Injection control pressure strategy during activation of an engine retarder

摘要

A control strategy for mitigation of the effect of increased engine back-pressure on fuel injectors (22) when an engine retarder is activated to slow the engine (10) of a motor vehicle. The strategy attenuates injection control pressure ICP of hydraulic fluid for the fuel injectors to a defined dwell pressure ICP_VRE_DWL, and once that dwell pressure has been attained, keeps the injection control pressure from exceeding it for the length of a dwell time ICP_DWL_TM. Upon elapse of the dwell time, the injection control pressure gradually increases above the dwell pressure using a pressure versus time map (54). When engine operating conditions call for greater injection control pressure while the retarder is activated, the strategy provides for greater injection control pressure using a pressure versus speed map (42).