technologies create three-dimensional objects based on the successive formation of layers of a fluid-like medium adjacent to previously formed layers of medium and the selective solidification of those layers according to cross-sectional data representing successive slices of the threedimensional object in order to form and adhere laminae. One specific stereolithography technology is known simply as stereolithography and uses a liquid medium which is selectively solidified by exposing it to prescribed stimulation. The liquid medium is typically a photopolymer and the prescribed stimulation is typically visible or ultraviolet electromagnetic radiation. Liquid-based stereolithography is disclosed in various patents, applications, and publications of which a number are briefly described in the Related Applications section hereinafter. Another stereolithography technology is known as Selective Laser Sintering (SLS). SLS is based on the selective solidification of layers of a powdered medium by exposing the layers to infrared electromagnetic radiation to sinter or fuse the particles. SLS is described in U.S. Pat. No. 4,863,538 to Deckard. A third technology is known as Three Dimensional Printing (3DP). 3DP is based on the selective solidification of layers of a powdered medium which are solidified by the selective deposition of a binder thereon. 3DP is described in U.S. Pat. No. 5,204,055 to Sachs.
The present invention is primarily directed to stereolithography using liquid-based building materials (i.e. medium). The present invention presents techniques for building high resolution objects by overcoming recoating problems that can exist when using such a medium. It is believed, however, that the techniques of the present invention may have application in the other stereolithography technologies for the purposes of enhancing resolution and/or reducing distortion.
Selective Deposition Modeling, SDM, involves the build-up of three-dimensional objects by selectively depositing solidifiable material on a lamina-by-lamina basis according to cross-sectional data representing slices of the three-dimensional object.
One such technique is called Fused Deposition Modeling, FDM, and involves the extrusion of streams of heated, flowable material which solidify as they are dispensed onto the previously formed laminae of the object. FDM is described in U.S. Pat. No. 5,121,329 to Crump. Another technique is called Ballistic Particle Manufacturing, BPM, which uses a 5-axis, ink-jet dispenser to direct particles of a material onto previously solidified layers of the object. BPM is described in PCT publication numbers WO 96-12607; WO 96-12608; WO 96-12609; and WO 96-12610, all assigned to BPM Technology, Inc. A third technique is called Multijet Modeling, MJM, and involves the selective deposition of droplets of material from multiple ink jet orifices to speed the building process. MJM is described in U.S. patent application Ser. Nos. 081722,326, filed Sep. 27, 1996, and 08/722,335, filed Sep. 27, 1996, (both assigned to 3D Systems, Inc. as is the instant application). Laminated Object Manufacturing, LOM, techniques involve the formation of threedimensional objects by the stacking, adhering, and selective cutting of sheets of material, in a selected order, according to the cross-sectional data representing the three-dimensional object to be formed. LOM is described in U.S. Pat. No. 4,752,352 to Feygin; and U.S. Pat. No. 5,015,312 to Kinzie, and in PCT Publication No. WO 95-18009 to Morita.
Though, as noted above, the techniques of the instant invention are directed primarily to liquid-based stereolithography object formation, it is believed that the techniques may have application in the SDM technologies to enhance object resolution for a given droplet or stream size and/or to reduce object distortion. It is further believed that the techniques may have application in the LOM technologies to enhance object resolution when a minimum cutting depth is greater than the thickness of the individual sheets being used to form the object.
Various techniques for enhancing the resolution of three-dimensional objects formed using stereolithography have been described previously. In particular various techniques have been described in (1) U.S. Pat. No. 5,597,520 and its CIP, U.S. patent application Ser. No. 08/428,951, filed Apr. 25, 1995, both to Smalley, et. al; (2) EP Laid Open Patent Application Publication No. 388 129 to Yamamoto; (3) U.S. Pat. No. 5,209,878 to Smalley, et.al; (4) Japanese Laid Open Patent Application Publication No. 2-95830A to Nakamura et.al; and (5) Japanese Laid Open Patent Application Publication No. 2-95831A to Kuribayashi, et. al.
The '520 patent and '951 application describe the use of Simultaneous Multiple Layer Curing Techniques in Stereolithography. These techniques address issues related to the formation of objects with resolution which is finer than a Minimum Solidification Depth (hereafter "MSD") possessed by the building material. These techniques further address the formation of objects with finer resolution than a Minimum Recoating Depth (hereafter "MRD") associated with the building material. MRD may be defined as the minimum thickness of coatings that can be reliably formed over previously solidified laminae. In strict layer-by-layer object formation, the MRD sets the minimum layer thickness that can be reliably used in forming the object. To obtain a desired resolution which is finer than the MRD (i.e. layer thickness thinner than the MRD), the techniques described in this application require complex data manipulations. There is a desire in the art for simpler techniques that can enhance resolution, while relying on less complex algorithms and building techniques (e.g. ones that use simpler data handling techniques).
Yamamoto, the '129 publication, discloses the use of boundary exposures in association with alternating layers (i.e. layers N, N+2, N+4, etc.) and the use of raster exposures to solidify internal portions of laminae in association with the opposite alternating layers (i.e., N+1, N+3, N+5, etc.). According to the teachings of this reference, each pair of consecutive layers is exposed with the same shape, one exposing boundaries and the other exposing internal regions. The resolution increment for an object produced according to the teachings of this reference is equal to two layer thicknesses. The exposure of boundaries solidifies the material associated with the layer of the boundary only; while the exposure of internal regions solidifies material associated with not only the layer of exposure, but the previous layer as well. This publication does not achieve enhanced object resolution. Achieved object resolution is not based on the thickness of a single layer (i.e. thickness between consecutively applied coatings). This publication does not address the need for enhanced resolution, let alone the need for enhanced resolution in view of an MRD which is larger than desired. Furthermore, this reference fails to address any techniques for handling formation of outward facing regions that may be associated with any given lamina.
Smalley, et al., in the '878 patent, discloses the use of thick structural laminae in combination with thin fill laminae and/or meniscus smoothing to fill discontinuities at the edges of the thick structural laminae. These thin fill laminae or meniscus regions form a portion of the outward-facing, sloped regions of an object. This reference does not address recoating difficulties (e.g. MRD related issues) that may limit the ability to form the thin layers desired.
Nakamura, et al., in the '830 publication teaches a technique for reducing discontinuities between thick layers which form the interior portion of the object by forming thin fill layers in exterior regions of the object. As with the '878 patent, this publication does not address recoating difficulties (e.g. MRD related issues) that may limit the ability to form the thin layers desired.
Kuribayashi, et al., in the '831 publication teaches a technique for reducing discontinuities between thick layers by filling in these discontinuities with resin and then exposing the resin within the discontinuities to solidifying radiation. This technique leads to improved surface finish, but fails to provide a building technique that achieves enhanced object resolution when recoating difficulties exist.
All patents, applications, and publications referred to in this section are hereby incorporated by reference as if set forth in full.
A need exists in the art for simplified techniques that can be used to form objects having a desired resolution finer than that reliably allowed by the MRD of the material (i.e. the MRD associated with forming coatings over entire cross-sectional laminae).
2. Other Related Patents and Applications
The patents and applications in the following table are hereby incorporated by reference herein as if set forth in full. The gist of each patent and application is included in the table to aid the reader in finding specific types of teachings. It is not intended that the incorporation of subject matter be limited to those topics specifically indicated, but instead the incorporation is to include all subject matter found in these applications and patents. The teachings in these incorporated references can be combined with the teachings of the instant application in many ways. For example, the references directed to various data manipulation techniques may be combined with the teachings herein to derive even more useful, modified object data that can be used to more accurately and/or efficiently form objects. As another example, the various apparatus configurations disclosed in these references may be used in conjunction with the novel features of the instant invention.
TABLE 1 __________________________________________________________________________ Related Patent and Applications Patent No. Application No. Inventor Subject __________________________________________________________________________ 4,575,330 Hull Discloses fundamental elements of stereolithography. 4,999,143 Hull, et al. Discloses various removable support structures applicable to stereolithography. 5,058,988 Spence Discloses the application of beam profiling techniques useful in stereolithography for determining cure depth and scanning velocity, etc. 5,059,021 Spence, et al. Discloses the utilization of drift correction techniques for eliminating errors in beam positioning resulting from instabilities in the beam scanning system 5,076,974 Modrek, et al. Discloses techniques for post processing objects formed by stereolithography. In particular exposure techniques are described that complete the solidification of the building material. Other post processing steps are also disclosed such as steps of filling in or sanding off surface discontinuities. 5,104,592 Hull Discloses various techniques for reducing distortion, and particularly curl type distortion, in objects being formed by stereolithography. 5,123,734 Spence, et al. Discloses techniques for calibrating a scanning system. In particular techniques for mapping from rotational mirror coordinates to planar target surface coordinates are disclosed 5,133,987 Spence, et al. Discloses the use of a stationary mirror located on an optical path between the scanning mirrors and the target surface to fold the optical path in a stereolithography system. 5,174,931 Almquist, et al. Discloses various doctor blade configurations for use in forming coatings of medium adjacent to previously solidified laminae. 5,182,056 Spence, et al. Discloses the use of multiple wavelengths in the exposure of a stereolithographic medium. 5,182,715 Vorgitch, et al. Discloses various elements of a large stereolithographic system. 5,184,307 Hull, et al. Discloses a program called Slice and various techniques for from app. no. converting three-dimensional object data into data descriptive 07/331,644, filed of cross-sections. Disclosed techniques include line width March 31, 1989 compensation techniques (erosion routines), and object sizing techniques. The application giving rise to this patent included a number of appendices that provide further details regarding stereolithography methods and systems. 5,209,878 Smalley, et al. Discloses various techniques for reducing surface discontinuities between successive cross-sections resulting from a layer-by-layer building technique. Disclosed techniques include use of fill layers and meniscus smoothing. 5,234,636 Hull, et al. Discloses techniques for reducing surface discontinuities by coating a formed object with a material, heating the material to cause it to become flowable, and allowing surface tension to smooth the coating over the object surface. 5,238,639 Vinson, et al. Discloses a technique for minimizing curl distortion by balancing upward curl to downward curl. 5,256,340 and Allison, et al. Discloses various build/exposure styles for forming objects 08/766,956, filed including various techniques for reducing object distortion. December 16, 1996 Disclosed techniques include: (1) building hollow, partially hollow, and solid objects, (2) achieving more uniform cure depth, (3) exposing layers as a series of separated tiles or bullets, (4) using alternate sequencing exposure patterns from layer to layer, (5) using staggered or offset vectors from layer to layer, and (6) using one or more overlapping exposure patterns per layer. 5,321,622 Snead, et al. Discloses a computer program known as CSlice which is used to convert three-dimensional object data into cross-sectional data. Disclosed techniques include the use of various Boolean operations in stereolithography. 5,597,520 and Smalley, et al. Discloses various exposure techniques for enhancing object 08/428,951, filed formation accuracy. Disclosed techniques address formation April 25, 1995 of high resolution objects from building materials that have a Minimum Solidification Depth greater than one layer thickness and/or a Minimum Recoating Depth greater than the desired object resolution. 08/722,335, filed Thayer, et al. Discloses build and support styles for use in a Multi-Jet September 27, 1996 Modeling selective deposition modeling system. 08/722,326, filed Earl, et al. Discloses data manipulation and system control techniques for September 27, 1996 use in a Multi-Jet Modeling selective deposition modeling system. 08/790,005, filed Almquist, et al. Discloses various recoating techniques for use in January 28, 1997 stereolithography. Disclosed techniques include 1) an ink jet dispensing device, 2) a fling recoater, 3) a vacuum applicator, 4) a stream recoater, 5) a counter rotating roller recoater, and 6) a technique for deriving sweep extents. 08/847,855, filed Partanen, et al. Discloses the application of solid-state lasers to April 28, 1997 stereolithography. 08/792,347, filed Partanen, et al. Discloses the use of a pulsed radiation source for solidifying January 31, 1997 layers of building material and in particular the ability to limit pulse firing locations to only selected target locations on a surface of the medium. 08/855,125, filed Nguyen, et al. Discloses techniques for interpolating originally supplied cross- May 13, 1997 sectional data descriptive of a three-dimensional object to produce modified data descriptive of the three-dimensional object including data descriptive of intermediate regions between the originally supplied cross-sections of data. 08/854,950, filed Manners, et al. Discloses techniques for identifying features of partially formed May 13, 1997 objects. Identifiable features include trapped volumes, effective trapped volumes, and solid features of a specified size. The identified regions can be used in automatically specifying recoating parameters and or exposure parameters. __________________________________________________________________________
The following two books are also incorporated by reference herein as if set forth in full: (1) Rapid Prototyping and Manufacturing: Fundamentals of Stereolithography, by Paul F. Jacobs; published by the Society of Manufacturing Engineers, Dearborn Mich.; 1992; and (2) Stereolithography and other RP&M Technologies: from Rapid Prototyping to Rapid Tooling; by Paul F. Jacobs; published by the Society of Manufacturing Engineers, Dearborn Mich.; 1996.

Simplified stereolithographic object formation methods of overcoming minimum recoating depth limitations


A camshaft phaser, including: a drive sprocket; a stator; a rotor at least partially rotatable with the stator; a rotor extension fixedly connected to the rotor, having a slot at at least one outer circumferential position; a spring for biasing the rotor relative to the stator, having a first and a second end, the first end secured in the slot in the rotor extension and the second end secured on the stator.

Camshafts are used in internal combustion engines in order to actuate gas exchange valves. The camshaft in an internal combustion engine includes a plurality of cams that engage cam followers (i.e. bucket tappets, finger levers or rocker arms). When the camshaft rotates, the cams lift or depress the cam followers which in turn actuate gas exchange valves (intake, exhaust). The position and shape of the cams dictate the opening period and amplitude as well as the opening and closing time of the gas exchange valves.
Camshaft phasers are used to advance or retard the opening or closing period, phasing the camshaft with respect to the crankshaft rotation. Camshaft phasers generally comprise a timing gear, which can be a chain, belt or gear wheel connected in fixed rotation to a crankshaft by a chain, belt or gear drive, respectively, acting as an input to the phaser. The phaser includes an output connection to the camshaft. A phasing input is also provided in the form of a hydraulic, pneumatic or electric drive in order to phase or adjust the output rotation of the camshaft relative to the input rotation of the crankshaft.
Camshaft phasers are generally known in two forms, a piston-type phaser with an axially displaceable piston and a vane-type phaser with vanes that can be acted upon and pivoted in the circumferential direction. With either type, the camshaft phaser is fixedly mounted on the end of a camshaft. An example mounting may be performed as disclosed in U.S. Pat. No. 6,363,896, entitled "Camshaft Adjuster for Internal Combustion Engines", by Wolfgang Speier, issued on Apr. 2, 2002, using a clamping screw forming the element of the camshaft phaser that effects centering relative to the camshaft.
Camshaft phasers that operate according to the vane-cell principle for use on single camshafts are known in the art. U.S. Pat. No. 6,805,080, entitled "Device for changing the control times of gas exchange valves of internal combustion engines, particularly rotary piston adjustment device for rotation angle adjustment of a camshaft relative to a crankshaft", by Eduard Golovatai-Schmidt et al., issued on Oct. 19, 2004, generally shows a construction of a vane-cell type camshaft phaser for use in an internal combustion engine. These single camshaft phasers are commonly used on dual overhead cam (DOHC) engines where intake and exhaust cam lobes are located on separate intake and exhaust camshafts.
It is known to receive oil for chambers in a camshaft phaser, formed by a rotor and a stator for the phaser and used to control phasing of the phaser, in radially aligned channels opening to a radially central space. However, the requirement for a radially central space increases both the radial extent of the phaser and limits the spaces into which the phaser can be installed as well as the options for supplying oil to the chambers. With increasing engine sizes and decreasing space in engine compartments, axial and radial space is becoming limited, sometimes requiring multi-piece phaser assemblies in order to assemble a phaser in position. Commonly-owned co-pending patent application No. 61/824,033 discloses a phaser section including a stator non-rotatably connected to the drive sprocket, a rotor at least partially rotatable with respect to the stator and a rotor extension non-rotatably connected to the rotor, and a plurality of chambers formed by the rotor and the stator; and a rotor nose separately formed from the phaser section and non-rotatably connected to the phaser section, extending past a front side of the phaser section in a first axial direction. The rotor nose and rotor plate or extension are separately assembled and allow for assembly of the cam phaser assembly onto engines with restricted axial and radial space. U.S. patent application No. 61/824,033 is incorporated herein by reference.
U.S. Pat. No. 7,409,935 discloses a method and apparatus for setting a bias or return spring load during assembly of a camshaft phaser. A spring retainer is used with a first end of a bias spring engaged in a notch, the spring wrapped around the spring retainer and secured at a second end by an eccentric bolt or fastener. The spring is wound about the spring retainer and the spring retainer, in turn is secured to the rotor of the cam phaser. Where there is limited axial and radial space, such a separate component, such as a spring retainer can not be utilized. A method and apparatus for attaching and winding the return spring in a multi-piece phaser assembly is needed.

Method and apparatus for winding a return spring with a two piece rotor for a cam phaser


A method of making a reticle. Design data, i.e., GDSII data is read in, then a scribe or frame is built, and the design is placed in the scribe. Then, Boolean operations, sizing, OPC corrections and phase shifting are performed, as needed, perhaps using third party tools. Then, the GDS data is sorted, and a new GDS hierarchy is created where each mask layer can be generated as one mask making pattern, i.e., new cells are created representing each masking image location on the reticle, each new cell is placed in a topcell, then a gds2 file is produced where the gds2 file can be used to create a reticle or can be used to create reticle making data.

The present invention generally relates to reticles and methods of making same, and more specifically relates to a method for reducing reticle set cost.
As wafer technologies have become more and more complex, reticle costs have been increasing at a high rate. For example, in G10P (i.e., 0.35 micron node in Tskuba), a full set of reticles for a given device was less than $50,000. In Gflx, the cost of a full set of reticles can exceed $650,000. In G90, the cost for a full set of reticles is expected to be more than $1,500,000.
Many solutions have been attempted to keep reticle costs reasonable. One solution that has been attempted is to place more than one design on a reticle set. A problem is that a multiple chip wafer, which is generated from the multiple chip reticle, is difficult to assemble, saw, and sort (i.e., test). When a wafer is sawed and sorted, one must keep track of which dies are which. While it may be possible to cut each wafer for one type of die, depending on the die size and layout of the die on the wafer, the reticle set cannot be created until all designs are completed, and this may, in turn, delay designs. Additionally, each chip on the wafer may require a different process flow. Assuming there are two designs associated with the reticle set, a common process flow between the two designs must be created. This may be complicated, for example, in the case where one chip is a three layer metal design while the other chip is a four layer metal design. Finally, there is a high probability, depending on die size, that silicon space will be wasted on the wafer. For example, if one die is larger by a non-integer multiplier, generally there is no way to fit the designs on a wafer without leaving open space on the wafer.
Another solution that has been attempted is to use multiple layer reticles. This is a solution that has been used in the industry in connection with Ultratech 1X steppers. The solution involves placing more than one masking layer on each reticle. Individual patterns for each masking layer are given to the mask maker, along with instructions as to where to place the patterns. The mask maker then creates a jobdeck, which places each layer on a given mask in a specified location. The mask maker needs to create the jobdeck correctly, as well as maintain the individual pattern files for each layer. As such, compared to methods used to form standard reticles, this method requires that much more information be transferred to the reticle vendor, and has the potential for having more mistakes.
Still another solution which has been attempted is to reduce reticle specifications and simplify the reticle manufacturing process. The problem with this approach is that reticle specifications can be reduced only to a certain extent. While reducing reticle specifications does generally result in a cost savings, the savings is not enough. While a further approach has been to research the most cost effective methods, including using laser beam systems to generate reticles, the cost of reticles has continued to increase.


An electrical unit includes a contactor having a housing member, a first terminal, a second terminal, and/or a contact member disposed in the housing member and configured to selectively electrically connect the first terminal and the second terminal. The electrical unit may include a cooling member connected to the housing member, a first bus bar connected to the cooling member and the first terminal, and/or a second bus bar connected to the cooling member and the second terminal. The cooling member may be configured to dissipate heat that is generated via electrical current flowing through the contact member.

This background description is set forth below for the purpose of providing context only. Therefore, any aspect of this background description, to the extent that it does not otherwise qualify as prior art, is neither expressly nor impliedly admitted as prior art against the instant disclosure.
Some electrical units are not configured for use with large electrical currents and some electrical units may not be configured to sufficiently dissipate heat generated via large electrical currents.
There is a desire for solutions/options that minimize or eliminate one or more challenges or shortcomings of electrical units. The foregoing discussion is intended only to illustrate examples of the present field and is not a disavowal of scope.


A lighting system and method for illuminating a deck area. The wiring for the lighting system is hidden from view, providing a more aesthetically pleasing appearance. Furthermore, the lighting system can be installed simultaneously with the deck itself, or afterwards. The system has several embodiments of illumination including post lights, baluster lights, and stair lights. Embodiments of the lighting system may be optionally be installed by the end user and do not require professional design and installation, thus providing a more cost effective solution.

Embodiments of the present invention relate generally to lighting systems and methods such as for outdoor deck areas, for lighting purposes as well as decorative purposes, and also to a method of wiring the lighting area.
Outdoor deck areas are very popular as they add to the beauty of the home as well as provide a functional place to enjoy the outdoors. However, many decks do not have sufficient lighting such that they can be enjoyed during the night time as well as the day time. Furthermore, the decks that currently employ lighting systems may run the wiring on the surface of the posts, railings, and deck surface, providing a look that is not aesthetically pleasing.
Exemplary embodiments of the present invention may provide a lighting system for an outdoor deck area that provides sufficient lighting while at the same time adding to the aesthetic value of the area. Exemplary embodiments of the present invention may substantially hide the wiring from view. In some examples, the light housings may be incorporated into or effectively use the deck materials.
Exemplary embodiments of the present invention may provide a lighting system that may be built specifically with the deck, including the deck surface, railings, and posts, to provide a total deck experience. For example, the deck may not need to be torn up and rearranged to put in the lighting system. Instead, the deck may be manufactured to allow easy installation of the lighting system.
Exemplary embodiments of the present invention may provide features that are affordable to the average homeowner. This means that the lighting system may not have to be tailor-made for every home, but may easily be manufactured at a high rate and may be installed at any home easily. Also, exemplary embodiments may not need to be installed by a specialized carpenter, but instead may easily be installed by the homeowner, if desired. In this way, cost may be minimized.
Different embodiments of the lighting system may employ any combination of various types of lights including, but not limited to, post lights, baluster lights, and stair riser lights. For example, post lights may be found at the top of posts (e.g., below post caps) or along the lengths or sides of posts. In some exemplary embodiments, baluster lights may be provided in association with the balusters. As a further example, stair riser lights may be found on the stairs, such as on the stair riser boards. Various other locations may also be possible.
In addition to the novel features and advantages mentioned above, other benefits will be readily apparent from the following descriptions of the drawings and exemplary embodiments.


A direct injection spark ignition multi-cylinder internal combustion engine operative in a controlled auto-ignition combustion mode includes a direct fuel injection system, a spark ignition system and a controllable engine valve system. The air/fuel ratio in the exhaust gas feedstream and an intake mass air flow are measured and an actual air/fuel ratio is calculated based upon the intake mass air flow and engine fueling. Magnitude of a negative valve overlap period between an exhaust valve closing and an intake valve opening is adjusted based upon the measured mass air flow. Timing of pre-injection fueling is adjusted during the negative valve overlap period based upon the measured air/fuel ratio.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Known spark ignition engines introduce a fuel/air mixture into each cylinder which is compressed in a compression stroke and ignited by a spark plug. Known compression ignition engines inject pressurized fuel into a combustion cylinder near top dead center (hereafter 'TDC') of the compression stroke which ignites upon injection. Combustion for both gasoline engines and diesel engines involves premixed or diffusion flames controlled by fluid mechanics.
An engine configured for spark ignition can be adapted to operate in a homogeneous charge compression ignition (hereafter 'HCCI') mode, also referred to as controlled auto-ignition combustion, under predetermined speed/load operating conditions. The controlled auto-ignition combustion comprises a distributed, flameless, auto-ignition combustion process that is controlled by oxidation chemistry. An engine operating in the HCCI mode has an intake charge that is preferably homogeneous in composition, temperature, and residual exhaust gases at intake valve closing time. Controlled auto-ignition combustion is a distributed kinetically-controlled combustion process with the engine operating at a dilute fuel/air mixture, i.e., lean of a fuel/air stoichiometric point, with relatively low peak combustion temperatures, resulting in low NOx emissions. The homogeneous fuel/air mixture minimizes occurrences of rich zones that form smoke and particulate emissions.
When an engine operates in the HCCI mode, the engine control comprises lean air/fuel ratio operation with the throttle wide open to minimize engine pumping losses. When the engine operates in the spark-ignition combustion mode, the engine control comprises stoichiometric air/fuel ratio operation, with the throttle valve controlled over a range of positions from 0% to 100% of the wide-open position to control intake air flow to achieve the stoichiometric air/fuel ratio. It is known that combustion in each cylinder can vary significantly due to differences in individual fuel injector characteristics and other factors in a multi-cylinder HCCI engine.
Known engine valve control strategies comprise an exhaust recompression strategy to control the cylinder charge temperature by trapping hot residual gas from the previous combustion cycle. This can include advancing closing timing of the exhaust valve and correspondingly delaying opening timing of the intake valve, preferably symmetrical to the exhaust valve closing timing about TDC of the intake stroke to create a negative valve overlap (hereafter 'NVO') period. The NVO period is defined as a crank angle duration between the exhaust valve closing and the intake valve opening. The cylinder charge composition and temperature are affected by the exhaust valve closing timing. In particular, greater amounts of hot residual gas from the previous combustion cycle can be retained with the advanced closing of the exhaust valve, reducing incoming fresh air mass into the cylinder, resulting in increased cylinder charge temperature and lower cylinder charge oxygen concentration.
It is known to couple the engine valve control strategy and a fuel injection strategy to stabilize combustion. For example, at a low fueling rate, temperature of the cylinder charge may preclude achieving stable auto-ignited combustion of the cylinder charge regardless of the NVO period. It is known to increase temperature of the cylinder charge by pre-injecting fuel into the combustion chamber, preferably during the NVO period. A portion of the pre-injected fuel reforms due to pressure and temperature during recompression, releasing heat energy and increasing the cylinder charge temperature to achieve auto-ignited combustion of the cylinder charge created by a subsequent main fueling during the compression stroke. It is known that the amount of auto-thermal fuel reforming is based upon mass and timing of the pre-injection fueling, with the fuel reforming increasing with earlier timing of the pre-injection fueling and/or greater fuel mass of the pre-injection fueling. It is known that an amount of fuel reforming that is greater than required for stable combustion can increase brake-specific fuel consumption, and that an amount of fuel reforming that is less than required for stable combustion can increase combustion instability. Fuel reforming can vary due to injection timing, trapped exhaust gas temperature and pressure, and other factors.

Method and apparatus for controlling fuel reforming under low-load operating conditions using exhaust recompression in a homogeneous charge compression ignition engine