Development of a New 1.5L I4 Turbocharged Gasoline Direct Injection Engine 2016-01-1020
A 1.5 L downsizing turbocharged engine was developed to achieve both driving and environmental performance. The engine is intended to replace 1.8 - 2.4 L class NA engines. In downsizing turbocharged engines, mixture homogeneity is important for suppressing knocking and emission reduction. Particularly under high load, creating rapid combustion and a homogeneous mixture are key technologies. The authors used a long-stroke direct injection engine, which has outstanding rapid combustion and thermal efficiency, as a base engine meeting these requirements. They combined this with a high-tumble port and shallow-dish piston intended to support tumble flow. The combination enhanced flow within the cylinder. The combustion system was built to include a sodium-filled exhaust valve to reduce knocking and a multi-hole injector (six holes) for mixture homogeneity and to reduce the fuel wall wetting. The above combustion system is able to achieve high rates of in-cylinder pressure rise with its rapid combustion and therefore improves IMEP, even with a retard ignition timing setting at 1500 rpm full load. Dual VTC makes it possible to set the optimal intake and exhaust valve overlap and valve timing for the engine speed and load. The use of this in combination with the above-described combustion system achieved a minimum BSFC of 220 g/kWh and maximum thermal efficiency of 38%. This paper will also introduce the engine’s output, fuel economy, its technologies for achieving lower emissions, reducing vibration and noise, and achieving light weight, and the performance of the finished vehicle.