FUEL INJECTION SYSTEM METHOD AND APPARTUS USING OXYGEN SENSOR SIGNAL CONDITIONING TO MODIFY AIR/FUEL RATIO

• US 20040020480A1
• Filed: 08/05/2002
• Published: 02/05/2004
• Est. Priority Date: 08/05/2002
• Status: Active Grant

• Current Assignee: Dynojet Research, Inc.
• Original Assignee: Dynojet Research, Inc.
• Inventors: Beauregard, Chad D., Kreikemeier, Michael L.
• Granted Patent: US 6,681,752 B1
• Time in Patent Office: Days
• US Class Current: 123/683
• CPC Class Codes: F02D 2400/11 After-sales modification devices designed to be used to modify an engine afterwards
• CPC Class Codes: F02D 41/1454 the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/1456 with sensor output signal being linear or quasi-linear with the concentration of oxygen
• CPC Class Codes: F02D 41/1476 Biasing of the sensor
• CPC Class Codes: F02D 41/1479 Using a comparator with variable reference

Abstract

A method and apparatus for externally modifying the operation of a closed loop electronic fuel injection control system that is normally used with a standard oxygen sensor, which method and apparatus includes replacing the standard oxygen sensor with a wide band oxygen sensor. The signal from the wide band oxygen sensor is processed in a first signal-conditioning module and coupled to the input of the electronic fuel injection control system. The first signal-conditioning module simulates the appearance of a standard oxygen sensor to the electronic fuel injection control system. In a second embodiment, a method and apparatus for externally modifying the operation of a closed loop electronic fuel injection control system that is normally used with a wide band oxygen sensor, includes intercepting the signal from the wide band oxygen sensor in a second signal-conditioning module. The second signal-conditioning module receives a first current from the wide band oxygen sensor and provides a second current to the electronic fuel injection control system.

Claims

1. In an internal combustion engine having a combustion chamber with an intake air channel, a fuel injector disposed in said intake air channel, an exhaust channel coupled to said combustion chamber, a standard oxygen sensor disposed in said exhaust channel, said standard oxygen sensor being of the type having a first output level indicating the presence of oxygen in said exhaust channel and a second output level indicating the absence of oxygen in said exhaust channel, and an electronic control unit connected to said standard oxygen sensor and responsive to said first and second output levels for controlling the amount of fuel injected by said fuel injector into said intake air channel, a method for modifying the operation of said internal combustion engine, said method comprising:

disconnecting said standard oxygen sensor from said electronic control unit;

installing a wide band oxygen sensor in said exhaust channel, said wide band oxygen sensor being of the type for sensing unburned fuel and oxygen in said exhaust channel and having an output signal proportional to the air/fuel ratio in said intake air channel;

providing a signal conditioning module have a respective input and output terminal;

connecting said output of said wide band oxygen sensor to said input terminal of a said signal conditioning module; and

connecting said output terminal of said signal conditioning module to said electronic control unit.

2. A method in accordance with claim 1, wherein said signal conditioning module simulates said first and second output levels forming the output signal of a standard oxygen sensor at a stoichiometric air/fuel ratio to said electronic control unit.

3. A method in accordance with claim 1, wherein said signal conditioning module is responsive to an engine operating condition to simulate said first and second output levels forming the output signal of a standard oxygen sensor at a stoichiometric air/fuel ratio to said electronic control unit.

4. A method in accordance with claim 3, wherein said engine operating condition is throttle position.

5. A method in accordance with claim 3, wherein said engine operating condition is engine speed.

6. In an internal combustion engine combination comprising:

a combustion chamber;

an intake air channel coupled to said combustion chamber;

a fuel injector disposed in said intake air channel;

an exhaust channel coupled to said combustion chamber,

a wide band oxygen sensor disposed in said exhaust channel, said wide band oxygen sensor being of the type for sensing unburned fuel and oxygen in said exhaust channel and having an output signal proportional to the air/fuel ratio in said intake air channel;

a signal conditioning module coupled to said wide band oxygen sensor; and

an electronic control unit coupled to said signal conditioning module,

wherein said signal conditioning module modifies the operation of said internal combustion engine by modifying said signal from said wide band oxygen sensor.

7. An apparatus in accordance with claim 6, wherein

said signal conditioning module is responsive to said wide band oxygen sensor to simulate a standard oxygen sensor of the type having a first output level indicating the presence of oxygen in said exhaust channel and a second output level indicating the absence of oxygen in said exhaust channel.

8. An apparatus in accordance with claim 7, wherein said signal conditioning module simulates said first and second output levels forming the output signal of a standard oxygen sensor at a stoichiometric air/fuel ratio to said electronic control unit.

9. An apparatus in accordance with claim 7, wherein said signal conditioning module is responsive to an engine operating condition to simulate said first and second output levels forming the output signal of a standard oxygen sensor at a stoichiometric air/fuel ratio to said electronic control unit.

10. An apparatus in accordance with claim 9, wherein said engine operating condition is throttle position.

11. An apparatus in accordance with claim 9, wherein said engine operating condition is engine speed.

12. An apparatus in accordance with claim 6, wherein

said signal conditioning module is responsive to said wide band oxygen sensor operating at a programmed target air/fuel ratio to simulate an output signal of a wide band oxygen sensor operating at a new target air/fuel ratio in said intake air channel.

13. An apparatus in accordance with claim 12, wherein said signal conditioning module is responsive to an engine operating condition to simulate said output signal of a wide band oxygen sensor operating at said new target air/fuel ratio in said intake air channel to said electronic control unit.

14. An apparatus in accordance with claim 13, wherein said engine operating condition is throttle position.

15. An apparatus in accordance with claim 13, wherein said engine operating condition is engine speed.

16. In an internal combustion engine having a combustion chamber with an intake air channel, a fuel injector disposed in said intake air channel, an exhaust channel coupled to said combustion chamber, a wide band oxygen sensor disposed in said exhaust channel, said wide band oxygen sensor being of the type for sensing unburned fuel and oxygen in said exhaust channel and having an output signal proportional to the air/fuel ratio in said intake air channel, and an electronic control unit connected to said wide band oxygen sensor and responsive to said output signal from said wide band oxygen sensor for controlling the amount of fuel injected by said fuel injector into said intake air channel, a method for modifying the operation of said internal combustion engine, said method comprising:

disconnecting said wide band oxygen sensor from said signal conditioning module;

providing a signal conditioning module have a respective input and output terminals;

connecting said output of said wide band oxygen sensor to said input terminal of a said signal conditioning module; and

connecting said output terminal of said signal conditioning module to said electronic control unit.

17. An method in accordance with claim 16, wherein said signal conditioning module is responsive to said wide band oxygen sensor operating at a programmed target air/fuel ratio to simulate an output signal of a wide band oxygen sensor operating at a new target air/fuel ratio in said intake air channel.

18. A method in accordance with claim 17, wherein said signal conditioning module is responsive to an engine operating condition to simulate said output signal of a wide band oxygen sensor operating at said new target air/fuel ratio in said intake air channel to said electronic control unit.

19. A method in accordance with claim 18, wherein said engine operating condition is throttle position.

20. A method in accordance with claim 18, wherein said engine operating condition is engine speed.