Hydraulic hybrid vehicle

• US 6,719,080 B1
• Filed: 01/10/2000
• Issued: 04/13/2004
• Est. Priority Date: 01/10/2000
• Status: Expired due to Term

• Current Assignee: US Environmental Protection Agency (Government of the United States of America)
• Original Assignee: United States Environmental Protection Agency
• Inventors: Gray, Charles L. Jr.
• Primary Examiner(s): Rice, Kenneth R.
• Assistant Examiner(s): GORT, ELAINE L
• Application Number:
  US09/479,844
• Time in Patent Office: 1,555 Days
• Field of Search: 180/165, 180/305, 180/307, 180/308, 604/14, 604/16, 604/25, 604/17
• US Class Current: 180/165
• CPC Class Codes: B60K 17/10 of fluid gearing of fluid clutches B60K17/02
• CPC Class Codes: B60K 2006/126 the hydraulic accumulator starts the engine
• CPC Class Codes: B60K 26/02 of initiating means or elements
• CPC Class Codes: B60K 6/12 by means of a chargeable fluidic accumulator
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/18 including control of braking systems
• 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 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/09 Other types of propulsion units, e.g. fluid motors, or type not specified
• CPC Class Codes: B60W 2710/24 Energy storage means
• CPC Class Codes: B60W 2720/24 Direction of travel
• CPC Class Codes: B60W 30/18127 Regenerative braking
• CPC Class Codes: F16H 61/4096 with pressure accumulators
• CPC Class Codes: F16H 61/44 with more than one pump or motor in operation
• CPC Class Codes: F16H 61/448 Control circuits for tandem pumps or motors
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10T 74/19014 Plural prime movers selectively coupled to common output
• CPC Class Codes: Y10T 74/19033 Fluid drive divides or combines alternate paths

Abstract

An automotive powertrain includes a hydraulic drive circuit including at least one of: (1) a hydraulic pump/motor having a shaft fixed to for rotation with the crankshaft of an internal combustion engine and (2) a pair of pump/motors coaxially arranged to share a common shaft on which is mounted a gear of a gear set for transmitting output to the vehicle drive wheels. Hydraulic control logics are provided for control of the various pump/motors of the hybrid powertrain.

Claims

1. An automotive powertrain comprising:

a pair of drive wheels;

at least one accumulator for receiving hydraulic fluid and storing pressure and for discharging the stored pressure;

a first hydraulic pump/motor for driving said drive wheels in a motor mode responsive to receipt of hydraulic fluid and for pumping hydraulic fluid to said accumulator responsive to braking;

an internal combustion engine having an engine crankshaft extending from said engine to a distal end;

a second hydraulic pump/motor utilizing said engine crankshaft as its input/output shaft and, when operating in a pump mode, pumping hydraulic fluid to at least one of said accumulator and said first hydraulic pump/motor wherein said second hydraulic pump/motor is a bent-axis piston pump including a drive plate fixed to said distal end of said engine crankshaft and pistons for rotatably driving said drive plate; and

a common set of bearings used both as back bearings for said crankshaft and as drive bearings for said second hydraulic pump/motor.

2. The automotive powertrain of claim 1 additionally comprising a gear set through which said first hydraulic pump/motor is connected to said drive wheels, said first pump/motor providing input/output at a first input/output shaft integral therewith and fixed to one gear of said gear set for rotation therewith.

3. The automotive powertrain of claim 2 wherein said gear set is a reduction gear differential.

4. The automotive powertrain of claim 2 further comprising a third pump/motor providing input/output at a second input/output shaft integral therewith and fixed to said one gear for rotation therewith, said first and third pump/motors being located on opposing sides of said one gear with said first and second input/output shafts axially aligned with each other and joined together to form a single shaft with said one gear mounted thereon.

5. The automotive powertrain of claim 4 wherein said first and second drive shafts are integrated into a single drive shaft for said one gear.

6. The automotive powertrain of claim 4 wherein said first, second and third pump/motors are inline piston pumps.

7. The automotive powertrain of claim 6 wherein said first, second and third pump/motors are bent-axis piston pumps.

8. The automotive powertrain of claim 1 wherein said second hydraulic pump is a pump/motor which is also operable in a motor mode to start said engine.

9. The automotive powertrain of claim 1 wherein said distal end of said engine crankshaft is a flange and said drive plate is axially aligned with said engine crankshaft and fixed to said flange.

10. An automotive powertrain comprising:

a pair of drive wheels;

an internal combustion engine;

a first pump/motor for driving said drive wheels in a motor mode responsive to receipt of high pressure fluid from a high pressure line and for operation in a pump mode to deliver high pressure fluid to the high pressure line responsive to braking of said drive wheels;

a second pump/motor driven by said internal combustion engine for operation in a pump mode to deliver high pressure fluid to said high pressure line;

a high pressure accumulator for receiving and discharging high pressure fluid through said high pressure line;

a low pressure accumulator for receiving and discharging low pressure fluid through a low pressure line;

a hydraulic controller, connected to said high and low pressure lines, for controlling fluid flow to and from said first and second pump/motors and to and from said high and low pressure accumulators;

first and second parallel lines connecting respective opposing sides of said first pump/motor to said hydraulic controller;

a cutoff valve in said high pressure line for, in a closed state, preventing flow of hydraulic fluid to said high pressure accumulator; and

an auxiliary accumulator having a smaller capacity than said high pressure accumulator and located between said cutoff valve and said second hydraulic pump, said auxiliary accumulator moderating pressure within said high pressure line when said high pressure accumulator is not allowed to receive fluid.

11. The automotive powertrain of claim 10 additionally comprising a check valve, in parallel with said cutoff valve, for preventing flow of hydraulic fluid into said high pressure accumulator while allowing flow of hydraulic fluid from said high pressure accumulator.

12. An automotive powertrain comprising:

a pair of drive wheels;

an internal combustion engine;

a first pump/motor for driving said drive wheels in a motor mode responsive to receipt of high pressure fluid from a high pressure line and for operation in a pump mode to deliver high pressure fluid to the high pressure line responsive to braking of said drive wheels;

a second pump/motor driven by said internal combustion engine for operation in a pump mode to deliver high pressure fluid to said high pressure line;

a high pressure accumulator for receiving and discharging high pressure fluid through said high pressure line;

a low pressure accumulator for receiving and discharging low pressure fluid through a low pressure line;

a hydraulic controller, connected to said high and low pressure lines, for controlling fluid flow to and from said first and second pump/motors and to and from said high and low pressure accumulators;

first and second parallel lines connecting respective opposing sides of said first pump/motor to said hydraulic controller;

first and second cutoff valves in parallel between (1) said high pressure accumulator and (2) said high pressure line and said hydraulic controller;

first and second check valves in parallel with each other and in series with, respectively, said first and second cutoff valves, said first check valve permitting flow only into said high pressure accumulator and said second check valve permitting flow only from said high pressure accumulator.

13. The automotive powertrain of claim 12 further comprising:

an auxiliary accumulator, having a smaller capacity than said high pressure accumulator, connected to said high pressure line and to said second pump/motor through a by-pass line and a control valve in said by-pass line for, when opened, allowing high pressure fluid to flow from said auxiliary accumulator to operate said second pump/motor in a motor mode to start said internal combustion engine.

14. The automotive powertrain of claim 13 further comprising:

a check valve between said auxiliary accumulator and said high pressure line to allow fluid flow only in a direction from said high pressure line into said auxiliary accumulator.

15. An automotive powertrain comprising:

a pair of drive wheels;

an internal combustion engine with a crankshaft for power output;

at least one accumulator for receiving hydraulic fluid and storing pressure and for discharging the stored pressure;

a gear set connected to said drive wheels

first and second hydraulic pump/motors, located on opposing sides of one gear of said gear set and sharing a common input/output shaft therebetween with said one gear mounted thereon, said first and second hydraulic motors being axially aligned and fixed to opposite ends of the common input/output shaft, said first and second hydraulic motors, operating in a motor mode to drive said drive wheels through said gear set and in a pump mode for pumping hydraulic fluid into said accumulator responsive to braking of said drive wheels;

a third hydraulic pump driven by said internal combustion for pumping hydraulic fluid to at least one of said accumulator and said first and second hydraulic pump/motors in a pump mode.

16. The automotive powertrain of claim 15 wherein said first and second hydraulic pump/motors are inline piston pumps.

17. The automotive powertrain of claim 15 wherein said first and second hydraulic pump/motors are bent-axis piston pumps.

18. The automotive powertrain of claim 15 wherein said third hydraulic pump has a shaft fixed to said crankshaft for rotation therewith.

19. An automotive powertrain comprising:

a pair of drive wheels;

an internal combustion engine;

a first pump/motor for driving said drive wheels in a motor mode responsive to receipt of high pressure fluid from a high pressure line and for operation in a pump mode to deliver high pressure fluid to the high pressure line responsive to braking of said drive wheels;

a second pump/motor driven by said internal combustion engine for operation in a pump mode to deliver high pressure fluid to said high pressure line;

a high pressure accumulator for receiving and discharging high pressure fluid through said high pressure line;

a low pressure accumulator for receiving and discharging low pressure fluid through a low pressure line;

first and second parallel lines for connecting, in parallel, one side of said first pump/motor to said high pressure and low pressure lines, respectively, said first parallel line having a first valve which opens to admit high pressure fluid from said high pressure line to said one side of said first pump/motor in forward drive, said second parallel line having a second valve which opens to admit low pressure fluid from said low-pressure line to said one side of said first pump/motor in reverse drive;

third and fourth parallel lines connecting, in parallel, a second side of said first pump/motor to said low pressure and high pressure lines, respectively, said third parallel line having a third valve which opens to admit low pressure fluid from said low pressure line to said second side of said first pump/motor in forward drive, said fourth parallel line having a fourth valve which opens to admit high pressure fluid from said high pressure line to said second side of said first pump/motor in reverse drive, wherein all of said first through fourth valves are check valves and are in a closed, checked position in said pump mode.

20. The automotive powertrain of claim 19 further comprising:

fifth and sixth parallel lines connecting, in parallel, one side of said second pump/motor to said high pressure and low pressure lines, respectively, said fifth parallel line having a fifth valve which opens to admit high pressure fluid from said high pressure line to said one side of said second pump/motor, said sixth parallel line having a sixth valve in the form of a check valve preventing fluid flow form said high pressure line to said low pressure line; and

seventh and eighth parallel lines connecting, in parallel, a second side of said second pump/motor, said seventh parallel line having a seventh valve which opens to admit low pressure fluid from said low pressure line to said second side of said second pump/motor, said eighth parallel line having a eighth valve in the form of a check valve preventing flow from said high pressure line into said low pressure line.

21. The automotive powertrain of claim 20 wherein said valves in said sixth and eight parallel lines are check valves.

22. The automotive powertrain of claim 20 further comprising:

a third pump/motor for driving said drive wheels in a motor mode responsive to feed of high pressure fluid thereto and for operation in a pump mode to discharge high pressure fluid to the high pressure line responsive to braking of said wheels;

ninth and tenth parallel lines connecting, in parallel, one side of said third pump/motor to said high pressure and low pressure lines, respectively, said ninth parallel line having a ninth valve which opens to admit high pressure fluid from said high pressure line to one side of said third pump/motor, said tenth parallel line having a tenth valve in the form of a check valve preventing high pressure fluid from flowing from said high pressure line into said low pressure line; and

eleventh and twelfth parallel lines connecting, in parallel, a second side of said third pump/motor to said low pressure and high pressure lines, respectively, said eleventh parallel line having a valve which opens to admit low pressure fluid from said low pressure line to said second side of said third pump/motor and said twelfth parallel line having a twelfth valve in the form of a check valve to prevent high pressure fluid from flowing from said high pressure line into said low pressure line.

23. The automotive powertrain of claim 22 further comprising:

gear set through which said drive wheels are driven by said first and third pump/motors; and

wherein said first and third pump/motors are mounted coaxially on opposing sides of one gear of said gear set, said first and third pump/motors each providing input/output at an input/output shaft integral therewith, said input/output shafts integrated into a single driveshaft having said one gear mounted thereon.

24. The automotive powertrain of claim 22 wherein said valves in said sixth and eighth lines are check valves.

25. The automotive powertrain of claim 22 wherein:

said first, second, third, fourth, fifth, seventh, ninth and eleventh valves have check valve functions when closed; and

said first, fourth, fifth and ninth valves always allow high pressure flow from said pump/motor into said high pressure line; and

said second, third, seventh and eleventh valves always allow flow from said pump/motor into said low pressure line.

26. The automotive power train of claim 19 wherein said high pressure and low pressure accumulators contain a compressible gas.

27. An automotive powertrain comprising:

a pair of drive wheels;

an internal combustion engine;

a first pump/motor operable over center for driving said drive wheels in a motor mode responsive to receipt of high pressure fluid from a high pressure line and for operation in a pump mode to deliver high pressure fluid to said high pressure line responsive to braking of said drive wheels;

a second pump/motor operable over center for starting said internal combustion engine in a motor mode responsive to receipt of high pressure fluid from said high pressure line and driven by said internal combustion engine for operation in a pump mode to deliver high pressure fluid to said high pressure line;

a high pressure accumulator in communication with said high pressure line;

a low pressure accumulator in communication with a low pressure line;

first and second parallel lines for connecting, in parallel, one side of said first pump/motor to said high pressure and low pressure lines, respectively, said first parallel line having a first valve which opens to admit high pressure fluid from said high pressure line to said one side of said first pump/motor, said second parallel line having a second valve in the form of a check valve for preventing fluid flow from said high pressure line to said low pressure line;

wherein a second side of said first pump/motor is connected to said low pressure line; and

third and fourth parallel lines connecting, in parallel, one side of said second pump/motor to said high pressure and low pressure lines, respectively, said third parallel line having a third valve which opens to admit high pressure fluid from said high pressure line to said one side of said second pump/motor, said fourth parallel line having a fourth valve in the form of a check valve for preventing fluid flow from said high pressure line to said low pressure line; and

wherein a second side a second pump/motor is connected to said low pressure line.

28. An automotive powertrain according to claim 27 additionally comprising:

a third pump/motor operable overcenter for driving said drive wheels in a motor mode responsive to feed of high pressure fluid thereto and for operation in a pump mode to discharge high pressure fluid to the high pressure line responsive to braking of said drive wheels;

fifth and sixth parallel lines connecting, in parallel, one side of said third pump/motor to said high pressure and low pressure lines, respectively, said fifth parallel line having a fifth valve which opens to admit high pressure fluid from said high pressure line to said one side of said third pump/motor, said sixth parallel line having a sixth valve in the form of a check valve preventing high pressure fluid from flowing from said high pressure line into said low pressure line; and

wherein a second side of said third pump/motor is connected directly to said low pressure line.

29. An automotive powertrain according to claim 28 wherein said valves in said second, fourth and sixth parallel lines are check valves.

30. The automotive powertrain of claim 28 further comprising:

a gear set through which said drive wheels are driven by said first and third pump/motors; and

wherein said first and third pump/motors are mounted coaxially with and on opposing sides of a drive gear of said gear set, said first and third pump/motors having shafts integrated into one drive shaft for said drive gear.

31. The automotive powertrain of claim 28 wherein said first, third and fifth valves have check valve functions when closed to always allow high pressure flow from said pump/motors to said high pressure line.

32. An automotive powertrain according to claim 27 wherein said valve in said second parallel line is a check valve.

33. An automotive powertrain according to claim 27 wherein said valves in said second and fourth parallel lines are check valves.

34. An automotive powertrain comprising:

a pair of drive wheels;

an internal combustion engine;

a first fluidic motor for driving said drive wheels responsive to receipt of high pressure fluid from a high pressure line;

a pump driven by said internal combustion engine to deliver high pressure fluid to said high pressure line;

a high pressure accumulator for receiving and discharging high pressure fluid through said high pressure line;

a low pressure accumulator for receiving and discharging low pressure fluid through a low pressure line;

a second fluidic motor, having a smaller capacity than said first fluidic motor, for driving said drive wheels responsive to receipt of high pressure fluid from said high pressure line;

a sensor for detecting position of an accelerator element within a range of movement divided into zones; and

an electronic control unit for selectively generating command signals for operation of said first fluidic motor and/or said second fluidic motor in accordance with the zone in which the accelerator element is positioned, said electronic control unit generating a first command signal for operation of said second fluidic motor alone in a first zone, said first command signal changing responsive to positioning of said accelerator element within a subzone of the first zone and leaving said first command signal unchanged with movement of said accelerator element within another subzone of the first zone, generating a second command signal for operation of said first fluidic motor alone responsive to detection of said accelerator element within a second zone and generating command signals for operation of both of said first and second fluidic motors responsive to detection of said accelerator element within a third zone.

35. The automotive powertrain of claim 34:

wherein said accelerator element is an accelerator pedal; and

wherein, upon depression of said accelerator pedal, said accelerator pedal moves, in succession, through said first, second and third zones.