Study on emission characteristics of off-road air-cooler diesel engine

With a SEMTECH onboard emission measuring device and an electrical low-pressure impactor (ELPI), the gaseous emissions of an off-road air-cooler naturally aspirated diesel engine were measured, and the number and mass weighted size distribution of PM were studied. Based on the test cycle of China off-road emission, the test results showed high NO_x concentrations from off-road diesel engine. Meanwhile, the particle number weighted size showed the unimodal and lognormal distributions, and the number of Accumulation Mode particle was increased as engine load is increased. The mean diameter of particle from the off-road engine was larger than that of the vehicle-use engine. However, the mass weighted size of the particle gave the bimodal distribution, corresponding to the Accumulation Mode and the Coarse Mode. The study indicated that Accumulation Mode particle would contribute more to mass, but had different proportion compared with that of the vehicle-use engine.