US 6,587,775 B2Granted

Driving force control system for four-wheel drive vehicles

AssigneeHonda Giken Kogyo Kabushiki Kaisha

InventorsKenzo Nishida, Norihisa Nihanda

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Abstract

A driving force control system for a four-wheel drive vehicle, which is capable of preventing occurrence of a tight-turn braking phenomenon by relatively simple construction to thereby reduce the manufacturing cost thereof, and at the same time, enhancing the response of slippage-eliminating control on main drive wheels, and stability of the vehicle. The 2/WD·ECU of the driving force control system controls electromagnetic clutches of a four-wheel drive vehicle having front wheels as main drive wheels and rear wheels as auxiliary drive wheels, whereby the LSD torque to be distributed to the rear wheels is controlled. More specifically, the front-wheel/rear-wheel slip ratio is determined from the average front wheel speed and the average rear wheel speed, and the left/right rear-wheel speed ratio and the front-wheel/rear-wheel slip ratio threshold are determined according to the rear wheel speeds, and a first LSD torque for use in calculation of the LSD torque is determined based on the difference between the front-wheel/rear-wheel slip ratio and the front-wheel/rear-wheel slip ratio threshold.

Claims8

Dependent claims

A driving force control system for a four-wheel drive vehicle including a pair of front wheels, a pair of rear wheels, an engine, a transmission for connecting one of said pair of front wheels and said pair of rear wheels to said engine, as main drive wheels, and left and right clutches for connecting another of said pair of front wheels and said pair of rear wheels to said main drive wheels, as left and right auxiliary drive wheels, respectively, the driving force control system controlling the engagement force of each of said left and right clutches to thereby control distribution of a driving force of said main drive wheels to said auxiliary left and right wheels,

the driving force control system comprising:
wheel speed detection means for detecting wheel speeds indicative of respective rotational speeds of said front and rear wheels;
average wheel speed calculation means for calculating an average wheel speed of said main drive wheels and an average wheel speed of said auxiliary drive wheels, based on the detected wheel speeds;
first index calculation means for determining a first index representative of a relative relationship in magnitude between said average wheel speed of said main drive wheels and said average wheel speed of said auxiliary drive wheels;
second index calculation means for calculating a second index representative of a relative relationship in magnitude between said wheel speeds of said left and right auxiliary wheels;
and
clutch engagement force determination means for determining respective engagement forces of said left and right clutches, in dependence on a relative relationship in magnitude between said first index and said second index.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/824,802Filed 4 Apr 2001
Priority: JP 2000-1054656 Apr 2000
Published: US 2002/0002436 A13 Jan 2002
Granted: 1 Jul 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

B60K 17/35
Having differential means for driving one set of wheels, e.g. the front, at one speed and the other set, e.g. the rear, at a different speed:…
B60K 23/0808
For changing number of driven wheels , for switching from driving one axle to driving two or more axles: for varying torque distribution between…
B60W 30/18145
Related to particular drive situations: cornering
B60K 17/20
Of differential gearing: in which the differential movement is limited