Other Engines VII. Devaere Engineering Engines.

Opposed Piston EngineKarl Benz played a prominent role in advertising the improvement of the automobile. Because of the 90 degree lead of the secondary crankshaft, the prime dead center positions of every piston, indicated as TDC, lap each other and the closest position amongst the pistons is between these lapped positions at roughly 45 degrees past leading dead center of the secondary piston movement, and 45 degrees prior to top dead center of the key piston movement.

A major object of the invention is to supply an novel and enhanced opposed piston engine, wherein the rotation of one crankshaft is phased to lag the rotation of the other by approximately 90 degrees to improve the operative, cyclic action of the prime mover gas inside the cylinder chambers between the pistons and to an improved sustained torque output with a substantial reduction in vibration making effects.

It is also to be noted that during the later portion of the function cycle, past the point of maximum expansion, the gas is slightly compressed just before exhaust commences and this slight compression portion of the cycle of rotation, from around 45 degrees prior to bottom dead center of the major piston to bottom dead center, permits the fuel to far more absolutely burn and as a result, minimizes the presence of undesirable exhaust gas fumes.

In this arrangement, a carburetor 62, possessing a gasoline feedline 63 and a two-branch intake line 64 extending to every crankcase, is mounted on one particular side of the engine. This is accomplished in a traditional manner by offering a ridge 60 on the face of the main piston 43 which traverses the piston between the diametrically opposed inlet and exhaust ports.

The advantage is obvious, for an engine could be started with the crankshafts in a position where the compression ratio is, say for example, 7 to 1. Soon after it is operating at high speed, a phase shift can then be made exactly where the compression ratio increases to, say for example, 11 to 1, delivering a substantial boost in power and efficiency in the engine output for the fuel becoming used.