Review of Induction System Design and a Comparison Between Prediction and Results from a Single Cylinder Diesel Engine 921727

Induction tuning is now used on a wide range of spark ignition and diesel engines. It has also been the subject of research and publications over many years. The literature on induction tuning is reviewed here, and contradictions are identified and clarified. The use of resonator volume systems are also discussed and the various ways of modelling these systems are compared.

In order to reconcile the differing theories, and to attempt to clarify the means by which induction tuning occurs, experiments have been undertaken with a single cylinder diesel engine. This was chosen as a single cylinder engine represents the simplest system, and a diesel engine does not have fuel in the induction system (which would otherwise modify the thermodynamic properties.

The experimental measurements include the instantaneous air mass flow rate entering the induction system, and the pressure at the inlet port. The induction system was of a modular design, so that pipes of varying length, and resonator of variable volume could be incorporated into the system. A volumetric efficiency of over 115 per cent was achieved over 65 per cent of the engine speed range. Data are also presented for the effect that the increased air flow has on reducing the fuel consumption and the smoke emissions. The tuned induction system performance is compared with the predictions made by various induction tuning models.