System and method for coupled and decoupled engine starting in a hybrid vehicle

• US 9,937,919 B2
• Filed: 03/10/2016
• Issued: 04/10/2018
• Est. Priority Date: 03/10/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Zhang, Chen, Wang, Xiaoyong
• Primary Examiner(s): To, Tuan C
• Application Number:
  US15/066,263
• Publication Number:
  US 20170259810A1
• Time in Patent Office: 761 Days
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• CPC Class Codes: B60K 6/387 Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• 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 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60Y 2300/63 Starter motor mode
• CPC Class Codes: B60Y 2400/46 Engine start hydraulic or electric motors
• CPC Class Codes: B60Y 2400/608 Clutch motors, i.e. having rotating stators
• CPC Class Codes: F02N 11/006 using a plurality of electric motors
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 2300/2002 : using different starting modes, methods, or actuators depending on circumstances, e.g. engine temperature or component wear
• 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: Y10S 903/906 : Motor or generator
• CPC Class Codes: Y10S 903/914 : Actuated, e.g. engaged or disengaged by electrical, hydraulic or mechanical means
• CPC Class Codes: Y10S 903/919 : Stepped shift
• CPC Class Codes: Y10S 903/93 : Conjoint control of different elements

Abstract

A system and method for controlling engine starting in a hybrid vehicle having first and second electric machines include starting the engine in response to an engine start request using the first electric machine and releasing second electric machine reserved engine starting torque for use in propelling the vehicle. The first electric machine may be controlled to start the engine in response to the first engine start after key-on and when the vehicle speed is below a corresponding threshold, with the second electric machine used when vehicle speed is above the threshold. The first electric machine may be an integrated starter-generator.

Claims

1. A vehicle having an engine with a starter motor and coupled by a first clutch to an electric machine, which is coupled by a second clutch to a step-ratio transmission, comprising:

a processor programmed to start the engine using the starter motor for a first engine start after vehicle key-on and if vehicle speed is less than an associated threshold, and using the electric machine if vehicle speed exceeds the associated threshold, the processor further programmed to release electric machine torque reserved for starting the engine to propel the vehicle in response to scheduling a subsequent engine start using the starter motor.

2. The vehicle of claim 1, the processor further programmed to start the engine using the electric machine in response to a starter motor fault.

3. The vehicle of claim 1, the processor further programmed to start the engine using the starter motor in response to an electric machine fault.

4. The vehicle of claim 1, the processor further programmed to disengage the first clutch when starting the engine using the starter motor.

5. The vehicle of claim 1, the processor further programmed to engage the first clutch before starting the engine using the electric machine.

6. A method for controlling a hybrid vehicle, comprising:

starting an engine using a first electric machine in response to a first engine start request after key-on and when vehicle speed is below a threshold;

starting the engine using a second electric machine coupled to the engine through an engaged clutch in response to the vehicle speed being above the threshold or a fault in the first electric machine; and

scheduling a subsequent engine start using the second electric machine and releasing reserved torque of the first electric machine for use in propelling the vehicle.

7. The method of claim 6 further comprising disengaging the clutch prior to starting the engine using the first electric machine.

8. The method of claim 6 wherein the first electric machine comprises an integrated starter-generator.

9. The method of claim 6 further comprising releasing reserved torque of the second electric machine for vehicle propulsion in response to scheduling a subsequent engine start using the first electric machine.