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A new V-6 stoichiometric gasoline direct injection engine was developed for high performance FR (Front Engine Rear Drive) vehicles. High power performance, low fuel consumption and low exhaust emissions were achieved by employing a stoichiometric direct injection system that uses Toyota's unique slit nozzle injector that generates a fan-shaped fuel spray and variable intake and exhaust valve timing systems. Focusing on the power performance, maximum power of 183kW (61kW/L) is achieved at 6200rpm and maximum torque is 312Nm at 3600rpm. This power performance is among the top production 3.0 L gasoline engines in the world. This paper outlines the features of this engine and some special technologies contributing to the achievement of the above-mentioned high performance. Optimizing the intake-port design was done to improve power performance.

A new V-6 3.5-liter gasoline engine (2GR-FSE) uses a newly developed stoichiometric direct injection system with two fuel injectors in each cylinder (D-4S: Direct injection 4-stroke gasoline engine system Superior version). One is a direct injection injector generating a dual-fan-shaped spray with wide dispersion, while the other is a port injector. With this system, the engine achieves a power level among the highest for production engines of this displacement and a fuel economy rating of 24mpg on the EPA cycle. Emissions are among the lowest level for this class of sedans, meeting Ultra Low Emission Vehicle standards (ULEV-II). The dual-fan-shaped spray was adopted to improve full-load performance. The new spray promotes a homogeneous mixture without any devices to generate intense in-cylinder air-motion at lower engine speeds.

This paper describes the analyses to improve both stratified and homogeneous charge combustion of a gasoline direct injection engine. In this study, computational fluid dynamics (CFD) and high-speed hydrocarbon (HC) measurement were employed to observe the mixture formation process. The analysis of the combustion flame propagation was conducted by in-cylinder visualization and ion current measurement. As a result of the analyses, the following conclusions were made: 1 An oval shaped wall cavity can direct the mixture gas to the vicinity of the spark plug better than a conventional shell-shaped wall cavity. The oval shaped wall cavity can improve fuel consumption and HC emission at stratified charge combustion. 2 A shallow cavity improves the homogenization of mixture gases and wide open throttle (WOT) performance.