System for restarting internal combustion engine when engine restart request occurs

• US 20100050970A1
• Filed: 09/01/2009
• Published: 03/04/2010
• Est. Priority Date: 09/02/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Niimi, Masami, Haruno, Kiyokazu, Okumoto, Kazushige, Murata, Mitsuhiro, Senda, Takashi, Kato, Akira
• Granted Patent: US 8,069,832 B2
• Time in Patent Office: Days
• US Class Current: 123/179.400
• CPC Class Codes: F02N 11/0844 with means for restarting the engine directly after an engine stop request, e.g. caused by change of driver mind
• CPC Class Codes: F02N 11/0855 during engine shutdown or after engine stop before start command, e.g. pre-engagement of pinion
• CPC Class Codes: F02N 15/067 the starter comprising an electro-magnetically actuated lever
• CPC Class Codes: F02N 2200/022 Engine speed
• 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: F02N 99/006 Providing a combustible mixture inside the cylinder
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In a system, a starter includes a motor for rotatably driving an output shaft with a pinion and an actuator that shifts the pinion toward a ring gear to be engaged with the ring gear. A monitor unit monitors a rotational speed of the internal combustion engine. The rotational speed of the internal combustion engine drops after an automatic control for stop of the engine. When an engine restart request occurs with the rotational speed being within a preset range during the rotational speed of the internal combustion engine dropping by the automatic control for stop of the engine, a drive unit drives the actuator to shift the pinion toward the ring gear to be engaged with the ring gear. The drive unit rotatably drives the motor with the pinion being engaged with the ring gear to thereby crank the crankshaft.

Claims

1. A system for restarting, according to an occurrence of an engine restart request, an internal combustion engine that has been automatically controlled for stop thereof in response to an engine automatic stop request, the internal combustion engine normally working to burn fuel therein to rotate a crankshaft with a ring gear attached thereto, the system comprising:

a starter provided with a motor for rotatably driving an output shaft with a pinion and an actuator working to shift the pinion toward the ring gear to be engaged with the ring gear;

a monitor unit working to monitor a rotational speed of the internal combustion engine, the rotational speed of the internal combustion engine dropping by the automatic control for stop of the internal combustion engine; and

when the engine restart request occurs with the rotational speed being within a preset range during the rotational speed of the internal combustion engine dropping by the automatic control for stop of the internal combustion engine, a drive unit working to;

drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear; and

rotatably drive the motor with the pinion being at least partly engaged with the ring gear to thereby crank the crankshaft of the internal combustion engine.

17. The system according to claim 1, wherein the monitor unit works to estimate, based on an elapsed time from any one of the occurrence of the engine automatic stop request and a stop of the burning of the fuel in the internal combustion engine, the rotational speed of the internal combustion engine.

30. The system according to claim 1, wherein the starter is designed to individually drive the motor and the actuator.

2. A system for restarting, according to an occurrence of an engine restart request, an internal combustion engine that has been automatically controlled for stop thereof in response to an engine automatic stop request, the internal combustion engine normally working to burn fuel therein to rotate a crankshaft with a ring gear attached thereto, the system comprising:

a starter provided with a motor for rotatably driving an output shaft with a pinion and an actuator working to shift the pinion toward the ring gear to be engaged with the ring gear;

a monitor unit working to monitor a rotational speed of the internal combustion engine, the rotational speed of the internal combustion engine dropping by the automatic control for stop of the internal combustion engine; and

an executing unit working to;

select, based on the rotational speed of the internal combustion engine at a timing of the occurrence of the engine restart request, any one of a first restart task and a second restart task;

execute, when the first restart task is selected, the first restart task to thereby;

rotatably drive the motor,

determine whether the pinion is allowed to be rotated with the ring gear, and

after it is determined that the pinion is allowed to be rotated with the ring gear, drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear to thereby crank the crankshaft of the internal combustion engine; and

execute, when the second restart task is selected, the second restart task to thereby;

drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear, and

rotatably drive the motor with the pinion being at least partly engaged with the ring gear to thereby crank the crankshaft of the internal combustion engine.

3. The system according to claim 2, wherein the executing unit works to select the first restart task when the rotational speed of the internal combustion engine at the timing of the occurrence of the engine restart request is equal to or lower than a first preset speed and higher than a second preset speed, the second preset speed being lower than the first preset speed, and the executing unit works to select the second restart task when the rotational speed of the internal combustion engine at the timing of the occurrence of the engine restart request is equal to or lower than the second preset speed.

4. The system according to claim 3, wherein the executing unit works to select, based on the rotational speed of the internal combustion engine at the timing of the occurrence of the engine restart request, any one of the first restart task, the second restart task, and a third restart task,

the executing unit working to:

select the third restart task when the rotational speed of the internal combustion engine at the timing of the occurrence of the engine restart request is higher than the first preset speed; and

execute, when the third restart task is selected, the third restart task to thereby;

restart a burning of the fuel in the internal combustion engine, thus restarting the internal combustion engine without cranking the crankshaft.

5. The system according to claim 2, wherein the executing unit works to monitor a rotational speed of the pinion, and determine that the pinion is allowed to be rotated with the ring gear when a difference between the rotational speed of the internal combustion engine and the rotational speed of the pinion is within ±

250 rpm.

6. The system according to claim 5, wherein the executing unit works to determine that the pinion is allowed to be rotated with the ring gear when the difference between the rotational speed of the internal combustion engine and the rotational speed of the pinion is within ±

200 rpm.

7. The system according to claim 2, wherein the executing unit works to monitor a difference between a first peripheral speed on a first pitch circle on the ring gear and a second peripheral speed of a second pitch circle on the pinion, and determine that the pinion is allowed to be rotated with the ring gear when the difference between the first peripheral speed on the first pitch circle on the ring gear and the second peripheral speed of the second pitch circle on the pinion is within ±

3.1 meters per second.

8. The system according to claim 2, further comprising:

a one-way clutch rotatably provided on the output shaft of the motor and designed to only transfer rotational motion of the ring gear to the pinion when the pinion is engaged with the ring gear,

the executing unit working to monitor a rotational speed of the pinion, and determine that the pinion is allowed to be rotated with the ring gear when the rotational speed of the internal combustion engine is higher than the rotational speed of the pinion and a difference between the rotational speed of the internal combustion engine and the rotational speed of the pinion is equal to or lower than a preset value.

9. The system according to claim 8, wherein the executing unit works to determine that the pinion is allowed to be rotated with the ring gear when a difference between the rotational speed of the internal combustion engine and the rotational speed of the pinion is within ±

250 rpm.

10. The system according to claim 9, wherein the executing unit works to determine that the pinion is allowed to be rotated with the ring gear when the difference between the rotational speed of the internal combustion engine and the rotational speed of the pinion is within ±

200 rpm.

11. The system according to claim 2, further comprising:

a one-way clutch rotatably provided on the output shaft of the motor and designed to only transfer rotational motion of the ring gear to the pinion when the pinion is engaged with the ring gear,

the executing unit working to monitor a difference between a first peripheral speed on a first pitch circle on the ring gear and a second peripheral speed of a second pitch circle on the pinion, and determine that the pinion is allowed to be rotated with the ring gear when the difference between the first peripheral speed on the first pitch circle on the ring gear and the second peripheral speed of the second pitch circle on the pinion is within ±

3.1 meters per second.

12. The system according to claim 2, wherein the executing unit works to select, based on the rotational speed of the internal combustion engine at the timing of the occurrence of the engine restart request, any one of the first restart task, the second restart task, and a third restart task,

the executing unit working to execute, when the third restart task is selected, the third restart task to thereby:

restart a burning of the fuel in the internal combustion engine, thus restarting the internal combustion engine without cranking the crankshaft,

the executing unit working to;

select the third restart task when the rotational speed of the internal combustion engine at the timing of the occurrence of the engine restart request is higher than a first preset speed;

wait when the rotational speed of the internal combustion engine at the timing of the occurrence of the engine restart request is equal to or lower than the first preset speed and higher than a second preset speed, the second preset speed being lower than the first preset speed;

select the second restart task when the rotational speed of the internal combustion engine reaches equal to or below the second preset speed; and

select the second restart task when the rotational speed of the internal combustion engine at the timing of the occurrence of the engine restart request is equal to or lower than the second preset speed.

13. The system according to claim 3, wherein the executing unit works to execute, when the rotational speed of the internal combustion engine reaches a third preset speed higher than zero and lower than the second preset speed without the engine restart request occurring, a fourth task to thereby:

drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear; and

when the engine restart request occurs after the engagement of the pinion with the ring gear, rotatably drive the motor to thereby crank the crankshaft of the internal combustion engine.

14. The system according to claim 3, wherein the internal combustion engine is designed such that a behavior of the rotational speed of the internal combustion engine positively and negatively oscillates after the rotational speed of the internal combustion engine has first reached zero, and the executing unit works to execute, when the rotational speed of the internal combustion engine reaches a third preset speed higher than zero and lower than the second preset speed without the engine restart request occurring, a fifth task to thereby:

drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear; and

when the engine restart request occurs after the engagement of the pinion with the ring gear, rotatably drive the motor to thereby crank the crankshaft of the internal combustion engine.

15. The system according to claim 3, wherein the first preset speed is selected from a range of 300 to 700 rpm.

16. The system according to claim 3, wherein the second preset speed is selected from a range of 50 to 450 rpm.

18. The system according to claim 5, wherein the starter works to supply a current to the motor to thereby energize the motor, the energized motor rotatably driving the output shaft with the pinion, and the executing unit works to estimate, based on at least one of an energization duration of the motor and an amount of the current to be supplied to the motor, the rotational speed of the internal combustion engine.

19. A system for restarting, according to an occurrence of an engine restart request, an internal combustion engine that has been automatically controlled for stop thereof in response to an engine automatic stop request, the internal combustion engine normally working to burn fuel therein to rotate a crankshaft with a ring gear attached thereto, the system comprising:

a starter provided with a motor for rotatably driving an output shaft with a pinion and an actuator working to shift the pinion toward the ring gear to be engaged with the ring gear;

a monitor unit working to monitor a rotational speed of the internal combustion engine, the rotational speed of the internal combustion engine dropping by the automatic control for stop of the internal combustion engine; and

when the rotational speed of the internal combustion engine reaches a preset speed close to or higher than zero without the engine restart request occurring, a drive unit working to;

drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear; and

when the engine restart request occurs after the engagement of the pinion with the ring gear, rotatably drive the motor to thereby crank the crankshaft of the internal combustion engine.

20. The system according to claim 19, wherein the internal combustion engine is designed such that a behavior of the rotational speed of the internal combustion engine positively and negatively oscillates after the rotational speed of the ring gear has first reached zero.

21. The system according to claim 19, wherein the drive unit works to:

energize the actuator so as to drive the actuator, the driven actuator shifting the pinion toward the ring gear to be engaged with the ring gear; and

deenergize the actuator at least one of when a preset time has elapsed since the energization of the actuator and when it is checked that the pinion is engaged with the ring gear.

22. The system according to claim 20, wherein the preset time is an elapsed time since the energization of the actuator to a timing when the rotational speed of the internal combustion engine becomes zero after the positive and negative oscillation has been completed.

23. A system for restarting, according to an occurrence of an engine restart request, an internal combustion engine that has been automatically controlled for stop thereof in response to an engine automatic stop request, the internal combustion engine normally working to burn fuel therein to rotate a crankshaft with a ring gear attached thereto, the system comprising:

a starter provided with a motor for rotatably driving an output shaft with a pinion and an actuator working to shift the pinion toward the ring gear to be engaged with the ring gear;

a monitor unit working to monitor a parameter associated with a difference between a rotational speed of the internal combustion engine and a rotational speed of the pinion, the rotational speed of the internal combustion engine dropping by the automatic control for stop of the internal combustion engine, a behavior of the rotational speed of the internal combustion engine positively and negatively oscillating after the rotational speed of the internal combustion engine has first reached zero; and

when the engine restart request occurs at least one of;

during the rotational speed of the internal combustion engine dropping, and during the behavior of the rotational speed of the internal combustion engine positively and negatively oscillating, after the parameter has been within a preset range, a drive unit working to;

drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear; and

rotatably drive the motor with the pinion being at least partly engaged with the ring gear to thereby crank the crankshaft of the internal combustion engine.

24. The system according to claim 23, wherein the parameter is the difference between the rotational speed of the internal combustion engine and the rotational speed of the pinion, and the preset range is set to be ±

250 rpm.

25. The system according to claim 23, wherein the parameter is a difference between a first peripheral speed on a first pitch circle on the ring gear and a second peripheral sped of a second pitch circle on the pinion, and the preset range is set to be ±

3.1 meters per second.

26. A system for restarting, according to an occurrence of an engine restart request, an internal combustion engine that has been automatically controlled for stop thereof in response to an engine automatic stop request, the internal combustion engine normally working to burn fuel therein to rotate a crankshaft with a ring gear attached thereto, the system comprising:

a starter provided with a motor for rotatably driving an output shaft with a pinion and an actuator working to shift the pinion toward the ring gear to be engaged with the ring gear;

a monitor unit working to monitor a parameter associated with a difference between a rotational speed of the internal combustion engine and a rotational speed of the pinion, the rotational speed of the internal combustion engine dropping by the automatic control for stop of the internal combustion engine, a behavior of the rotational speed of the internal combustion engine positively and negatively oscillating after the rotational speed of the internal combustion engine has first reached zero; and

when the engine restart request occurs at least one of;

during the rotational speed of the internal combustion engine dropping, and during the behavior of the rotational speed of the internal combustion engine positively and negatively oscillating, a drive unit working to;

rotatably drive the motor to thereby rotate the pinion so that the monitored parameter has been within a preset range; and

drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear to thereby crank the crankshaft of the internal combustion engine.

27. The system according to claim 26, wherein the parameter is the difference between the rotational speed of the internal combustion engine and the rotational speed of the pinion, further comprising:

a one-way clutch rotatably provided on the output shaft of the motor and designed to only transfer rotational motion of the ring gear to the pinion when the pinion is engaged with the ring gear,

the drive unit working to, when the engine restart request occurs during the rotational speed of the internal combustion engine dropping, drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear to thereby crank the crankshaft of the internal combustion engine after the rotational speed of the internal combustion engine is higher than the rotational speed of the pinion and the difference between the rotational speed of the internal combustion engine and the rotational speed of the pinion is equal to or lower than 200 rpm.

28. The system according to claim 26, wherein the parameter is a difference between a first peripheral speed on a first pitch circle on the ring gear and a second peripheral sped of a second pitch circle on the pinion, and the preset range is set to be ±

3.1 meters per second.

29. The system according to claim 26, wherein the parameter is the difference between a first peripheral speed on a first pitch circle on the ring gear and a second peripheral sped of a second pitch circle on the pinion, further comprising:

a one-way clutch rotatably provided on the output shaft of the motor and designed to only transfer rotational motion of the ring gear to the pinion when the pinion is engaged with the ring gear,

the drive unit working to, when the engine restart request occurs during the rotational speed of the internal combustion engine dropping, drive the actuator to shift the pinion toward the ring gear to be engaged with the ring gear to thereby crank the crankshaft of the internal combustion engine after the first peripheral speed on the first pitch circle on the ring gear is higher than the second peripheral speed of the second pitch circle on the pinion and the difference between the first peripheral speed on the first pitch circle on the ring gear and the second peripheral speed of the second pitch circle on the pinion is equal to or lower than 3.1 meters per second.