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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.

The purpose of the present study is to improve the on-street exhaust noise measurement technique for regulating vehicles emitting unacceptably large exhaust noise. The method under development uses racing operation of engines with a wide-open throttle. Due to the high engine acceleration in this operation, exhaust pulsation amplitudes at resonant speeds may not increase sufficiently to represent the amplitudes under full-load acceleration conditions. To investigate the seriousness of this problem, experiments and numerical simulations were conducted. As a result, the sound level measurement error caused by the insufficient resonance growth was found to be sufficiently small for on-street tests.

One potential method by which to realize better acoustic in-car entertainment with a minimum of space is to adopt very thin Flat-Panel Speakers (FPSs), which use a combination of an array of coils printed on a flexible thin plastic film and permanent magnets. In the present report, the optimal panel material was investigated through experimental modal analysis. The optimal driving unit placement over the board was then determined using FEM based modal analyses. Finally, structural modifications to the sound radiating board in order to obtain a wider efficient frequency range were investigated experimentally. Among several design alternatives, satisfactory results were obtained by either dividing the sound radiating board into virtually independent sub-panels or adding resilient damping material supported by a restraining material.