Exhaust Emissions from Two Euro 6d-Compliant Plug-In Hybrid Vehicles: Laboratory and On-Road Testing 2021-01-0605

This paper discusses the legislative situation regarding type approval of plug-in hybrid vehicles (also known as off-vehicle charging hybrid-electric vehicles, OVC-HEV) in the range of exhaust emissions and fuel consumption. A range of tests were conducted on two Euro 6d-complaint OVC-HEVs to quantify emissions. Procedures were based on EU legislative requirements. For laboratory (chassis dyno) testing, two different test cycles and three different ambient temperatures were used for testing. Furthermore, in some cases additional measurements were performed, including measurement of emissions of particulate matter and continuous analysis of regulated and unregulated pollutants in undiluted exhaust. Consumption of electrical energy was also monitored. On-road testing was conducted on the test vehicle tested on the chassis dyno in the tests mentioned above, as well as on a second OVC-HEV test vehicle. Both vehicles were tested using portable emissions measurement system (PEMS) in accordance with the EU’s real driving emissions (RDE) requirements. Testing was performed over an RDE-compliant route, from cold start, commencing with a fully charged and fully depleted battery (in turn). The emissions behavior of the powertrain was analyzed based on results of the comprehensive emissions measurements described above. The battery’s state of charge was found to have a noticeable impact on regulated emissions and especially fuel consumption, although the low battery charge start condition was not always associated with higher emissions than the fully charged condition. Overall, it can be stated that both vehicles easily met all EU emissions requirements, regardless of the battery charge condition at test start.