Methods and system for an evaporative emissions system leak test using an external pressure source
First Claim
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1. A method for an engine, comprising:
- at engine shut-down, applying pressure stored in a coolant system degas bottle, coupled to an engine cooling system and to a fuel system via a vapor line, to the fuel system including a fuel vapor canister coupled to an engine intake and a fuel tank; and
indicating a leak in the fuel system responsive to a pressure measured by a pressure sensor.
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Abstract
Methods and systems are provided for conducting an evaporative emissions system leak test. In one example, at engine shut-down, pressure stored in a coolant degas bottle is applied to a fuel system in order to pressurize the system. In this way, pressure build-up in the degas bottle may be advantageously utilized to enable a leak test to be conducted.
14 Citations
20 Claims
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1. A method for an engine, comprising:
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at engine shut-down, applying pressure stored in a coolant system degas bottle, coupled to an engine cooling system and to a fuel system via a vapor line, to the fuel system including a fuel vapor canister coupled to an engine intake and a fuel tank; and indicating a leak in the fuel system responsive to a pressure measured by a pressure sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for a fuel system comprising:
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responsive to a first condition, isolating the fuel system from atmosphere and indicating a leak in the fuel system based on a pressure build-up in the fuel system, where pressure in the fuel system builds due to heat rejection from one or more of an engine and ambient and the pressure build-up is measured by a pressure sensor; and responsive to a second condition, pressurizing the fuel system via pressure stored in a coolant system degas bottle and indicating a leak in the fuel system based on a pressure bleed-down in the fuel system as measured by the pressure sensor, the coolant system degas bottle coupled to a cooling system configured to route coolant to the engine, and additionally coupled to the fuel system via a vapor line fluidically coupling the coolant system degas bottle to a canister vent line of the fuel system. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A system for an engine comprising:
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a fuel system including a fuel vapor canister coupled to an engine intake via a canister purge valve and additionally coupled to a fuel tank, the fuel system further including a canister vent line coupled between the fuel vapor canister and atmosphere and controlled via a canister vent valve; and a coolant system degas bottle coupled to a cooling system configured to route coolant to the engine, and additionally coupled to the fuel system via a routing valve positioned in a vapor line fluidically coupling the coolant system degas bottle to the canister vent line of the fuel system. - View Dependent Claims (17, 18, 19, 20)
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Specification