Thanks to the progress in both computer system hardware and software, the engine performance and exhaust emission precisely can be simulated by using virtual engine model of one dimension with codes. Therefore, it came to be able to shift from a relative evaluation by the single cylinder model with the overall turbocharger efficiency to an absolute evaluation by the multi cylinder model (full model) with the turbocharger map. As a result, the simulation accuracy for the engine performance and

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... haust emission estimation has been improved. This paper presents the improvement of engine performance simulation technology by using the examples of engine simulation calculations and engine experimental results. In these analyses, the multi cylinder model is introduced for simulating the engine performance and exhaust emission and the results are compared with the experimental results.