High pressure air spray assistant power supply control strategies and their effects on diesel engine under transient operations

Abstract

In order to reduce smoke from direct-injection (DI) turbo-charged and after-cooled (TCA) diesel engines under transient operations, the real-time controlling and measuring system of a high pressure air spray assistant power supply (HPAS) was developed. Effects of HPAS on a DI TCA diesel engine under constant engine speed and increased torque (CSIT) transient operations were studied by using different control strategies. Pre-spray (PS) strategy, which means supplying highly pressurized air into the exhaust manifold two seconds before the accelerating-graph begins to rise and stopping spraying air when the accelerating-graph stops rising. Two other strategies—full-time-spray (FTS) and middle-time-spray (MTS)—were used to fully exploit HPAS potential. With the FTS and MTS strategies, the HPAS system can remarkably decrease smoke from DI TCA diesel engines under transient operations.