US4982809A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for controlling 4-wheel drive system for a motor vehicle
Assignee: Aisin AW Co Ltd
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Filing: 1988-09-22
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Granted: 1991-01-08
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Expires: 2008-09-22
Abstract
Abstract A method and an apparatus for controlling a 4-wheel drive system of a motor vehicle having front wheels and rear wheels and a power transmission. The 4-wheel drive system includes a differential control clutch having input and output elements which are rotatable relative to each other with a controlled amount of engagement therebetween, so as to control a ratio of distribution of a torque from the power transmission to front and rear wheels. When it is determined that the power transmission is commanded to be shifted from a first gear position to a second gear position whose speed ratio is different from that of the first gear position, the differential control clutch is temporarily placed in a fully disengaged position thereof for a predetermined time duration. With the clutch placed in the fully disengaged position upon each shifting operation of the transmission to the second gear position, the separated friction surfaces of the clutch may be lubricated to maintain high durability of the clutch.
Inventors
- 👤 Yasunari Nakamura
- 👤 Kojiro Kuramochi
- 👤 Teruo Akashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:41
CPC Classifications
B; B60; B60K; B60K23/00; B60K23/08; B60K23/0808
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
151 words
A method of controlling a 4-wheel drive system of a motor vehicle having a pair of front wheels and a pair of rear wheels and a power transmission, the 4-wheel drive system including clutch means having input and output elements which are rotatable relative to each other with a controlled amount of engagement therebetween, so as to control a ratio of distribution of a torque from the power transmission to front and rear wheels, said method comprising the steps of: determining whether said power transmission is commanded to be shifted from a first gear position to a second gear position whose speed ratio is different from that of said first gear position; and if said power transmission is commanded to be shifted to said second gear position, temporarily placing said clutch means in a fully disengaged position thereof for a predetermined time duration to thereby improve durability of said clutch means.
Claim 2
Independent Claim
151 words
A method of controlling a 4-wheel drive system of a motor vehicle having a pair of front wheels and a pair of rear wheels and a power transmission, the 4-wheel drive system including clutch means having input and output elements which are rotatable relative to each other with a controlled amount of engagement therebetween, so as to control a ratio of distribution of a torque from the power transmission to front and rear wheels, said method comprising the steps of: determining whether said power transmission is commanded to be shifted from a first gear position to a second gear position whose speed ratio is different from that of said first gear position; and if said power transmission is commanded to be shifted to said second gear position, temporarily placing said clutch means in a fully disengaged position thereof for a predetermined time duration to thereby improve durability of said clutch means.
Claim 3
Dependent Claim
25 words
A method according to claim 1, wherein said second gear position has a speed ratio which is lower than that of said first gear position.
Claim 4
Dependent Claim
35 words
A method according to claim 1, wherein said clutch means is temporarily placed in said fully disengaged position immediately after a shifting action of said power transmission to establish said second gear position is completed.
Claim 5
Dependent Claim
92 words
A method according to claim 1, wherein said step of determining whether said power transmission is commanded to be shifted to said second gear position comprises determining whether there is generated a shift command to shift said power transmission to said second gear position, said method further comprising a step of measuring a predetermined time period after the generation of said shift command, said step of temporarily placing said clutch means in said fully disengaged position being initiated when said predetermined time period has elapsed after the generation of said shift command.
Claim 6
Dependent Claim
35 words
A method according to claim 2, wherein said power transmission has a plurality of forward-drive gear positions, and said second gear position is one of said forward-drive gear positions whose speed ratio is the lowest.
Claim 7
Dependent Claim
82 words
A method according to claim 1, further comprising the steps of: determining whether there is generated a shift command to shift said power transmission from said second gear position while said clutch means is placed in said fully disengaged position; and upon determination that said shift command is generated, immediately restoring said clutch means to an operable position thereof in which the amount of engagement between said input and output elements is controllable to control said ratio of distribution of said torque.
Claim 8
Dependent Claim
53 words
A method according to claim 1, further comprising a step of determining whether a running condition of said vehicle is stabilized after said power transmission is shifted to said second gear position, said clutch means is brought to said fully disengaged position upon determination that said running condition of the vehicle is stabilized.
Claim 9
Dependent Claim
62 words
A method according to claim 7, wherein said step of determining whether a running condition of said vehicle is stabilized comprises detecting a running speed of the vehicle and an amount of operation of an accelerator pedal of the vehicle, and effecting the determination on said running condition, based on the detected running speed and amount of operation of the accelerator pedal.
Claim 10
Dependent Claim
56 words
A method according to claim 7, wherein said step of determining whether a running condition of said vehicle is stabilized comprises detecting an amount of operation of an accelerator pedal of the vehicle, and effecting the determination on said running condition, based on said second gear position and the detected operating amount of the accelerator pedal.
Claim 11
Dependent Claim
79 words
A method according to claim 7, wherein said step of determining whether a running condition of said vehicle is stabilized comprises detecting an amount of change in a running speed of the vehicle and an amount of change in an operating amount of an accelerator pedal of the vehicle, and effecting the determination on said running condition, based on the detected amounts of change in said running speed of the vehicle and said operating amount of said accelerator pedal.
Claim 12
Independent Claim
159 words
An apparatus for controlling a 4-wheel drive system of a motor vehicle having a pair of front wheels and a pair of rear wheels and a power transmission, the 4-wheel drive system including clutch means having input and output elements which are rotatable relative to each other with a controlled amount of engagement therebetween, so as to control a ratio of distribution of a torque from the power transmission to front and rear wheels, said apparatus comprising: determining means for determining whether said power transmission is commanded to be shifted from a first gear position to a second gear position whose speed ratio is different from that of said first gear position; and releasing means for temporarily placing said clutch means in a fully disengaged position thereof for a predetermined time duration, if said determining means determines that said power transmission is commanded to be shifted to said second gear position to thereby improve durability of said clutch means.
Claim 13
Independent Claim
159 words
An apparatus for controlling a 4-wheel drive system of a motor vehicle having a pair of front wheels and a pair of rear wheels and a power transmission, the 4-wheel drive system including clutch means having input and output elements which are rotatable relative to each other with a controlled amount of engagement therebetween, so as to control a ratio of distribution of a torque from the power transmission to front and rear wheels, said apparatus comprising: determining means for determining whether said power transmission is commanded to be shifted from a first gear position to a second gear position whose speed ratio is different from that of said first gear position; and releasing means for temporarily placing said clutch means in a fully disengaged position thereof for a predetermined time duration, if said determining means determines that said power transmission is commanded to be shifted to said second gear position to thereby improve durability of said clutch means.
Claim 14
Dependent Claim
25 words
An apparatus according to claim 11, wherein said second gear position has a speed ratio which is lower than that of said first gear position.
Claim 15
Dependent Claim
93 words
An apparatus according to claim 11, wherein said determining means further determines whether there is generated a shift command to shift said power transmission from said second gear position after said power transmission is commanded to be shifted to said second gear position, and restoring means operable upon determination by said determining means that said shift command is generated, for immediately restoring said clutch means to an operable position thereof in which the amount of engagement between said input and output elements is controllable to control said ratio of distribution of said torque.
Claim 16
Dependent Claim
58 words
An apparatus according to claim 11, wherein said determining means further determines whether a running condition of said vehicle is stabilized after said power transmission is shifted to said second gear position, said releasing means bringing said clutch means to said fully disengaged position, when said determining means determines that the running condition of the vehicle is stabilized.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |