Vehicle Fuel Economy by Optimizing Effective Rolling Tire Resistance

• US 20150034399A1
• Filed: 02/10/2012
• Published: 02/05/2015
• Est. Priority Date: 02/10/2012
• Status: Active Grant

• Current Assignee: Compagnie générale des établissements Michelin, Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Original Assignee: Compagnie générale des établissements Michelin, Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Inventors: Clayton, William Bennett, Bradley, Calvin Rhett
• Granted Patent: US 9,481,415 B2
• Time in Patent Office: Days
• US Class Current: 180/24.02
• CPC Class Codes: B60G 17/015 the regulating means comprising electric or electronic elements B60G17/002, B60G17/005 take precedence
• CPC Class Codes: B60G 17/017 characterised by their use when the vehicle is stationary, e.g. during loading, engine start-up or switch-off
• CPC Class Codes: B60G 2204/47 Means for retracting the suspension
• CPC Class Codes: B60G 2400/60 Load
• CPC Class Codes: B60G 2400/61 Load distribution
• CPC Class Codes: B60G 2800/214 by varying the load distribution
• CPC Class Codes: B62D 61/12 with variable number of ground engaging wheels, e.g. with some wheels arranged higher than others, or with retractable wheels for manoeuvring purposes only B60S
• CPC Class Codes: B62D 61/125 the retractable wheel being a part of a set of tandem wheels resilient suspension for a single set of tandem wheels B60G5/00

Abstract

The subject matter of the present invention relates generally to a vehicle that has axles with tires mounted thereon with at least one axle that is a lift axle, and more specifically, to a method that optimizes the effective tire rolling resistance by adjusting the load on the tires, resulting in an improvement in the fuel economy of the vehicle. According to one embodiment, the method takes into consideration the rolling resistance characteristics of the tires placed onto the axles of the vehicle and provides an algorithm for optimizing their rolling resistance by raising or lowering the lift axle.

Claims

1. A method for improving the fuel economy of a vehicle by optimizing effective tire rolling resistance, the method comprising the following steps:

providing a vehicle with at least one principal axle and one lift axle, said axles having tires mounted thereon; and

determining whether the total load carried by the vehicle is greater than the sum of maximum allowable axle load multiplied by the number of lift axles added to the minimum allowable axle load necessary multiplied by the number of principal axles;

or

determining whether the total load carried by the vehicle is less than or equal to the sum of maximum allowable axle load multiplied by the number of lift axles added to the minimum allowable axle load necessary multiplied by the number of principal axles while also being greater than the total number of axles multiplied by the minimum allowable axle load necessary, or

determining whether the total load carried by the vehicle is less than or equal to the total number of axles multiplied by minimum allowable axle load necessary; and

further comprising the step of determining that the tires on a lift axle have lower rolling resistance characteristics than the tires on a principal axle.

5. The method of any of the preceding claims in which the total number of axles on the vehicle is two, wherein said at least one principal axle is a drive axle and said at least one lift axle is a tag axle, and wherein said determining steps include:

determining whether the total load carried by the vehicle is greater than the sum of the maximum allowable axle load and minimum allowable axle load;

or

determining whether the total load carried by the vehicle is less than or equal to the sum of maximum allowable axle load and minimum allowable axle load while also being greater than two multiplied by the minimum allowable axle load;

or

determining whether the total load carried by the vehicle is less than or equal to two multiplied by the minimum allowable axle load while also being greater than or equal to the minimum allowable axle load.

6. The method of claim 5, wherein the total load carried by the vehicle is determined to be greater than the sum of maximum allowable axle load and the minimum allowable axle load, said method further comprising the step of moving the tag axle until the axle load of the tag axle is the maximum allowable axle load and the axle load of the drive axle is equal to total load carried by the vehicle minus the maximum allowable axle load.

7. The method of claim 5, wherein the total load carried by the vehicle is determined to be less than or equal to the sum of maximum allowable axle load and minimum allowable axle load while also being greater than two multiplied by the minimum allowable axle load, said method further comprising the step of moving the tag axle until the tag axle load equals the total load carried by the vehicle minus the minimum axle load and drive axle load equals the minimum allowable axle load.

8. The method of claim 5, wherein total load carried by the vehicle is determined to be less than or equal to two multiplied by the minimum allowable axle load while also being greater than or equal to the minimum allowable axle load, said method further comprising the step of moving the tag axle until drive axle load equals the tag axle load.

2. The method of claim 0, wherein the total load carried by the vehicle is determined to be greater than the sum of the maximum allowable axle load multiplied by the number of lift axles added to the minimum allowable axle load necessary multiplied by the number of principal axles, said method further comprising the step of moving at least one lift axle so that a lift axle carries the maximum allowable axle load and a principal axle carries less load than one lift axle.

3. The method of claim 0, wherein the total load carried by the vehicle is determined to be less than or equal to the sum of maximum allowable axle load multiplied by the number of lift axles added to the minimum allowable axle load necessary multiplied by the number of principal axles while also being greater than the total number of axles multiplied by the minimum allowable axle load necessary, said method further comprising the step of moving at least one lift axle so a principal axle carries a minimum axle load and a lift axle carries a load greater than a principal axle.

4. The method of claim 0, wherein the total load carried by the vehicle is determined to be less than or equal to the total number of axles multiplied by the minimum allowable axle load necessary, said method further comprising the step of moving at least one lift axle so a principal axles carries the same load as a lift axle.

9. (canceled)

10. A method for improving the fuel economy of a vehicle by optimizing effective tire rolling resistance, the method comprising the following steps:

providing a vehicle with at least one principal axle and one lift axle, said axles having tires mounted thereon; and

determining whether the quantity of the total load carried by the vehicle minus the product of the maximum allowable axle load multiplied by the number of principal axles is greater than the minimum allowable axle load necessary multiplied by the number of lift axles;

or

determining whether the quantity of the total load carried by the vehicle minus the product of the maximum allowable axle load multiplied by the number of principal axles is less than or equal to the product of minimum allowable axle load multiplied by the number of lift axles while at the same time the total load is greater than or equal to the total number of axles multiplied by the minimum allowable axle load necessary, or

determining whether the quantity of the total load carried by the vehicle is less than the total number of axles multiplied by the minimum allowable axle load necessary, or

determining whether the quantity of the load carried by the vehicle minus the product of the maximum allowable axle load multiplied by the number of lift axles is less than or equal to the product of the minimum allowable axle load multiplied by the number of principal axles while at the same time the total load is greater than or equal to the total number of axles multiplied by the minimum allowable axle load necessary; and

further comprising the step of determining that the tires on a lift axle have the same or higher rolling resistance characteristics than the tires on a principal axle.

11. The method of claim 10, wherein the quantity of the total load carried by the vehicle minus the product of the maximum allowable axle load multiplied by the number of principal axles is determined to be greater than the minimum allowable axle load necessary multiplied by the number of lift axles, said method further comprising the step of moving at least one lift axle so a principal axle carries the maximum allowable axle load.

12. The method of claim 10, wherein the quantity of the total load carried by the vehicle minus the product of the maximum allowable axle load multiplied by the number of principal axles is determined to be less than or equal to the minimum allowable axle load necessary multiplied by the number of lift axles while at the same time the total load carried by the vehicle is greater than or equal to the total number of axles multiplied by the minimum allowable axle load necessary, said method further comprising the step of moving at least one lift axle so a lift axle carries the minimum allowable axle load, or wherein the quantity of the total load carried by the vehicle minus the product of the maximum allowable axle load multiplied by the number of lift axles is determined to be less than or equal to the minimum allowable axle load necessary multiplied by the number of principal axles while at the same time the total load carried by the vehicle is greater than or equal to the total number of axles multiplied by the minimum allowable axle load necessary, said method further comprising the step of moving at least one lift axle so a principal axle carries the minimum allowable axle load.

13. The method of claim 10, wherein the quantity of the total load carried by the vehicle is determined to be less than the total number of axles multiplied by the minimum allowable axle load necessary, said method further comprising the step of moving at least one lift axle so a lift axle carries no load or so that a principal axle carries no load.

14. The method of any one of claims 10 to 13, in which the total number of axles on the vehicle is two, wherein said at least one principal axle is a drive axle and said at least one lift axle is a tag axle, and wherein said determining steps include:

determining whether the total load carried by the vehicle minus the maximum allowable axle load is greater than the minimum allowable axle load;

or

determining whether the total load carried by the vehicle minus the maximum allowable axle load is less than or equal to the minimum allowable axle load while also being greater than zero;

or

determining whether the total load carried by the vehicle minus the maximum allowable axle load is less than or equal to zero.

15. The method of claim 14, wherein the quantity of the total load carried by the vehicle minus the maximum allowable axle load is determined to be greater than the minimum allowable axle load, said method further comprising the step of moving the tag axle so the drive axle carries the maximum allowable axle load.

16. The method of claim 14, wherein the quantity of the total load carried by the vehicle minus the maximum allowable axle load is determined to be less than or equal to the minimum allowable axle load while at the same time the total load carried by the vehicle is greater than the maximum allowable axle load necessary, said method further comprising the step of moving the tag axle so that the tag axle carries the minimum allowable axle load.

17. The method of claim 14, wherein the quantity of the total load carried by the vehicle minus the maximum allowable axle load is determined to be less than or equal to zero, said method further comprising the step of moving the tag axle so the tag axle carries no load.

18. (canceled)

19. A system for improving vehicle fuel economy for a vehicle having at least one lift axle and one principal axle, comprising:

tires mounted on the lift and principal axles;

an input device for entering instructions or information;

a memory for storing instructions, data or programs having algorithms;

load sensors for determining the loads on the principal and lift axles;

a lift mechanism for lowering or raising the lift axle;

at least one processing device in communication with said input device, said memory, said load sensors, and said lift mechanism, said processing device configured for

receiving measurements indicative of the load placed on the principal and lift axles as well as the total load carried by the vehicle;

executing an algorithm depending on whether the tires on the lift axle have rolling resistance characteristics that are higher, lower or the same as the tires on the principal axle and subsequently sending a signal to the lift mechanism in order to move the lift axle to change the loads placed on the principal and lift axles;

stopping the movement of the lift mechanism once the desired loads on the principal and lift axles have been reached; and

,

monitoring the total vehicle load over time.

20. The system of claim 19, further comprising an output device for alerting the operator that the lift mechanism should be activated to adjust the load on the principal and lift axles so that the operator can signal the processing device to activate the lift mechanism.

21. The system of claim 19, further comprising an RFID chip attached to the tire, said RFID configured for storing and sending information concerning the rolling resistance characteristics of the tire to the processing device via the input device.

22. The system of claim 19, further comprising a SAE J1939 compliant bus that interfaces with an electronic control system that acts as the processing device for controlling the lift mechanism.

23. The system of claim 22, further comprising a SAE J1708 compliant bus that is connected with said electronic control system, said SAE J1708 compliant bus also communicating with switches for positioning the lift axle.