US 8,948,991 B2 · Left-right wheel drive force distribution control apparatus for a vehicle

Abstract

Upon determining than an over-steered state exits, a feedback control coefficient for a rear wheel total drive force is set to 0 and a feedback control coefficient for a rear wheel drive force difference is also set to 0 to impose a two-wheel drive state. As a result, it is possible to avoid a turn cruising instability caused by cruising in four-wheel drive in an over-steered state. Upon determining that an under-steered state exists, the feedback control coefficients are set such that four-wheel drive is allowed but a drive force difference is not set between the left and right rear wheels. As a result, when the under-steered state exists, excellent traction can be enjoyed by operating in four-wheel drive and the phenomenon of riding up a canted road surface due to a drive force difference set between the left and right rear wheels can be avoided.

Claims4

Dependent claims

A four-wheel drive vehicle drive force distribution control apparatus comprising:

a controller programmed to execute a distributed output of a total drive force to main drive wheels and subordinate drive wheels of a vehicle with a portion of a main wheel drive force for the main drive wheels being redirected to the subordinate drive wheels between a left subordinate drive wheel and a right subordinate drive wheel in accordance with a drive force distribution control, the controller including
an under-steering determining section that determines whether the vehicle is in an under-steered state in which an actual turning behavior is insufficient to meet a target turning behavior computed based on a vehicle operating state;
and
an under-steering left-right wheel drive force difference control section that sets a drive force difference between the left and right subordinate drive wheels to 0 upon the under-steering determining section determining that the under-steered state exists.

1 more element

A four-wheel drive vehicle drive force distribution control apparatus comprising:

a controller programmed to execute a distributed output of a total drive force to main drive wheels and subordinate drive wheels of a vehicle with a portion of a main wheel drive force for the main drive wheels being redirected to the subordinate drive wheels between a left subordinate drive wheel and a right subordinate drive wheel in accordance with a drive force distribution control, the controller including
an over-steering determining section that determines whether the vehicle is in an over-steered state in which an actual turning behavior is excessive with respect to a target turning behavior computed based on a vehicle operating state;
and
an over-steering left-right wheel drive force difference control section that sets a drive force difference between the left and right subordinate drive wheels to 0 upon the over-steering determining section determining that the over-steered state exists;
an under-steering determining section that determines whether the vehicle is in an under-steered state in which an actual turning behavior is insufficient to meet a target turning behavior computed based on a vehicle operating state;
and
an under-steering left-right wheel drive force difference control section that sets a drive force difference between the left and right subordinate drive wheels to 0 upon the under-steering determining section determining that the under-steered state exists.

4 more elements

Dependencies are inferred from the claim text.

Left-right wheel drive force distribution control apparatus for a vehicle

Life of this patent

Left-right wheel drive force distribution control apparatus for a vehicle

Life of this patent

Abstract

Claims4