Method and a system for controlling the propulsion of a motor vehicle

• US 6,524,219 B2
• Filed: 08/02/2001
• Issued: 02/25/2003
• Est. Priority Date: 08/02/2000
• Status: Expired due to Term

• Current Assignee: C.R.F. Societa Consortile Per Azioni
• Original Assignee: C.R.F. Societa Consortile Per Azioni
• Inventors: Fossanetti, Massimo, Osella, Giancarlo, Ellena, Giovanni, Porta, Attilio, Lupo, Massimo, Mesiti, Domenico
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): ABDELNOUR, DENNIS J
• Application Number:
  US09/919,805
• Publication Number:
  US 20020019290A1
• Time in Patent Office: 572 Days
• Field of Search: 477/3, 477/5, 180/65.2, 180/65.3, 180/65.4, 180/65.8
• US Class Current: 477/5
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/486 Operating parameters
• 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 10/10 including control of change-speed 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 2050/0045 using databus protocols
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2510/1015 Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/945 Characterized by control of gearing, e.g. control of transmission ratio
• CPC Class Codes: Y10S 903/946 Characterized by control of driveline clutch

Abstract

A first clutch and a second clutch, which are operable selectively, control the coupling of the rotor of a reversible electrical machine with the transmission and with the internal combustion engine, respectively. A control system is provided for implementing a stop-start function in which, in a stop stage, the internal combustion engine is disconnected from the electrical machine and from the transmission and is switched off, in first predetermined operating conditions of the vehicle and then, as a result of the occurrence of second operating conditions, such as a command imparted by the driver, in a subsequent start stage, is automatically restarted by means of the electrical machine operating as a motor, and is then reconnected to the transmission. The system is characterized especially by particular methods of controlling the clutches and the electrical machine during the start stage.

Claims

1. A system for controlling propulsion for a motor vehicle, provided with:

an internal combustion engine,

a transmission including a gearbox provided with associated actuator means,

a reversible electrical machine which includes a rotor and a stator, and which is interposed between the internal combustion engine and the transmission and is adapted to operate selectively as a generator and as an electric motor,

a first clutch and a second clutch adapted to be operated selectively in order to control the coupling of the rotor of the electrical machine with the transmission and with the internal combustion engine, respectively,

sensor means for providing electrical signals indicative of operating conditions of the vehicle, of the internal combustion engine, and of the electrical machine, and

control means arranged to control the internal combustion engine, the electrical machine, the first clutch and the second clutch, as well as the gearbox actuator means, in dependence on the signals provided by the sensor means,

the control means being arranged, to implement a stop-start function in which, in a stop stage, the internal combustion engine is disconnected from the electrical machine and from the transmission and is switched off in first predetermined operating conditions of the vehicle and then, upon the occurrence of second predetermined operating conditions, in a subsequent start stage, is automatically restarted by the electrical machine, operating as a motor, and is then reconnected to the transmission,

the control means being arranged to bring about during the start stage;

activation of the electrical machine as a motor whilst the second clutch is substantially disengaged and the first clutch is engaged in controlled manner in order to bring about driving of the transmission by the electrical machine,

monitoring of the driving torque demanded, which corresponds to the degree of operation of the accelerator pedal and, when this torque reaches a predetermined threshold value;

partial disengagement of the first clutch, controlled in a manner such that a torque equal to the threshold value continues to be applied to the transmission whilst the electrical machine is caused to deliver substantially its maximum torque, and

a first engagement of the second clutch as soon as the speed of rotation of the electrical machine exceeds a predetermined threshold so that the internal combustion engine is rotated in order to be started by means of the electrical machine.

2. A system according to claim 1 in which the control means are arranged to bring about the first engagement of the second clutch when the difference between the speed of rotation of the electrical machine and the speed of rotation of the input shaft of the transmission exceeds a predetermined value.

3. A system according to claim 1 in which the first engagement of the second clutch has a predetermined duration, after which the second clutch is substantially disengaged again and is then finally re-engaged.

4. A system according to claim 3 in which, after the final re-engagement of the second clutch, the first clutch is also progressively re-engaged.

5. A method of controlling propulsion in a motor vehicle provided with:

an internal combustion engine,

a transmission including a gearbox provided with associated actuator means,

a reversible electrical machine which includes a rotor and a stator, and which is interposed between the internal combustion engine and the transmission and is adapted to operate selectively as a generator and as an electric motor,

a first clutch and a second clutch adapted to be operated selectively in order to control the coupling of the rotor of the electrical machine with the transmission and with the internal combustion engine, respectively,

the method comprising the implementation of a stop-start function including;

initiating a stop stage by disconnecting and switching off the internal combustion engine from the electrical machine and from the transmission, and

restarting the internal combustion engine by means of the electrical machineoperating as a motor and then reconnecting the engine to the transmission;

wherein during the start stage the method includes;

starting the electrical machine as a motor whilst the second clutch is substantially disengaged and the first clutch is engaged in controlled manner in order to bring about driving of the transmission by the electrical machine,

monitoring the driving torque demanded, which corresponds to the degree of operation of the accelerator pedal of the motor vehicle, and when this torque reaches a predetermined threshold value;

partially disengaging the first clutch in a controlled manner such that a torque equal to the threshold value continues to be applied to the transmission whilst the electrical machine is caused to deliver substantially its maximum torque, and

initiating a first engagement of the second clutch as soon as the speed of rotation of the electrical machine exceeds a predetermined threshold, so as to rotate the internal combustion engine in order to start it by means of the electrical machine.

6. A method according to claim 5 in which the first engagement of the second clutch is brought about when the difference between the speed of rotation of the electrical machine and the speed of rotation of the input shaft of the transmission exceeds a predetermined value.

7. A method according to claim 5 in which the first engagement of the second clutch has a predetermined duration and the second clutch is then substantially disengaged and is then finally re-engaged.

8. A method according to claim 7 in which, after the final re-engagement of the second clutch, the first clutch is also progressively re-engaged.