the charge mass is contained in the cavity and air cell. When the injector fires, the jet of fuel enters the air cell and ignites. This results in a jet of flame shooting back out of the air cell directly into the jet of fuel still issuing from the injector. The heat and turbulence give excellent fuel vaporisation and mixing properties. Also, since the majority of the combustion takes place outside the air cell in the cavity, which communicates directly with the cylinder, there is less heat loss involved in transferring the burning charge into the cylinder. Air cell injection can be considered as a compromise between indirect and direct injection, gaining some of the efficiency advantages of direct injection while retaining the simplicity and ease of development of indirect injection. Air cell chambers are commonly named Lanova air chambers. The Lanova combustion system was developed by the Lanova company, which was founded in 1929 by Franz Lang, Gotthard Wielich and Albert Wielich. In the US, the Lanova system was used by Mack Trucks. An example is the Mack-Lanova ED diesel engine fitted to the Mack NR truck. Advantages of indirect injection combustion chambers Smaller diesels can be produced. The injection pressure required is low, so the injector is cheaper to produce. The injection direction is of less importance. Indirect injection is much simpler to design and manufacture, especially for gasoline engines. Less injector development is required and the injection pressures are low (1500 psi/100 bar versus 5000 psi/345 bar and higher for direct injection) The lower stresses that indirect injection imposes on internal components mean that it is possible to produce petrol and indirect injection diesel versions of the same basic engine. At best such types differed only in the cylinder head and the need to fit a distributor and spark plugs in the petrol version whilst fitting an injection pump and injectors to the diesel. Examples include the BMC A-Series and B-Series engines and the Land Rover 2.25/2.5-litre 4-cylinder types. Such designs allow petrol and diesel versions of the same vehicle to be built with minimal design changes between them. Higher engine speeds can be reached, since burning continues in the prechamber. Alternative fuels like bio-diesel and waste vegetable oil are less likely to damage the fuel system in an indirect-injection diesel engine, as high injection pressures are not needed. In direct-injection engines (especially modern engines using high-pressure