A Study on Valve Recession Caused by Non-leaded Gasoline : Measurement by means of R. I.

Abstract

The amount of wear debris from the exhaust value seat in condensed water of exhaust gas was continuously measured by means of the R.I. method. At the same time, rotational and lateral motion of the value were measured. Then the mechanism of the exhaust value recession in using lead free gasoline as a fuel of the automobile engine was made clear as follows: Cast iron flakes were removed from the value seat and they adhered to the value surface. And then, these deposits wore off the value seat because of rotational and rolling motions of the value. Especially, during about 20 minutes after the running conditions were changed, the valve motions became more violent and the wear also increased rapidly. Thus the overall abnormal wear of the value seat was caused mainly by above mentioned transient phenomenon.