Advantages and Disadvantages of the Application of a Single Entry Turbine for Pulse System Turbocharging of 4-Cylinder Engine 972775

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. The results of simulation agree well with experimental results and enable a reasonable comparison of both double and single entry turbine systems to be made. The differences between systems, regarding scavenging process and pumping work, are small and some conclusions confirming the advantages of single entry turbine may be made.