Effects of Environmental Parameters on Real-World NO_x Emissions and Fuel Consumption for Heavy-Duty Diesel Trucks Using an OBD Approach

摘要

OBD (On-Board Diagnostic) test system is applied to research influences of environmental parameters (altitude and environment temperature) on real-world NO_x emission and fuel consumption for heavy-duty diesel trucks in this paper. The research results indicate that altitude and environment temperature have great influence on NO_x emission rate and fuel consumption. High altitude in range of 3000～4000 m results in NO_x emission rate is lower than low and moderate temperature because of air intake amount decreasing. However the fuel consumption rate is higher than lower altitude because altitude influences real-time changes of air inflow and combustion conditions in the cylinder of the engine. NO_x emission rate and fuel consumption is more stable at different vehicle speed, VSP and RPM at high altitude, and NO_x emission rate fluctuate dramatically at low and moderate altitude. The fuel consumption rate is higher at 10～20 °C than that at lower and higher temperature. The environment temperature of 20～35 °C provides beneficial conditions for NO_x production and deteriorates emission, and the environment temperature of -10～10 °C provides oxygen enrichment environment because of low temperature and high air density, so increases in production amount of NO_x. Effects of altitude and environment temperature on NO_x emission rate and fuel consumption rate show an opposite tendency. Compared with fuel consumption rate, NO_x emission rate is more sensitive to vehicle speed, VSP and rotating speed.