Super-Handling AWD System (BIG pics)

[jinny]

from: http://world.honda.com/news/2004/4040401.html


Automobile April 1 , 2004

Honda Develops World’s First Super Handling All-Wheel-Drive
Available this fall in the Acura RL (North America) and the Legend (Japan)

TOKYO - April 1, 2004 --- Honda Motor Co., Ltd. today announced the development of a new Super Handling All-Wheel-Drive system, called SH-AWD, that provides cornering performance that responds faithfully to driver input, and outstanding vehicle stability. A world’s first, the SH-AWD system combines front-rear torque distribution control with independently regulated torque distribution to the left and right rear wheels to freely distribute the optimum amount of torque to all four wheels in accordance with driving conditions. The new system will be available this fall in the Acura RL (North America) and the Legend (Japan).

By monitoring driver input and driving conditions, the SH-AWD system determines the optimum front-rear and lateral (left-right) torque distribution. This information is then conveyed to the rear differential, where direct electromagnetic clutches continuously regulate and vary front-rear torque distribution between ratios of 30:70 and 70:30, and lateral torque distribution in the rear wheels between ratios of 100:0 and 0:100. Torque is used not only for propulsion, but for cornering as well, resulting in a significant enhancement in vehicle maneuverability.

The SH-AWD system is composed of sensors to detect steering angle, lateral g, and other vehicle information; an ECU; and the rear differential. The direct electromagnetic clutches inside the rear differential, another world’s first, employ electromagnets to obtain precise control over the multi-plate clutches. Built-in search coils monitor the gaps between the electromagnets and the magnetic body to achieve precise, continuously variable torque regulation.

The rear differential is also equipped with a built-in acceleration device, yet another world’s first. During cornering, the track of the outside rear wheel normally falls outside the average of the tracks of the front wheels. The outside rear wheel does not rotate fast enough to keep up with the front wheels, preventing efficient transmission of torque. To counteract this problem, the SH-AWD acceleration device alters the gearing to speed up the outside rear wheel’s rotation relative to the front wheels. This reduces torque transmission losses and significantly improves vehicle maneuverability.

At Honda, driving pleasure is regarded as one of the most important factors in vehicle development. The new SH-AWD system features “feed-forward” control, which utilizes the degree of driver input to determine appropriate torque distribution. This results in a super-neutral steering feel that responds with optimal faithfulness to the driver’s handling of the steering wheel, realizing outstanding driving comfort and stability.




SH-AWD system (rear differential cutaway model)


*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 center 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 synchronization 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 synchronization 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 demeanor, and driving conditions such that the SH-AWD ECU can calculate ideal torque distribution.

System Overview




Operational Flow




Rear Differential Unit

click here for a link to a video about SH-AWD...





click any of the pics below for larger image

[enigma]

I likeeeeeee. just hope they will make RWD RL someday.

[jinny]

Originally posted by enigma
I likeeeeeee. just hope they will make RWD RL someday.

Why would they need RWD if they got an AWD already?

[enigma]

Originally posted by jinny
Why would they need RWD if they got an AWD already?

true.

[jinny]

more of same info from www.acuranews.com

Acura To Debut Super-Handling AWD System at New York International Auto Sho
System is First To Distribute Torque Front to Rear and Between Left and Right Rear Wheels

Torrance, Calif. 04/01/2004 -- The Acura RL Prototype, which will make its world debut at the New York International Auto Show, features a revolutionary new all-wheel-drive system called SH-AWD(TM). The SH-AWD system is the first and only all-wheel-drive platform that distributes the optimum amount of torque not only between the front and rear wheels but also between the left and right rear wheels. The result is precise cornering performance that reduces torque steer and provides outstanding vehicle stability.

By monitoring driver input and driving conditions, the SH-AWD system determines the optimum front-rear and lateral (left-right) torque distribution. This information is then conveyed to the rear differential, where direct electromagnetic clutches continuously vary the torque by up to 70 percent in either direction - front or rear. Rear torque can also be proportioned between the left and right rear tires by up to 100 percent on either side.

The SH-AWD system is composed of an ECU, sensors that detect steering angle, lateral g-force, and other vehicle information, and a rear differential. The direct electromagnetic clutches inside the rear differential, another industry first, employ electromagnets to maintain precise control over the multi-plate clutches.

The SH-AWD system uses torque not only for propulsion, but also to increase cornering precision and dramatically enhance vehicle maneuverability. During cornering, the track of the outside rear wheel normally falls outside the track of the front wheels. Because of this, the outside rear wheel does not rotate fast enough to keep up with the front wheels, preventing efficient transmission of torque. To counteract this condition, the SH-AWD system's rear differential is equipped with a built-in acceleration device that can overdrive the outside rear wheel. This acceleration device, which is another industry first, uses a planetary gear to speed up the outside rear wheel's rotation relative to the front wheels. The result is a significant enhancement in vehicle maneuverability during cornering.

SH-AWD system torque regulation

• Acceleration while cornering: Torque to the rear wheels is continuously varied to supply up to 100 percent to the outside wheel. This creates an inward yaw moment, significantly improving vehicle handling precision.
• Deceleration (throttle closed) while cornering - Torque to the outside rear wheel is varied to change from an inward to an outward yaw moment, helping vehicle stability at all times.
• Straight-line driving - Front-rear torque distribution is modulated for optimum performance. During rapid acceleration, torque is redistributed from the front wheels to the rear wheels. Conversely, during cruising, torque is concentrated in the front wheels. The result is additional driving stability.

[Therm]

nevermind

[jinny]

a video in english about SH-awd...

http://world.honda.com/HDTV/news/2004-4040401a/