Machine having a multiple-ratio transmission

• US 20090325762A1
• Filed: 06/30/2008
• Published: 12/31/2009
• Est. Priority Date: 06/30/2008
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Coutant, Alan R., Daniel, Steven A., Thomson, Norval P., Cronin, Michael G.
• Granted Patent: US 8,118,706 B2
• Time in Patent Office: Days
• US Class Current: 477/107
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 30/1882 characterised by the working point of the engine, e.g. by using engine output chart

Abstract

A method of operating a machine is disclosed. The machine may have a power system that includes a prime mover, a multiple-ratio transmission, a propulsion device, and power-system controls. The method may include propelling the machine by transmitting power from the prime mover to the propulsion device through the multiple-ratio transmission, while controlling operation of the prime mover and the multiple-ratio transmission with the power-system controls. This may include determining with the power-system controls at least one energy-efficiency estimate based at least in part on energy-efficiency characteristics of the prime mover and energy-efficiency characteristics of the multiple-ratio transmission. Controlling the prime mover and the multiple-ratio transmission may further include controlling a prime-mover operating speed of the prime mover and a transmission drive ratio of the multiple-ratio transmission based at least in part on the at least one energy-efficiency estimate.

Claims

1. A method of operating a machine having a power system that includes a prime mover, a multiple-ratio transmission, a propulsion device, and power-system controls, the method comprising:

propelling the machine by transmitting power from the prime mover to the propulsion device through the multiple-ratio transmission, while controlling operation of the prime mover and the multiple-ratio transmission with the power-system controls, including

determining with the power-system controls at least one energy-efficiency estimate based at least in part on energy-efficiency characteristics of the prime mover and energy-efficiency characteristics of the multiple-ratio transmission, and

controlling a prime-mover operating speed of the prime mover and a transmission drive ratio of the multiple-ratio transmission based at least in part on the at least one energy-efficiency estimate.

2. The method of claim 1, wherein determining the at least one energy-efficiency estimate includes determining multiple energy-efficiency estimates associated with alternative combinations of the prime-mover operating speed and the transmission drive ratio.

3. The method of claim 2, wherein controlling the prime-mover operating speed and the transmission drive ratio based at least in part on the at least one energy-efficiency estimate includes:

selecting a combination of the prime-mover operating speed and the transmission drive ratio associated with one of the multiple energy-efficiency estimates as a first target for the prime-mover operating speed and the transmission drive ratio; and

controlling the prime-mover operating speed and the transmission drive ratio based at least in part on the first target.

4. The method of claim 3, wherein controlling the prime-mover operating speed and the transmission drive ratio based at least in part on the at least one energy-efficiency estimate further includes:

determining a second target for the prime-mover operating speed and the transmission drive ratio, the second target being associated with responsiveness of the power system to increased power demands; and

controlling the prime-mover operating speed and the transmission drive ratio based at least in part on the first target and the second target.

5. The method of claim 4, wherein controlling the prime-mover operating speed and the transmission drive ratio based at least in part on the first target and the second target includes:

if the first target overlaps with the second target, controlling the prime-mover operating speed and the multiple-ratio transmission to coincide with the first target.

6. The method of claim 4, wherein controlling the prime-mover operating speed and the transmission drive ratio based at least in part on the first target and the second target includes:

if the first target deviates from the second target, controlling the prime-mover operating speed and the transmission drive ratio to coincide with the second target.

7. The method of claim 6, wherein:

the second target is a range of prime-mover operating speeds and associated transmission drive ratios; and

controlling the prime-mover operating speed and the transmission drive ratio to coincide with the second target includes biasing the prime-mover operating speed and the transmission drive ratio within the range of the second target toward the first target.

8. The method of claim 1, wherein:

the power system includes one or more additional power loads operable with power from the prime mover; and

the at least one energy-efficiency estimate is further based on energy-efficiency characteristics of at least one of the one or more additional power loads.

9. The method of claim 1, further including:

determining a power demand value based at least in part on one or more throttling inputs from an operator of the machine; and

wherein controlling the prime-mover operating speed and the transmission drive ratio based at least in part on the at least one energy-efficiency estimate includes controlling the prime-mover operating speed based at least in part on the power-demand value.

10. The method of claim 1, wherein:

determining the at least one energy-efficiency estimate includes determining an energy-efficiency estimate for each of a plurality of candidate combinations of prime-mover operating speed and transmission drive ratio capable of meeting an estimated power demand on the power system; and

controlling the prime-mover operating speed and transmission drive ratio based at least in part on the at least one energy-efficiency estimate includes selecting from among the candidate combinations of prime-mover operating speed and transmission drive ratio based on the associated energy-efficiency estimates.

11. A machine, comprising:

a power system, including

a prime mover;

a propulsion device;

a multiple-ratio transmission; and

power-system controls that selectively operate the power system to propel the machine by transmitting power from the prime mover to the propulsion device through the multiple-ratio transmission, including

determining a first target for a prime-mover operating speed of the prime mover and a transmission drive ratio of the multiple-ratio transmission, the first target being associated with promoting energy efficiency,

determining a second target for the prime-mover operating speed and the transmission drive ratio, the second target being associated with promoting responsiveness of the power system to increased power demands, and

controlling the prime-mover operating speed and the transmission drive ratio based at least in part on both the first target and the second target.

12. The machine of claim 11, wherein determining the first target for the prime-mover operating speed and the transmission drive ratio includes determining an energy-efficiency estimate associated with at least one combination of the prime-mover operating speed and the transmission drive ratio based at least in part on energy-efficiency characteristics of the multiple-ratio transmission.

13. The machine of claim 11, wherein controlling the prime-mover operating speed and the transmission drive ratio based at least in part on the first target and the second target includes

if the first target overlaps with the second target, controlling the prime-mover operating speed and the transmission drive ratio to coincide with the first target.

14. The machine of claim 13, wherein controlling the prime-mover operating speed and the transmission drive ratio based at least in part on the first target and the second target further includes

if the first target deviates from the second target, controlling the prime-mover operating speed and the transmission drive ratio to coincide with the second target.

15. The machine of claim 14, wherein:

the second target is a range of prime-mover operating speeds and associated transmission drive ratios; and

controlling the prime-mover operating speed and the transmission drive ratio to coincide with the second target when the first target deviates from the second target includes biasing the prime-mover operating speed and transmission drive ratio within the range of the second target toward the first target.

16. A machine, comprising:

a power system, including

a prime mover;

a propulsion device;

a multiple-ratio transmission; and

power-system controls that selectively operate the power system to propel the machine by transmitting power from the prime mover to the propulsion device through the multiple-ratio transmission, including

determining a first target for a combination of a prime-mover operating speed of the prime mover and a transmission drive ratio of the multiple-ratio transmission, including

determining multiple combined energy-efficiency estimates for a plurality of components of the power system at multiple alternative combinations of the prime-mover operating speed and the transmission drive ratio, and

selecting the first target based at least in part on the multiple combined energy-efficiency estimates;

determining a second target for the combination of the prime-mover operating speed and the transmission drive ratio, the second target being associated with promoting responsiveness of the power system to increased power demands; and

controlling the prime-mover operating speed and the transmission drive ratio based at least in part on both the first target and the second target.

17. The machine of claim 16, wherein each of the multiple combined energy-efficiency estimates for the plurality of components is based at least in part on energy-efficiency characteristics of the prime mover and energy-efficiency characteristics of the multiple-ratio transmission.

18. The machine of claim 17, wherein:

the power system includes one or more additional components operable with power from the prime mover; and

each of the multiple combined energy-efficiency estimates is further based on energy-efficiency characteristics of at least one of the one or more additional components.

19. The machine of claim 16, wherein selecting the first target based at least in part on the multiple combined energy-efficiency estimates includes selecting as the first target the combination of the prime-mover operating speed and the transmission drive ratio associated with the highest of the multiple combined energy-efficiency estimates.

20. The machine of claim 16, wherein:

the second target is a range of prime-mover operating speeds and associated transmission drive ratios; and

controlling the prime-mover operating speed and the transmission drive ratio based at least in part on both the first target and the second target includes

if the first target deviates from the second target, controlling the prime-mover operating speed and the transmission drive ratio to coincide with the second target while biasing the prime-mover operating speed and the transmission drive ratio within the range of the second target toward the first target.