Next-generation vehicles which include the Electric Vehicles, the Hybrid Electric Vehicles and the Plug-in Hybrid Electric Vehicles are researched and expected to reduce carbon dioxide (CO2) emission in the future. In order to reduce the emissions of the heavy-duty diesel plug-in hybrid electric vehicles (PHEV), it is necessary to provide the high exhaust-gas temperature and to keep the exhaust-gas aftertreatment system effective. The engine starting condition of the PHEV is cold, and the engine start and stop is repeated. And, the engine load of the PHEV is assisted by the electric motor. Therefore, the exhaust-gas aftertreatment system of the PHEV is not able to get the enough high exhaust-gas temperature. And, the warm-up of the exhaust-gas aftertreatment system for the PHEV is spent the long time. So, it is worried about a bad effect on the emission characteristics of the PHEV.
In this study, we focused on the Electrical Heating Catalyst (EHC) system, which is one of the next generation electrical technologies. This test PHEV was equipped with an EHC. The fuel economy and emission characteristics of this test PHEV were estimated using the extended-HILS, which is combined the real engine with the PHEV model of the HILS (Hardware-In-the-Loop-Simulator).
This result is that an EHC showed good performance at the engine low speed and low torque range. And, NOx emission was reduced when the tailpipe layout was setup in order of the urea solution injector, an EHC and the Selective Catalytic Reduction (SCR) catalyst. NOx and CO2 emission of this test PHEV which was equipped with an EHC was good, compared with the heavy-duty diesel engine vehicle, the heavy-duty diesel hybrid electric vehicle and the PHEV which was not equipped with an EHC.