CONTROL METHOD FOR INTERNAL COMBUSTION ENGINE SYSTEM, AND INTERNAL COMBUSTION ENGINE SYSTEM

• US 20090241883A1
• Filed: 03/02/2009
• Published: 10/01/2009
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: Mazda Motor Corporation
• Original Assignee: Mazda Motor Corporation
• Inventors: Yoshida, Katsumasa, Tetsuno, Masayuki, Nagoshi, Masahiro
• Granted Patent: US 8,408,177 B2
• Time in Patent Office: Days
• US Class Current: 123/179.400
• CPC Class Codes: F02N 11/0825 related to prevention of engine restart failure, e.g. disabling automatic stop at low battery state
• CPC Class Codes: F02N 11/0848 with means for detecting successful engine start, e.g. to stop starter actuation
• CPC Class Codes: F02N 11/0866 comprising several power sources, e.g. battery and capacitor or two batteries
• CPC Class Codes: F02N 2200/062 Battery current
• CPC Class Codes: F02N 2200/063 Battery voltage
• CPC Class Codes: F02N 2250/06 Engine stall and related control features, e.g. for automatic restart
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

The invention relates to a control method for an internal combustion engine system, capable of preventing an internal combustion engine in a state after being automatically stopped, from falling into an unrestartable state. Upon satisfaction of a given automatic stop condition, the engine 10 being running is automatically stopped (Step 11). A value of current I_EBAT flowing out of a starter battery 520 is compared with a given current value I_EBAT—TH, in an automatically stopped state of the engine 10 (Step S30) to diagnosis a discharging status of the starter battery 520. If a result of the diagnosis indicates that the value of current I_EBAT flowing out of the starter battery 520 is greater than the given current value I_EBAT—TH, it is determined that a post-attached load is detected, and the engine 10 is restarted irrespective of the satisfaction or non-satisfaction of a given restart condition.

Claims

1. A control method for an internal combustion engine system which includes an internal combustion engine, an electric drive unit adapted to start up the internal combustion engine, and a starter battery for use as an electric power source for activating the electric drive unit, the control method comprising:

an automatic stop step of, upon satisfaction of a given automatic stop condition, automatically stopping the internal combustion engine being running;

a restart step of, upon satisfaction of a given restart condition after the internal combustion engine is automatically stopped, supplying electric power from the starter battery to the electric drive unit to automatically restart the internal combustion engine;

a post-attached load detection step of detecting the presence or absence of a post-attached load to be supplied with electric power from the starter battery, based on a discharging status of the starter battery in the automatically stopped state of the internal combustion engine; and

a forcible restart step of, when the post-attached load is detected as a result of the post-attached load detection step, restarting the internal combustion engine irrespective of the satisfaction or non-satisfaction of the restart condition.

2. The control method as defined in claim 1, comprising a stopped-state current-value diagnosis step of comparing a value of current flowing out of the starter battery with a predetermined current value, in the automatically stopped state of the internal combustion engine, wherein the stopped-state current-value diagnosis step corresponds to said post-attached load detection step.

3. The control method as defined in claim 2, further comprising:

a running-state current-value diagnosis step of comparing a value of current flowing out of the starter battery with the predetermined current value, upon the satisfaction of the automatic stop condition; and

an automatic-stop prohibition step of, when a result of the running-state current-value diagnosis step indicates that the value of current flowing out of the starter battery is greater than the predetermined current value, prohibiting the automatic stop step irrespective of the satisfaction or non-satisfaction of the automatic stop condition.

4. The control method as defined in claim 1, comprising a stopped-state voltage-change diagnosis step of comparing a change in voltage value of the starter battery with a predetermined threshold value, in the automatically stopped state of the internal combustion engine, wherein the stopped-state voltage-change diagnosis step corresponds to said post-attached load detection step.

5. The control method as defined in claim 2, further comprising:

a running-state voltage-change diagnosis step of comparing a change in voltage value of the starter battery with a predetermined threshold value, upon the satisfaction of the automatic stop condition; and

an automatic-stop prohibition step of, when a result of the running-state voltage-change diagnosis step indicates that the change in voltage value of the starter battery is greater than the predetermined threshold value, prohibiting the automatic stop step irrespective of the satisfaction or non-satisfaction of the automatic stop condition.

6. The control method as defined in claim 4, further comprising:

a running-state voltage-change diagnosis step of comparing a change in voltage value of the starter battery with the predetermined threshold value, upon the satisfaction of the automatic stop condition; and

an automatic-stop prohibiting stop of, when a result of the running-state voltage-change diagnosis step indicates that the change in voltage value of the starter battery is greater than the predetermined threshold value, prohibiting the automatic stop step irrespective of the satisfaction or non-satisfaction of the automatic stop condition.

7. The control method as defined in claim 2, further comprising a stopped-state voltage-change diagnosis step of comparing a change in voltage value of the starter battery with a predetermined threshold value, in the automatically stopped state of the internal combustion engine, wherein the forcible restart step includes, when a result of the stopped-state voltage-change diagnosis step indicates that the change in voltage value of the starter battery is greater than the predetermined threshold value, restarting the internal combustion engine irrespective of the satisfaction or non-satisfaction of the restart condition.

8. The control method as defined in claim 1, wherein the internal combustion system includes an electric load adapted to be activated in a stopped state of the internal combustion engine, and a general-purpose battery for supplying electric power to the electric load,

wherein the control method further comprises a stopped-state electric-power supply step of supplying electric power from the general-purpose battery to the electric load, in the stopped state of the internal combustion engine, and wherein the forcible restart step includes supplying electric power from both the general-purpose battery and the starter battery to the electric drive unit.

9. The control method as defined in claim 2, wherein the internal combustion system includes an electric load adapted to be activated in a stopped state of the internal combustion engine, and a general-purpose battery for supplying electric power to the electric load,

wherein the control method further comprises a stopped-state electric-power supply step of supplying electric power from the general-purpose battery to the electric load, in the stopped state of the internal combustion engine, and wherein the forcible restart step includes supplying electric power from both the general-purpose battery and the starter battery to the electric drive unit.

10. The control method as defined in claim 4, wherein the internal combustion system includes an electric load adapted to be activated in a stopped state of the internal combustion engine, and a general-purpose battery for supplying electric power to the electric load,

wherein the control method further comprises a stopped-state electric-power supply step of supplying electric power from the general-purpose battery to the electric load, in the stopped state of the internal combustion engine, and wherein the forcible restart step includes supplying electric power from both the general-purpose battery and the starter battery to the electric drive unit.

11. An internal combustion engine system comprising an internal combustion engine, an electric drive unit adapted to start up the internal combustion engine, a starter battery for use as an electric power source for activating the electric drive unit, and running control unit configured to govern a running control of the internal combustion engine, the running control unit including:

automatic stop unit operable, upon satisfaction of a given automatic stop condition, to automatically stop the internal combustion engine being running;

restart unit operable, upon satisfaction of a given restart condition after the internal combustion engine is automatically stopped, to allow electric power to be supplied from the starter battery to the electric drive unit so as to automatically restart the internal combustion engine;

post-attached load detection unit operable to detect the presence or absence of a post-attached load to be supplied with electric power from the starter battery, based on a discharging status of the starter battery in the automatically stopped state of the internal combustion engine; and

forcible restart unit operable, when the post-attached load is detected as a detection result of the post-attached load detection unit, to restart the internal combustion engine irrespective of the satisfaction or non-satisfaction of the restart condition.

12. The internal combustion engine system as defined in claim 11, which comprises stopped-state current-value diagnosis unit operable to compare a value of current flowing out of the starter battery with a predetermined current value, in the automatically stopped state of the internal combustion engine, wherein the stopped-state current-value diagnosis unit serves as the post-attached load detection unit.

13. The internal combustion engine system as defined in claim 12, further comprising:

running-state current-value diagnosis unit operable to compare a value of current flowing out of the starter battery with the predetermined current value, upon the satisfaction of the automatic stop condition; and

automatic-stop prohibition unit operable, when a diagnosis result of the running-state current-value diagnosis unit indicates that the value of current flowing out of the starter battery is greater than the predetermined current value, to prohibit the operation of the automatic stop unit irrespective of the satisfaction or non-satisfaction of the automatic stop condition.

14. The internal combustion engine system as defined in claim 11, which comprises stopped-state voltage-change diagnosis unit operable to compare a change in voltage value of the starter battery with a predetermined threshold value, in the automatically stopped state of the internal combustion engine, wherein the stopped-state voltage-change diagnosis unit serves as the post-attached load detection unit.

15. The internal combustion engine system as defined in claim 12, further comprising:

running-state voltage-change diagnosis unit operable to compare a change in voltage value of the starter battery with a predetermined threshold value, upon the satisfaction of the automatic stop condition; and

automatic-stop prohibition unit operable, when a diagnosis result of the running-state voltage-change diagnosis unit indicates that the change in voltage value of the starter battery is greater than the predetermined threshold value, to prohibit the operation of the automatic stop unit irrespective of the satisfaction or non-satisfaction of the automatic stop condition.

16. The internal combustion engine system as defined in claim 14, further comprising:

running-state voltage-change diagnosis unit operable to compare a change in voltage value of the starter battery with the predetermined threshold value, upon the satisfaction of the automatic stop condition; and

automatic-stop prohibition unit operable, when a diagnosis result of the running-state voltage-change diagnosis unit indicates that the change in voltage value of the starter battery is greater than the predetermined threshold value, to prohibit the operation of the automatic stop unit irrespective of the satisfaction or non-satisfaction of the automatic stop condition.

17. The internal combustion engine system as defined in claim 12, further comprising stopped-state voltage-change diagnosis unit operable to compare a change in voltage value of the starter battery with a predetermined threshold value, in the automatically stopped state of the internal combustion engine, wherein the forcible restart unit is operable, when a diagnosis result of the stopped-state voltage-change diagnosis unit indicates that the change in voltage value of the starter battery is greater than the predetermined threshold value, to restart the internal combustion engine irrespective of the satisfaction or non-satisfaction of the restart condition.

18. The internal combustion engine system as defined in claim 11, further comprising:

an electric load adapted to be activated in a stopped state of the internal combustion engine;

a general-purpose battery for supplying electric power to the electric load; and

stopped-state electric-power supply unit operable to allow electric power to be supplied from the general-purpose battery to the electric load, in the stopped state of the internal combustion engine,

wherein the forcible restart unit is operable to allow electric power to be supplied from both the general-purpose battery and the starter battery to the electric drive unit.

19. The internal combustion engine system as defined in claim 12, further comprising:

an electric load adapted to be activated in a stopped state of the internal combustion engine;

a general-purpose battery for supplying electric power to the electric load; and

stopped-state electric-power supply unit operable to allow electric power to be supplied from the general-purpose battery to the electric load, in the stopped state of the internal combustion engine,

wherein the forcible restart unit is operable to allow electric power to be supplied from both the general-purpose battery and the starter battery to the electric drive unit.

20. The internal combustion engine system as defined in claim 14, further comprising:

an electric load adapted to be activated in a stopped state of the internal combustion engine;

a general-purpose battery for supplying electric power to the electric load; and

stopped-state electric-power supply unit operable to allow electric power to be supplied from the general-purpose battery to the electric load, in the stopped state of the internal combustion engine,

wherein the forcible restart unit is operable to allow electric power to be supplied from both the general-purpose battery and the starter battery to the electric drive unit.