Research On Real-world Emission Performance Of Clean Energy Buses

In this research,clean energy buses with different kind of fuel(diesel electric hybrid,natural gas)were tested on road using Portable Emission Measurement System(PEMS)compared with diesel buses,and these buses contain different emission standards,different post-processing systems. The VSP method was used to analyze the CO2-based pollutant emission. The result showed:In the state of low speed and low load,the CO2 emission of China National-III diesel buses was same to National-IV and National-V diesel buses,but In the state of high load,the CO2 emission was increasing fast. The CO and NOX emission of different emission standard buses difference were insignificant,the THC emission of China National-V buses was a little lower than National-III and National-IV buses. the PM emission of China National-III buses was much higher than National-IV buses,and National-IV buses was much higher than National- V buses.In the state of low speed and low load,the CO2 emission of diesel electric hybrid buses was much lower than diesel buses,while didn’t have much advance in the state of high speed and high load. The CO and THC emission of diesel electric hybrid buses were lower than diesel buses,and the CO2-based NOX emission was higher than diesel buses. The PM emission of different diesel electric hybrid buses had many differences,so we couldn’t make sure that whether hybrid buses have advance to diesel buses.Comparing different emission standard natural gas buses,the CO and THC emission of China National-V buses were much lower than National-III and National-IV buses. The NOX emission of National-III buses was a little higher than National-IV buses,and much higher than National-V buses. The PM emission of different emission standard buses was very different,and didn’t have clear trend.Comparing different post-processing system natural gas buses,the CO2-based CO emission of natural gas buses with OC+SCR was same to natural gas buses with TWC。The THC、NOX and PM emission of natural gas buses with OC+SCR were higher than natural gas buses with TWC,and diesel buses have lowest THC emission and highest NOX、PM emission. The exhaust gas temperature of natural gas buses with OC+SCR was same to natural gas buses with TWC,and higher than diesel buses,and the temperature fluctuates more greatly than diesel buses.