Based On The Imo Annex Vi For Marine Diesel Engine Nox Emissions

Diesel engines are used widely as the power sources of ships due to their high thermal efficiency, high fuel economy and durable performance. However, the gaseous and solid substances exhausted from Diesel engines during the combustion process cause air pollution, in particular around harbor regions. In this dissertation, NO_X emission reduction is studied based on a single cylinder Diesel engine. The main content and achievement include:1. The IMO convention annex VI and Diesel engine emission statues in China ships market are introduced. The reduction of Diesel engine SO_X and NO_X emission are briefly introduced as well, especially the NO_X. Considering the cost and efficiency, fuel injection timing optimization & EGR are the best solution for NO_X emission reduction.2. The best fuel injection timing is not only to keep the Diesel engine good power performance & lower NO_X emission, but also to keep good fuel economy. If fuel injection timing delay too much, NO_X emission will improved , but CO , HC and fuel consumption will be increased. In this dissertation, fuel injection timing optimization is studied.3. External cooled EGR is an efficient method to reduce NO_X emission. Effects of EGR on combustion performance and emission performance of diesel-fueled combustion are studied. When the EGR rate is increased, combustion phasing is delayed and maximum in-cylinder pressure is decreased. The start of combustion is delayed about 7℃A when the EGR rate achieves 40%. Increasing EGR rate can reduce the tendency of knock-combustion and reduce the NO_X emission. The CO emission increases with EGR rate increasing.4. IMO NO_X emission test method is introduced. As an illustrative instance for a China ship NO_X emission test is introduced as well.