Engine starting system

Patent metadata

Field	Value
Publication number	US-10288028-B2
Application number	US-201715447849-A
Country	US
Kind code	B2
Filing date	Mar 2, 2017
Priority date	Mar 3, 2016
Publication date	May 14, 2019
Grant date	May 14, 2019

Abstract

A control device sets reverse rotation period as a cranking prohibition period, and when a start request of an engine is generated during reverse rotation period, cranking is started by driving either or both of the first starter and the second starter when it is detected that a crankshaft is shifted from reverse rotation to forward rotation based on an information of a rotation angle sensor. As a result, the delay from generation of the start request of the engine until cranking is started can be reduced, so that the starting time of the engine can be shortened.

First claim

What is claimed is:

1. An engine starting system comprising:
a starting device for transmitting a rotational force thereof to a crankshaft of an engine to drive the crankshaft, the starting device including a first starter constantly connected to the crankshaft and a second starter connected to the crankshaft by a disengageable coupling; and
a control device for controlling an operation of the starting device in response to a start request of the engine; wherein
the engine starting system includes a rotation determination section capable of discriminating a rotation direction of the crankshaft;
when a period where the crankshaft rotates in a reverse direction while the engine is stopping is referred to as a reverse rotation period;
the control device sets the reverse rotation period as a cranking prohibition period for prohibiting the starting device from driving the crankshaft;
if the start request is generated during the reverse rotation period, the starting device is operated to drive the crankshaft based on an information from the rotation determination section when it is detected that the crankshaft has shifted from reverse rotation to forward rotation by driving the crankshaft by either one of the first starter and the second starter, or both the first starter and the second starter;
the first starter is an alternator that varies a rotational speed according to a power source frequency; and
the control device is an inverter that includes a switching element for varying a frequency to be applied to the alternator according to an on/off operation of the switching element, and a control circuit for controlling an on/off operation of the switching element while managing a drive timing of the second starter.

2. The engine starting system according to claim 1 , wherein
the control device drives the starting device to drive the crankshaft when the control device detects that the crankshaft has shifted from a first reverse rotation to the forward rotation.

3. The engine starting system according to claim 1 , wherein
by operating the first starter, the control device suppresses the reverse rotation of the crankshaft from being caused when the reverse rotation of the crankshaft is detected based on the information from the rotation determination section.

4. The engine starting system according to claim 1 , wherein
the first starter has a rotation angle detection section capable of detecting a rotational position of the first starter; and
the rotation determination section discriminates the rotation direction of the crankshaft by inputting the rotational position of the first starter detected by the rotation angle detection section.

5. The engine starting system according to claim 1 , wherein
the rotation determination section discriminates the rotation direction of the crankshaft based on a physical quantity managed by the control device to control an operation of the first starter.

6. The engine starting system according to claim 1 , wherein
the control device:
operates the second starter prior to the first starter to drive the crankshaft when driving the crank shaft by using both the first starter and the second starter;
determines whether or not a piston of the engine can go over a top dead center in a first compression stroke based on at least one piece of information among a rotational speed, torque, and current of the first starter; and
after determining that the piston can go over the top dead center, switching from the second starter to the first starter to drive the crankshaft.

7. The engine starting system according to claim 1 , wherein
the control device:
operates the second starter prior to the first starter to drive the crankshaft when driving the crank shaft by using both the first starter and the second starter;
determines whether or not a piston of the engine can go over a top dead center in a first compression stroke based on at least one piece of information among a rotational speed, torque, and current of the first starter; and
after determining that the piston has gone over the top dead center, switching from the second starter to the first starter to drive the crankshaft.

8. The engine starting system according to claim 6 , wherein
a torque transmitted from the second starter to the crankshaft is larger than a torque transmitted from the first starter to the crankshaft.

9. The engine starting system according to claim 1 , wherein
the disengageable coupling of the second starter includes a pinion that can mesh with a ring gear connected to the crankshaft, and a solenoid that generates an electromagnetic force in response to a drive command outputted from the control device; and
the pinion is pushed toward the ring gear by utilizing the electromagnetic force of the solenoid.

10. The engine starting system according to claim 1 , wherein
the first starter is connected to the crankshaft via a belt.

11. An engine starting system comprising:
a starting device for transmitting a rotational force thereof to a crankshaft of an engine to drive the crankshaft, the starting device including a first starter constantly connected to the crankshaft and a second starter connected to the crankshaft by a disengageable coupling; and
a control device for controlling an operation of the starting device in response to a start request of the engine; wherein
the engine starting system includes a rotation determination section capable of discriminating a rotation direction of the crankshaft;
when a period where the crankshaft rotates in a reverse direction while the engine is stopping is referred to as a reverse rotation period;
the control device sets the reverse rotation period as a cranking prohibition period for prohibiting the starting device from driving the crankshaft;
if the start request is generated during the reverse rotation period, the starting device is operated to drive the crankshaft based on an information from the rotation determination section when it is detected that the crankshaft has shifted from reverse rotation to forward rotation by driving the crankshaft by either one of the first starter and the second starter, or both the first starter and the second starter; and
the control device:
operates the second starter prior to the first starter to drive the crankshaft when driving the crank shaft by using both the first starter and the second starter;
determines whether or not a piston of the engine can go over a top dead center in a first compression stroke based on at least one piece of information among a rotational speed, torque, and current of the first starter; and
after determining that the piston can go over the top dead center, switching from the second starter to the first starter to drive the crankshaft.

12. The engine starting system according to claim 11 , wherein
the control device drives the starting device to drive the crankshaft when the control device detects that the crankshaft has shifted from a first reverse rotation to the forward rotation.

13. The engine starting system according to claim 11 , wherein
by operating the first starter, the control device suppresses the reverse rotation of the crankshaft from being caused when the reverse rotation of the crankshaft is detected based on the information from the rotation determination section.

14. The engine starting system according to claim 11 , wherein
the first starter has a rotation angle detection section capable of detecting a rotational position of the first starter; and
the rotation determination section discriminates the rotation direction of the crankshaft by inputting the rotational positio

Assignees

• Denso Corp

Inventors

• Nakaoka Takuro
• Imura Akihiro

Classifications

• F02N2300/104

  Control of the starter motor torque · CPC title

• F02N11/0844

  with means for restarting the engine directly after an engine stop request, e.g. caused by change of driver mind · CPC title

• F02N2300/2011

  Control involving a delay; Control involving a waiting period before engine stop or engine start · CPC title

• F02N11/04

  the motors being associated with current generators · CPC title

• F02N11/0833 Primary

  Vehicle conditions (F02N11/0822, F02N11/0825 take precedence) · CPC title