| Honda has come up with the most amazing | | | | SH-AWD also does that. |
| 4-wheel-drive system, not for | | | | More power to outer rear wheel for |
| off-roaders but to improve the handling | | | | better cornering |
| and stability of fast cars. It is being | | | | The side-to-side variation in power is |
| used first in the new Acura RL (Honda | | | | used to improve cornering power and |
| Legend). | | | | stability. For example, when you |
| Why is it so advanced? This SH-AWD | | | | accelerate through a corner, extra power |
| system has the potential to increase | | | | through the outer rear wheel counteracts |
| cornering power and cornering safety by | | | | understeer, letting the car corner on |
| leaps and bounds. It will be ideal for | | | | rails. In fact, stability control |
| supercars as well as luxury coupes.(More | | | | systems used on many cars now do this by |
| information about supercars at ) | | | | reducing the amount of torque sent to |
| First, it allows the amount of power | | | | the inner wheel – this means that |
| sent to the wheels to be varied from 30% | | | | you actually corner slower than you |
| front and 70% rear to 70% front and 30% | | | | could do. SH-AWD lets you corner faster. |
| rear. True, some other systems get near | | | | On the over-run, you don't need that, |
| that, but this allows the system to | | | | and less power is sent through the outer |
| adjust itself to completely different | | | | wheel for optimum stability. But that |
| conditions. On top of that, it can alter | | | | isn't enough because when a car corners, |
| the torque from zero to 100% to the left | | | | the outer wheels have to travel further |
| or right rear wheel. | | | | than the inner ones – by 5-10% on |
| In other words, all the power can one to | | | | very tight corners, so the outer wheel |
| the right wheel one minute, and if | | | | normally goes slower. |
| necessary can be reversed so that all | | | | Honda overcomes this with some gears in |
| the power goes to the other wheel in an | | | | the back axle gear set which actually |
| instant. This might be needed in slushy | | | | drive the outer wheel faster when |
| or snowy conditions, where there was a | | | | cornering! This improves maneuverability |
| patch of bare road for a bit on one side | | | | and cornering at low speeds. |
| offering good grip, but a bit later on a | | | | Electro-magnetic multi-plate clutches |
| bare patch on the other side. | | | | All this is accomplished by multi-plate |
| In addition to those features, the outer | | | | clutches operated electro-magnetically |
| rear wheel can be speeded up so that it | | | | – a world first – and the |
| goes faster than the inside wheel! All | | | | gear/clutch set used for acceleration. |
| done continuously depending on | | | | In fact, these gears also serve as the |
| conditions. A few years ago this would | | | | rear differential. |
| have considered desirable, but science | | | | An advantage of the electro-magnetic |
| fiction. | | | | clutches is that the electronic |
| More power to the rear wheel for | | | | controller does not need to control a |
| acceleration | | | | hydraulic actuation system as used |
| Confused? Well, let's start with the | | | | normally but an electric actuator |
| front-to-rear power. When you | | | | – this reduces cost and weight. |
| accelerate, the weight of the car is | | | | Is this the best thing since sliced |
| thrown on to the back wheels by the | | | | bread? For the person who wants to have |
| force of acceleration, so you want more | | | | stability and control, and doesn't want |
| power to go to the back wheels – | | | | to know what is happening to the car |
| if it all goes to the front you get | | | | -yes. Such a system is bound to reduce |
| wheelspin. When cornering, you generally | | | | the input the driver gets from the road. |
| want as much or more power to the rear | | | | He will be less aware of whether the |
| wheels. SH-AWD does that. | | | | surface is slippery, or whether the car |
| On the other hand, when you are cruising | | | | is understeering more than usual because |
| along, you want more power to the front | | | | the SH-AWD system is correcting things |
| wheels as this increases stability. | | | | all the time. |