Hybrid vehicle powertrain and control therefor

• US 6,176,808 B1
• Filed: 07/15/1999
• Issued: 01/23/2001
• Est. Priority Date: 07/15/1999
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Brown, Larry Thomas, Ortmann, Walter Joseph, Kraska, Marvin Paul
• Primary Examiner(s): Marmor, Charles A
• Assistant Examiner(s): Parekh, Ankur
• Application Number:
  US09/353,290
• Time in Patent Office: 558 Days
• Field of Search: 477/2, 477/3, 477/5, 477/6, 477/906, 746/61, 475/5, 192/85.AA, 192/86, 180/65.2
• US Class Current: 477/5
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/405 Housings
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2220/12 Induction machines
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: F16H 2200/0043 the gear ratios comprising four forward speeds
• CPC Class Codes: F16H 2200/2007 with two sets of orbital gears
• CPC Class Codes: F16H 2200/201 with three sets of orbital gears
• CPC Class Codes: F16H 2200/2043 with five engaging means
• CPC Class Codes: F16H 3/66 composed of a number of gear trains without drive passing from one train to another
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y10S 903/91 : Orbital, e.g. planetary gears
• CPC Class Codes: Y10S 903/945 : Characterized by control of gearing, e.g. control of transmission ratio

Abstract

A powertrain assembly for an automotive vehicle having an interanal combustion engine and transmission gearing for delivering engine torque to traction wheels of a vehicle. An electric induction motor is situated in the torque flow path between the engine and the transmission. The induction motor complements engine torque which permits the engine to be turned off when the vehicle is at rest, thereby improving fuel economy and rendering undesirable exhaust gas emissions from the internal combustion engine. The torque multiplication that would normally be available from a hydrokinetic torque converter in the transmission is essentially replaced with auxiliary launch torque supplied by the induction motor during vehicle startup. The vibration damping function of a hydrokinetic torque converter during engine idle is also performed by the induction motor. Therefore, a hydrokinetic torque converter in the transmission in not necessary. The induction motor, during those operating modes of the vehicle when induction motor torque is not required to deliver driving torque, functions as an alternator during periods of regenerative braking with the internal combustion engine inactive and with the vehicle in a coast mode.

Claims

1. A hybrid vehicle powertrain comprising an internal combustion engine, a multiple-ratio power transmission mechanism, and an electric motor;

the transmission mechanism having multiple-ratio gearing and clutch and brake means for establishing and disestablishing multiple torque flow paths through the gearing;

the clutch and brake means including a controllable, pressure-actuated friction clutch in a torque flow path between the engine and torque input elements of the gearing;

a torque input shaft of the transmission mechanism being connected to the engine through the friction clutch;

the electric motor being drivably connected to the torque input shaft in parallel disposition with respect to the engine whereby each is capable of delivering driving torque to the torque input shaft;

the motor thereby forming a source of driving torque that complements driving torque of the engine when the engine is activated and forming a sole source of driving torque when the engine is deactivated;

means for controlling electronic engagement of the friction clutch during engine idle comprising means for detecting engine torque and determining a torque signal indicative of an idle torque offset from the engine torque; and

means for combining engine torque during idle with electric motor torque and for maintaining a regulated clutch actuating pressure responsive to the torque signal whereby engine idle torque variations are modified during engine idle by electric motor torque to effect electronic damping of engine torque during engine idle.

3. The hybrid vehicle powertrain set forth in claim 1 wherein the clutch and brake means includes an engine disconnect clutch that establishes and disestablishes a torque flow path between the engine and the multiple-ratio gearing.

5. The hybrid vehicle powertrain set forth in claim 1 wherein the clutch and brake means include hydraulic pressure actuators including movable actuator pistons that are stroked from a clutch and brake release position to a clutch and brake apply position;

the transmission mechanism having an engine-driven fluid pressure pump and a control valve circuit means for selectively supplying actuating fluid pressure from the engine-driven pump to the hydraulic pressure actuators; and

an auxiliary pump with a driving torque source independent of the engine-driven pump, said control valve circuit including passage structure connecting the auxiliary pump to the hydraulic pressure actuators when the engine is inactive thereby maintaining a threshold pressure in the hydraulic pressure actuators.

7. The hybrid vehicle powertrain set forth in claim 5 wherein the control valve circuit comprises solenoid-operated valve means for controlling pressure distribution to the pressure actuators, and a pitot pressure generator comprising a pitot pickup element and a body of fluid forming a part of the valve circuit, the body of fluid and the pitot pickup element being relatively rotatable, one with respect to the other, at a speed proportional to engine speed;

and means for distributing velocity pressure from the pitot pickup element to the control circuit whereby the pitot pressure generator applies circuit pressure to the valve circuit to replace transmission engine-driven pump pressure when the solenoid-operated valve means are nonfunctional.

9. The hybrid vehicle powertrain set forth in claim 5 wherein control valve circuit means includes priority valve elements disposed between the engine-driven pump and the hydraulic pressure actuators;

and

means for activating the priority valve elements to effect pressure distribution to first ones of the hydraulic pressure actuators that establish torque flow paths in the gearing for power delivery with a first torque ratio while preventing pressure distribution to second ones of the pressure actuators for power delivery with a second torque ratio.

2. A hybrid vehicle powertrain comprising a throttle controlled internal combustion engine, a multiple-ratio power transmission and an electric motor;

the transmission having multiple-ratio gearing and clutch and brake means for establishing and disestablishing multiple torque flow paths through the gearing;

a friction clutch;

a torque input member of the transmission being connected directly to the engine through the clutch; and

an electric motor drivably connected to the torque input member in parallel disposition with respect to the engine whereby each is capable of delivering driving torque to the torque input member;

the friction clutch, when it is disengaged, interrupting torque delivery from the engine to the torque input member;

the motor forming a source of driving torque that complements driving torque of the engine when the friction clutch is engaged and forming a source of torque independent of the engine when the friction clutch is disengaged;

means for combining electric motor torque with engine torque during launch of the vehicle including means for computing vehicle speed during launch as a function of clutch gain;

means for detecting actual vehicle speed and engine throttle position during launch;

an electronic controller including a stored functional relationship between throttle position and actual vehicle speed to determine desired power from the electric motor;

means for determining a target engine speed as a function of throttle position and computed vehicle speed; and

means for controlling friction clutch gain as a function of the error between target engine speed and actual engine speed whereby a smooth vehicle launch is accomplished.

4. The hybrid vehicle powertrain set forth in claim 2 wherein the gearing, upon reverse torque delivery therethrough during coasting, drives the electric motor to effect regenerative braking that converts kinetic energy in the powertrain to electrical voltage energy.

6. The hybrid vehicle powertrain as set forth in claim 2 wherein the torque flow paths include a separate clutch located between the engine and the electric motor.

8. A hybrid vehicle powertrain comprising an internal combustion engine, a power transmission and an electric motor;

a friction clutch;

a torque input member of the transmission being connected to the engine through the clutch;

the electric motor being drivably connected to the torque input member in parallel disposition with respect to the engine whereby each is capable of delivering driving torque to the torque input member;

the clutch, when it is disengaged, interrupting torque delivery from the engine to the torque input member;

the motor forming a source of driving torque that complements driving torque of the engine when the clutch is engaged and forming a source of torque independent of the engine when the friction clutch is disengaged;

the clutch comprising driving and driven clutch discs in a disc assembly and a clutch piston actuator for applying a clutch disc engaging force to the disc assembly;

a fluid pressure clutch chamber defined in part by the clutch piston actuator;

the clutch chamber, when pressurized, creating a clutch disc engaging force on the clutch piston actuator; and

a clutch spring acting on the clutch piston actuator thereby creating a threshold clutch disc engaging force that creates a reduced delay in establishing clutch torque capacity as clutch piston actuator pressure is distributed to the clutch chamber.

10. A hybrid vehicle powertrain comprising an internal combustion engine, a multiple-ratio power transmission mechanism, and an electric motor;

the transmission mechanism having multiple-ratio gearing and clutch and brake means for establishing and disestablishing multiple torque flow paths through the gearing;

the clutch and brake means including a controllable, pressure-actuated friction clutch in a torque flow path between the engine and torque input elements of the gearing;

a torque input shaft of the transmission mechanism being connected to the engine through the friction clutch;

the electric motor being drivably connected to the torque input shaft in parallel disposition with respect to the engine whereby each is capable of delivering driving torque to the torque input shaft;

the motor thereby forming a source of driving torque that complements driving torque of the engine when the engine is activated and forming a sole source of driving torque when the engine is deactivated;

means for controlling electronic engagement of the friction clutch during engine idle comprising means for detecting engine torque and determining a torque signal indicative of engine idle torque;

means for combining engine torque during idle with electric motor torque and for maintaining a regulated clutch actuating pressure responsive to the torque signal whereby engine idle torque variations are modified during engine idle by electric motor torque to effect electronic damping of engine torque during engine idle;

means for combining electric motor torque with engine torque during launch of the vehicle including means for computing vehicle speed during launch as a function of friction clutch gain;

means for detecting actual vehicle speed and engine throttle position during launch;

an electronic controller including a stored functional relationship between throttle position and actual vehicle speed to determine desired power from the electric motor;

means for determining a target engine speed as a function of throttle position and computed vehicle speed; and

means for controlling clutch gain as a function of the error between target engine speed and actual engine speed whereby a smooth vehicle launch is accomplished.