Nissan Motor Co Ltd disclosed its HEV (Hybrid Electric Vehicle) test vehicle, which is currently under development, at the Advanced Technology Briefing in August 2008.
The test vehicle is based on the "Skyline" and houses a Li-ion secondary battery in the luggage room. The parallel hybrid vehicle incorporates a transmission integrating an electric motor and two clutches. The Skyline was used only for testing purpose, and the vehicle scheduled to be commercialized in 2010 will be based on another model.
Nissan manufactured about 40 test vehicles and has been conducting driving tests on its test courses in Tochigi Prefecture, Japan, and the US. This time, the company brought in two test vehicles for the briefing. The vehicles were left-hand drive, perhaps for driving tests in the US.
The company did not announce the mileage of the test vehicles, but it is about 1.6 times higher compared with existing models of the Skyline, according to Nissan.
The power train of the test vehicle is a combination of a "VQ35" engine, a 3.5L naturally-aspirated V6 engine, and a motor-integrated transmission. The transmission, which is based on a 7-speed automatic transmission, is equipped with a clutch and a motor instead of a torque converter, and has another clutch on the rear end of the transmission mechanism.
With two clutches, the vehicle can run as an EV using only the electric motor (i.e., without the engine). Also, brake energy regeneration is possible.
Furthermore, if the clutch on the rear of the transmission is disengaged, the secondary battery can be charged by using the engine even when the vehicle is not moving. While running on the engine, the engine will be run under the most fuel-efficient condition and the surplus energy will be used to charge the battery during driving.
The motor output was not disclosed, but it is estimated to be about 10-20kW, judging from motors of other manufacturers. Nissan did not unveil the capacity of the Li-ion secondary battery either, but it may be about 1kWh, because the company said its capacity is a little lower than 1.3kWh of Toyota's "Prius."
The battery, manufactured by Automotive Energy Supply Corp (AESC), is a laminated type with a manganese oxide-based cathode.
The EV running distance is "equivalent to that of Prius," according to Nissan. It seems that the battery's SOC (state of charge) for EV running is higher although the capacity is comparatively low. The SOC is between 30 to 70%, approximately 40%, the company said. Though the EV running distance will vary depending on the SOC and the frequency of acceleration and braking, it is reportedly 2-3km for Prius.
The energy density of the battery was not disclosed, but the output density was announced to be 2500W/kg, which is twice that of the "Tino Hybrid" released in April 2000.
The battery pack mounted inside the luggage room is integrated with a DC-DC converter, a battery control module and a junction box. The precise dimensions of the battery pack could not be confirmed, because it was housed inside a metal case.
However, Nissan explained the size is "about 2/3, a little bigger than half" compared with a Ni-hydrogen battery. Apparently, it was smaller in width compared with battery packs used in various models of Toyota.