Diesel engine has the advantages of strong power, low fuel consumption and good durability, so it has been widely used in transportation, automobile, ship and other fields. However, the nitrogen oxides(NOx) and particulate matter(PM) emitted by diesel engines have become one of the main causes of air pollution. Especially during idling, the engine temperature is low, and there are more residual exhaust gases in the combustion chamber, resulting in the formation of more harmful emissions. In this study, performance of a single cylinder, four-stroke, direct injection (DI) diesel engine fueled with diesel–biodiesel mixtures has been experimentally investigated.

The purpose of this study is to verify the effects of a port throttling and 1/4 diagonal port masking of an intake port of an SI engine. The fuel consumption rate increased with port throttling and masking under all operating conditions. However, the rapid combustion effect was increased in all operating conditions. It is consider that this is more influential on the suction resistance than the combustion efficiency increase through intake control. In addition, the increase in the burning velocity indicates that the flame propagation speed is increased by increasing the swirl moment during combustion.

In this study, we investigated the effects of EGR rate and engine load on the emission characteristics in a 4-cylinder common rail direct injection diesel engine fueled with canola oil biodiesel (BD) blended fuel. The biodiesel blend fuel, BD20 (20 vol.% biodiesel and 80 vol.% ULSD blend) was used at an engine speed of 1,500rpm. The experimental results showed that with the increasing of EGR rate, the combustion pressure and rate of heat release (ROHR) of three test fuels were decreased, and the ignition delay was extended, the carbon monoxide (CO) and particulate matter (PM) emissions increased slightly, but the nitrogen oxide (NOx) emission decreased clearly. On the other hand, with the increasing of engine load, the combustion pressure and ROHR were increased, and the CO and PM emissions decreased. However, the NOx emission was increased due to the rise of the combustion temperature.