Variable tire pressure traction control enhancement

• US 5,839,801 A
• Filed: 04/04/1997
• Issued: 11/24/1998
• Est. Priority Date: 04/04/1997
• Status: Expired due to Fees

• Current Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Original Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Inventors: Ferguson, Steven C.
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US08/833,156
• Time in Patent Office: 599 Days
• Field of Search: 303/113.2, 303/113.3, 303/191, 303/192, 303/DIG. 7, 303/133, 303/139, 303/122, 303/122.09, 303/122.15, 303/145, 340/440-448, 701/29, 701/70, 73/146, 73/146.2, 73/146.3-146.8, 152/415, 152/416, 141/38, 141/1, 141/98, 301/5.24, 244/103 R, 137/224, 137/223, 188/4 R, 188/4 B
• US Class Current: 303/191
• CPC Class Codes: B60C 23/00354 Details of valves
• CPC Class Codes: B60C 23/00372 characterised by fluid diagrams
• CPC Class Codes: B60T 8/3205 acceleration B60T8/34, B60T8/52, B60T8/54, B60T8/56, B60T8/58, B60T8/72, B60T8/86, B60T8/88 take precedence
• CPC Class Codes: B60T 8/4809 Traction control, stability control, using both the wheel brakes and other automatic braking systems
• CPC Class Codes: B60T 8/56 having means for changing the coefficient of friction
• CPC Class Codes: Y10S 303/07 Small tire digest

Abstract

A traction enhancement system includes an electronic controller, first and second pneumatic tire and wheel assemblies, a first wheel brake, a second wheel brake, a source of pressurized air, an air pressure sensor, and a vehicle speed sensor. The first and second pneumatic tire and wheel assemblies each define a pneumatic chamber having pressurized air therein. The first wheel brake operably resists rotation of the first tire and wheel assembly. The second wheel brake likewise operably resists rotation of the second tire and wheel assembly. The source of pressurized air is connected to the tire and wheel assemblies. The air pressure sensor is located and configured to monitor the pressure of the pneumatic chambers, and is electrically connected to the controller. The vehicle speed sensor is electrically connected to the controller as well. The electronic controller includes structure for selectively controlling the pressure within the pneumatic chambers responsive to signals from the vehicle speed sensor and from the air pressure sensor and structure for selectively applying the first and second wheel brakes, and structure for determining the slippage of a given wheel. When one of the first and the second tire and wheel assemblies slips at a vehicle speed less than a predetermined first threshold speed, the pressure in the slipping tire and wheel assembly is decreased to improve traction.

Claims

1. A traction enhancement system for a vehicle comprising:

an electronic controller;

a drive axle having first and second axle shafts;

first and second pneumatic tire and wheel assemblies with each defining a pneumatic chamber having pressurized air therein and rotatably fixed to the first and second axle shafts respectively;

a first rotary speed sensor located at one of the first tire and wheel assembly and a part that rotates substantially in unison with the first tire and wheel assembly and the first sensor being electrically connected to the electronic controller wherein the first rotary speed sensor provides an electrical signal corresponding to the rotary speed of the first tire and wheel assembly;

a second rotary speed sensor located at one of the second tire and wheel assembly and a part that rotates substantially in unison with the second tire and wheel assembly and the second sensor being electrically connected to the electronic controller wherein the second rotary speed sensor provides an electrical signal corresponding to the rotary speed of the second tire and wheel assembly;

a first wheel brake operably resisting rotation of the first tire and wheel assembly;

a second wheel brake operably resisting rotation of the second tire and wheel assembly;

a source of pressurized air connected to the pneumatic chambers;

an air pressure sensor located and configured to monitor the pressure of air within the pneumatic chamber of one of the tire and wheel assemblies and the air pressure sensor being electrically connected to the controller;

a vehicle speed sensor electrically connected to the controller; and

the electronic controller including means for selectively controlling the pressure within the pneumatic chambers responsive to signals from the rotary speed sensors and from the air pressure sensor, means for selectively applying the first and second wheel brakes, and means for determining slippage of the tire and wheel assemblies using the electrical signals from the rotary speed sensors, wherein one of the first and second tire and wheel assemblies slips at a vehicle speed less than a predetermined first threshold speed, the pressure in the slipping tire and wheel assembly is decreased to improve traction and the wheel brake associated with the slipping wheel and tire assembly is intermittently applied to develop drive torque at the other of the first and second wheels.

2. A traction enhancement system as claimed in claim 1 wherein a pressure modulator includes a plurality of electrically responsive valves which are disposed between the source of pressurized air and the pneumatic chambers with the valves being electrically connected to the electronic controller.

3. A traction enhancement system as claimed in claim 1 wherein a valve is disposed between the source of pressurized air and the pneumatic chambers and is electrically connected to the electronic controller.

4. A traction enhancement system as claimed in claim 2 wherein a first valve is disposed between the pressure modulator and the pneumatic chambers and is electrically connected to the electronic controller.

5. A traction enhancement system as claimed in claim 4 wherein the first valve and the pressure sensor are disposed proximate to the one of the pneumatic chambers and another pressure sensor which is electrically connected to the electronic controller and a second valve which is electrically connected to the electronic controller and is disposed between the pressure modulator and the other pneumatic chamber with both the other pressure sensor and the second valve being disposed proximate to the other pneumatic chamber.

6. A traction enhancement system for a vehicle comprising:

an electronic controller;

first and second pneumatic tire and wheel assemblies defining a first pneumatic chamber and a second pneumatic chamber respectively with each of the chambers having pressurized air therein;

first and second rotary speed sensors electrically connected to the electronic controller and located in a position facilitating the sensors providing signals of the rotative speed of the first and second tire and wheel assemblies respectively;

a selectively actuable source of pressurized air connected to the pneumatic chambers;

an air pressure sensor located and configured to monitor a pressure of air within one of the pneumatic chambers and being electrically connected to the electronic controller;

first and second electronically responsive inflation control valves disposed between the source of pressurized air and the first and second pneumatic chambers respectively and the first and second valves being electronically connected to the electronic controller;

first and second wheel brake assemblies operably resisting the rotation of the first and second tire and wheel assemblies respectively being selectively actuable;

a vehicle speed sensor electrically connected to the electronic controller;

the electronic controller including means for selectively actuating the first and second wheel brakes, and means for identifying a tire and wheel assembly slipping in an over speed mode and means for selectively applying the brake associated with the tire and wheel assembly identified as slipping, means for decreasing the pressure in the pneumatic chamber of the slipping tire and wheel assembly employing the associated inflation control valve and the source of pressurized air wherein when one of the first and second tire and wheel assemblies slips the pressure in the pneumatic chamber of the slipping tire and wheel assembly is decreased and the brake associated with the slipping tire and wheel assembly is selectively applied to increase cumulative tractive effort of the first and second tire and wheel assemblies.

7. A traction enhancement system as claimed in claim 6 wherein the means of the electronic controller for decreasing the pressure in the pneumatic chamber is configured to simultaneously decrease the pressure in the pneumatic chambers of both the first and second tire and wheel assemblies responsive to an indication of slippage of either of the tire and wheel assemblies.

8. A traction enhancement system as claimed in claim 6 wherein the pressure modulator includes a pressure regulator connected air supply lines extending from pressure regulator to the first and second inflation control valves and selectively controlled by the electronic controller.

9. A traction enhancement system as claimed in claim 8 wherein the first and second brakes are fluid actuated responsive to an increase in pressure within the brake lines and the pressure regulator includes a pressure actuation valve electronically connected to the electronic controller and selectively actuated by the electronic controller to provide intermittent application of the brake of the slipping tire and wheel assembly.