METHOD AND SYSTEM FOR ENGINE CONTROL

摘要

Methods and systems are provided for slowly rotating an engine, unfueled, via a motor prior to an imminent engine restart to heat the engine. By rotating the engine so that heat generated in the compression stroke of a cylinder can be transferred to cylinder walls, thereby expediting engine warm-up. By warming the engine before a restart, particulate emissions generated during an engine cold-start due to direct injection of fuel can be reduced.

主权项

1. A method, comprising:
while propelling a hybrid vehicle via only motor torque, rotating an engine unfueled at slower than a threshold speed until a piston temperature is higher than a threshold.