Patent US4751856A successfully refreshed from Google Patents.
US4751856A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for controlling 4wd vehicle central differential restriction device according to vehicle road speed and engine load, and method of operation thereof
Assignee: Toyota Motor Corp
•
Filing: 1987-05-18
•
Granted: 1988-06-21
•
Expires: 2007-05-18
Abstract
Abstract In a four wheel drive vehicle, a central differential device receives rotational power from an engine and provides it to the combination of the front wheels of the vehicle and also to the combination of the rear wheels of the vehicle. This central differential device includes a device for selectively restricting its operation. A control device is provided for this central differential device operation restriction device, and includes: (a) a means for detecting a condition representative of the road speed of the vehicle and of the load on the engine; and (b) a means for controlling the device for selectively restricting the operation of the central differential device, so that the operation of the central differential device is less restricted than otherwise, when the vehicle speed is relatively high and also the engine output is not relatively high. Various specializations of this control device, and also the method of operation thereof, are also disclosed.
Inventors
- 👤 Yasunari Nakamura
- 👤 Mitsuru Takada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 04:57
CPC Classifications
B; B60; B60K; B60K23/00; B60K23/08; B60K23/0808; B60K17/00; B60K17/34; B60K17/344; B60K17/346; B60K17/3462; Y; Y10; Y10S; Y10S477/00; Y10S477/908
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
147 words
For a four wheel drive vehicle with two front wheels, two rear wheels, an engine, and a central differential device, rotational power from said engine being provided via said central differential device to the combination of the front wheels of said vehicle and also to the combination of the rear wheels of said vehicle, and further comprising a device for selectively restricting the operation of said central differential device: a central differential operation restriction device control device, comprising: (a) a means for detecting a condition representative of the road speed of said vehicle and of the load on said engine; and: (b) a means for controlling said device for selectively restricting the operation of said central differential device, so that: said operation of said central differential device is less restricted than otherwise, when said vehicle speed is relatively high and said engine output is not relatively high.
Claim 2
Dependent Claim
147 words
For a four wheel drive vehicle with two front wheels, two rear wheels, an engine, and a central differential device, rotational power from said engine being provided via said central differential device to the combination of the front wheels of said vehicle and also to the combination of the rear wheels of said vehicle, and further comprising a device for selectively restricting the operation of said central differential device: a central differential operation restriction device control device, comprising: (a) a means for detecting a condition representative of the road speed of said vehicle and of the load on said engine; and: (b) a means for controlling said device for selectively restricting the operation of said central differential device, so that: said operation of said central differential device is less restricted than otherwise, when said vehicle speed is relatively high and said engine output is not relatively high.
Claim 3
Dependent Claim
66 words
A central differential operation restriction device control device according to claim 1, said vehicle further comprising a gear transmission mechanism provided in the rotational power transmission path between said engine and said central differential device, wherein said condition representative of the road speed of said vehicle and of the load on said engine is the engagement of the highest speed stage of said gear transmission mechanism.
Claim 4
Dependent Claim
60 words
A central differential operation restriction device control device according to claim 2, wherein said means for controlling said device for selectively restricting the operation of said central differential device does so in such a manner than said operation of said central differential device is less restricted than otherwise, when said highest speed stage of said gear transmission mechanism is engaged.
Claim 5
Dependent Claim
60 words
A central differential operation restriction device control device according to claim 2, wherein the timing of switching over of control of said device for selectively restricting the operation of said central differential device is coordinated with the timing of shifting of engagement of said gear transmission mechanism so as to at least partially overlap the individual torque shocks caused thereby.
Claim 6
Dependent Claim
100 words
A central differential operation restriction device control device according to claim 1, said vehicle further comprising a gear transmission mechanism provided in the rotational power transmission path between said engine and said central differential device, and a torque converter comprising a lock up clutch and provided in the rotational power transmission path between said engine and said gear transmission mechanism, wherein said condition representative of the road speed of said vehicle and of the load on said engine is the engagement of the highest speed stage of said gear transmission mechanism and the simultaneous engagement of said lock up clutch.
Claim 7
Dependent Claim
68 words
A central differential operation restriction device control device according to claim 5, wherein said means for controlling said device for selectively restricting the operation of said central differential device does so in such a manner that said operation of said central differential device is less restricted than otherwise, when said highest speed stage of said gear transmission mechanism is engaged and also said lock up clutch is engaged.
Claim 8
Dependent Claim
49 words
A central differential operation restriction device control device according to claim 1, wherein said condition representative of the road speed of said vehicle and of the load on said engine is the combination of the actual road speed of said vehicle and of the actual load on said engine.
Claim 9
Dependent Claim
56 words
A central differential operation restriction device control device according to claim 7, wherein said means for controlling said device for selectively restricting the operation of said central differential device does so in such a manner that said operation of said central differential device is more restricted, when said actual load on said engine is the larger.
Claim 10
Dependent Claim
70 words
A central differential operation restriction device control device according to claim 7, wherein said means for controlling said device for selectively restricting the operation of said central differential device does so in such a manner that, when said actual load on said engine is at least a determinate engine load value, said operation of said central differential device is selectively restricted, according to the actual road speed of said vehicle.
Claim 11
Dependent Claim
70 words
A central differential operation restriction device control device according to claim 9, wherein said means for controlling said device for selectively restricting the operation of said central differential device does so in such a manner that, when said actual load on said engine is at least determinate engine load value, said operation of said central differential device is more restricted, when said actual road speed of said vehicle is lower.
Claim 12
Dependent Claim
77 words
A central differential operation restriction device control device according to claim 10, wherein said means for controlling said device for selectively restricting the operation of said central differential device does so in such a manner that, when said actual load on said engine is at least said determinate engine load value, said operation of said central differential device is restricted, when said actual road speed of said vehicle is lower than a determinate vehicle road speed value.
Claim 13
Dependent Claim
144 words
For a four wheel drive vehicle with two front wheels, two rear wheels, an engine, and a central differential device, rotational power from said engine being provided via said central differential device to the combination of the front wheels of said vehicle and also to the combination of the rear wheels of said vehicle, and further comprising a device for selectively restricting the operation of said central differential device: a central differential operation restriction device control method, wherein: (a) a condition representative of the road speed of said vehicle and of the load on said engine is detected; and: (b) said device for selectively restricting the operation of said central differential device is controlled, so that: said operation of said central differential device is less restricted than otherwise, when said vehicle speed is relatively high and also said engine output is not relatively high.
Claim 14
Dependent Claim
144 words
For a four wheel drive vehicle with two front wheels, two rear wheels, an engine, and a central differential device, rotational power from said engine being provided via said central differential device to the combination of the front wheels of said vehicle and also to the combination of the rear wheels of said vehicle, and further comprising a device for selectively restricting the operation of said central differential device: a central differential operation restriction device control method, wherein: (a) a condition representative of the road speed of said vehicle and of the load on said engine is detected; and: (b) said device for selectively restricting the operation of said central differential device is controlled, so that: said operation of said central differential device is less restricted than otherwise, when said vehicle speed is relatively high and also said engine output is not relatively high.
Claim 15
Dependent Claim
66 words
A central differential operation restriction device control method according to claim 12, said vehicle further comprising a gear transmission mechanism provided in the rotation power transmission path between said engine and said central differential device, wherein said condition representative of the road speed of said vehicle and of the load on said engine is the engagement of the highest speed stage of said gear transmission mechanism.
Claim 16
Dependent Claim
56 words
A central differential operation restriction device control method according to claim 13, wherein said device for selectively restricting the operation of said central differential device is controlled in such a manner that said operation of said central differential device is less restricted than otherwise, when said highest speed stage of said gear transmission mechanism is engaged.
Claim 17
Dependent Claim
60 words
A central differential operation restriction device control method according to claim 13, wherein the timing of switching over of control of said device for selectively restricting the operation of said central differential device is coordinated with the timing of shifting of engagement of said gear transmission mechanism so as to at least partially overlap the individual torque shocks caused thereby.
Claim 18
Dependent Claim
100 words
A central differential operation restriction device control method according to claim 12, said vehicle further comprising a gear transmission mechanism provided in the rotational power transmission path between said engine and said central differential device, and a torque converter comprising a lock up clutch and provided in the rotational power transmission path between said engine and said gear transmission mechanism, wherein said condition representative of the road speed of said vehicle and of the load on said engine is the engagement of the highest speed stage of said gear transmission mechanism and the simultaneous engagement of said lock up clutch.
Claim 19
Dependent Claim
64 words
A central differential operation restriction device control method according to claim 16, wherein said device for selectively restricting the operation of said central differential device is controlled in such a manner that said operation of said central differential device is less restricted than otherwise, when said highest speed stage of said gear transmission mechanism is engaged and also said lock up clutch is engaged.
Claim 20
Dependent Claim
49 words
A central differential operation restriction device control method according to claim 12, wherein said condition representative of the road speed of said vehicle and of the load on said engine is the combination of the actual road speed of said vehicle and of the actual load on said engine.
Claim 21
Dependent Claim
52 words
A central differential operation restriction device control method according to claim 18, wherein said device for selectively restricting the operation of said central differential device is controlled in such a manner that said operation of said central differential device is more restricted, when said actual load on said engine is the larger.
Claim 22
Dependent Claim
53 words
A central differential operation restriction device control method according to claim 18, wherein said device for selectively restricting the operation of said central differential device is controlled in such a determinate engine load value, said operation of said central differential device is selectively restricted, according to the actual road speed of said vehicle.
Claim 23
Dependent Claim
67 words
A central differential operation restriction device control method according to claim 20, wherein said device for selectively restricting the operation of said central differential device is controlled in such a manner than, when said actual load on said engine is at least said determinate engine load value, said operation of said central differential device is more restricted, when said actual road speed of said vehicle is lower.
Claim 24
Dependent Claim
73 words
A central differential operation restriction device control method according to claim 21, wherein said device for selectively restricting the operation of said central differential device is controlled in such a manner than, when said actual load on said engine is at least said determinate engine load value, said operation of said central differential device is restricted, when said actual road speed of said vehicle is lower than a determinate vehicle road speed value.
References Cited (Backward Citations)
US3845671A
Cited
US4538700A
Cited
GB2168116A
Cited
US4693143A
Cited
US4690239A
Cited
US4702341A
Cited
US4699236A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-21 | 1991-12-21 | 1992-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-21 | 1995-12-21 | 1996-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-21 | 1999-12-21 | 2000-06-21 | $7700.00 | Window Closed / Lapsed |