The Effect of Valve Control on a Motor Vehicle Engine Performance

Ishmael Zibani, Joseph Chuma, and Rapelang R. Marumo


Camshaft, Engine Performance, Poppet valve, crankshaft, Timing Belt, otto cycle


A camshaft controlled car engine poppet valve system has been in use for many years since the industrial revolution. The crankshaft synchronously drives the camshaft using a timing belt. The camshaft in turn opens and closes the poppet valves during the Otto cycle. The main disadvantage of this system is the high possibility of damage to the valves, pistons or perhaps the engine itself in the event of a timing belt failure. Another drawback is the labour-intensive job of replacing a timing belt. A number of research activities have gone into computer controlled camshaft to make the system more reliable and predictable. But as long as the valve and piston paths cross, a collision is invertible at some point. The belt requires regular replacement. An electronically controlled rotary valve (ecrv) has been proposed. Its motion is perpendicular to the piston, averting any possibility of a collision. In this study, timing parameters of the poppet valve system are discussed and compared to those of the ecrv. Furthermore, the operational difference between the two valve types is extensively covered, clearly demonstrating performacnce advantages of the ecrv. At the time of writing this script, a prototype engine was being implemented.

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