Idle characteristics of a hydrogen fueled SI engine

This paper investigates the effect of the equivalence ratio Φ and ignition advance angle θi on idle characteristics of a turbocharged hydrogen fueled SI engine. The experimental data was conducted under various operating conditions including different Φ and θi. It is found that, the ignition advance angle at MBT point decreases gradually with the equivalence ratio increasing from 0.4 to 0.9. Indicated thermal efficiency decreases as Φ increases. Emissions of NOx increase as Φ increases. When Φ is kept constant, the stated emissions increase as θi increases. During idle conditions of a hydrogen fueled engine, a lean mixture with an Φ less than 0.4 is suitable, and the θi should be increased appropriately. The maximum cylinder pressure rises with an increase of Φ and θi. The trend of the maximum rate of pressure rise is similar at different Φ. Only under the conditions of Φ = 0.4 and θi < 10 °CA, the maximum pressure rise rate remains almost unchanged.