Analysis of Intake Valve Wear When Using E100 Fuel by Utilizing a Radioisotope Tracer

Abstract

In order to clarify the effects of ethanol fuels on intake valve wear, wear measurements utilizing a radioisotope technique have been performed. The results indicated that wear tended to increase when the cooling water temperature was low. To identify the cause of the wear increase, we measured the concentration of acid in the exhaust gas, analyzed deposits adhering to the valve, and observed the area around the intake valve. Based on the results, it was concluded that intake valve wear increased due to the presence of an acidic liquid film adhering to the valve surface.