The Investigation Of Diesel/methanol Compound Combustion Engine Emissions And After-treatment Technology

Nowadays, diesel engines have been established as the most efficient of all the engines, which convert energy from hydrocarbon fuels into work.For this reason,it has received much attention,and has been the subject of numerous investigations in recent years. Modern engines have more remarkably improved on combustion and emissions than traditional engines. But the tightening of recent and future exhaust emission limits for diesel engines challenge our investigation. In order to compensate shortage of fossil fuel and reduce the atmospheric pollutants emitted by I.C. engines, it is worthwhile to assess the suitability of clean burning fuels. Methanol offer the most promising substitutes for petroleum as engines fuels at present because it contains oxygen up to 50%, can be completely burned in cylinder of engines and has low pollution emissions. Additionally, coal is abundance in China and coal-to-methanol technology is practicable because of its low cost. The methanol-fueled diesel engine can considerably depress smoke density and Oxides of Nitrogen (NO_x) emissions. Therefore, the investigation of diesel engines fuelled with methanol has been attented.Previous research results showed that diesel/methanol compound combustion (DMCC) mode could be successfully applied to diesel engines and promised reduction of smoke and NOx emissions simultaneously and replaced part of diesel fuel. But we also found that diesel engines with DMCC mode hydrocarbon (HC) and carbon monoxide (CO) emissions had an appreciable increase. In this study, the oxidation catalyst technique will be employed to decrease HC and CO emissions.The present contribution describes an experimental investigation conducted on the 4-cylinder D.I. engine, which has been properly modified to operate under DMCC mode. Methanol injection quantity and injection timing were controlled by self-development electrically controlled unit (ECU). Diesel and methanol amount measurements were carried out by two fuel consumption meter, respectively. The DMCC engine performance and emissions characteristics were investigated with/without oxidation catalyst, revealing the effect of DMCC engine equipped with oxidation catalyst on exhaust emissions. The NO_x, HC, and CO measurements were carried out by exhaust gas analyzer in ppm. Particulate matter (PM) measurements were carried by a high volume sampler which is connected to the tail pipe of the engine. The NO_x, HC, and CO emissions were measured using CLD, FID, and NDIR...