# US 8,751,138 B2 · Automatic stop and restart device for an engine

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- Number: US 8,751,138 B2
- Document ID: US8751138B2
- Status: Granted
- Kind: B2
- Application number: 13/944,976
- Filed: 2013-07-18
- Published: 2013-11-14
- Granted: 2014-06-10
- Earliest claimed: 2010-04-28
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Kensuke Hayashi; Osamu Ishikawa; Tomohisa Shoda
- Web page: https://patentgrep.com/patent/US8751138B2

## CPC

- B60W 10/06: including control of combustion engines
- B60W 10/10: including control of change-speed gearings
- B60W 30/18018: {Start-stop drive, e.g. in a traffic jam}
- F02D 45/00: Electrical control not provided for in groups F02D41/00 - F02D43/00
- F02N 11/0844: {with means for restarting the engine directly after an engine stop request, e.g. caused by change of driver mind}
- F02N 11/0855: {during engine shutdown or after engine stop before start command, e.g. pre-engagement of pinion}
- B60W 10/115: with planetary gears
- B60W 2510/101: Transmission neutral state
- B60W 2710/1005: Transmission ratio engaged
- F02N 11/0825: {related to prevention of engine restart failure, e.g. disabling automatic stop at low battery state}
- F02N 2200/022: Engine speed
- F02N 2200/048: Information about pinion speed, both translational or rotational speed
- F02N 2200/0802: Transmission state, e.g. gear ratio or neutral state
- F02N 2300/2006: using prediction of future conditions
- F02N 2300/2011: Control involving a delay; Control involving a waiting period before engine stop or engine start
- Y02T 10/40: Engine management systems
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- F02N: STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## 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

### Claim 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;
a pinion gear thrust unit configured to thrust the pinion gear to the ring gear so that the pinion gear engages with the ring gear to crank the engine; and
a ring gear rotation speed detection unit configured to detect a ring gear rotation speed,
the automatic stop and restart device comprising a controller which comprises a transmission state determination unit configured to determine 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 unit if a predetermined restart condition is satisfied after the predetermined automatic engine stop condition is satisfied, wherein the controller further comprises:
a starter drive time measurement unit configured to measure starter motor drive time from a time point when the drive of the starter motor is started;
a pinion gear rotation speed estimation unit configured to estimate a pinion gear rotation speed based on the starter motor drive time;
a first pinion gear thrust timing determination unit configured to drive the pinion gear thrust unit at a 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
a second pinion gear thrust timing determination unit configured to drive the pinion gear thrust unit at a 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.