Effect of Ceramic Wall on Diesel Particulate Emission.

Effects of heat insulation of combustion chamber walls on particulate emissions were investigated using a single-cylinder direct-injection diesel engine. Two types of coated pistons which had thin PSZ layers on different portions of their surfaces were prepared to examine the effects of insulation on emissions of particulates, especially on soluble organic fractions (SOF). Results show that the weak insulation, which has little effect on the gas temperature and combustion process on a large scale in the combustion chamber, can change SOF and THC emissions. The piston with an entirely coated upper surface promotes SOF emission at medium equivalence ratios. A difference of locations of insulated surfaces gives different trends for SOF and THC.