Performance Improvement of a Multi-Cylinder CR Diesel Engine for Mini-Car Application 2010-32-0113

The present work investigates a multi-cylinder Diesel engine with integrated automatic transmission and gearbox, equipped with a common rail injection system for mini-car sector application.

Previous research work has been devoted to examine the engine NVH characteristics; the attention has been addressed to the analysis of the direct relationship existing between in-cylinder pressure and engine block vibration signals with the final purpose of developing and setting up a methodology able to monitor and optimize the combustion process by means of non-intrusive measurements.

The aim of this paper is to improve the performance of the engine in different operating conditions by means of both experimental and numerical approaches.

Experimental tests have been conducted on the engine in a dynamic test bed in order to account for the actual loading conditions. In-cylinder pressure has been measured, intake and exhaust pressure and temperature signals have been acquired and the exhaust emissions have been measured.

Concerning the numerical approach, the model of the complete engine system has been realized within the AVL BOOST software environment, in which lumped parameter and one-dimensional models are employed for the prediction of the thermo-fluid-dynamic processes involved in the intake-exhaust systems and in the cylinders.

On the basis of the predicted and validated thermo-fluid-dynamic traces, the effects of variations of both intake and exhaust systems geometry as regards the engine standard configuration have been investigated. Results of the optimized configuration of the engine system are presented and discussed.