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Engine torque profile shaping strategies have been proposed to reduce noise & vibration for passenger cars. However, it has not been sufficiently studied that feasible torque profile for vibration suppression is dependent on engine speed and target torque shape. On the other hand, combustion pressure profile shaping strategies have been proposed to reduce noise. However, there is almost no research of the quantitative evaluation of contribution of combustion pressure profile. First, the torque profile shaping was studied. Pre-compensated torque and 2-step torque were selected as typical target torque profiles. An effectiveness of vibration suppression by two torque profiles was evaluated by both drivetrain vibration model and engine torque profile model which have been established well. As a result of studying the torque profile shaping, timing of torque rise by the 2-step torque generation is delayed or advanced.

During acceleration, engine combustion is the major sound source in passenger vehicles.[1] This sound characterizes the overall impression made by the vehicle. Automobile manufactures have been developing engines to have better sound characteristics since the late 1980s.[2] However, fundamental and systematic knowledge of the relationship between the basic structural dynamics of the engine and its sound characteristics has not yet been reported. In addition, in the design stage, engine designers were not previously able to listen to the sound generated by the engines. This paper introduces a tool that synthesizes engine combustion sound by specifying the combustion process and a basic engine structural dynamics model having a small number of parameters. Using this tool, the authors obtained important relationships between combustion process and subjective sound characteristics evaluation scores.