Controller for controlling element temperature of exhaust gas sensor

• US 20040016228A1
• Filed: 05/14/2003
• Published: 01/29/2004
• Est. Priority Date: 05/16/2002
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Kitagawa, Hiroshi, Yasui, Yuji
• Granted Patent: US 6,978,203 B2
• Time in Patent Office: Days
• US Class Current: 60/285
• CPC Class Codes: F02D 2041/288 for performing a transformation into the frequency domain, e.g. Fourier transformation
• CPC Class Codes: F02D 41/1446 the characteristics being exhaust temperatures
• CPC Class Codes: F02D 41/1456 with sensor output signal being linear or quasi-linear with the concentration of oxygen
• CPC Class Codes: F02D 41/1494 Control of sensor heater
• CPC Class Codes: G01N 27/4067 Means for heating or controlling the temperature of the solid electrolyte

Abstract

A controller for controlling a temperature of an element disposed in an exhaust gas sensor is provided. The exhaust gas sensor further comprises a heater for heating the element. The controller comprises a control unit. The control unit performs response assignment control to determine a duty ratio of energization of the heater. In one embodiment, the response assignment control uses a switching function that specifies a response of the element temperature to a target temperature. The energization duty ratio is determined based on the integral of the switching function. In one embodiment, the element temperature of the exhaust gas sensor is estimated. The control unit determines the energization duty ratio of the heater based on the estimated element temperature. The element temperature may be estimated based on the temperature of exhaust gas.

Claims

1. A controller for controlling a temperature of an element provided in an exhaust gas sensor, the exhaust gas sensor comprising a heater for heating the element, the controller comprising a control unit configured to:

perform response assignment control to determine a duty ratio of energization of the heater.

2. The controller of claim 1, wherein the control unit is further configured to determine the energization duty ratio so that the element temperature converges to a target temperature.

3. The controller of claim 1, wherein the control unit is further configured to:

determine a switching function for the response assignment control, the switching function specifying a response of the element temperature to a target temperature; and

determine the energization duty ratio based on the integral of the switching function.

4. The controller of claim 1, further comprising an estimator for estimating the element temperature of the exhaust gas sensor,

wherein the control unit is further configured to determine the energization duty ratio based on the estimated element temperature.

5. The controller of claim 4, wherein the control unit is further configured to determine the energization duty ratio so that the estimated element temperature converges to a target temperature.

6. The controller of claim 4,

wherein the exhaust gas sensor is provided in an exhaust manifold of an engine,

wherein the estimator is further configured to estimate the element temperature based on an operating state of the engine.

7. The controller of claim 4,

wherein the exhaust gas sensor is provided in an exhaust manifold of an engine,

wherein the estimator is further configured to estimate the element temperature based on a temperature of exhaust gas.

8. The controller of claim 7, wherein the estimator is further configured to:

estimate the temperature of the exhaust gas based on an operating state of the engine; and

estimate the element temperature based on the estimated exhaust gas temperature.

9. The controller of claim 8, further comprising a memory for storing a map in which predicted steady state temperatures of exhaust gas corresponding to steady operating states of the engine are provided,

wherein the estimator is further configured to:

acquire a current operating state of the engine;

extract from the map a steady state temperature corresponding to the acquired operating state; and

estimate the temperature of the exhaust gas based on the extracted steady state temperature.

10. The controller of claim 9, wherein the operating state of the engine is represented by rotational speed of the engine and pressure of an intake manifold of the engine.

11. A method for controlling a temperature of an element provided in an exhaust gas sensor, the exhaust gas sensor comprising a heater for heating the element, the method comprising the step of:

performing response assignment control to determine a duty ratio of energization of the heater.

12. The method of claim 11, further comprising the step of:

determining the energization duty ratio so that the element temperature converges to a target temperature.

13. The method of claim 11, further comprising the steps of:

determining a switching function for the response assignment control, the switching function specifying a response of the element temperature to a target temperature; and

determining the energization duty ratio based on the integral of the switching function.

14. The method of claim 11, further comprising the steps of:

estimating the element temperature of the exhaust gas sensor; and

determining the energization duty ratio based on the estimated element temperature.

15. The method of claim 14, further comprising the step of determining the energization duty ratio so that the estimated element temperature converges to a target temperature.

16. The method of claim 14,

wherein the exhaust gas sensor is provided in an exhaust gas manifold of an engine,

wherein the step of estimating the element temperature further comprises the step of estimating the element temperature based on an operating state of the engine.

17. The method of claim 14,

wherein the exhaust gas sensor is provided in an exhaust gas manifold of an engine,

wherein the step of estimating the element temperature further comprises the step of estimating the element temperature based on a temperature of exhaust gas.

18. The method of claim 17, wherein the step of estimating the element temperature based on a temperature of exhaust gas further comprises the steps of:

estimating the temperature of the exhaust gas based on an operating state of an engine; and

estimating the element temperature based on the estimated exhaust gas temperature.

19. The method of claim 18, wherein the step of estimating the temperature of the exhaust gas further comprises the steps of:

storing in a memory a map in which predicted steady state temperatures of exhaust gas corresponding to steady operating states of the engine are provided;

acquiring a current operating state of the engine;

extracting from the map a steady state temperature corresponding to the acquired operating state; and

estimating the temperature of the exhaust gas based on the extracted steady state temperature.

20. The method of claim 19, wherein the operating state of the engine is represented by rotational speed of the engine and pressure of an intake manifold of the engine.

21. A computer program stored on a computer readable medium for use in controlling a temperature of an element provided in an exhaust gas sensor, the exhaust gas sensor further comprising a heater for heating the element, the computer program comprising:

program code for performing response assignment control to determine a duty ratio of energization of the heater.

22. The computer program of claim 21, further comprising:

program code for determining the energization duty ratio so that the element temperature converges to a target temperature.

23. The computer program of claim 21, further comprising:

program code for determining a switching function for the response assignment control, the switching function specifying a response of the element temperature to a target temperature; and

program code for determining the energization duty ratio based on the integral of the switching function.

24. The computer program of claim 21, further comprising:

program code for estimating the element temperature of the exhaust gas sensor; and

program code for determining the energization duty ratio based on the estimated element temperature.

25. The computer program of claim 24, further comprising:

program code for determining the energization duty ratio so that the estimated element temperature converges to a target temperature.

26. The computer program of claim 24,

wherein the exhaust gas sensor is provided in an exhaust manifold of an engine,

wherein the program code for estimating the element temperature further comprises program code for estimating the element temperature based on an operating state of the engine.

27. The computer program of claim 24,

wherein the exhaust gas sensor is provided in an exhaust manifold of an engine,

wherein the program code for estimating the element temperature further comprises program code for estimating the element temperature based on a temperature of exhaust gas.

28. The computer program of claim 27, wherein the program code for estimating the element temperature based on a temperature of exhaust gas further comprises:

program code for estimating the temperature of the exhaust gas based on an operating state of an engine; and

program code for estimating the element temperature based on the estimated exhaust gas temperature.

29. The computer program of claim 28, further comprising a computer readable map for providing predicted steady state temperatures of exhaust gas corresponding to steady operating states of the engine,

wherein the program code for estimating the exhaust gas temperature further comprises:

program code for acquiring a current operating state of the engine;

program code for extracting from the map a steady state temperature corresponding to the acquired operating state; and

program code for estimating the temperature of the exhaust gas based on the extracted steady state temperature.

30. The computer program of claim 29, wherein the operating state of the engine is represented by rotational speed of the engine and pressure of an intake manifold of the engine.