Honda Develops World's First Super Handling All-Wheel Drive
Published: 3rd April 2004
Torque Distribution Regulation
- Acceleration during cornering
- Torque to the rear wheels is continuously varied to supply up to 100% to the outside wheel and 0% to the inside wheel. This creates an inward yaw moment, significantly improving vehicle handling.
- *Yaw moment is turning torque relative to the vertical axis running through the vehicle’s centre of gravity.
Deceleration during cornering (throttle closed)
- Torque to the outside rear wheel is freely varied to change from an inward to an outward yaw moment, ensuring vehicle stability at all times.
Straight-line driving
- Front-rear torque distribution is regulated for optimum performance in accordance with the amount of torque produced. During rapid acceleration the load on the front wheels is reduced; conversely, rear-wheel load is reduced during cruising. The result is stable driving at all times.
System Configuration
- World's first direct electromagnetic clutch
- An electromagnetic coil (electromagnet) attracts a magnetic body which, in turn, presses on the multi-plate clutch to facilitate torque transmission.
- A compact clutch unit, equipped with a planetary gear step-up mechanism to increase torque, permits transmission of substantial amounts of torque. A built-in search coil monitors the gap between the electromagnetic coil and the magnetic body. Current flow in the electromagnetic clutch is then adjusted to achieve highly precise torque regulation.
Acceleration device
- During straight-ahead driving, the twin-pinion planetary carrier spins in synchronisation with the propeller shaft, causing the front and rear wheels to turn at the same speed. When the vehicle enters a curve, however, the planetary carrier is locked to the case, releasing the device from synchronisation with the propeller shaft and accelerating the rotation speed of the rear wheels. A hydraulic actuator which turns the clutches on and off, and a one-way clutch are included in this compact configuration.
Sensors - ECU
- The input of steering angle, lateral g, yaw rate, wheel speed and other sensors monitor driver input, vehicle demeanour, and driving conditions such that the SH-AWD ECU can calculate ideal torque distribution.
