Intake charge temperature effect on performance characteristics of direct injection low-temperature combustion engines

摘要

The low-temperature combustion (LTC) concept presents solutions for simultaneous reduction in pollution and fuel consumption of internal combustion engines. However, the most important challenges of this concept are the lack of any direct combustion phasing control method and the limited operating range. Two LTC concepts, namely direct injection (DI) homogeneous charge compression ignition (HCCI) and partially premixed combustion, together with DI diesel can be combined to provide the desired performance for the whole load range. Although this combination provides the solution for the limited operating range, there still remains the problem with the method for combustion phasing control. Inlet temperature modulation may be used to regulate the combustion phasing. Therefore, this study investigates the effect of the intake charge temperature on the DI-HCCI combustion. The investigations are based on a novel two-stage combustion model. The combustion is predicted with the single-zone approach from the intake valve closing to the end of injection. Thereupon, it is predicted by the multi-zone approach. The results indicate that intake charge temperature has profound effects on in-cylinder charge pressure and temperature. It alters heat release rate magnitude and phasing, thus changing combustion timing. Moreover, this parameter affects indicated delivered power of the DI-HCCI combustion engine.