Fuel Consumption Test Protocol Concept for Plug-in Hybrid Electric Vehicle

A plug-in hybrid vehicle (PHEV) is recently developed technology and it will be put in the market in the near future. In existing hybrid electric vehicles (HEV), it was possible to suppress the petroleum consumption by regenerating the kinetic energy of vehicles during deceleration into electrical energy. A PHEV can use petroleum fuel as with traditional vehicles including HEV, and in addition, use the electrical energy supplied from the commercial power for running energy. That is, the existing HEV technology suppresses petroleum energy consumption. In contrast, the PHEV technology alternates part of vehicle drive petroleum energy with electric energy. Commercial electric generation can use many kinds of energy source other than the fossil oil. PHEV is a promising technology to reduce the well to wheel CO₂ emission and one of the solutions for energy security issue. On the other hand, from the point of view of vehicle emission and fuel consumption performance evaluation, current test protocols cannot produce sufficient response to the peculiarities of PHEV, which use two kinds of energy source, such as petroleum fuel and electrical power and fuel consumption ratio which changes depending on the mileage. New test protocol for PHEV is anticipated. Information of battery durability and reliability are also anticipated. Since electric-motor vehicles (including PHEV) use electrical power to actually drive the vehicle, performance of the battery which stores electrical power has direct affect on emission, fuel consumption performance and electric drive range. In this paper, the measurement methods for fuel consumption for PHEV and the concept of type approval test protocol for PHEV in Japan, which are currently being considered, will be discussed.