Vacuum detection component

• US 6,508,235 B2
• Filed: 02/21/2001
• Issued: 01/21/2003
• Est. Priority Date: 02/22/2000
• Status: Active Grant

• Current Assignee: Siemens Canada Limited (Siemens AG)
• Original Assignee: Siemens Canada Limited (Siemens AG)
• Inventors: Fabre, Laurent
• Primary Examiner(s): Wolfe, Willis R.
• Assistant Examiner(s): Gimie, Mahmoud
• Application Number:
  US09/789,420
• Publication Number:
  US 20010032625A1
• Time in Patent Office: 699 Days
• Field of Search: 123/520, 123/198.D, 123/519, 123/518, 123/516, 731/19.A, 73/497
• US Class Current: 123/520
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system

Abstract

A method of leak detection in a closed vapor handling system of an automotive vehicle, implemented by a system, the method including providing a vacuum detection component having a microcontroller operatively coupled to actuators and sensors, receiving at least one sensor signal from the sensors to the vacuum detection component, processing the at least one sensor signal in the microcontroller, sending output to an engine management system based on the at least one processed sensor signal, processing the output in the engine management system operatively coupled to a control valve, transmitting input from the engine management system to the vacuum detection component based on the processed output, and sending actuator signals from the microcontroller to the actuators. The system including a vacuum detection component having a microcontroller operatively coupled to actuators and sensors, the microcontroller sending and receiving, respectively, signals therefrom and a processor communicating with the microcontroller, the microcontroller processing the signals and sending output based on the processed signals to the processor, the processor processing the output and transmitting input to the microcontroller based on the processed output.

Claims

1. A method of leak detection in a closed vapor handling system of an automotive vehicle having an engine that is shut-off, the method comprising:

providing a vacuum detection component having a microcontroller operatively coupled to actuators and sensors;

receiving when the engine is shut-off at least one sensor signal from the sensors by the vacuum detection component;

processing the at least one sensor signal in the microcontroller;

sending output to an engine management system based on the at least one processed sensor signal;

processing the output in the engine management system operatively coupled to a control valve;

transmitting input from the engine management system to the microcontroller based on the processed output; and

sending actuator signals from the microcontroller to the actuators.

2. The method of claim 1 wherein the providing comprises:

using a shut off valve as an actuator; and

employing a pressure sensing element and a temperature sensing element as sensors.

3. The method of claim 1 wherein the providing comprises:

employing at least one of a differential pressure sensor, a pressure switch that moves at a relative given vacuum and a pair of switches that move at different relative vacuums as sensors.

4. The method of claim 1 wherein the providing comprises:

employing at least one of a temperature sensor, a transducer that provides differential temperature and a model based on induction air temperature and engine coolant temperature with a statistical treatment as sensors.

5. The method of claim 1 wherein the providing comprises:

using a canister purge vent valve as an actuator.

6. The method of claim 1 wherein the receiving comprises:

obtaining a differential pressure and a differential temperature.

7. The method of claim 1 wherein the processing the at least one sensor signal comprises:

determining a small leak condition based on the at least one sensor signal; and

providing a communication interface.

8. The method of claim 7 further comprising:

determining a large leak condition based on the at least one sensor signal;

detecting whether a tank cap is missing; and

performing a component diagnosis.

10. The method of claim 1 wherein the sending comprises:

providing a diagnosis result.

11. The method of claim 10 further comprising:

requesting operation of the control valve, wherein the engine management system communicates with the control valve when an operation request is received; and

providing a request to an onboard diagnostic sequencer.

12. The method of claim 1 wherein the processing the output comprises:

providing a communication interface; and

detecting an onboard diagnostic error.

13. The method of claim 12 further comprising:

determining a large leak condition based on the output;

detecting whether a tank cap is missing; and

performing a component diagnosis.

14. The method of claim 1 wherein the transmitting comprises:

requesting a diagnosis;

deleting a diagnostic result; and

determining whether the engine is off.

15. The method of claim 14 wherein the transmitting comprises:

requesting operation of the shut off valve;

providing purge status; and

authorizing an onboard diagnostic sequencer.

16. The method of claim 1 further comprising:

providing a power source to the vacuum detection component.

17. The method of claim 1 further comprising:

providing at least one of a low side driver and a high side driver.

18. The method of claim 1 further comprising:

providing a shut off valve driver that communicates by a serial pulse signal at a frequency that prevents a shut off valve reaction.

19. The method of claim 1 further comprising:

providing a CAN driver to receive output and transmit input.

9. A method of leak detection in a closed vapor handling system of an automotive vehicle comprising:

providing a vacuum detection component having a microcontroller operatively coupled to actuators and sensors;

receiving at least one sensor signal from the sensors by the vacuum detection component;

processing the at least one sensor signal in the microcontroller, the processing the at least one sensor signal including;

obtaining a start temperature and a start pressure;

providing an evaluation temperature;

calculating a temperature differential between the start temperature and the evaluation temperature;

incrementing a time counter if the temperature differential is greater than a temperature control value;

computing a pressure differential between the start pressure and an evaluation pressure; and

comparing the time counter to a time control value if the pressure differential is not greater than a pressure control value;

sending output to an engine management system based on the at least one processed sensor signal;

processing the output in the engine management system operatively coupled to a control valve;

transmitting input from the engine management system to the microcontroller based on the processed output; and

sending actuator signals from the microcontroller to the actuators.

20. The method of claim 9, wherein the providing a vacuum detection component comprises:

using as an actuator at least one of a shut off valve and a canister purge vent valve; and

employing as a sensor at least one of a differential pressure sensor, a pressure switch that moves at a relative given vacuum, a pair of switches that move at different relative vacuums, a temperature sensor, a transducer that provides differential temperature, and a model based on induction air temperature and engine coolant temperature with a statistical treatment.

21. The method of claim 9, further comprising:

shutting-off an engine coupled to the engine management system.

22. A method of leak detection in a closed vapor handling system of an automotive vehicle having an engine that is shut-off, the method comprising:

providing a vacuum detection component having a microcontroller operatively coupled to a pressure switch, a temperature sensor, and a shut off valve, the vacuum detection component communicating with a power source and providing a communication interface;

receiving when the engine is shut-off a pressure signal and a temperature signal from the pressure switch and temperature sensor, respectively, by the microcontroller;

processing the pressure signal and the temperature signal in the microcontroller;

determining a diagnostic result in the microcontroller based on the signals, the diagnostic result including whether a leak condition exits, whether a tank cap is missing and whether a component diagnoses passes;

sending the diagnostic result to an engine management system;

processing the diagnostic result in the engine management system, the engine management system operatively coupled to a control valve, the engine management system providing a communication interface and detecting an onboard diagnostic error;

transmitting a diagnosis request, a reset diagnosis, purge status, and engine status from the engine management system to the microcontroller; and

sending an operation request from the engine management system to the shut off valve.

23. An automotive evaporative leak detection system operating when an engine is shut-off, the system comprising:

a vacuum detection component having a microcontroller operatively coupled to a pressure switch, a temperature sensor, and a shut off valve, the microcontroller sending and receiving, respectively, signals therefrom when the engine is shut-off, the vacuum detection unit located on a conduit between an atmosphere and a canister, the canister communicating with the engine and an atmosphere, the engine communicating with a fuel tank;

a control valve located between the canister and the engine; and

a processor communicating with the microcontroller, the processor operatively coupled to the control valve;

wherein the microcontroller processes the signals, determines a diagnostic result based on the signals, provides a communication interface, and sends the diagnostic result to the processor, the processor provides a communication interface, detects an onboard diagnostic error, requests a diagnosis, deletes a diagnosis result, determines whether the engine is off, requests operation of the shut off valve, and provides purge status.

24. An automotive evaporative leak detection system operating when an engine is shut-off, the system comprising:

a vacuum detection component having a microcontroller operatively coupled to actuators and sensors, the microcontroller sending and receiving, respectively, signals therefrom when the engine is shut-on; and

a processor communicating with the microcontroller, the microcontroller processing the signals and sending output based on the processed signals to the processor, the processor processing the output and transmitting input to the microcontroller based on the processed output.

25. The system of claim 24 wherein the sensors comprise a pressure sensing element in fluid communication with fuel tank vapor and a temperature sensing element in thermal contact with fuel tank vapor.

26. The system of claim 24 wherein the sensors comprise at least one of a differential pressure sensor, a pressure switch that moves at a given relative vacuum and a pair of pressure switches that move at different relative vacuums.

27. The system of claim 24 wherein the sensors comprise a temperature sensor, a transducer that provides differential temperature and a model based on induction air temperature and engine coolant temperature with a statistical treatment.

28. The system of claim 24 wherein the microcontroller calculates a temperature differential between a start temperature and an evaluation temperature, increments a time counter, computes a pressure differential between a start pressure and an evaluation pressure, and compares a time counter to the time control value.

29. The system of claim 24 wherein the processor is operatively coupled to a control valve.

30. The system of claim 24 wherein the actuators comprises canister purge vent valve.

31. The system of claim 24 wherein the actuators comprise a shut off valve.

32. The system of claim 24 wherein the signals comprise a differential pressure and a differential temperature.

33. The system of claim 24 wherein the sensors comprise a temperature sensing element and a pressure sensing element and the actuators comprise a shut off valve, further comprising:

a fuel tank communicating with an engine;

a canister communicating with the fuel tank, the engine and an atmosphere; and

a control valve operatively coupled to the processor and located between the canister and the engine,

wherein the vacuum detection unit is located on a conduit between the canister and the atmosphere.

34. The system of claim 24 wherein the output comprises a diagnostic result.

35. The system of claim 24 wherein the output comprises a control valve operation request and an onboard diagnostic sequencer request.

36. The system of claim 24 wherein the processor provides a communication interface, detects an onboard diagnostic error, requests a diagnosis, deletes a diagnostic result, determines whether the engine is off, requests operation of the shut off valve, provides purge status, and authorizes an onboard diagnostic sequencer.

37. The system of claim 24 wherein the processor determines a large leak condition based on the output, detects whether a tank cap is missing, performs a component diagnosis, provides a communication interface, detects an onboard diagnostic error, requests a diagnosis, deletes a diagnostic result, and determines whether the engine is off.

38. The system of claim 24 wherein the processor and the microcontroller communicate by at least one of a low side driver and a high side driver.

39. The system of claim 24 wherein the processor and the microcontroller communicate by a CAN driver.

40. The system of claim 24 wherein the processor and the microcontroller communicate by a shut off valve driver that sends and receives serial pulse signals at a frequency that prevents a shut off valve reaction.

41. The system of claim 24 wherein the vacuum detection component communicates with a power source.