Development of V-6 3.5-liter Engine Adopting New Direct Injection System

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 fullload performance. The new spray promotes a homogeneous mixture without any devices to generate intense in-cylinder air-motion at lower engine speeds. For this reason the engine has improved volumetric efficiency compared to engines having these charge motion devices, resulting in improved full-load performance throughout the engine speed range. Together with Dual VVT-i (Variable intake and exhaust Valve Timing intelligence), the engine achieves specific power near the top of all naturally aspirated production gasoline engines in the world: 66kW/L, 228kW at 6400r/min. Fuel economy is improved compared to a conventional DISI engine with both injectors optimized to improve combustion. As for improvement of the exhaust emissions, simultaneous injection by the two injectors is effective in reduction of HC emissions during cold start.