Predicting the combustion behaviour of a diesel HCCI engine using a zero-dimensional single-zone model

Abstract

Homogeneous charge compression ignition (HCCI) engines use a new mode of combustion whose technology has not matured sufficiently to be commercialized. There are several challenges in developing HCCI engines: auto-ignition control of the mixture, achieving a cold start and controlling knock at high load operation. In principal, HCCI engines have no spark plug or fuel injector to control the combustion: auto-ignition occurs in multiple spots once the mixture has reached its chemical activation energy. The chemical reaction of the mixture is influenced by changing input parameters such as: intake temperature, equivalence ratio and fuel type. A zero-dimensional single-zone model is used to investigate the combustion behaviour of a diesel engine operating in HCCI mode, with n-heptane used as a surrogate fuel for diesel. The combustion phasing is predicted in accordance with the experiment, with higher in-cylinder peak pressure. This paper will study methods of controlling the auto-ignition timing through hydrogen addition and by altering the intake air temperature and equivalence ratio. The auto-ignition timing changes with the change of all those factors, where the combustion phasing is advanced by increasing all the parameters.