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The pulse turbocharging system is most suitable for engines whose manifolds connect groups of three or fewer cylinders to a turbine inlet. Thus, 2 cylinder grouping and double entry turbines are usually used with 4 cylinder engines. Weather such an arrangement is really advantageous or not depends on several conditions, one of which is the specific characteristics of the engine. To decide whether to apply a double entry or a single entry turbine, the advantages and disadvantages of both systems should be carefully examined. A turbocharged 4-cylinder diesel engine has been studied using a one-dimensional computer simulation. Special attention has been paid to the interference of exhaust pressure waves coming from another cylinder or reflected from the turbine, and the influence of wave interference on the scavenging process has been studied. The pumping work has been computed by numerical integration as well.

A statistical method is described which allows a very accurate determination of the correlation between pressure and volume. The basis of the method is the pressure measurement of an engine under motoring conditions and correcting the pressure diagram with respect to heat and blow-by losses. Computation of the polytropic exponent dependent on error of phase lag determines the correlation in the pressure volume diagram. Since the internal processes in an IC engine under motoring conditions differ significantly from the ones under firing conditions, some modifications in the heat and blow-by losses models are necessary in order to be successfully applied in the proposed method. A simple optimization approach has therefore been used to correct both models. Several pressure diagrams measured under engine motoring conditions and at the different engine speeds have been studied.