AUTOMATIC STOP AND RESTART DEVICE FOR AN ENGINE

• US 20110270512A1
• Filed: 12/01/2010
• Published: 11/03/2011
• Est. Priority Date: 04/28/2010
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: HAYASHI, Kensuke, Shoda, Tomohisa, Ishikawa, Osamu
• Granted Patent: US 8,712,672 B2
• Time in Patent Office: Days
• US Class Current: 701/112
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/115 with planetary gears
• CPC Class Codes: B60W 2510/101 Transmission neutral state
• CPC Class Codes: B60W 2710/1005 Transmission ratio engaged
• CPC Class Codes: B60W 30/18018 Start-stop drive, e.g. in a traffic jam
• CPC Class Codes: F02D 45/00 Electrical control not provided for in groups F02D41/00 - F02D43/00
• 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 11/0844 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 2200/022 Engine speed
• CPC Class Codes: F02N 2200/048 Information about pinion speed, both translational or rotational speed
• CPC Class Codes: F02N 2200/0802 Transmission state, e.g. gear ratio or neutral state
• CPC Class Codes: F02N 2300/2006 using prediction of future conditions
• CPC Class Codes: F02N 2300/2011 Control involving a delay; Control involving a waiting period before engine stop or engine start
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Provided is an automatic stop and restart device for an engine that is capable of suppressing occurrence of an abnormal condition even if a transmission state is changed during an engine restart process after an engine restart condition is satisfied in an automatic engine stop process. A controller performs the automatic engine stop process and the engine restart process. If a determined state of a transmission is a drive range, a transmission state determination unit drives a pinion gear thrust unit at timing determined by a first pinion gear thrust timing determination unit. If the determined state of the transmission is a non-drive range, the transmission state determination unit drives the pinion gear thrust unit at timing determined by a second pinion gear thrust timing determination unit.

Claims

1. An automatic stop and restart device for an engine that is disposed in a start and transmission system of a vehicle which comprises:

a transmission for changing gears to transmit power of the engine to driving wheels of the vehicle;

a transmission operation device for receiving an external transmission operation to operate a transmission state of the transmission;

a ring gear that is provided to a crank shaft of the engine, a starter motor for starting the engine;

a pinion gear that is capable of approaching and separating from the ring gear and is driven by the starter motor to rotate;

pinion gear thrust means for thrusting the pinion gear to the ring gear so that the pinion gear engages with the ring gear to crank the engine; and

ring gear rotation speed detection means for detecting a ring gear rotation speed,

the automatic stop and restart device comprising a controller which comprises transmission state determination means for determining whether the transmission is in a drive range or in a non-drive range, the controller performing an automatic stop process for the engine if a predetermined automatic engine stop condition is satisfied, and a restart process for the engine by controlling drive of the starter motor and the pinion gear thrust means if a predetermined restart condition is satisfied after the predetermined automatic engine stop condition is satisfied, wherein the controller further comprises;

starter drive time measurement means for measuring starter motor drive time from a time point when the drive of the starter motor is started;

pinion gear rotation speed estimation means for estimating a pinion gear rotation speed based on the starter motor drive time;

first pinion gear thrust timing determination means for driving the pinion gear thrust means at timing when a difference between the ring gear rotation speed and the pinion gear rotation speed in a case where the transmission is in the drive range becomes a first predetermined value corresponding to a speed decrease amount of the ring gear rotation speed in the case where the transmission is in the drive range; and

second pinion gear thrust timing determination means for driving the pinion gear thrust means at timing when a difference between the ring gear rotation speed and the pinion gear rotation speed in a case where the transmission is in the non-drive range becomes a second predetermined value corresponding to a speed decrease amount of the ring gear rotation speed in the case where the transmission is in the non-drive range.

2. An automatic stop and restart device for an engine that is disposed in a start and transmission system of a vehicle which comprises:

a transmission for changing gears to transmit power of the engine to driving wheels of the vehicle;

a transmission operation device for receiving an external transmission operation to operate a transmission state of the transmission;

a ring gear that is provided to a crank shaft of the engine, a starter motor for starting the engine;

a pinion gear that is capable of approaching and separating from the ring gear and is driven by the starter motor to rotate;

pinion gear thrust means for thrusting the pinion gear to the ring gear so that the pinion gear engages with the ring gear to crank the engine; and

ring gear rotation speed detection means for detecting a ring gear rotation speed,

the automatic stop and restart device comprising a controller which comprises transmission state determination means for determining whether the transmission is in a drive range or in a non-drive range, the controller performing an automatic stop process for the engine if a predetermined automatic engine stop condition is satisfied, and a restart process for the engine by controlling drive of the starter motor and the pinion gear thrust means if a predetermined restart condition is satisfied after the predetermined automatic engine stop condition is satisfied, wherein, if the transmission operation device is changed from the drive range to the non-drive range during the restart process for the engine after the predetermined restart condition is satisfied in the automatic stop process for the engine, the controller maintains the transmission to be in the drive range, and changes the transmission to the non-drive range after the restart process for the engine is finished.

3. An automatic stop and restart device for an engine that is disposed in a start and transmission system of a vehicle which comprises:

a transmission for changing gears to transmit power of the engine to driving wheels of the vehicle;

a transmission operation device for receiving an external transmission operation to operate a transmission state of the transmission;

a ring gear that is provided to a crank shaft of the engine, a starter motor for starting the engine;

a pinion gear that is capable of approaching and separating from the ring gear and is driven by the starter motor to rotate;

pinion gear thrust means for thrusting the pinion gear to the ring gear so that the pinion gear engages with the ring gear to crank the engine; and

ring gear rotation speed detection means for detecting a ring gear rotation speed,

the automatic stop and restart device comprising a controller which comprises transmission state determination means for determining whether the transmission is in a drive range or in a non-drive range, the controller performing an automatic stop process for the engine if a predetermined automatic engine stop condition is satisfied, and a restart process for the engine by controlling drive of the starter motor and the pinion gear thrust means if a predetermined restart condition is satisfied after the predetermined automatic engine stop condition is satisfied, wherein, if the transmission operation device is changed from the drive range to the non-drive range during the restart process for the engine after the predetermined restart condition is satisfied in the automatic stop process for the engine, the controller stops the drive of the starter motor.

4. An automatic stop and restart device for an engine according to claim 3, wherein the controller performs the restart process for the engine after a predetermined restart inhibit time passes from a time point when the drive of the starter motor is stopped.

5. An automatic stop and restart device for an engine according to claim 4,

wherein the controller further comprises:

starter motor drive stop time measurement means for measuring starter motor drive stop time from the time point when the drive of the starter motor is stopped;

starter motor stop pinion gear rotation speed estimation means for estimating a pinion gear rotation speed after the drive of the starter motor is stopped based on a pinion gear rotation speed at the time point when the drive of the starter motor is stopped and the starter motor drive stop time measured by the starter motor drive stop time measurement means; and

gear rotation stop time point prediction means for predicting a gear rotation stop time point when both the pinion gear rotation speed after the drive of the starter motor is stopped, which is estimated by the starter motor stop pinion gear rotation speed estimation means and the ring gear rotation speed become zero, and

wherein the controller sets a period from the time point when the drive of the starter motor is stopped to the gear rotation stop time point predicted by the gear rotation stop time point prediction means as the predetermined restart inhibit time, and performs the predetermined restart process for the engine after the predetermined restart inhibit time passes.

6. An automatic stop and restart device for an engine according to claim 5, wherein the controller thrusts the pinion gear and drives the starter motor to crank the engine when a difference between the pinion gear rotation speed after the drive of the starter motor is stopped, which is estimated by the starter motor stop pinion gear rotation speed estimation means and the ring gear rotation speed becomes a predetermined value after the drive of the starter motor is stopped.