An Improvement on Low Temperature Combustion in Neat Biodiesel Engine Cycles

摘要

Extensive empirical work indicates that the exhaust emission and fuel efficiency of modern common-rail diesel engines characterize strong resilience to biodiesel fuels when the engines are operating in conventional high-temperature combustion cycles. However, as the engine cycles approach the low-temperature combustion (LTC) mode, which could be implemented by the heavy use of exhaust gas recirculation (EGR) or the homogeneous charge compression ignition (HCCI) type of combustion, the engine performance starts to differ between the use of conventional and biodiesel fuels. Therefore, a set of fuel injection strategies were compared empirically under independently controlled EGR, intake boost, and exhaust backpressure in order to improve the neat biodiesel engine cycles. For instance, the single pulse injection was applied to commensurate with the heavy EGR-incurred LTC under light loads; and the multi-pulse early injection was applied with the EGR-assisted HCCI under higher loads to facilitate the high homogeneity that is more difficult to generate with a single pulse injection.