The most common automotive drivelines transmit the engine torque to the driven axle through the differential. Semi-active versions of such device ([10], [11], [12]) have been recently conceived to improve vehicle handling at limit and in particular maneuvers. All these differentials are based on the same structural hypothesis of the passive one but they try to manipulate the vehicle dynamics controlling a quantity which was fixed in the passive mechanisms. In this way it’s possible to control the amount of the stabilizing torque but it’s not possible to apply it in both directions. This fact is a great draw drawback of the semi-active differential because a complete yaw control can’t be developed. On the other hand, active differentials [17] can both apply the best yaw moment (in terms of amplitude) and do this with the right sign. Although classic active differentials are greatly versatile, they can’t (or hardly can) reproduce an extreme torque distribution as 0–100% when there is not a μ-split condition. That is because there is always a bias value due to the presence of a gear that has to be decreased by active clutch action. And these clutches are often not able to do that. The most innovative device presented in the last years is the Super Handling-All Wheel Drive (SH-AWD) by Honda ([2], [3], [4], [5]). It can freely distribute the drive torque to the desired wheel, maintaining one of them in free rolling condition, if this is necessary. This flexibility in the lateral torque distribution can hugely increase the vehicle manoeuvrability. Author has carried out a feasibility study to evaluate the handling improvement due to such a device on a high performance rear wheel drive vehicle normally equipped with a semi-active differential.

This content is only available via PDF.
You do not currently have access to this content.