The effect of intake temperature on the performance of a high compression ratio engine for hybrid vehicles

The performance characteristics of the engine at the intake temperature of 30, 50, 60 and 70 °C were studied on a naturally aspirated direct injection gasoline engine bench for hybrid vehicles under medium load and full load conditions. The test results show that with the increasing intake temperature, the torque at full load decreases, the ignition time is delayed, the exhaust temperature and the cyclic variation increases. Additionally, an increase in intake temperature results in reduced brake thermal efficiency and lower emissions of NOx and CO, but at high-speed conditions, excessive intake temperature will lead to an increase in CO emissions.