The Variable Stroke Engine - Problems and Promises 780700
The concept of the variable stroke engine (VSE) is explained and the problems related to its use are discussed. Single cylinder combustion data are combined with published multi-cylinder VSE friction data to formulate engine model. This engine model is coupled with a vehicle model to make projections of 55/45 fuel economy and NOx g/mile which are compared with similar projections for a throttled engine. At an NOx level of 0.93 g/km (1.5 g/mile), VSE fuel economy improvements ranged from 2 to 20%, depending upon the frictional losses and vehicle power-to-weight ratio used in the models.