Analyses of mechanism on roadside pollution by on-board emissions measurement system (characteristics of NO_X emissions in vehicles with and without EGR system in real traffic conditions)

On-board measurement system that can simultaneously obtain such information as road infrastructure, traffic conditions, driver's operations, vehicle running conditions and exhaust mass emissions, was installed in a light duty freight with EGR system and in one box vehicle without EGR system. In order to analyze mechanism of roadside pollution caused by vehicles, road tests were carried out in real traffic conditions. The vehicle with EGR system showed intensive NO_x pollution to roadside in vehicle start, in which EGR rate was low, but it was effective to reduce NO_X mass emissions at low speed running in traffic jams where EGR rate was rather high. In case of the vehicle without EGR system, intensive NO, pollution was observed in low speed running such as in traffic jams. The reduction of NO_X during vehicle start is important for vehicles with EGR system to reduce intensive NO _X pollution at roadside. EGR system is effective to reduce intensive NO_x pollution for vehicles without EGR system during low speed running like in traffic jams.