A side view. The fuel tank and the engine for power generation are located under the seats. Battery cells are arranged under the floor.
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An in-wheel motor is attached to each of the right and left rear wheels.
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Continued from Yamaha Motor Shows Off 4-wheeled Series HEV (1)

Because the concept car is expected to be a series HEV, it stores electricity generated by an engine in a battery and runs on a motor. As an engine, Yamaha Motor plans to use a single-cylinder engine designed for two-wheeled vehicles, but the company said, "We are still considering engine performance and so forth."

Yamaha Motor will probably use a new engine developed only for the MWC-4 because it eliminates the need to consider the compatibility with the transmission. The engine is transversely placed due to the limited installation space. The piston moves in the width direction of the vehicle.

The engine is placed under the seats. A fuel tank for the engine and the engine for power generation are located in the front and rear areas, respectively, under the seats. For power generation, it is necessary to rotate the engine at a constant rotation speed. Therefore, a vibration absorbing material is used to reduce the vibration transmitted to the seats.

The battery is located under the floor. When the engine and the fuel tank are detached, the MWC-4 can be used as an electric vehicle (EV).

"In consideration of practical drive range, a series HEV is desirable at this point," Yamaha Motor said. "We will consider making it an EV when battery technologies advance."

While Yamaha Motor is considering developing the MWC-4 as an EV, it is easier for the company, which has a strength in engine technologies for two- and four-wheeled vehicles, to develop a series HEV.

The MWC-4 is a rear-wheel-drive car that uses a water-cooled in-wheel motor (IWM) attached to each of the right and left rear wheels. It does not need differential gears, enabling to reduce weight. By controlling the torque applied to the right and left wheels, it becomes easier to realize swift driving through torque vectoring, etc.

The series HEV is equipped with a linear steering that is similar to the steering of a two-wheeled vehicle, and the steering is used to control the front wheels. As in the case of two-wheeled vehicles, the body of the MWC-4 is tilted by weight shift.

The vehicle measures 2,680 (L) x 900 (W) x 1,480mm (H). Though it has two seats, the rear seat is supplementary, Yamaha Motor said.

Original Japanese article