The motor generator shown in Fig. 4 is a compact, high speed, high efficiency permanent magnet type synchronous motor with built-in gear reducer. The specifications of the electric motor section are maximum revolutions of 12,700 rpm, rated output of 25.5 kW, and maximum output of 29 kW. And this electric motor system is nearly capable of recovering the kinetic energy of the light duty distribution truck during deceleration in urban driving. Employment of the reduction gear results in a compact size with an outside diameter of the stator of 198 mm and high torque output. The motor generator is water cooled and designed to withstand continuous operation under heavy load. While the reduction gears are oil bath splash lubricated, bearings are semi-forced lubricated from a special oil path in order to establish the durability required of a commercial vehicle.

The high capacity, high output inverter shown in Fig. 5 is possible because of the direct water-cooling of the IGBT (Insulated Gate Bipolar Transistor). The newly developed small driver IC is used for the compact structure and high reliability. For safety, an interlocking cover is used at the terminal section.

This is the first commercial use of the lithium ion battery in hybrid trucks in Japan. The lithium ion battery is compact with a high output and long life suitable for use in hybrid commercial vehicles. Fig. 6 shows the outside view of the battery.

Fig. 7 shows the Hybrid Unit Box. The upper compartment is sealed construction housing the high voltage components of the battery, and the lower compartment houses the cooling system for the motor generator and the inverter. The Hybrid Unit Box has metal construction for electrical safety (detection of electrical leakage), electromagnetic interference, and strength. The sealed construction of the upper compartment is possible because of the lithium ion battery, which has a service life equivalent to that of the vehicle and uses maintenance-free high voltage devices.