[subbieatnz]

Thanks to Paddlesnz for the translation work!


Translation of Main Body of Text

Currently, the only vehicle in the Subaru range employing 4WS, is the top model of the advanced 4WD SVX sports car.

The 4WS mechanism is operated as a result of data from a steering angle input sensor and a steering wheel input speed sensor. This data is relayed to an ECU at the rear, and at middle to high speeds, the ECU signals a small motor to turn the rear wheels in the same direction as the front wheels, up to a maximum of 15 degrees. With a vehicle speed sensor, steering input sensors and rear wheel angle/speed sensors, this system allows for a perfect rear steering angle, no matter what the speed or driving conditions.

And the adoption of a quicker steering ratio ensures compatibility between high-speed driving and sharp handling through corners.

Other 4WS systems, in order to reduce a vehicle's turning area, steer the rear wheels in the opposite direction to those of the front at low speeds but Subaru's system does not do this.

The latest 4WS systems have stopped using hydraulics and instead employ an electric motor to turn the rear wheels and this is what Subaru has adopted. The SVX's system is not a hydraulic but an all-electric one, which compared to a hydraulic system, allows not only more linear control but also better stability and control. Also, hydraulic systems often put more strain on a vehicles's power steering but Subaru's system does not have this problem, resulting in no increase in engine load and this no effect on fuel economy.

In abnormal situations, the Subaru's system cuts power to the rear electric motor, however the worm gear set up does not allow the rear wheels to return to a normal straight ahead position. The vehicle can be safely brought to a stop though.

The system also uses a 'self-check' diagnostic system. If a problem is detected, the ECU goes into a 'fail-safe' mode, a dashboard warning light is activated and the problem is stored in the ECU's memory where it can be recalled later by a mechanic.

This 4WS system is perfectly suited for this type of long cruising/high speed driving GT vehicle.
Thanks to Paddlesnz for the translation work!

Updated: 29 May 2001
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