Effect of EGR and intake air throttling on engine-out-responses of double split fuel injection diesel engine fueled with B60 palm biodiesel.

The air intake path of a commercial diesel engine is designed for maximum airflow rate under high load conditions. At part load, the excessive intake airflow might cause a higher formation rate of oxides of nitrogen (NOX), this is especially true for biodiesel with inherent oxygen content. Thus, air intake throttling coupled with exhaust gas recirculation (EGR) might be a reasonable approach to reduce intake airflow during engine part load conditions. In this study, a common-rail direct injection diesel engine has been integrated with an in-house made electronic control unit (ECU) capable of customizing multiple injection strategies. The effect of intake air throttling and EGR on double split injection with B60 palm biodiesel blend has been investigated. The result showed that without EGR, intake throttling was able to reduce NOX and soot simultaneously, but with a minor penalty in fuel economy. On the other hand, under the engine operation with EGR, the intake air throttling has been found to enhance the positive effect of EGR by inducing more exhaust gas flow through the EGR path. Besides, Gaussian distribution was constructed to study the effect of intake throttling on combustion characteristic of cycle-to-cycle variation of indicated effective mean pressure (COVIMEP). In most cases, intake air throttling has affected the COVIMEP. [ABSTRACT FROM AUTHOR]