Reduction of smoke and NOx from diesel engines using a diesel/methanol compound combustion system

This paper presents the concept of a diesel methanol compound combustion (DMCC) system and some experimental results on the application of the system to two diesel engines. In the DMCC system, diesel fuel is used for engine starting and for low load operation. At medium to high load, a fixed amount of diesel fuel is maintained while extra energy is acquired by injecting methanol into the intake manifold to form a homogeneous methanol/air mixture. The system was tested on two 4-cylinder diesel engines: one naturally aspirated and the other turbocharged. In both cases, the DMCC is found to reduce brake specific equivalent fuel consumption, reduce smoke emission, and reduce NOx emission but increase CO and HC emissions.