Real World Emissions from Light Duty Diesel Vehicles

Arvind  Thiruvengadam, West Virginia University

This presentation discusses the study that reported significantly increased exhaust emissions during on-road operation and initiated an in-depth investigation by the U.S. EPA and California Air Resources Board (CARB) into emissions from Volkswagen (VW) light-duty Diesel engines, and finally culminated in VW acknowledging the use of “defeat device” to circumvent proper operation of emissions reduction systems during real-world vehicle operation. Earlier studies conducted in Europe have identified off-cycle NOx emissions from diesel fueled light-duty vehicles (LDVs) to substantially exceed the Euro 3-5 emissions standards on average by a factor of 4 to 7 over specific test routes. These results have demonstrated that the introduction of tighter emissions limits for the purpose of vehicle certification might not necessarily translate into effective on-road NOx reductions of the same magnitude.