Control device for internal combustion engine and control method for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10837372-B2
Application number	US-201716316566-A
Country	US
Kind code	B2
Filing date	Jun 29, 2017
Priority date	Jul 14, 2016
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

An internal combustion engine in which when an ECU receives an engine stop command by an ON-operation of an engine stop switch, a supply of fuel from an injector to a fuel reformation chamber is stopped while a supply of fuel from an injector to a combustion chamber is continued, and the residual amount of a reformed fuel in passages is estimated, in this state. When the estimated residual amount reaches a predetermined amount or zero, the fuel supply from the injector to the combustion chamber is stopped, and an internal combustion engine is stopped.

First claim

The invention claimed is:

1. A control device for an internal combustion engine including a fuel reformation device capable of generating reformed fuel through a fuel reforming operation and an output cylinder to which the reformed fuel generated in the fuel reformation device is supplied through a reformed fuel supply path, the output cylinder being configured to yield an engine power by combusting the reformed fuel, the control device comprising:
a reformed fuel processing unit configured to:
execute a reformed fuel processing operation, upon receiving an engine stop command or after the internal combustion engine is stopped, for drawing out and processing the reformed fuel from the reformed fuel supply path until a residual amount of reformed fuel in the reformed fuel supply path is a predetermined amount or less; and
initiate, based on receiving the engine stop command, introduction of the reformed fuel in the reformed fuel supply path into the output cylinder and combustion of the reformed fuel in the output cylinder.

2. The control device according to claim 1 , wherein:
an exhaust path is provided in which the reformed fuel in the reformed fuel supply path flows while bypassing the output cylinder, an oxidation catalyst is provided in the exhaust path, and an alarm unit configured to issue an alarm is provided; and
the reformed fuel processing operation introduces the reformed fuel in the reformed fuel supply path into the exhaust path after the internal combustion engine is stopped, and when a gas temperature thereof is equal to or higher than a predetermined temperature, the reformed fuel is oxidized and detoxified by the oxidation catalyst and then discharged into atmosphere, and an alarm is issued by the alarm unit.

3. The control device according to claim 1 , further comprising
a residual amount estimator configured to estimate a residual amount of the reformed fuel in the reformed fuel supply path, based on concentration of a reformed fuel component in the reformed fuel supply path or based on temperature and pressure in the reformed fuel supply path,
wherein the reformed fuel processing unit is configured to execute the reformed fuel processing operation until the residual amount of the reformed fuel estimated by the residual amount estimator becomes equal to or less than a predetermined amount.

4. The control device according to claim 1 , further comprising
a residual amount estimator configured to estimate a residual amount of reformed fuel in the reformed fuel supply path by subtracting an integrated value of an amount of the reformed fuel combusted in the output cylinder, from an integrated value of an amount of the reformed fuel generated in the fuel reformation device from a start of the fuel reforming operation,
wherein the reformed fuel processing unit is configured to execute the reformed fuel processing operation until the residual amount of the reformed fuel estimated by the residual amount estimator becomes equal to or less than a predetermined amount.

5. The control device according to claim 1 , wherein:
the fuel reformation device is structured by a reciprocation type fuel reformation cylinder in which a piston reciprocates in the reciprocation type fuel reformation cylinder, and
when the engine stop command is received, the reformed fuel processing unit executes the reformed fuel processing operation to stop a fuel supply to the fuel reformation cylinder, and continue the fuel supply to the output cylinder to continue driving of the output cylinder, and
the reformed fuel processing operation is executed until a fuel supply amount to the output cylinder for continuing driving of the output cylinder reaches a predetermined amount.

6. The control device according to claim 2 , wherein:
the exhaust path is provided with an open/close valve capable of being opened/closed, and the open/close valve is closed in the fuel reforming operation and opened in the reformed fuel processing operation.

7. The control device according to claim 2 , wherein:
the exhaust path is provided with an exhaust unit configured to cause the reformed fuel in the reformed fuel supply path to bypass the output cylinder and forcedly exhaust the reformed fuel into atmosphere through the oxidation catalyst.

8. A control method for an internal combustion engine including a fuel reformation device for generating reformed fuel through a fuel reforming operation and an output cylinder to which the reformed fuel generated in the fuel reformation device is supplied through a reformed fuel supply path, the output cylinder being configured to yield an engine power by combusting the reformed fuel, the control method comprising:
executing a reformed fuel processing operation based on receiving an engine stop command or detecting the internal combustion engine is in a stopped state, the reformed fuel processing operation comprising:
drawing out the reformed fuel from the reformed fuel supply path until a residual amount of reformed fuel in the reformed fuel supply path becomes a predetermined amount or less; and
processing the reformed fuel drawn out from the reformed fuel supply path; and

stopping the reformed fuel processing operation based on a determination that the residual amount of reformed fuel in the reformed fuel supply path is less than or equal to the predetermined amount.

9. The control method according to claim 8 , further comprising:
receiving the engine stop command;
determining the residual amount of reformed fuel in the reformed fuel supply path; and
comparing the residual amount of reformed fuel in the reformed fuel supply path to the predetermined amount.

10. The control method according to claim 8 , further comprising, based on executing the reformed fuel processing operation:
stopping fuel injection from a first injector into the fuel reformation device;
injecting fuel into the output cylinder from a second injector when the residual amount of reformed fuel in the reformed fuel supply path is greater than the predetermined amount; and
stopping fuel injection into the output cylinder from the second injector when the residual amount of reformed fuel in the reformed fuel supply path is less than or equal to the predetermined amount.

11. The control method according to claim 8 , wherein the reformed fuel processing operation is executed by an engine control unit.

12. The control method according to claim 11 , wherein the engine control unit comprises a memory and a processor.

13. An apparatus comprising:
a control device configured to:
initiate, based on receipt of an engine stop command or detection of an engine being in a stopped state, a reformed fuel process configured to remove a reformed fuel from a reformed fuel supply path between a fuel reformation device and a cylinder;
perform a comparison between an amount of reformed fuel within the reformed fuel supply path to a threshold; and
based on a determination that an amount of reformed fuel within the reformed fuel supply path is less than or equal to the threshold, initiate stoppage of the reformed fuel process.

14. The apparatus according to claim 13 , wherein the control device comprises an engine control unit.

15. The apparatus according to claim 14 , wherein the engine control unit comprises a memory and a processor.

16. The apparatus according to claim 13 , wherein the control device is configured to:
receive the engine stop command from an engine stop switch;
identify the amount of reformed fuel within the reformed fuel supply path; and
determine, based on the comparison, that the amount of r

Assignees

• Yanmar Co Ltd
• Yanmar Power Technology Co Ltd

Inventors

• Asai Go

Classifications

• F02M27/02

  by catalysts · CPC title

• F02D19/0676

  Multi-way valves; Switch-over valves · CPC title

• F02D19/02 Primary

  peculiar to engines working with gaseous fuels · CPC title

• F02D19/0671

  Means to generate or modify a fuel, e.g. reformers, electrolytic cells or membranes · CPC title

• F02M25/025

  Adding water · CPC title