A Study on the Mechanism of Exhaust Valve Sticking

In order to understand and resolve the exhaust valve carbon sticking problem, the engine parameters effective on the phenomenon are shown by bench tests. Based on the results, a new test code which can evaluate the exhaust valve sticking has been developed. And by using the test code, the effects of engine hardware, gasoline properties, and warm-up enrichment are shown. Finally, the detailed mechanism of the exhaust valve carbon sticking is clarified and solution to it is proposed.