Engine control system

Patent metadata

Field	Value
Publication number	US-9657661-B2
Application number	US-201514689427-A
Country	US
Kind code	B2
Filing date	Apr 17, 2015
Priority date	Apr 23, 2014
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

An engine control system is a system configured to selectively switch between first fuel and second fuel and perform an operation control of a single engine, including: a sensor configured to detect an oxygen concentration of an exhaust gas that is exhausted from the engine; and a control device configured to perform an air-fuel ratio feedback control such that an air-fuel ratio becomes a target air-fuel ratio based on an output signal of the sensor, wherein the control device calculates a correction coefficient of an air-fuel ratio feedback control during an operation with the second fuel, and further stores a fuel composition correction coefficient that is a value in a predetermined range and corrects a difference between the calculated correction coefficient and a targeted correction coefficient arising from a change in composition of the second fuel.

First claim

What is claimed is:

1. An engine control system configured to selectively switch between a first fuel and a second fuel and perform an operation control of a single engine, the engine control system comprising:
a sensor configured to detect an oxygen concentration of an exhaust gas that is exhausted from the engine; and
a control device configured to perform an air-fuel ratio feedback control using an air-fuel ratio correction coefficient such that an air-fuel ratio becomes a target air-fuel ratio based on an output signal of the sensor, wherein
the second fuel is a gas fuel; and
the control device comprises:
a correction device configured to calculate an air-fuel ratio correction coefficient of an air-fuel ratio feedback control during an operation with the second fuel and further correct, using a fuel composition correction coefficient, a difference between the calculated air-fuel ratio correction coefficient and a targeted air-fuel ratio correction coefficient arising from a change in composition of the second fuel;
a storage device configured to store the fuel composition correction coefficient that is a value in a predetermined range; and
a limiting device configured to set a limit to a changing range when the fuel composition correction coefficient is stored.

2. The engine control system according to claim 1 , wherein
the control device calculates the fuel composition correction coefficient when the air-fuel ratio feedback control is in operation and while a purge control is stopped.

3. The engine control system according to claim 2 , wherein
an allowable value of the fuel composition correction coefficient is set in a range such that the change of the composition of the second fuel can be corrected while a predetermined operation state is continued for a predetermined duration.

4. The engine control system according to claim 3 , wherein
the control device does not store the fuel composition correction coefficient in a state where the load of the engine or the rotation number of the engine is high.

5. The engine control system according to claim 2 , wherein
the control device does not store the fuel composition correction coefficient in a state where the load of the engine or the rotation number of the engine is high.

6. The engine control system according to claim 1 , wherein
an allowable value of the fuel composition correction coefficient is set in a range such that the change of the composition of the second fuel can be corrected while a predetermined operation state is continued for a predetermined duration.

7. The engine control system according to claim 6 , wherein
the control device does not store the fuel composition correction coefficient in a state where the load of the engine or the rotation number of the engine is high.

8. The engine control system according to claim 1 , wherein
the control device does not store the fuel composition correction coefficient in a state where the load of the engine or the rotation number of the engine is high.

Assignees

• Keihin Corp

Inventors

• Hibira Takashi
• Yokoyama Shinji
• Ootsuka Masaya
• Haruta Makoto
• Sumisya Noriaki

Classifications

• Y02T10/30

  Use of alternative fuels, e.g. biofuels · CPC title

• F02D41/0032

  Controlling the purging of the canister as a function of the engine operating conditions · CPC title

• F02D41/126

  transitional corrections at the end of the cut-off period · CPC title

• F02D19/0621

  Purging of the fuel system · CPC title

• F02D41/0027 Primary

  the fuel being gaseous (non-electrical control F02D19/02) · CPC title