Method for engine starting in a hybrid vehicle

Patent metadata

Field	Value
Publication number	US-9481358-B2
Application number	US-201214649378-A
Country	US
Kind code	B2
Filing date	Dec 7, 2012
Priority date	Dec 7, 2012
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

A starting method for starting an internal combustion engine of a hybrid vehicle involves detecting at least one engine related parameter to determine whether an electric machine is to be used for cranking the engine and opening the clutch to separate the electric machine from the engine. Subsequently, the at least one detected engine related parameter is used to select rotatable components to be used for assisting engine start. The selected components are rotated by connecting the countershaft to the clutch. The electric machine is operated. The clutch is then closed in order to start the engine.

First claim

The invention claimed is:

1. A method for starting an internal combustion engine of a hybrid vehicle, the vehicle comprising:
the engine provided with an engine output shaft connectable to a driveline for driving at least one pair of driving wheels;
a single or dual-clutch transmission, which transmission comprises multiple rotatable components for transmitting torque from the engine to the driving wheels;
the transmission having at least one input shaft wherein at least one clutch is arranged to connect a corresponding input shaft to the engine,
the transmission has an output shaft and at least a first countershaft which are connectable to the at least one clutch;
an electric machine, which is mechanically connected to the first countershaft downstream of the at least one clutch, so that the at least one clutch is interposed between the electric machine and the engine;
wherein the method comprises the steps of:
detecting at least one engine related parameter to determine whether the electric machine is to be assisted for cranking the engine;
opening at least one clutch of the at least one clutch to separate the electric machine from the engine;
controlling the transmission for separating the electric machine from the driving wheels;
selecting at least one of a number of sets of rotatable transmission components to be used for assisting engine start, based on the at least one detected engine related parameter;
engaging at least one gear, connecting the at least one selected set of rotatable transmission components to the at least one clutch;
operating the electric machine as a motor to rotate the at least one selected set of rotatable transmission components and to reach predetermined crank rotation speed; and
closing at least one clutch of the at least one clutch when the electric machine reaches the crank rotation speed, in order to start the engine.

2. The method according to claim 1 , comprising operating the electric machine and selecting a first set of rotatable components for assisting engine start when at least one detected engine related parameter is below a first predetermined limit.

3. The method according to claim 2 , comprising operating the electric machine and selecting a second set of rotatable components for assisting engine start when at least one detected engine related parameter is below a second predetermined limit.

4. The method according to claim 3 , wherein the moment of inertia of the second set of rotatable components is greater than the moment of inertia of the first set of rotatable components.

5. The method according to claim 1 , comprising detecting the state of charge of an energy storage and determining that the electric, machine is to be assisted for cranking the engine when the state of charge is below at least a first predetermined limit.

6. The method according to claim 1 , comprising detecting the energy storage temperature and determining that the electric machine is to be assisted for cranking the engine when the energy storage temperature is below at least a first predetermined limit.

7. The method according to claim 1 , comprising detecting the ambient temperature and determining that the electric machine is to be assisted for cranking the engine when the ambient temperature is below at least a first predetermined limit.

8. The method according to claim 1 , comprising detecting the coolant temperature of the engine and determining that the electric machine is to be assisted for cranking the engine when the coolant temperature is below at least a first predetermined limit.

9. The method according to claim 1 , wherein the transmission is a dual-clutch transmission having first and second input shafts of the at least one input shaft, of which the first input shaft is connected to a first clutch of the at least one clutch and the second input shaft is connected to a second clutch of the at least one clutch, the output shaft of the transmission and at least the first countershaft, where the output shaft of the transmission and the first countershaft are connectable to the first clutch and the second clutch, respectively; comprising the steps of:
engaging an initial, gear, connecting at least the first countershaft to one clutch of the first and second clutches;
engaging a further gear, connecting at least the first countershaft to other clutch of the first and second clutches;
operating the electric machine as a motor to rotate the selected rotatable components and to reach predetermined crank rotation speed; and
closing one of the first and second clutches when the electric machine reaches the crank rotation speed, in order to start the engine.

10. The method according to claim 9 , comprising operating the electric machine and using a first set of rotatable components, comprising the rotary masses of the electric machine, the first countershaft, the first and second input shafts and the first and second clutches, for assisting the electric machine when cranking the engine.

11. The method according to claim 10 , comprising using the first gear for connecting the first countershaft to the first clutch.

12. The method according to claim 10 , comprising using the second gear for connecting the first countershaft to the second clutch.

13. The method according to claim 10 , comprising using the second gear for connecting the first countershaft to the first clutch.

14. The method according to claim 9 , comprising closing the second clutch when the electric machine reaches the crank rotation speed.

15. The method according to claim 9 , comprising separating the electric machine from the driving wheels by disconnecting the first and second input shafts from the output shaft of the transmission.

16. The method according to claim 9 , comprising operating the electric machine and using a first and a second set of rotatable components, comprising the rotary masses of the electric machine, the first countershaft, the first and second input shafts, the first and second clutches and the output shaft of the transmission, for assisting the electric machine when cranking the engine.

17. The method according to claim 16 , comprising using the second gear for connecting the first countershaft to the second clutch.

18. The method according to claim 16 , comprising using a base gear for connecting the first countershaft and the output shaft for starting an internal combustion engine of a hybrid vehicle to the first clutch.

19. The method according to claim 9 , comprising closing the first clutch when the electric machine reaches the crank rotation speed.

20. The method according to claim 9 , comprising separating the electric machine from the driving wheels by disconnecting the output shaft of the transmission from a range gear interposed between the output shaft of the transmission and the driving wheels.

21. The method according to claim 1 , wherein the transmission a single clutch transmission having an input shaft of the at least one input shaft, connected to a first clutch of the at least one clutch, the output shaft of the transmission and at least the first countershaft, where the output shaft of the transmission and the first countershaft are connectable to the first clutch; comprising the steps of:
engaging an initial gear, connecting at least the first countershaft to the first clutch;
operating the electric machine as a motor to rotate the selected rotatable components and to reach predetermined crank rotation speed; and
closing the first clutch when the ele

Assignees

• Volvo Truck Corp

Inventors

• Hansson Mattias

Classifications

• B60W2555/20

  Ambient conditions, e.g. wind or rain · CPC title

• B60W20/40 Primary

  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 title

• B60W2510/0676

  Engine temperature · CPC title

• B60W2710/1005

  Transmission ratio engaged · CPC title

• B60W10/06

  including control of combustion engines · CPC title