Development of a New V-6 High Performance Stoichiometric Gasoline Direct Injection Engine

Authors

S. Abe, M. Sugiyama, H. Kishi, J. Harada, Toyota Motor Corporation, Aichi, Japan

Year

2004

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 566

Summary

A new V-6 stoichiometric gasoline direct injection engine was developed for high performance FR vehicles at the end of 2003. High power performance, low fuel consumption and low exhaust emission were achieved by employing stoichiometric direct injection system and variable intake and exhaust valve timing systems. Focusing on the power performance, maximum power is achieved 188kW, 63kW/L at 6200rpm and maximum torque is 314Nm at 3600rpm. This power performance is top level of 3.0 L gasoline engines in the world. In this direct injection system, Toyota’s original slit nozzle injector which can generate fanshaped fuel spray, was applied. In this paper, outline features of this engine and some special technologies contributing to achieve above-mentioned high performances were described. Optimizing the intake-port design was done to improve power performance. In the conventional intakeport design, flow-rate coefficient was decreased to generate in-cylinder air-flow which is required for homogeneous mixture formation, and the advantage of the direct injection system could not be utilized sufficiently. In the development of this engine, the intake-port which can obtain both of high flow-rate coefficient and high tumble ratio, was designed by employing CFD - 83 - 25. Internationales Wiener Motorensymposium 2004 analyses. Improvement of power performance, therefore, could be obtained efficiently as an advantage of direct injection system. To improve the fuel consumption, the variable intake and exhaust valve timing systems were employed to decrease pumping loss and increase expansion ratio. As a result of combustion pressure analyses, it was found that the initial combustion speed could be improved under the condition with internal exhaust gas recirculation( EGR) and the engine could be operated with larger amount of EGR. One of the advantages of the direct injection system was utilized to improve exhaust emission under the cold start and warm-up conditions. Amount of fuel injected at cold start condition could be significantly reduced adopted stratified charge combustion with sufficiently atomized fuel spray by high fuel pressure. Under the warm-up condition, stratified charge combustion, which enable to retard spark ignition timing, was also employed to significantly improve the warm-up speed of the catalyst.

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