Abstract
Engine engineers increasingly depend on computer-aided engineering (CAE) tools such as engine cycle simulation to help meet significant design challenges posed by the conflicting requirements of improved performance, economy and durability. These goals must also be satisfied over ever-widening engine speed and load ranges. Such tools can provide invaluable insight into engine operation, guiding and accelerating the design process, reducing costs and ultimately resulting in better products. However, the engineer must rely on the tool providing accurate and meaningful simulation results over the complete engine speed and load range in question. This paper follows on from a previous paper presented by the authors at SAE Congress, March 2002, in which the results of a validation study on full load operation of a 1.9 litre 4-stroke direct injection turbocharged diesel (TDI) engine were presented. In that paper, the accuracy of a comprehensive engine cycle simulation tool, namely VIRTUAL 4-STROKE, was compared with measured performance and indicated data. This paper will present the results of a validation study using the same engine cycle simulation tool on the same TDI engine but under part load operation. Results are presented over the full engine speed and load range, indicating the suitability of such a tool in today's demanding engine design process.