Abstract
Experimental studies were carried out to clarify the influence of air-factor on the exhaust valve seat wear, using a pre-combustion type diesel engine.
In the first place, the composite influence of air-factor on the seat wear was examined and the second place, the influence of oxygen concentration in exhaust gas and that of seat temperature were examined by the procedure of inlet air pre-heating.
As the results of experiment, the following conclusions have been reached.
(1) In the diesel engine, wears in valve face and seat decrease with increase in air-factor.
(2) Wear quantities of valve face and seat are proportional to the oxygen concentration in exhaust gas.
(3) Wears increase as the rotating speed of the engine increases. However, pure mechanical wear may be unexpectedly small. And it seems that the impact load acts main role in the removal of oxide film and accelerates the corrosive wear at high temperature.
