AUXILIARY POWER UNIT HAVING A CONTINUOUSLY VARIABLE TRANSMISSION

• US 20120258839A1
• Filed: 04/03/2012
• Published: 10/11/2012
• Est. Priority Date: 04/04/2011
• Status: Active Grant

• Current Assignee: Fallbrook Intellectual Property Company LLC (Fallbrook Technologies Incorporated)
• Original Assignee: Fallbrook Technologies Incorporated
• Inventors: Smithson, Robert, Pohl, Brad P., Lohr, Charles B., McBroom, Scott T., Solis, Javier, Nielsen, Terry, Munguia, Nicole
• Granted Patent: US 8,845,485 B2
• Time in Patent Office: Days
• US Class Current: 477/42
• CPC Class Codes: B60H 1/3222 characterised by the compressor driving arrangements, e.g. clutches, transmissions or multiple drives B60H1/3208, B60H1/3226 take precedence
• CPC Class Codes: B60H 1/3226 Self-contained devices, i.e. including own drive motor
• CPC Class Codes: B60K 25/02 directly from an engine shaft
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 30/1886 Controlling power supply to auxiliary devices
• CPC Class Codes: F16H 15/42 in which two members co-operate by means of rings or by means of parts of endless flexible members pressed between the first mentioned members
• CPC Class Codes: F16H 61/6648 controlling of shifting being influenced by a signal derived from the engine and the main coupling
• CPC Class Codes: Y02T 10/60 Other road transportation technologies with climate change mitigation effect

Abstract

Inventive embodiments are directed to components, subassemblies, systems, and/or methods for auxiliary power units (APU). In one embodiment, the APU includes a source of rotational power such as a combustion engine operably coupled to a continuously variable transmission (CVT). The CVT can be coupled to a load. In some embodiments, the load is provided by a generator. In one embodiment, the APU has a control system configured to control the operation of the engine and the operation of the CVT. The control system can facilitate substantially constant speed operation of the generator in the presence of variable operation of the engine. In another embodiment, the APU includes a continuously variable accessory drive (CVAD) operably coupled to an engine. The CVAD can include a continuously variable transmission operably coupled to a generator. In one embodiment, a skew-based control system is adapted to facilitate a change in the ratio of a CVAD.

Claims

1. A method of controlling an auxiliary power unit having an engine, a generator, and a continuously variable transmission (CVT) coupled to the engine and the generator, the method comprising the steps of:

sensing a change in a load on the generator;

adjusting the engine to correspond to said change in load; and

adjusting the speed ratio of the CVT substantially simultaneously with the adjustment of the engine.

2. The method of claim 1, further comprising the step of maintaining a substantially constant speed of the generator.

3. The method of claim 2, wherein adjusting the speed ratio of the CVT comprises the step of tilting axes of a plurality of balls.

4. The method of claim 3, wherein tilting axes further comprises the step of applying a skew condition to the CVT.

5. The method of claim 1, wherein adjusting the engine comprises the step of commanding an engine actuator.

6. The method of claim 5, wherein commanding an engine actuator comprises the step of providing an engine speed set point.

7. The method of claim 5, wherein commanding an engine actuator comprises the step of providing an engine fuel rate set point.

8. The method of claim 3, wherein adjusting the speed ratio is based at least in part on a difference between a speed of the generator and a speed of the engine.

9. An auxiliary power unit (APU) comprising:

a combustion engine having an engine control system adapted to operate the engine at a requested condition;

a continuously variable transmission (CVT) having a plurality of tiltable balls, the CVT operably coupled to the engine, the CVT having a CVT control system in communication with the engine control system; and

a generator operably coupled to the CVT, the generator configured to operate at substantially constant speed, wherein the CVT control system is adapted to sense a change in speed of the generator and adjust the CVT based at least in part on said change in speed.

10. The APU of claim 9, further comprising an engine actuator coupled to the engine, the engine actuator in communication with the engine control system.

11. The APU of claim 10, wherein the engine actuator is configured to receive a set point from the CVT control system.

12. The APU of claim 11, wherein the set point is a desired engine speed.

13. The APU of claim 12, wherein the set point is a desired fuel rate for the engine.

14. The APU of claim 13, wherein the CVT control system comprises a CVT actuator, the CVT actuator operably coupled to the CVT, the CVT actuator configured to adjust a transmission ratio of the CVT.

15. The APU of claim 14, further comprising an enclosure configured to support and enclose the engine, the CVT, and the control system.

16. A method of controlling an auxiliary power unit (APU) having an engine, a generator, and a continuously variable transmission (CVT) coupled to the engine and the generator, the method comprising the steps of:

determining a change in load based at least in part on a signal from an accessory;

adjusting the engine to correspond to said change in load; and

adjusting the speed ratio of the CVT substantially simultaneously with the adjustment of the engine.

17. The method of claim 16, wherein determining a change in load comprises the step of receiving a signal from a blower.

18. The method of claim 16, wherein determining a change in load comprises the step of receiving a signal from an air conditioning system.

19. The method of claim 16, wherein determining a change in load comprises the step of receiving a signal from a heater.

20. The method of claim 18, wherein determining a change in load comprises the step of using a look-up table.