SYSTEM FOR RESTARTING INTERNAL COMBUSTION ENGINE WHEN ENGINE RESTART CONDITION IS MET

• US 20100229815A1
• Filed: 03/12/2010
• Published: 09/16/2010
• Est. Priority Date: 03/12/2009
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: KAWAHARA, Kenji, SENDA, Takashi
• Granted Patent: US 8,302,575 B2
• Time in Patent Office: Days
• US Class Current: 123/179.400
• CPC Class Codes: F02N 11/0833 Vehicle conditions F02N11/0822, F02N11/0825 take precedence
• CPC Class Codes: F02N 11/10 Safety devices F02N11/08 takes precedence
• CPC Class Codes: F02N 2200/0801 Vehicle speed
• CPC Class Codes: F02N 2200/101 Accelerator pedal position
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In a system installed in a vehicle, an automatic stop of an engine is carried out when an engine automatic stop condition is met during the vehicle being decelerated. The automatically stopped engine is restarted when an engine restart condition is met before the vehicle is stopped. A vehicle speed obtaining unit obtains a vehicle speed, and a threshold determining unit determines a threshold based on a predetermined-timing value of the vehicle speed. The predetermined-timing value is obtained at a predetermined timing when or after the engine restart condition is met. The threshold is used to determine whether to enable a next automatic stop of the engine. A stop enabling unit enables the next automatic stop of the engine when the speed of the vehicle obtained after the engine restart condition is met is equal to or higher than the threshold.

Claims

1. A system installed in a vehicle having an internal combustion engine, the system being configured to carry out an automatic stop of the internal combustion engine when at least one engine automatic stop condition is met during the vehicle being decelerated, and restart the automatically stopped internal combustion engine when at least one engine restart condition is met before the vehicle is stopped, the system comprising:

a vehicle speed obtaining unit that obtains a speed of the vehicle;

a threshold determining unit that determines a threshold based on a predetermined-timing value of the speed of the vehicle, the predetermined-timing value of the speed of the vehicle being obtained by the vehicle speed obtaining unit at a predetermined timing when or after the at least one engine restart condition is met, the threshold being used to determine whether to enable a next automatic stop of the internal combustion engine; and

a stop enabling unit that enables the next automatic stop of the internal combustion engine when the speed of the vehicle obtained after the at least one engine restart condition is met is equal to or higher than the threshold.

2. The system according to claim 1, wherein the threshold determining unit is configured to:

have a preset value for the speed of the vehicle, the preset value being used to determine whether the internal combustion engine that has been automatically restarted since the speed of the vehicle of zero is automatically stopped; and

determine the threshold as a sum of the preset value and the predetermined-timing value of the speed of the vehicle.

3. The system according to claim 1, wherein the threshold determining unit is configured to:

have a preset value for the speed of the vehicle, the preset value being used to determine whether the internal combustion engine that has been automatically restarted since the speed of the vehicle of zero is automatically stopped; and

when the threshold based on the predetermined-timing value of the speed of the vehicle is higher than the preset value and the vehicle is decelerated after the restart of the internal combustion engine, reduce the threshold.

4. The system according to claim 3, wherein the threshold determining unit is configured to reduce the threshold according to a rate of reduction in the speed of the vehicle.

5. The system according to claim 3, wherein the threshold determining unit is adapted to reduce the threshold up to the preset value as a lower limit.

6. The system according to claim 4, wherein the threshold determining unit is adapted to reduce the threshold up to the preset value as a lower limit.

7. The system according to claim 3, wherein the threshold determining unit is configured to:

determine whether the speed of the vehicle is lower than the predetermined-timing value of the speed of the vehicle; and

reduce the threshold when determining that the speed of the vehicle is lower than the predetermined-timing value of the speed of the vehicle.

8. The system according to claim 3, wherein the threshold determining unit is configured to reduce the threshold at a timing when the speed of the vehicle is reversed from up to down.

9. The system according to claim 1, wherein the threshold determining unit is configured to:

set, as the predetermined-timing value of the speed of the vehicle, a restart-timing value of the speed of the vehicle, the restart-timing value of the speed of the vehicle being obtained by the vehicle speed obtaining unit at a timing when the at least one engine restart condition is met; and

determine the threshold based on the restart-timing value of the speed of the vehicle.

10. The system according to claim 1, wherein the threshold determining unit is configured to determine the threshold based on the predetermined-timing value of the speed of the vehicle only when the predetermined-timing value of the speed of the vehicle is within a preset range.

11. The system according to claim 2, wherein the threshold determining unit is configured to:

increase the preset value of the speed of the vehicle with increase in the predetermined-timing value of the speed of the vehicle; and

reduce the preset value of the speed of the vehicle with reduction in the predetermined-timing value of the speed of the vehicle.

12. The system according to claim 2, wherein the threshold determining unit is configured to carry out any one of:

change of the threshold to the preset value at a timing when the speed of the vehicle is reversed from up to down after the restart of the internal combustion engine; and

change of the threshold to the preset value after an elapse of time since the speed of the vehicle is reversed from up to down after the restart of the internal combustion engine.