Virtual Turbospeed Control, or VTC, is a technology that maximizes engine performance by optimally controlling the turbocharger. A turbocharger is a device that improves engine performance by compressing the air in the atmosphere and forcibly injecting it into the engine combustion chamber. It is usually used in high-performance vehicles to produce greater power.
But even a turbocharger, essential in a high-performance car, may not perform as usual when driving on winding roads on mountains and at high altitudes. If a turbocharger is generating compressed air in an environment where the atmospheric pressure is low, the device’s durability may be compromised. To prevent this, the turbocharger restricts its operating capacity. Achieving maximum engine performance becomes a challenge.
Hyundai’s newly developed VTC overcomes the shortcomings of the existing turbocharger control system at high altitudes by predicting and preemptively controlling its operating conditions, using driving variables based on model predictive control (MPC) technology. The turbocharger takes a more active role in engine function by quickly and accurately determining variables such as its current operating state and driving conditions, so its durability is not affected.
Thanks to VTC technology, the Hyundai i20 N has a maximum torque of 28.0 kg·m in a wide 1,750-4,500 rpm engine rotation. In the driving mode in which the overboost is activated (N mode), VTC maximizes turbocharger control, increasing maximum torque in the 2,000-4,000 rpm range to 31.0 kg·m. When maximum torque increases, the vehicle’s acceleration performance and responsiveness improve.
To understand VTC, it’s important to understand MPC. MPC is a technology that predicts future situations based on the results of collected data entered into a predictive model. It’s similar to an athlete’s performance record. A pole vaulter who could jump seven meters usually jumps around six.
Climate and external conditions and psychological factors such as concerns about injuries may interfere with his ability to perform. But if the athlete’s condition, the stadium conditions, and his past records are analyzed, and a goal of 6.8 meters is set, he has the potential to surpass his previous record, while minimizing the risk of injury.
MPC technology is like driving. For decades, people have been driving on MPC principles. A driver predicts road conditions based on driving information and vehicle flow, and determines steering, acceleration, deceleration, and the route ahead. MPC works the same way. It predicts future events by entering sensor-captured data on the current state into a predictive model and then provides optimal control based on that prediction.
Until quite recently, MPC was mainly used for chemical process control in industries like oil refining and petrochemicals, where many variables are in play, but system response is slow and the scope of controller computation is limited. However, MPC-based control technologies are now finding applications in other sectors, such as robot control, urban air mobility (UAM), self-driving cars, aerospace, integrated building energy control, smart grids, and financial engineering. Dramatic advances in sensing technologies, such as GPS, cameras, radar, and LiDAR, have increased the amount of high-quality data that can be used to predict the operating environment, and thanks to improved CPU performance, large amounts of data can be rapidly processed.
Yet MPC has rarely been applied in the automotive industry because of the challenges involved in computing a wide range of control variables, such as driving environment and conditions, in real time. As a result, model predictive control was considered less effective for automobiles. However, in recent years, with advances in the engine management system, or EMS, which analyzes data such as fuel quantity, air quantity, and exhaust pressure, accurate gaging of the current state is within reach. Moreover, as the accuracy of the MPC model has improved, applications for MPC-based technology are increasing.
How then does MPC used in VTC apply to the i20 N? Before we examine how MPC controls the turbocharger, let’s take a look at how the turbocharger works. A turbocharger is a device that compresses air in the atmosphere, using the energy of exhaust gas discharged at high temperature and high pressure, and forcibly thrusts it into the engine combustion chamber. A pinwheel (impeller mounted on the turbine) is attached to the passage through which the exhaust gas passes, and another pinwheel (impeller mounted on the compressor) connected to that pinwheel rotates. This sucks air from the outside and forcibly injects it into the engine combustion chamber. A fuel that is properly mixed according to the amount of air injected into the engine combustion chamber raises the volume of the exhaust gas and significantly increases engine performance.
The rotational speed of the impeller, i.e., the turbo speed, is controlled by the amount of exhaust gas passing through the turbine. When a large amount of exhaust gas passes, the impeller rotates quickly, and when a small amount of exhaust gas passes, the impeller rotates slowly. If the turbo speed is higher than necessary, it can be lowered by opening a valve (wastegate) that controls the amount of exhaust gas flowing in.
In order for the turbocharger control system to accurately and precisely control the turbo, it must accurately determine the turbo speed. Conventional turbocharger control systems estimate turbo speed by measuring the amount of air or air pressure (known as boost pressure) entering the engine. If the sensor is attached to the impeller, the exact turbo speed can be determined, but in the harsh environment of the turbocharger, blasted by high temperatures and high-pressure exhaust gases, the sensor takes quite a beating. As a result, turbo speed sensors have found no applications in mass-produced cars.
In general, the impeller of a turbocharger rotates at up to 200,000 times per minute (200,000 rpm). If this is significantly exceeded, the impeller may be damaged. The turbocharger control system must therefore optimize the turbocharger (and maximize engine performance) within a range that guarantees the durability of the impeller.
Optimal control has long been a challenge for conventional turbocharger control systems, which estimate turbo speed based on boost pressure only. The actual turbo speed tends to be higher because of external variables, especially when the vehicle is being driven at a high altitude. In such environments, boost pressure is lower than the pressure of the surrounding environment, and the impeller has to rotate more quickly in order to produce the same boost pressure obtained at lower altitudes.
For example, if the turbocharger has a turbo speed of 210,000 rpm when forming a boost pressure of 1.0 bar in the lowlands, the actual turbo speed will exceed 210,000 rpm with the same 1.0 bar boost pressure in the highlands. Failure to consider such external variables when controlling the turbocharger may result in a damaged system, as the turbo speed exceeds the design-allowable limit in a driving environment with low atmospheric pressure. In a conventional turbocharger control system, if it is determined that the vehicle is traveling at high altitude, engine performance may be reduced, for example, because the turbo speed may fall.
In order to overcome the limitations of the existing turbocharger control system, the Hyundai Motor Company has developed VTC, a turbocharger control system using MPC, and applied it to the high-performance i20 N. VTC provides a more precise estimate of turbo speed by using a predictive model to analyze various data, such as the amount of fuel and air, exhaust pressure, and boost pressure. It also predicts the outcome of the control (e.g., turbo speed and engine output) for the immediate future (roughly one second away) by using various external variables and then controls the turbocharger in advance by adjusting the wastegate directly responsible for turbo speed.
For example, if VTC determines that the turbo speed will exceed the design-allowable limit in approximately one second, it issues a command to open the wastegate valve to adjust the amount of exhaust gas flowing into the turbocharger to reduce the rotational speed of the turbine. More importantly, VTC maximizes engine performance while ensuring the turbocharger remains undamaged, unlike the conventional turbocharger control system. This is why VTC has been applied to i20 N, a high-performance model that guarantees the best engine performance in any situation and encapsulates the joy of driving.
Currently, Hyundai Motor Company is reviewing plans to apply VTC technology, which increases the marginal performance of the engine, to other models in the future. The application of this technology is in line with Hyundai’s N philosophy, which emphasizes “joy of driving” in the base model and contributes to performance development based on the experiences and technologies gained through the development of high-performance N models. It also plans to utilize MPC-based control technology not only in high-performance cars, but also in the field of eco-friendly cars and self-driving technology such as “integrated thermal management control for electric vehicles” and “predictive cruise control” that improves fuel efficiency by controlling vehicle speed according to the prediction of road conditions.
Technical advisor: Chi-kyoung Kim, Head of Electrification Control Development Group
HMG Journal Operation Teamgroup@hyundai.com
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Virtual Turbo Speed Control (VTC) ni teknolojia ya kuendesha injini kwa kutumia injini ya turbo. Turbocharger ni kifaa ambacho huongeza utendaji wa injini kwa compressing hewa katika anga na forcibly injecting yake katika chumba cha moto injini. Kwa kawaida hutumiwa katika magari yenye utendaji wa juu ili kutokeza nguvu zaidi. Hata hivyo, hata turbocharger, ambayo ni muhimu katika gari lenye uwezo mkubwa, inaweza kutofanya kazi kama kawaida wakati wa kuendesha gari kwenye barabara zenye kupinda-pinda kwenye milima na kwenye maeneo ya juu. Kama turbocharger ni kuzalisha hewa compressed katika mazingira ambapo shinikizo la anga ni chini, kudumu kifaa inaweza kuathiriwa. Ili kuzuia hili, turbocharger inazuia uwezo wake wa uendeshaji. Kufikia utendaji wa juu wa injini inakuwa changamoto. VTC mpya ya Hyundai inashinda mapungufu ya mfumo wa kudhibiti turbocharger kwa urefu wa juu kwa kutabiri na kudhibiti hali zake za uendeshaji, kwa kutumia vigezo vya kuendesha kulingana na teknolojia ya udhibiti wa utabiri wa mfano (MPC). Turbocharger inachukua jukumu la kazi katika kazi ya injini kwa kuamua kwa haraka na kwa usahihi vigezo kama vile hali yake ya sasa ya uendeshaji na hali za kuendesha gari, hivyo kudumu kwake hakuathiriwa. Kwa sababu ya teknolojia ya VTC, Hyundai i20 N ina torque ya juu ya 28.0 kgm katika mzunguko wa injini pana wa 1.750-4.500 rpm. Katika hali ya kuendesha gari ambayo overboost ni kuanzishwa (N mode), VTC maximizes turbocharger udhibiti, kuongeza torque upeo katika 2,000-4,000 rpm mbalimbali kwa 31.0 kg.m. Wakati torque upeo huongezeka, gari's kasi utendaji na majibu kuboresha. Kuelewa VTC, ni muhimu kuelewa MPC. MPC ni teknolojia ambayo inabiri hali za baadaye kulingana na matokeo ya data zilizokusanywa zilizopigwa katika mfano wa utabiri. Ni sawa na rekodi ya utendaji wa mwanariadha. Mchezaji anayeweza kuruka kwa nguzo kwa meta saba kwa kawaida huruka kwa mita sita. Hali ya hewa na hali za nje na mambo ya kisaikolojia kama vile wasiwasi kuhusu majeraha yanaweza kuingilia uwezo wake wa kufanya kazi. Lakini ikiwa hali ya mwanariadha, hali ya uwanja, na rekodi zake za zamani zinatathminiwa, na lengo la mita 6.8 limewekwa, ana uwezo wa kuzidi rekodi yake ya awali, wakati wa kupunguza hatari ya jeraha. Teknolojia ya MPC ni kama kuendesha gari. Kwa miaka mingi, watu wamekuwa wakitumia kanuni za MPC. Dereva hutabiri hali za barabara kulingana na habari za kuendesha gari na mtiririko wa gari, na kuamua kuongoza, kuharakisha, kupunguza mwendo, na njia iliyo mbele. MPC inafanya kazi kwa njia ile ile. Inatabiri matukio ya baadaye kwa kuingiza data iliyokamatwa na sensorer juu ya hali ya sasa katika mfano wa utabiri na kisha hutoa udhibiti bora kulingana na utabiri huo. Mpaka hivi karibuni, MPC ilitumika hasa kwa ajili ya udhibiti wa mchakato wa kemikali katika viwanda kama vile mafuta ya kusafisha na petrochemicals, ambapo vigezo vingi ni katika kucheza, lakini mfumo wa majibu ni polepole na wigo wa kompyuta ya udhibiti ni mdogo. Hata hivyo, teknolojia za udhibiti wa MPC sasa zinapata matumizi katika sekta nyingine, kama vile udhibiti wa roboti, usafiri wa hewa wa mijini (UAM), magari ya kujiongoza, anga, udhibiti wa nishati ya jengo, gridi za akili, na uhandisi wa kifedha. Maendeleo makubwa katika teknolojia za utambuzi, kama vile GPS, kamera, rada, na lidar, yameongeza kiasi cha data ya ubora wa juu ambayo inaweza kutumika kutabiri mazingira ya uendeshaji, na shukrani kwa utendaji bora wa CPU, kiasi kikubwa cha data inaweza kusindika haraka. Hata hivyo, MPC haijawahi kutumika katika sekta ya magari kwa sababu ya changamoto zinazohusika katika kuhesabu mbalimbali ya vigezo, kama vile mazingira ya kuendesha gari na hali, katika muda halisi. Matokeo yake, mfano udhibiti wa utabiri ilionwa kuwa chini ya ufanisi kwa ajili ya magari. Hata hivyo, katika miaka ya hivi karibuni, kwa maendeleo katika mfumo wa usimamizi wa injini, au EMS, ambayo inachambua data kama vile kiasi cha mafuta, kiasi cha hewa, na shinikizo la kutolea nje, gage sahihi ya hali ya sasa iko ndani ya kufikia. Kwa kuongezea, kwa kuwa usahihi wa mfano wa MPC umeboresha, maombi ya teknolojia ya msingi wa MPC yanaongezeka. Jinsi gani MPC ya VTC inatumika kwa i20 N? Kabla ya kuchunguza jinsi MPC udhibiti turbocharger, hebu kuchukua kuangalia jinsi turbocharger kazi. Turbocharger ni kifaa cha compressing hewa katika anga, kutumia nishati ya gesi ya kutolea nje katika joto la juu na shinikizo la juu, na kwa nguvu pushes ndani ya injini ya chumba cha kuchoma. Pini (impeller iliyowekwa kwenye turbine) imeunganishwa na njia ambayo gesi ya kutolea nje hupita, na pini nyingine (impeller iliyowekwa kwenye compressor) iliyounganishwa na pini hiyo inazunguka. Hii huchukua hewa kutoka nje na kuingiza kwa nguvu ndani ya chumba cha kuchoma cha injini. Kwa mfano, mafuta ambayo ni vizuri kuchanganywa kulingana na kiasi cha hewa injected katika chumba cha moto injini huongeza kiasi cha gesi ya kutolea nje na kwa kiasi kikubwa huongeza utendaji wa injini. Kasi ya mzunguko wa impeller, yaani, kasi ya turbo, inadhibitiwa na kiasi cha gesi ya kutolea nje inayopita kupitia turbine. Wakati kiasi kikubwa cha gesi ya kutolea nje hupita, impeller huzunguka haraka, na wakati kiasi kidogo cha gesi ya kutolea nje hupita, impeller huzunguka polepole. Ikiwa kasi ya turbo ni ya juu kuliko inahitajika, inaweza kupunguzwa kwa kufungua valve (wastegate) ambayo inadhibiti kiasi cha gesi ya kutolea nje inayotiririka. Turbocharger ni mfumo wa kudhibiti wa turbochargers ambayo inahitajika ili kuendesha turbo kwa usahihi na kwa usahihi. Turbocharger kawaida mfumo wa kudhibiti makadirio turbo kasi kwa kupima kiasi cha hewa au shinikizo la hewa (jinajulikana kama shinikizo kuongeza) kuingia injini. Ikiwa sensor imewekwa kwenye impeller, kasi halisi ya turbo inaweza kuamuliwa, lakini katika mazingira magumu ya turbocharger, iliyoangushwa na joto la juu na gesi za kutolea nje za shinikizo la juu, sensor inachukua kupigwa. Kwa sababu hiyo, sensorer za kasi za turbo hazijawahi kutumiwa katika magari yanayotengenezwa kwa wingi. Kwa kawaida, turboprop inazunguka mara 200,000 kwa dakika. Kama hii ni kwa kiasi kikubwa zaidi, impeller inaweza kuharibiwa. Turbocharger mfumo wa kudhibiti lazima kwa hiyo optimize turbocharger (na kuongeza utendaji wa injini) ndani ya mbalimbali ambayo inahakikisha uimara wa impeller. Udhibiti bora kwa muda mrefu imekuwa changamoto kwa ajili ya kawaida turbocharger udhibiti mifumo, ambayo makadirio turbo kasi kulingana na kuongeza shinikizo tu. Kasi halisi ya turbo huwa kubwa zaidi kwa sababu ya vigezo vya nje, hasa wakati gari linasafirishwa kwa urefu mkubwa. Katika mazingira kama hayo, shinikizo la kuongeza ni chini kuliko shinikizo la mazingira ya karibu, na impeller lazima izunguke haraka ili kuzalisha shinikizo sawa la kuongeza linalopatikana kwa urefu wa chini. Kwa mfano, kama turbocharger ina kasi ya turbo ya 210,000 rpm wakati wa kuunda shinikizo la kuongeza ya 1.0 bar katika maeneo ya chini, kasi halisi ya turbo itazidi 210,000 rpm na shinikizo la kuongeza la 1.0 bar katika maeneo ya juu. Kushindwa kuzingatia vigezo vya nje wakati wa kudhibiti turbocharger inaweza kusababisha mfumo kuharibiwa, kama kasi turbo inazidi muundo-kuruhusiwa kikomo katika mazingira ya kuendesha gari na chini ya shinikizo la anga. Katika mfumo wa kawaida wa kudhibiti turbocharger, ikiwa imedhamiriwa kuwa gari linasafiri kwa urefu mkubwa, utendaji wa injini unaweza kupunguzwa, kwa mfano, kwa sababu kasi ya turbo inaweza kushuka. Ili kuondoa mapungufu ya mfumo wa kudhibiti turbo, Hyundai Motor Company imebuni VTC, mfumo wa kudhibiti turbo kutumia MPC, na kuitumia kwa i20 N. VTC hutoa makadirio sahihi zaidi ya kasi ya turbo kwa kutumia mfano wa utabiri wa kuchambua data mbalimbali, kama vile kiasi cha mafuta na hewa, shinikizo la kutolea nje, na shinikizo la kuongeza. Pia inabiri matokeo ya udhibiti (kwa mfano, kasi ya turbo na pato la injini) kwa siku zijazo za karibu (kwa sekunde moja) kwa kutumia vigezo mbalimbali vya nje na kisha kudhibiti turbocharger mapema kwa kurekebisha wastegate moja kwa moja kuwajibika kwa kasi ya turbo. Kwa mfano, kama VTC huamua kwamba kasi ya turbo itazidi kiwango cha kubuni-kuruhusiwa katika sekunde moja, inatoa amri ya kufungua valve ya wastegate ili kurekebisha kiasi cha gesi ya kutolea nje inayotiririka katika turbocharger ili kupunguza kasi ya mzunguko wa turbine. VTC inasaidia kuongeza utendaji wa injini na kuhakikisha turbocharger haiharibiki, tofauti na mfumo wa kawaida wa kudhibiti turbocharger. Hii ndiyo sababu VTTC imetumika kwa i20 N, mfano wa utendaji wa juu ambao unahakikisha utendaji bora wa injini katika hali yoyote na huingiza furaha ya kuendesha gari. Hyundai Motor Company inaendelea na mipango ya kutumia teknolojia ya VTC, ambayo huongeza utendaji wa marginal wa injini, kwa mifano mingine katika siku zijazo. "Utekelezaji wa teknolojia hii ni sawa na falsafa ya Hyundai ya ""N,"" ambayo inasisitiza ""furaha ya kuendesha"" katika mfano wa msingi na inachangia maendeleo ya utendaji kulingana na uzoefu na teknolojia zilizopatikana kupitia maendeleo ya mifano ya N ya utendaji wa juu." Kampuni hiyo pia imepanga kutumia teknolojia ya kudhibiti ya MPC sio tu katika magari ya utendaji wa hali ya juu, lakini pia katika uwanja wa magari ya mazingira na teknolojia ya kuendesha gari yenyewe kama vile "udhibiti wa usimamizi wa joto wa magari ya umeme" na "udhibiti wa cruise ya utabiri" ambayo inaboresha ufanisi wa mafuta kwa kudhibiti kasi ya gari kulingana na utabiri wa hali ya barabara. "Mwanzilishi wa kampuni ya Hyundai Motor Group, Chi-Kyong Kim, alisema: ""Kwa mujibu wa Creative Commons License 2.0 (CCL), watumiaji wote wanaweza kunakili, kusambaza, na kusambaza habari zinazopatikana kwenye chumba cha habari cha Hyundai Motor Group, au kuitumia kwa maonyesho na maonyesho." Tafadhali kumbuka, hata hivyo, kwamba habari zote ni kulindwa na haki za uchapaji. "Watumiaji wa habari lazima watumie habari inayopatikana kwenye chumba cha habari cha Hyundai Motor Group kwa madhumuni ya kibinafsi tu. """