LEAK VERIFICATION AND DETECTION FOR VEHICLE FUEL CONTAINMENT SYSTEMS

• US 20140257721A1
• Filed: 03/07/2013
• Published: 09/11/2014
• Est. Priority Date: 05/25/2010
• Status: Active Grant

• Current Assignee: Automotive Test Solutions, Inc.
• Original Assignee: Automotive Test Solutions, Inc.
• Inventors: Thompson, Bernie C., Pederson, Neal R.
• Granted Patent: US 9,390,565 B2
• Time in Patent Office: Days
• US Class Current: 702/51
• CPC Class Codes: G01M 3/226 for containers, e.g. radiators
• CPC Class Codes: G07C 5/00 Registering or indicating the working of vehicles

Abstract

An off-board vehicle fuel containment tester that utilizes a vacuum/pressure pump to change the pressure in the vehicle'"'"'s fuel handling and containment system. A microprocessor is programmed to control the vacuum/pressure pump system and through the reading produced by a pressure transducer will determine, by the pressure changes occurring in the containment system, if a leak is present and the size of the leak. Once a leak is determined to be present, a gas analyzer that can detect carbon monoxide and hydrocarbons is used to find the point of leakage in the vehicle containment system.

Claims

1. A method of detecting and locating a leak in a vehicle'"'"'s on-board fuel containment and handling system with an off-board diagnostic tool comprising a microprocessor, a positive/negative pressure pump, a CO2 detector, an HC detector, a calibration reservoir, a calibration orifice, and a pressure transducer, the method comprising the steps of:

(a) connecting said diagnostic tool to said vehicle'"'"'s on-board fuel containment and handling system;

(b) measuring and monitoring pressure within said on-board fuel containment and handling system with said pressure transducer;

(c) applying pressure into said on-board fuel containment and handling system;

(d) controlling said pressure within said on-board fuel containment and handling system;

(e) monitoring any resulting pressure changes within said on-board fuel containment and handling system with said pressure transducer;

(f) measuring vapor space volumes, pressure decay rates and pressure decay rate changes within said on-board fuel containment and handling system;

(g) analyzing said vapor space volumes, pressure decay rates and pressure decay changes to determine the presence and size of a leak in said on-board fuel containment and handling system;

(h) analyzing components of said on-board fuel containment and handling system to determine if said components are functioning properly and if a leak is present in any of said components;

(i) controlling the operation of said components in conjunction with said step of analyzing components;

(j) applying CO2 into said on-board fuel containment and handling system via said off-board diagnostic tool;

(k) detecting any CO2 or HC released by said on-board fuel containment and handling system through said leak with said CO2 and HC detectors;

(l) determining the location of said leak in said on-board fuel containment and handling system via said step of detecting any CO2 or HC released;

(m) calibrating said off-board diagnostic tool to the specific capacities of said on-board fuel containment and handling system;

(n) programming said microprocessor to control all said steps of measuring, applying, reading, monitoring, controlling, calibrating, analyzing, and determining;

(o) controlling all said steps of measuring, applying, reading, monitoring, controlling, calibrating, analyzing, and determining through said microprocessor.

2. A method of detecting the location of a leak from a leak site in a fuel containment system, the containment system including one or more external surfaces, the method including the use of a pressurized first composition of matter selected from the group including a gas from a source external to the containment system and vaporized fuel from the containment system (hereinafter “

hydrocarbons”

), at least one of which is capable of passing through the leak site, and a second composition of matter which is capable of adhering to at least a portion of the one or more external surfaces and which is capable of showing the presence of first pressurized composition of matter escaping from the leak site, the method including the steps of;

pressurizing the interior of the containment system to a pressure in excess of the pressure surrounding the containment system to force at least some of the first pressurized composition of matter through the leak site; and

covering at least a portion of the external surface with the second composition of matter to identify the location of the leak site by the interaction of the at least some of the first pressurized composition of matter escaping from the leak site with the second composition of matter.

3. The method as set forth in claim 2, wherein the second composition of matter includes at least one soap capable of forming a least one bubble in the presence of at the leaking first pressurized composition of matter, and the step of covering includes covering the area of the leak site.

4. The method as set forth in claim 2, wherein the second composition of matter is a solution, and the step of covering includes covering the area of the leak site so that the interaction of the solution and the leaking first pressurized composition of matter will form the at least one bubble.

5. The method as set forth in claim 2, wherein the step of covering includes the step of covering all of the surface area of the one or more external surfaces.

6. The method as set forth in claim 2, wherein the one or more external surfaces includes one or more of the group including seams, fittings, couplings and connectors (hereinafter “

connections”

), and wherein the step of covering includes the step of covering at least one of the one or more connections.

7. The method as set forth in claim 2, wherein the leak site is an opening having a cross sectional area less than the area of a 0.020″

diameter hole, and wherein the steps of forcing at least some of the first pressurized composition of matter through the leak site and covering the external surface in the area of the leak site determines the location of such leak site.

8. The method as set forth in claim 2, wherein the leak site is an opening having a cross sectional area down to at least the size of a hole 0.001″

in diameter, and wherein the steps of forcing at least some of the first pressurized composition of matter through the leak site includes forcing at least some of the gas through the leak site and covering the external surface in the area of the leak site determines the location of such leak site.

9. The method as set forth in claim 2, wherein the step of pressurizing the interior of the containment system to a pressure in excess of the pressure surrounding the containment system includes the step of injecting the gas from the external source into the containment system to a pressure in excess of the pressure surrounding the containment system.

10. The method as set forth in claim 9, wherein the gas is CO2.

11. The method as set forth in claim 9, further including the step of providing the source of gas with a pressure regulator, and wherein the method further includes the step of adjusting the pressure of the gas being injected into the containment system.

12. The method as set forth in claim 2 further including providing a detector capable of detecting the presence of at least one of the gas and the hydrocarbons, and wherein the method further includes the step of scanning at least some of the one or more external surfaces of the sealed system with the detector for the presence of at least one of the gas and the hydrocarbons escaping from the leak site, to identify at least the general location of the leak site.

13. A method of detecting the location of a leak site in a containment system, the containment system including one or more external surfaces, the method including the use of a source of a pressurized first composition of matter selected from the group including a gas external to the containment system and vaporized fuel from the containment system (hereinafter “

hydrocarbons”

), a detector capable of detecting the presence of at least one the gas and the hydrocarbons, and a second composition of matter which is capable of adhering to the one or more external surfaces and that will indicate the location of the leak site, the method including the steps of;

pressurizing the interior of the containment system to a pressure in excess of the pressure surrounding the containment system to force at least some of the first composition of matter through the leak site;

scanning with the detector at least some of the one or more external surfaces of the sealed system for the presence of at least some of the first composition of matter escaping from the leak site in the containment system to identify the general location of the leak site; and

covering the external surface in the area of the general location with the second composition of matter to identify the exact location of the leak site.

14. The method as set forth in claim 13, wherein the composition of matter includes at least one soap capable of forming at least one bubble in the presence of at least some of the first composition of matter escaping from the leak site, and wherein the method further includes the step generating one or more bubbles over the leak site by the interaction of the first composition of matter with the at least one soap.

15. A method of detecting the location of a leak site in a containment system, the containment system including one or more external surfaces, the method including the use of a compressible composition of matter selected from the group including a source of pressurized gas external to the sealed system and vaporized fuel from the containment system (hereinafter “

hydrocarbons”

) at least one of which is capable of passing through the leak site, the method further including the use of a detector including housing means and a sensor element capable of detecting the presence of at least some of the compressible composition of matter passing through the leak site, the method including the steps of;

pressurizing the interior of the containment system to a pressure in excess of the pressure surrounding the containment system to force at least some of the compressible composition of matter through the leak site; and

scanning with the detector over at least some of the one or more external surfaces of the sealed system for the presence of at least some of the compressible composition of matter escaping from the leak site in the containment system to identify at least the base location of the leak site.

16. The method as set forth in claim 15, wherein the detector also includes an alert system which is activated when the sensor element detects the presence of the at least some of the compressible composition of matter escaping from the leak site, and wherein the method includes the step of activating the alert system when the presence of the leaking compressible composition of matter is detected.

17. The method as set forth in claim 16, wherein the alert system includes an audio alert, and wherein the method includes the step of activating the audio alert when the presence of the leaking compressible composition of matter is detected.

18. The method as set forth in claim 16, wherein the alert system includes a visual alert, and wherein the method includes the step of activating the visual alert when the presence of the leaking compressible composition of matter is detected.

19. The method as set forth in claim 16, wherein the alert system includes both an audio alert and a visual alert, and wherein the method includes the step of activating the both alerts when the presence of the leaking compressible composition of matter is detected.

20. The method as set forth in claim 15, wherein the one or more external surfaces include areas that are hard to reach, wherein the sensor is connected to the detector housing means by a flexible connector which permits the sensor, as the detector is scanning, to scan the areas that are hard to reach, and wherein the step of scanning includes scanning at least some of the areas that are hard to reach with the sensor at the end of the flexible connector.

21. The method as set forth in claim 20, wherein the detector also includes an alert system which is activated when the sensor element detects the presence of the at least some of the compressible composition of matter escaping from the leak site, and wherein the method includes the step of activating the alert system when the presence of the leaking compressible composition of matter is detected.

22. The method as set forth in claim 21 wherein the time delay between detecting the presence of the gas escaping from the one leak site and the activation of the alert system is less than one second.

23. The method as set forth in claim 15, wherein the step of scanning is scanning by moving the sensor element over the at least some of the one or more external surfaces of the sealed system.

24. The method set forth in claim 23, wherein the one or more external surfaces include areas that are hard to reach, wherein the sensor is connected to the detector by a flexible connector which permits the sensor to scan the areas that are hard to reach, and wherein the step of scanning includes scanning at least some of the areas that are hard to reach with the sensor at the end of the flexible connector.

25. A detector for identifying the presence of a pressurized composition of matter selected from the group including a gas from a source external to a containment system and vaporized fuel from the containment system (herein after “

hydrocarbons”

) leaking from the containment system having one or more external surfaces, the detector including;

a housing means;

a sensor connected to the housing means which is capable of detecting the presence of at least one of the gas and the hydrocarbon leaking from the containment system; and

an alert system, incorporated in the housing means, which is activated when the sensor detects the presence of the gas.

26. The detector as set forth in claim 25, wherein the alert system includes both an audio and a visual alert.

27. The detector as set forth in claim 25, wherein the housing means includes a flexible connector having first and second ends, wherein the first end is connected to the housing means, and wherein the sensor is connected to the second end.

28. The detector as set forth in claim 25, wherein the sensor includes means for sensing the presence of the gas and means for sensing the presence of the hydrocarbons.

29. The detector as set forth in claim 28, wherein the means for sensing the presence of the gas is a gas analyzer cell, and wherein the means for sensing the presence of the hydrocarbons is a hydrocarbon (HC) cell.

30. The detector as set forth in claim 25, further including a source of the gas under pressure, and means for injecting the gas into the containment system.

31. The detector as set forth in claim 30, further including a pressure regulator connected between the source of gas under pressure and the means for injecting the gas into the containment system.

32. The detector as set forth in claim 30, further including smoke generating apparatus connected to the means for injecting the gas into the containment system.

33. The detector as set forth in claim 25, further including a means for holding a leak detecting composition of matter, and means for applying the composition of matter to at least some of the external surfaces of the containment system.

34. The detector as set forth in claim 33, wherein the means for applying the composition of matter includes an applicator and means for forcing the composition of matter through the applicator.

35. A method of diagnosing the fuel containment and handling system for a vehicle (hereinafter “

containment system”

) to determine whether or not there is a leak with an off board diagnostic tool;

the diagnostic tool including a microprocessor, a means for applying pressure within the containment system and regulating the pressure within the containment system, and a pressure transducer for reading the pressure within the containment system controlled by the microprocessor;

the method including the steps of;

a. pressurizing the containment system with the means for applying pressure;

b. programming the microprocessor to read the pressure transducer and to determine if there is a pressure decay rate;

c. reading the pressure within the containment system with a pressure transducer;

d. determining if there is a pressure decay in the containment system and the rate of decay; and

e. determining the pressure decay rate to determine if there is a leak.

36. The method according to claim 35, wherein the means for applying and regulating pressure can apply a negative pressure to the containment system, and further including the step of creating a negative pressure within the containment system.

37. The method according to claim 35, wherein the means for applying and regulating pressure can apply a positive pressure to the containment system, and further including the step of creating a positive pressure within the containment system.

38. The method according to claim 35, wherein the microprocessor is programmed to assign a value to the leak detected based on the vapor space volume within the containment system and decay rate, and wherein the method further includes the step of determining the vapor space within the containment system and assigning a leak value based on the vapor space volume and the decay rate.

39. The method according to claim 38, wherein the microprocessor is also programmed to assign a hole diameter to any detected leak, and wherein the method further includes the step of, in addition to assigning a leak value, assigning a hole diameter.

40. The method according to claim 38, wherein the microprocessor is also programmed to include a series of leak values and to assign one of the leak values to the detected leak depending on the size of the leak, and further including the step of assigning one of the series of leak values to the leak depending on the size of the detected leak.

41. The method according to claim 40, wherein the series of values includes “

very small leak”

, “

small leak”

, “

medium leak”

, “

large leak” and

“

gross leak”

, and the method includes the step of assigning one of the leak values depending on the size of the leak detected.

42. The method according to claim 35, wherein the microprocessor is programmed with set points that correspond to the pressure decay rate from the containment system which set points are used to determine the leak size of the containment system, and wherein the method includes the step of determining with the set points the leak size of the containment system.

43. The method according to claim 42, wherein the microprocessor is programmed to assign a “

pass”

or “

fail”

code depending on the size of the leak detected, and wherein the method further includes the step of assigning one or the other of the two codes depending on the size of the leak detected.

44. The method according to claim 42, wherein the pressure decay rate is monitored from one set point to a second set point in order to set the leak size.

45. The method according to claim 35, wherein the microprocessor is programmed with a target pressure and wherein the containment system has a leak large enough to prevent the means for applying pressure to pressurize the containment system to reach the target pressure, the method further including the step of categorizing the leak size by the pressure obtained.

46. The method according to claim 35, wherein the microprocessor is programmed to test the containment system with both a positive pressure and a negative pressure, and further including the step of testing the containment system with both positive and negative pressure.

47. The method according to claim 46, wherein the testing the containment system with both positive and negative pressure includes the steps of:

determining the maximum pressure obtained under positive pressure;

determining the maximum negative pressure obtained under negative pressure; and

comparing the two pressure readings to determine if there is a difference.

48. The method according to claim 47, further including the step of running one or more additional tests if the two pressure readings are different.

49. The method according to claim 48, wherein the microprocessor is programmed to run a test to determine of the gas cap of the containment system is leaking, and further including the step of running the gas cap leak test to determine whether or not the gas cap is the source of the containment system leak.

50. The method according to claim 48, wherein the microprocessor is programmed to run a test to determine if one or more hoses and connectors included in the containment system leak when they are wiggled, moved or shaken (collectively “

wiggled”

), and further including the step of running the leaking wiggle test to determine if one or more of the hoses and connectors are leaking.

51. The method according to claim 50, wherein the leaking wiggle test includes the step of monitoring the pressure changes in the containment system as the individual hoses and components are wiggled to determine the location of the leak.

52. The method according to claim 51, wherein the diagnostic tool includes alert means selected from the group including a visual alert and an audio alert, and wherein the microprocessor is programmed to activate alert means when the pressure change in the containment system breaks a set point, and further including the step of activating the alert means when the set point is broken.

53. The method according to claim 48, wherein the microprocessor is programmed to run a leak isolation test, and further including the step of running the leak isolation test.

80. The method set forth in claim 35, wherein the microprocessor is programmed to use a scan tool to collect data in order to diagnose the fuel containment and handling system.

81. The method set forth in claim 35, wherein the microprocessor is programmed to use a scan tool to operate solenoid valves to diagnose the fuel containment and handling system.

82. The method set forth in claim 35, wherein the microprocessor is programmed to use a scan tool to operate a self leak test to diagnose the fuel containment and handling system.

83. The method set forth in claim 35, wherein the microprocessor is programmed to use a scan tool to run tests to the fuel containment and handling system, while test leads are connected from the EVAP machine to the vehicle circuits in order to monitor the testing with the EVAP machine.

84. The method set forth in claim 35, wherein the microprocessor is programmed to check purge flow by pressure changes within the fuel containment and handling system when the purge valve opens.

85. The method set forth in claim 35, wherein the microprocessor is programmed to display a message to remove the purge hose from the intake manifold in order to test the system for leakage.

86. The method set forth in claim 35, wherein the microprocessor that is controlling the off board diagnostic tool has the capability built in to the unit to connect to the internet.

87. The method set forth in claim 35, wherein the off board diagnostic tool has a adsorption filter placed in the vent of the tool, so the vented pressure from the fuel containment and handling system can have the hydrocarbons removed.

88. The method set forth in claim 35, wherein the microprocessor is programmed to run tests no a Leak Detection Pump (LDP) with leads from a off board diagnostic tool to the vehicle.

89. The method set forth in claim 35, wherein the microprocessor is programmed to run tests on a Natural Vacuum Leak Detection (NVLD), with leads from a off board diagnostic tool to the vehicle.

90. The method set forth in claim 35, wherein the microprocessor is programmed to run tests on a Evaporative System Integrity Monitor (ESIM), with leads from a off board diagnostic tool to the vehicle.

91. The method set forth in claim 35, wherein the microprocessor is programmed to run tests on a Diagnostic Tank Leak Module (DTLM), with leads from a off board diagnostic tool to the vehicle.

93. The method set forth in claim 35, wherein the microprocessor is programmed to calculate the decay rate to determine the leak size within the fuel containment and handling system.

54. The method of diagnosing an actuator which is part of a control system of a vehicle with an off board diagnostic tool;

the actuator having an open and a closed position and a power and control circuit including a power wire and a control wire;

the diagnostic tool including, an electronic circuit that is used to control the actuator by turning it on or off as part of a testing sequence and two wires to connect the electronic circuit to the actuator;

the method including the steps of;

a. connecting one of the two connecting wires to the power wire;

b. connecting the other of the two connecting wires to the control wire;

c. using the electronic circuit to open the actuator as part of a test sequence; and

d. using the electronic circuit to close the actuator as part of the test sequence.

55. The method as set forth in claim 54, wherein the electronic circuit can read either the current within the actuator or the voltage across the actuator power and control circuit, further including the steps of:

a. reading the current within the actuator circuit when activated; and

b. reading the voltage drop across the actuator power and control circuit (the “

voltage drop across the actuator”

).

56. The method as set forth in claim 54, wherein the actuator is part of the vehicle'"'"'s fuel containment and handling system (the “

containment system”

) and the electronic circuit includes a control circuit to read the voltage drop on the actuator power and control circuit when activated and determine from such voltage drop which of the two wires is connected to the power wire and which is connected to the control wire, the method including the steps of;

a. reading the voltage drop across the actuator power and control circuit to determine which wire is the power wire;

b. reading the voltage drop across the actuator power and control circuit to determine which wire is the control wire; and

c. activating the actuator by turning on the control wire.

57. The method as set forth in claim 56, wherein the electronic circuit includes means to read the bias voltage applied to one of the power wire and the control wire (a “

test lead”

), further including the steps of;

a. applying a bias voltage to the test lead; and

b. reading the bias voltage to determine if the test lead is connected or not connected to the actuator circuit.

58. The method according to claim 56, wherein the diagnostic tool includes a means for applying pressure within the containment system and regulating the pressure within the containment system and a pressure transducer, wherein the electronic circuit includes means to read the pressure within the containment system with the pressure transducer, wherein the electronic circuit also includes means to control the pressure in the containment system, and wherein the microprocessor is also programmed to cycle the actuator on and off in response to a pressure change in the containment system, the method further including the steps of:

a. reading the pressure within the containment system with the pressure transducer;

b. using readings from the pressure transducer in order to control the pressure within the containment system based;

c. determining if the containment system is leaking based on monitoring pressure changes in the containment system; and

d. cycling the actuator if a leak has been detected.

59. The method according to claim 58, further including the step of running the engine, and wherein the step of cycling the actuator takes place while the engine is running.

60. The method according to claim 58, wherein the step or cycling the actuator takes place while the engine is off.

61. The method of diagnosing the fuel containment system with a microprocessor that is programmed to control pressure within the fuel containment and handing system, reading this pressure with a pressure transducer, using a calibration reservoir, using a calibration orifice, the method set forth includes the steps of:

a. programming the microprocessor to operate a solenoid valve that can switch in a calibration orifice;

b. programming the microprocessor to read the pressure changes with a pressure transducer and time these said pressure changes; and

c. programming the microprocessor to read the pressure transducer in order to find pressure changes within a calibration reservoir.

62. The method according to claim 61, wherein the microprocessor is programmed to switch into the pressure system a calibration orifice in order to calibrate the pressure decay rate from the calibration reservoir.

63. The method according to claim 61, wherein the microprocessor is programmed to time the pressure change from a first set point to a second set point while filling the calibration reservoir in order to calibrate volume fill time.

64. The method according to claim 61, wherein the microprocessor is programmed to switch into the fuel containment and handing system a calibration orifice that allows a calibrated pressure decay which will be clocked from one set point to a second set point, in order to calculate the vapor space within the fuel containment and handing system.

65. The method according to claim 61, wherein the microprocessor is programmed to time the pressure change from a first set point to a second set point while filling the fuel containment and handling system, in order to calculate the vapor space of the fuel containment and handling system.

66. The method according to claim 61, wherein the microprocessor is programmed to time the pressure change from a first set point to a second set point while filling the fuel containment and handling system, in order to calculate the vapor space of fuel containment and handling system, so a low volume in the system would indicate a restriction in the system.

67. The method according to claim 61, wherein the microprocessor is programmed to switch into the fuel containment and handling system a calibration orifice and time a first set point to a second set point in order to check the volume contained within the fuel containment and handing system, so a low volume in the system would indicate a restriction in the system.

68. The method of diagnosing the fuel containment system with a microprocessor that is programmed to control a pressure that is put into the fuel containment and handling system to check the RVP of the fuel, the method including the steps of:

a. programming the microprocessor to operate a pressure that is a positive pressure;

b. programming the microprocessor to operate a pressure that is a negative pressure;

c. programming the microprocessor to read the pressure within the containment and handing system with a pressure transducer;

d. programming the microprocessor to compare the positive pressure test to the negative pressure test in order to check the difference of pressure; and

e. programming the microprocessor to use the pressure from both pressure states and compare them to calculate the RVP of the fuel.

69. The method of diagnosing the fuel containment system with a microprocessor that is programmed to control a pressure that is put into the fuel containment and handling system to check the RVP of the fuel, the method set forth from claim 68 includes the steps of:

a. programming the microprocessor to apply positive pressure within the fuel containment and handing system, shaking the vehicle and taking a pressure reading, and

b. programming the microprocessor to apply negative pressure within the fuel containment and handing system, shaking the vehicle and taking a pressure reading.

70. The method of diagnosing the fuel containment system with a microprocessor that is programmed to check the fuel tank pressure sensor in the fuel containment system, with the fuel tank pressure sensor reading at atmospheric pressure and with the fuel tank pressure sensor reading under pressure and checking the said pressure with the EVAP machine pressure transducer, the method including the steps of:

a. programming the microprocessor to take in the data on the fuel pressure sensor;

b. programming the microprocessor to apply a pressure into the fuel containment and handling system; and

c. programming the microprocessor to calculate the difference between the fuel tank pressure sensor reading, and the EVAP machine pressure transducer.

71. The method of diagnosing the fuel containment system with a microprocessor that is programmed to check the fuel tank pressure sensor in the fuel containment system, with the fuel tank pressure sensor reading at atmospheric pressure and with the fuel tank pressure sensor reading under pressure and checking the said pressure with the EVAP machine pressure transducer, the method set forth in claim 70 including the steps of:

a. programming the microprocessor to apply a pressure into the fuel containment and handling system that is a negative pressure; and

b. programming the microprocessor to apply a pressure into the fuel containment and handling system that is a positive pressure.

72. The method of diagnosing the fuel containment system with a microprocessor that is programmed to check the fuel tank pressure sensor in the fuel containment system, with the fuel tank pressure sensor reading at atmospheric pressure and with the fuel tank pressure sensor reading under pressure and checking the said pressure with the EVAP machine pressure transducer, the method in claim 70 including the steps of:

a. programming the microprocessor to calculate the difference between the fuel tank pressure sensor reading, and the EVAP machine pressure transducer and determining if the fuel tank sensor is reading correctly; and

b. programming the microprocessor to calculate the difference between the fuel tank pressure sensor reading, and the EVAP machine pressure transducer and determining if the fuel tank sensor is reading incorrectly.

73. The method of diagnosing the location of a leak on a vehicle with an electronic circuit that is designed to monitor C02 gas traces in order to find the location of the leak, the method includes the steps of:

a. an electronic circuit to monitor C02 gas from a gas sensor;

b. having the circuit alert the technician when CO2 is detected; and

c. the use of C02 gas to find leakage on vehicles.

74. The method of diagnosing the location of a leak on a vehicle with an electronic circuit that is designed to monitor C02 gas traces in order to find the location of the leak, the method set forth in claim 73 including the steps of:

a. an electronic circuit to monitor C02 gas from a gas sensor;

b. having the circuit alert the technician when CO2 is detected from a fuel containment and handling system leak; and

c. the use of applying C02 gas in the fuel containment and handing system to find system leakage.

75. The method of diagnosing the location of a leak in the fuel containment and handling system with a microprocessor that is programmed to monitor HC gas traces in order to find the location of the leak, the method set forth in claim 73 including the steps of:

a. an electronic circuit to monitor HC gas from a gas sensor; and

b. programming the microprocessor to indicate a fuel system containment leak by the trace gas reading of HC gas.

76. The method set forth in claim 73, wherein the microprocessor is programmed to monitor C02 gas or HC gas traces to determine the location of a fuel system containment leak;

when said gas trace or gas traces break a preprogrammed set points a alert lamp is turn on indicating the location of the fuel containment leak.

77. The method set forth in claim 73, wherein the microprocessor is programmed to monitor C02 gas or HC gas traces to determine the location of a fuel system containment leak;

when said gas trace or traces break a preprogrammed set points a alert buzzer is turn on indicating the location of the fuel containment leak.

78. The method set forth in claim 73, wherein the microprocessor is programmed to dispense C02 gas into the fuel containment and handling system, and to control the CO2 volume and pressure that is put into the fuel containment and handling system in order to change the sensitivity of the leak detection.

79. The method as set forth in claim 73, wherein a leak detection solution is pumped on to the leak area, so the exact location of the leak can be identified.

92. (canceled)

94. The method of diagnosing the fuel containment and handling system of a vehicle (the “

containment system”

) with an off board diagnostic tool, the tool including a microprocessor that is programmed to calculate the vapor volume contained within the containment system from the fuel tank size and the level of the fuel in the tank, the method including the steps of;

a. determining the fuel tank size of the vehicle;

b. determining the fuel level in the fuel tank; and

c. calculating the vapor space within the containment system from the fuel tank size and fuel level.

95. The method of diagnosing set forth in claim 94, wherein the tool further includes a means for pressurizing the containment system from a first point to a second point (the “

set point”

), a pressure transducer and a timer means, wherein the microprocessor is programmed to pressurize the containment system to the set point, wherein the microprocessor is also programmed to time required to reach the set point (the “

pressure build time”

), the method further including the steps of;

a. pressurizing the containment system to the set point;

b. determining the pressure build time;

c. reading with the pressure transducer the pressure within the containment system; and

d. calculating the vapor space within the fuel tank from the pressure build time.

96. The method of diagnosing as set forth in claim 95, wherein the microprocessor is programmed to compare the vapor space determined from the fuel tank size and the fuel level with the vapor space determined from the pressure build time, including the step of determining the difference between the vapor space as determined from the fuel tank size and fuel level with the vapor space determined from the pressure build time to determine if the fuel level is reading correctly or incorrectly.

97. The method of diagnosing as set forth in claim 95, wherein the tool further includes a calibration orifice, and wherein the microprocessor is programmed to determine the time it takes to reduce the pressure in the containment system through the calibration orifice from the first set point to the second point (the “

orifice decay time”

), including the steps of;

a. depressurizing the fuel containment system;

b. determining the orifice decay time; and

c. calculating the vapor space with the orifice decay time.

98. The method of diagnosing as set forth in claim 97, wherein the microprocessor is also programmed to compare the vapor space determined from the fuel tank size and the fuel level with the vapor space determined from the orifice decay time, including the step of determining the difference between the vapor space as determined from the fuel tank size and fuel level with the vapor space determined from the orifice decay time to determine if the fuel level is reading correctly or incorrectly.

99. The method of diagnosing as set forth in claim 98, further including the step of comparing the vapor space as determined from the pressure build time to the vapor space as determined by the orifice decay time.