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Spark ignition engines for automotive applications must have good cold start performance characteristics at sub-zero ambient temperatures. Satisfactory performance is most difficult to achieve at the lower end of the temperature range, typically around -30°C. The start characteristics of a particular engine depend on basic design features, starter motor characteristics, and the calibration and strategy used to regulate fuel supply during start up. The paper reports a computational model which enables the investigation of these with the minimum of experimental data. The model has been developed to run on desk-top PC machines, specifically as a CAE development tool. The formulation of the model and the experimental tests were used to generate the input data required for particular applications are described.

The paper exemplifies the necessity to quantify the various noise sources present in modern automotive engines. Results demonstrate the non-linearity problems associated with many of the non-running engine rig tests currently in use. A new technique is described for combustion induced noise simulation using hydraulic excite ion. Results obtained using this experimental method are compared with those measured on the running engine.