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The acceleration response of a supercharged diesel engine passenger car, equipped with a particulate trap, is studied using a simulation program. The superchargers evaluated are the Comprex(R) pressure-wave supercharger as well as turbochargers with fixed and variable-geometry. The particulate trap is placed before the supercharger to promote the trap regeneration and to reduce the pumping gas-exchange work. Particulate traps currently used are such a large thermal sink that the acceleration response is unacceptable. There are promising innovations in progress to develop a particulate trap with less than a quarter of the present mass. The computations demonstrate that the acceleration response should then be acceptable.

The Comprex(R) is a pressure-wave supercharger (PWS) for passenger car diesel engines. It has many features which ideally suit it for the continually increasing demands on driveability, fuel economy and reduction of exhaust pollutants. To counter the disadvantages of the previously required belt drive, a free-running machine was developed. It is self driven by the kinetic energy of the exhaust gas; made possible by employing a rotor having reduced inertia. In addition to the well known Comprex features, this advanced development offers advantages such as rapid response, high efficiency, compactness and freedom in placement. The paper discusses the design of the free-running PWS, its construction, supercharging characteristics and preliminary experience.