Performance of Two-Stroke Compression Ignition Engines in Combination with Compressors and Turbines

Abstract

Several papers (1)-(5)^† have been written in recent years dealing with various aspects of the performance of turbocharged two-stroke compression ignition engines. None of these, however, provides a general method of performance prediction for a given engine-turbocharger combination over the complete range of load and speed, in terms of given design operating conditions and given compressor and turbine characteristics. Such calculations are complicated further by the inclusion in the system of a mechanically driven scavenge blower, usually in series with the turbocompressor. The paper provides a complete solution of this complex problem on the basis of certain necessary simplifying assumptions relating primarily to the engine cycle. Since the gas generator and compound engine have been recognized in recent years as, in certain circumstances, superior alternatives to the turbocharged engine, the method is extended to cover also these two cases. In all three cases the engine is assumed to be of the opposed-piston type, which is now recognized as being particularly suitable for high-pressure supercharging (6). The paper may be considered supplementary to a recent paper by Chatterton (6), in which the turbocharged, gas generator and compound cycles are compared purely on a basis of design point operating conditions.