The Influence of the Combustion Chamber Head Material of a Gasoline Engine on Exhaust HC 2000-01-3072
Aluminum alloy or cast iron is used for the combustion chamber head, and the influence of head material on engine performance and the exhaust characteristics were examined. Comparing the aluminum alloy head to the cast iron one, the differences between them in indicated mean effective pressure and in NOx concentration are minor, but the discrepancy is large in the HC concentration. This is attributed to the lower head wall temperature caused by high thermal conductivity of the aluminum alloy. From the calculated results, the head surface temperature rise and HC reduction is expected by coating the material having lower thermal conductivity.