Patent US4987967A successfully refreshed from Google Patents.
US4987967A
Expired / Lapsed
US
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Method of controlling a four wheel drive vehicle
Assignee: Toyota Motor Corp
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Filing: 1989-09-19
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Granted: 1991-01-29
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Expires: 2009-09-19
Abstract
Abstract A controlling method of a four wheel drive vehicle includes a detecting step and a controlling step. The detecting step detects difference in speeds between a front driving shaft and a rear driving shaft. The controlling step controls an apparatus for controlling a distribution ratio of driving torque of the four wheel drive vehicle so as to harmonize the difference in the speeds with a desired value.
Inventors
- 👤 Katsumi Kouno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:14
CPC Classifications
B; B60; B60K; B60K23/00; B60K23/08; B60K23/0808; B60K17/00; B60K17/34; B60K17/348
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
259 words
A method for controlling the drive train of a four wheel drive vehicle having an engine and front drive wheels and rear drive wheels, the four wheel drive vehicle including an apparatus for changing a distribution ratio of driving torque between the front wheels and the rear wheels, the apparatus including a transfer mechanism, and a first and a second clutch, the transfer mechanism receiving an output torque from said engine, and distributing the received output torque into two output torque lines connected to said front drive wheels and said rear drive wheels, respectively, the first clutch being located in one of said two output torque lines and transmitting a first amount of the output torque to a front driving shaft connected to said front drive wheels, while the second clutch being located in the other of said two output torque lines and transmitting a second amount of the output torque to a rear driving shaft connected to said rear drive wheels, said method comprising the steps of: detecting speeds of the front driving shaft and the rear driving shaft; calculating an actual difference in speed between the detected speeds of said front and rear driving shafts; and determining said first and second amounts of the output torque transmitted by said first and second clutches to said front and rear driving shafts, respectively, to change an actual distribution ratio of driving torques between said front and rear drive wheels, so that the calculated difference in speed between said front and rear driving shafts is reduced to a desired value.
Claim 2
Independent Claim
259 words
A method for controlling the drive train of a four wheel drive vehicle having an engine and front drive wheels and rear drive wheels, the four wheel drive vehicle including an apparatus for changing a distribution ratio of driving torque between the front wheels and the rear wheels, the apparatus including a transfer mechanism, and a first and a second clutch, the transfer mechanism receiving an output torque from said engine, and distributing the received output torque into two output torque lines connected to said front drive wheels and said rear drive wheels, respectively, the first clutch being located in one of said two output torque lines and transmitting a first amount of the output torque to a front driving shaft connected to said front drive wheels, while the second clutch being located in the other of said two output torque lines and transmitting a second amount of the output torque to a rear driving shaft connected to said rear drive wheels, said method comprising the steps of: detecting speeds of the front driving shaft and the rear driving shaft; calculating an actual difference in speed between the detected speeds of said front and rear driving shafts; and determining said first and second amounts of the output torque transmitted by said first and second clutches to said front and rear driving shafts, respectively, to change an actual distribution ratio of driving torques between said front and rear drive wheels, so that the calculated difference in speed between said front and rear driving shafts is reduced to a desired value.
Claim 3
Dependent Claim
11 words
The method of claim 1, wherein the desired value is zero.
Claim 4
Dependent Claim
71 words
A method according to claim 1, wherein said step of determining said first and second amounts of the output torque of said first and second clutches comprises increasing one of said first and second amounts which is transmitted to one of said front and rear driving shafts whose speed is lower that the other of said front and rear driving shafts, while decreasing the other of said first and second amounts.
Claim 5
Dependent Claim
106 words
A method according to claim 3, wherein said first and second clutches are hydraulically operated clutches which are operated by first and second hydraulic pressures applied thereto respectively, and wherein said step of determining said first and second amounts of the output torque comprises increasing one of said first and second hydraulic pressures which is applied to one of said first and second clutches which is located in one of said two output torque lines which is connected to said one driving shafts, while decreasing the other of said first and second hydraulic pressures which is applied to the other of said first and second clutches.
Claim 6
Dependent Claim
112 words
A method according to claim 4, wherein said step of determining said first and second amount of the output torque further comprises: comparing current values of said first and second hydraulic pressure with each other; determining a control value for a higher one of the compared values of said first and second hydraulic pressures depending upon an output torque of said transfer mechanism; and determining a control value for the other of said first and second hydraulic pressures depending upon the determined one of said first and second hydraulic pressures and said difference in speed between said front and rear driving shafts so that said difference is reduced to said desired value.
References Cited (Backward Citations)
US4546673A
Cited
JPS59151661A
Cited
US4605084A
Cited
US4551119A
Cited
US4619629A
Cited
GB2159110A
Cited
US4701853A
Cited
US4754835A
Cited
JPS61295133A
Cited
US4723624A
Cited
US4709775A
Cited
US4773500A
Cited
JPS62279127A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |