Power system

• US 20070179015A1
• Filed: 01/31/2006
• Published: 08/02/2007
• Est. Priority Date: 01/31/2006
• Status: Abandoned Application

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Johnson, Kris, Lane, William
• Application Number:
  US11/342,529
• Publication Number:
  US 20070179015A1
• Time in Patent Office: Days
• US Class Current: 477/8
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A power system has a prime mover. The power system may also include a multiple-ratio transmission having a rotary input member and a rotary output member. Additionally, the power system may include a coupler connected between the prime mover and the rotary input member of the multiple-ratio transmission. The power system may also include an electric machine. Additionally, the power system may include power-system controls operable to automatically control whether the rotary input member of the multiple-ratio transmission is drivingly connected to the prime mover, including automatically controlling whether the coupler has a power-transmitting operating state. The power-system controls may also be configured to operate the electric machine to reduce the speed of the prime mover in concert with an upshift of the multiple-ratio transmission.

Claims

1. A power system, comprising:

a prime mover;

a multiple-ratio transmission having a rotary input member and a rotary output member;

a coupler connected between the prime mover and the rotary input member of the multiple-ratio transmission;

an electric machine; and

power-system controls operable to

automatically control whether the rotary input member of the multiple-ratio transmission is drivingly connected to the prime mover, including automatically controlling whether the coupler has a power-transmitting operating state, and

in concert with an upshift of the multiple-ratio transmission from a first drive ratio to a second drive ratio, operate the electric machine to reduce the operating speed of the prime mover.

2. The power system of claim 1, wherein the power-system controls are further operable to

while operating the electric machine to reduce the operating speed of the prime mover, cause the rotary input member of the multiple-ratio transmission to be drivingly connected to the prime mover, including causing the coupler to have a power-transmitting operating state, so that the electric machine also reduces the operating speed of the rotary input member of the multiple-ratio transmission.

3. The power system of claim 2, wherein operating the electric machine to reduce the operating speeds of the prime mover and the rotary input member of the multiple-ratio transmission includes operating the electric machine to reduce the operating speeds of the prime mover and the rotary input member at least until the operating speed of the prime mover is substantially equal to a synchronous speed for the second drive ratio.

4. The power system of claim 2, wherein:

the coupler is a friction clutch; and

causing the coupler to have a power-transmitting operating state while operating the electric machine to reduce the operating speeds of the prime mover and the electric machine includes causing the coupler to be fully engaged.

5. The power system of claim 1, wherein the coupler is connected between the electric machine and the rotary input member of the multiple-ratio transmission.

6. The power system of claim 5, wherein the power-system controls are further operable to

in at least some circumstances, control the operating speed of the prime mover and an operating speed of the electric machine independent of an operating speed of the rotary input member of the multiple-ratio transmission while the coupler accommodates any incompatibilities between the operating speed of the rotary input member and the operating speeds of the prime mover and the electric machine by slipping.

7. The power-system of claim 5, wherein the coupler is operable to transmit power while slipping.

8. The power system of claim 5, wherein the power-system controls are further operable to

in order to start the prime mover, operating the electric machine as an electric motor driving the prime mover while the coupler accommodates any incompatibilities between the operating speed of the rotary input member of the multiple-ratio transmission and the operating speeds of the prime mover and the electric machine by slipping.

9. The power system of claim 8, wherein:

the power system is part of a mobile machine having one or more propulsion devices drivingly connected to the rotary output member of the multiple-ratio transmission; and

the power-system controls are further operable to

subsequent to starting the prime mover, with the rotary input member and the rotary output member of the multiple-ratio transmission drivingly connected, launch the mobile machine by causing the coupler to slip while transmitting power from the prime mover to the rotary input member.

10. The power system of claim 1, wherein:

the power system is part of a mobile machine having one or more propulsion devices drivingly connected to the rotary output member of the multiple-ratio transmission; and

the power-system controls are further operable to coordinate operation of the multiple-ratio transmission, the coupler, and the electric machine to launch the mobile machine while starting the prime mover, including simultaneously

causing the rotary input member and the rotary output member of the multiple-ratio transmission to be drivingly connected,

operating the electric machine as an electric motor while the coupler transmits power, so that the rotary electric machine drives the prime mover to enable starting the prime mover and also drives the propulsion devices through the multiple-ratio transmission to launch the mobile machine.

11. The power system of claim 1, wherein operating the electric machine to reduce the operating speed of the prime mover includes operating the electric machine to reduce the operating speed of the prime mover at least until the operating speed of the prime mover is substantially equal to a synchronous speed for the second drive ratio.

12. The power system of claim 1, wherein the power-system controls are further operable to

in concert with a downshift of the multiple-ratio transmission, operate the electric machine to increase the operating speed of the prime mover.

13. The power system of claim 1, wherein the power system is part of a mobile machine, the mobile machine including one or more propulsion devices drivingly connected to a rotary output member of the multiple-ratio transmission.

14. A method of operating a mobile machine, the mobile machine having a prime mover, an electric machine, a multiple-ratio transmission with a rotary input member and a rotary output member, one or more propulsion devices drivingly connected to the rotary output member, and a coupler connected between the rotary input member and each of the prime mover and the electric machine, the method comprising:

in at least some circumstances, controlling the operating speeds of the prime mover and the electric machine independently of the operating speed of the rotary input member while the coupler accommodates any incompatibilities between the operating speed of the rotary input member and the operating speeds of the prime mover and the electric machine by slipping;

selectively causing the coupler to slip while transmitting power between the rotary input member and at least one of the prime mover and the electric machine;

when the mobile machine is in motion, changing the drive ratio of the multiple-ratio transmission from a first drive ratio to a second drive ratio; and

in concert with changing the drive ratio of the multiple-ratio transmission, operating the electric machine to adjust an operating speed of the prime mover toward a synchronous speed for the second drive ratio.

15. The method of claim 14, wherein controlling the operating speeds of the prime mover and the electric machine independent of the operating speed of the rotary input member includes operating the electric machine as an electric motor to drive the prime mover when starting the prime mover.

16. The method of claim 15, wherein selectively causing the coupler to slip while transmitting power between the rotary input member and at least one of the prime mover and the electric machine includes

subsequent to starting the prime mover, with the rotary input member and the rotary output member of the multiple-ratio transmission drivingly connected, launching the mobile machine by causing the coupler to transmit power from the prime mover to the rotary input member while slipping.

17. The method of claim 14, further including:

while operating the electric machine to adjust the operating speed of the prime mover toward a synchronous speed for the second drive ratio, causing the rotary input member of the multiple-ratio transmission to be drivingly connected to the prime mover, including causing the coupler to have a power-transmitting operating state, so that the electric machine also adjusts the operating speed of the rotary input member toward a synchronous speed for the second drive ratio.

18. The method of claim 14, wherein operating the electric machine to adjust the operating speed of the prime mover toward a synchronous speed for the second drive ratio includes operating the electric machine to adjust the operating speed of the prime mover at least until the operating speed of the prime mover is substantially equal to the synchronous speed for the second drive ratio.

19. The method of claim 14, wherein selectively causing the coupler to slip while transmitting power between the rotary input member and at least one of the prime mover and the electric machine includes

with the rotary output member drivingly connected to the rotary input member, launching the mobile machine by causing the coupler to transmit power from the prime mover to the rotary input member while slipping.

20. The method of claim 14, further including:

selectively coordinating operation of the multiple-ratio transmission, the coupler, and the electric machine to launch the mobile machine while starting the prime mover, including simultaneously

causing the rotary input member and the rotary output member of the multiple-ratio transmission to be drivingly connected,

operating the electric machine as an electric motor while the coupler transmits power, so that the rotary electric machine drives the prime mover to enable starting the prime mover and also drives the propulsion devices through the multiple-ratio transmission to launch the mobile machine.

21. A power system, comprising:

a prime mover;

an electric machine;

a multiple-ratio transmission having a rotary input member and a rotary output member;

a variable-slip coupler connected between the prime mover and the rotary input member, the variable-slip coupler also being connected between the electric machine and the rotary input member; and

power-system controls operable to

selectively cause the variable-slip coupler to slip while transmitting power between the rotary input member of the multiple-ratio transmission and at least one of the prime mover and the electric machine, and

in concert with a change in a drive ratio of the multiple-ratio transmission from a first drive ratio to a second drive ratio, operate the electric machine to adjust an operating speed of the prime mover toward a synchronous speed for the second drive ratio.

22. The power system of claim 21, wherein the power-system controls are further operable to

while operating the electric machine to adjust the operating speed of the prime mover toward the synchronous speed for the second drive ratio, cause the rotary input member to be drivingly connected to the prime mover, including causing the variable-slip coupler to have a power-transmitting operating state, so that the electric machine also adjusts an operating speed of the rotary input member of the multiple-ratio transmission toward a synchronous speed for the second drive ratio.

23. The power system of claim 21, wherein the power-system controls are further operable to

when the prime mover is not operating under its own power, start the prime mover, including

operating the electric machine as an electric motor to drive the prime mover while causing the coupler to slip and the rotary input member of multiple-ratio transmission to be stationary.

24. The power system of claim 23, wherein:

the power system is part of a mobile machine having one or more propulsion devices drivingly connected to the rotary output member of the multiple-ratio transmission; and

causing the variable-slip coupler to slip while transmitting power between the rotary input member of the multiple-ratio transmission and at least one of the prime mover and the electric machine includes

subsequent to starting the prime mover, with the rotary input member and the rotary output member of the multiple-ratio transmission drivingly connected, launching the mobile machine by causing the prime mover to transfer power through the variable-slip coupler to the rotary input member of the multiple-ratio transmission while the variable-slip coupler slips.

25. The power system of claim 21, wherein operating the electric machine to adjust the operating speed of the prime mover toward the synchronous speed for the second drive ratio includes operating the electric machine to adjust the operating speed of the prime mover until the operating speed of the prime mover is approximately equal to the synchronous speed for the second drive ratio.

26. The power system of claim 21, wherein:

the power system is part of a mobile machine having one or more propulsion devices drivingly connected to the rotary output member of the multiple-ratio transmission;

the power-system controls are further operable to coordinate operation of the multiple-ratio transmission, the coupler, and the electric machine to launch the mobile machine while starting the prime mover, including simultaneously

causing the rotary input member and the rotary output member of the multiple-ratio transmission to be drivingly connected, and

operating the electric machine as an electric motor while the coupler transmits power, so that the rotary electric machine drives the prime mover to enable starting the prime mover and also drives the propulsion devices through the multiple-ratio transmission to launch the mobile machine.