Diesel engines have attracted attention because of their higher thermal efficiency and lower carbon dioxide emissions than gasoline engines. On the other hand, oxides of nitrogen (NOx) and particulate matter (PM) in the exhaust from diesel engines are difficult to be reduced simultaneously because a decrease in one is likely to result in an increase in the other. In this paper, an attempt has been made to compare the effect of the heat lost to the coolant in the cylinder block, and in the cylinder head with a conventional cooling circuit with corresponding effects in an engine with a dual cooling circuit. A dual cooling circuit employs separate cooling circuits for the cylinder block, and for the cylinder head. A... |