Direct electromagnetic clutch

New Honda All-Wheel-Drive System Available this autumn in the Acura RL in North America and in the Legend in Japan.The SH-AWD system is made up of sensors that detect the steering angle, lateral gand other vehicle information, as well as an ECU and a rear differential.

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32 AutoTechnology 4/2004

Honda is developing a new“super handling” all-wheel-drivesystem called SH-AWD. The sys-tem combines front/rear torquedistribution control with inde-pendently regulated torque distri-bution to the left and right rearwheels to freely distribute theoptimum amount of torque to allfour wheels in accordance withdriving conditions.

Front/Rear and lateraltorque distribution

By monitoring driver input anddriving conditions, the SH-AWDsystem determines the optimumfront/rear and lateral (left/right)torque distribution. This informa-tion is then conveyed to the reardifferential, where direct electro-

magnetic clutches continuouslyregulate and vary the front/reartorque distribution between ratiosof 30:70 and 70:30, as well as lat-eral torque distribution in therear wheels between ratios of100:0 and 0:100. Torque is usednot only for propulsion but alsofor cornering, resulting in a sig-nificant enhancement in vehiclemanoeuvrability.

The SH-AWD system is madeup of sensors that detect thesteering angle, lateral g andother vehicle information, aswell as an ECU and a rear differ-ential. The direct electromagnet-ic clutches inside the rear differ-ential employ electromagnets toobtain precise control over themulti-plate clutches. Built-insearch coils monitor the gapsbetween the electromagnets andthe magnetic body to achieveprecise, continuously variabletorque regulation.

Acceleration unit

SH-AWD systemdetermines the

optimum front/rearand lateral

(left/right) torquedistribution

The new SH-AWD system is said to offer a neutral steeringfeel that responds with faithfulness to the driver’s handling ofthe steering wheel.

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33AutoTechnology 4/2004

Acceleration deviceThe rear differential is also equipped with a built-inacceleration device. During cornering, the track ofthe outside rear wheel normally falls outside theaverage of the tracks of the front wheels. The out-side rear wheel does not rotate fast enough to keepup with the front wheels, thus preventing efficienttransmission of torque. To counteract this problem,the SH-AWD acceleration device alters the gearingto speed up the outside rear wheel’s rotation relativeto the front wheels. This reduces torque transmis-sion losses and significantly improves vehiclemanoeuvrability

The new SH-AWD system features “feed-for-ward” control, which utilizes the degree of driverinput to determine appropriate torque distribution.This results in a highly neutral steering feel thatresponds with optimum faithfulness to the driver’shandling of the steering wheel, thus achieving out-standing driving comfort and stability. (rs)

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AWD-Chassis Dynamometerfor climatic tests

Test System

Competency with Tradition and Future

It is the technology you must be able to rely on. For whoever wants to successfully lay the groundwork for customer loyalty must first and foremost think of the quality of his products and services.We at RENK have made quality our mostimportant maxim. We call that competency with tradition andfuture.

By the way: The RDDSXP test rig automation speciallydeveloped by RENK to control highly dynamicprocesses is a universal, modular, real timesystem based on MS Windows XP.

Drive and Motion

Rear differential unit.