Effects on Charge Non-Uniformity on Diesel Heat Release Analysis

A new model that includes the effects of spatial non-uniformity for the heat release analysis of internal combustion engine data has been formulated. The model has a form similar to the simple single zone thermodynamic models if two effective values of the ratio of specific heats T are defined. These values, denoted by γ_V and γ_H in the model, are weighted spatial average values of Y, and are dependent on the structure of the flame. These values have been evaluated using a three-dimensional numerical simulation of diesel combustion. Then the model is applied to the heat release analysis of diesel combustion data from a Rapid Compression Machine. The results show that the calculated cumulative net heat release is significantly higher (17% in this case) than that calculated using a single zone model.