Effect of starting temperature and belt width on lateral force of timing belt

Timing belts transmit crankshaft's power to rotate synchronously camshafts so that the engine's valves open and close at the proper times. Various vibrations will be imposed to timing belt during engine operation that could lead to movement and flapping of timing belt. Lateral belt tracking that pushes belt toward or outward of engine is one of these movements. This movement cause to improper contact between pulley's flange and timing belt that can produce annoyance noise and also accelerate the belt failure. There are many factors such as starting temperature, inclination of pulleys, inherent characteristics of belt, belt width, and position of tensioner which effect on belt tracking. This article evaluates effect of starting time, belt width and belt run-off on magnitude of lateral force in an internal combustion engine. According to test results, reducing starting temperature to lower than 30 C has considerable effect on rise of lateral force and belt movement. By 0.5 increase of belt width can reduce lateral force acceptably. Moreover, it is possible to control lateral movement by using timing belts with proper run-off.