Leak detection in a closed vapor handling system using a pressure switch, temperature and statistics
First Claim
1. A method of leak detection in a closed vapor handling system of an automotive vehicle, wherein an engine is shut off, comprising:
- obtaining a start temperature;
providing an evaluation temperature using a model based on induction air temperature and engine coolant temperature with a statistical treatment;
calculating a temperature differential between the start temperature and the evaluation temperature;
evaluating whether a pressure switch is closed if the temperature differential is greater than a temperature control value;
incrementing a time counter if the pressure switch is not closed; and
comparing the time counter to a time control value if the pressure switch is not closed.
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Accused Products
Abstract
A method of leak detection in a closed vapor handling system of an automotive vehicle, wherein an engine is shut off, implemented by a system, the method including obtaining a start temperature and start pressure, providing an evaluation temperature, calculating a temperature differential between the start temperature and the evaluation temperature, evaluating whether a pressure switch is closed if the temperature differential is greater than a temperature control value, incrementing a time counter if the pressure switch is not closed and comparing the time counter to a time control value if the pressure switch is not closed. The system includes a pressure switch, a temperature sensing element, and a processor operatively coupled to the pressure switch and the temperature sensing element and receiving, respectively, pressure and temperature signals therefrom, wherein the processor calculates a temperature differential between a start temperature and an evaluation temperature, evaluates whether the pressure switch is closed, increments a time counter, and compares the time counter to the time control value.
29 Citations
24 Claims
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1. A method of leak detection in a closed vapor handling system of an automotive vehicle, wherein an engine is shut off, comprising:
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obtaining a start temperature;
providing an evaluation temperature using a model based on induction air temperature and engine coolant temperature with a statistical treatment;
calculating a temperature differential between the start temperature and the evaluation temperature;
evaluating whether a pressure switch is closed if the temperature differential is greater than a temperature control value;
incrementing a time counter if the pressure switch is not closed; and
comparing the time counter to a time control value if the pressure switch is not closed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
closing a shut off valve.
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3. The method of claim 1 further comprising:
providing a pressure switch that moves at a given relative vacuum.
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4. The method of claim 1 further comprising:
providing a temperature sensing element.
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5. The method of claim 4 wherein the providing comprises:
using a temperature sensor.
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6. The method of claim 4 wherein the providing comprises:
using a transducer that supplies differential temperature.
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7. The method of claim 1 further comprising:
determining whether the engine is off.
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8. The method of claim 1 further comprising:
providing an engine management system to receive pressure and temperature signals from the pressure switch and a temperature sensing element.
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9. The method of claim 1 wherein the comparing comprises:
determining a leak condition if the time counter is greater than the time control value.
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10. The method of claim 9 wherein the determining comprises:
detecting a leak of about 0.5 millimeter.
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11. The method of claim 9 wherein the determining comprises:
detecting a leak of about 1 millimeter.
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12. The method of claim 1 wherein the computing comprises;
determining a no leak condition if the pressures switch is closed.
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13. The method of claim 1 further comprising:
comparing the temperature differential to the temperature control value.
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14. The method of claim 1 wherein the calculating comprises:
recalculating a new temperature differential between the start temperature and a new evaluation temperature if the temperature differential is not greater than the temperature control value.
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15. The method of claim 1 wherein the comparing comprises:
determining a diagnosis not performed condition if the time counter is not greater than the time control value.
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16. An automotive evaporative leak detection system comprising:
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a pressure switch;
a temperature sensing element including a model based on induction air temperature and engine coolant temperature with a statistical treatment; and
a processor operatively coupled to the pressure switch and the temperature sensing element and receiving, respectively, pressure and temperature signals therefrom;
wherein the processor calculates a temperature differential between a start temperature and an evaluation temperature, evaluates whether a pressure switch is closed, increments a time counter if the pressure switch is not closed, and compares a time counter to the time control value. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
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Specification