Abstract
A comprehensive development program conducted by CMC Research during the past 5 years has confirmed that the power density advantages expected from the application of a Scotch Yoke mechanism to an automo- tive internal automotive combustion engine can be achieved. A durable Scotch Yoke design and a function- ing system for the lubrication of the linear slider bearings are available and have been tested in dynamometer du- rability tests, and in a passenger vehicle, during many kilometers of road testing under day-to-day traffic condi- tions. The theoretical analyses together with dynamom- eter and 'in vehicle' tests indicate advantages over en- gines with conventional crankshafts and connecting rods, which were not all initially anticipated. These additional advantages are better mechanical efficiency, much im- proved NVH behaviour and a reduction in specific fuel consumption and NO. emissions.
The simple harmonic or sinusoidal motion of CMC Scotch Yoke engine pistons is one of the reasons why these en- gines behave so differently in comparison to engines with a conventional crank/connecting rod mechanism.