Evaporation system leak diagnostic apparatus
First Claim
1. An evaporation system leak diagnostic apparatus that purges fuel vapor from a fuel tank into an intake system of an internal combustion engine via a canister, comprising:
- a tank internal pressure detecting device that detects a tank internal pressure of the fuel tank;
a first closed system forming device that forms a first closed system in which the fuel tank is closed off;
a second closed system forming device that forms a second closed system in which the canister and the fuel tank form a combined space that is closed off;
a first closed system leak diagnostic unit that executes a leak diagnostic on the first closed system based on the tank internal pressure detected by the tank internal pressure detecting device, after a reference time has passed while the first closed system is formed with the first closed system forming device, and during a period of time from an on operation of an ignition switch until right before purging is first executed; and
a second closed system leak diagnostic unit that introduces pressure in the first closed system into the second closed system by forming the second closed system with the second closed system forming device, and executes a leak diagnostic on the second closed system based on the tank internal pressure detected by the tank internal pressure detecting device after the period of time until right before the purging is first executed, after the leak diagnostic by the first closed system leak diagnostic unit.
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Accused Products
Abstract
An evaporation system leak diagnostic apparatus that purges fuel vapor from a fuel tank into an intake system of an internal combustion engine via a canister, includes: a first closed system leak diagnostic unit that executes a leak diagnostic on a first closed system based on a tank internal pressure detected by a tank internal pressure detecting device while the first closed system is formed with a first closed system forming device; and a second closed system leak diagnostic unit that introduces pressure in the first closed system into a second closed system by forming a second closed system with a second closed system forming device, and executes a leak diagnostic on the second closed system based on the tank internal pressure detected by the tank internal pressure detecting device, after the leak diagnostic by the first closed system leak diagnostic unit.
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Citations
14 Claims
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1. An evaporation system leak diagnostic apparatus that purges fuel vapor from a fuel tank into an intake system of an internal combustion engine via a canister, comprising:
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a tank internal pressure detecting device that detects a tank internal pressure of the fuel tank; a first closed system forming device that forms a first closed system in which the fuel tank is closed off; a second closed system forming device that forms a second closed system in which the canister and the fuel tank form a combined space that is closed off; a first closed system leak diagnostic unit that executes a leak diagnostic on the first closed system based on the tank internal pressure detected by the tank internal pressure detecting device, after a reference time has passed while the first closed system is formed with the first closed system forming device, and during a period of time from an on operation of an ignition switch until right before purging is first executed; and a second closed system leak diagnostic unit that introduces pressure in the first closed system into the second closed system by forming the second closed system with the second closed system forming device, and executes a leak diagnostic on the second closed system based on the tank internal pressure detected by the tank internal pressure detecting device after the period of time until right before the purging is first executed, after the leak diagnostic by the first closed system leak diagnostic unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An evaporation system leak diagnostic apparatus that purges fuel vapor from a fuel tank into an intake system of an internal combustion engine via a canister, comprising:
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a tank internal pressure detecting device that detects a tank internal pressure of the fuel tank; a first closed system forming device that forms a first closed system in which the fuel tank is closed off; a second closed system forming device that forms a second closed system in which the canister and the fuel tank form a combined space that is closed off; a first closed system leak diagnostic unit that executes a leak diagnostic on the first closed system based on the tank internal pressure detected by the tank internal pressure detecting device while the first closed system is formed with the first closed system forming device; and a second closed system leak diagnostic unit that introduces pressure in the first closed system into the second closed system by forming the second closed system with the second closed system forming device, and executes a leak diagnostic on the second closed system after the leak diagnostic by the first closed system leak diagnostic unit, the second closed system leak diagnostic unit executes the leak diagnostic based on a determination regarding a change in the tank internal pressure detected by the tank internal pressure detecting device, before and after the second closed system is formed. - View Dependent Claims (11, 12, 13)
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14. An evaporation system leak diagnostic apparatus that purges fuel vapor from a fuel tank into an intake system of an internal combustion engine via a canister, comprising:
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a tank internal pressure detecting device that detects a tank internal pressure of the fuel tank; a first closed system forming device that forms a first closed system in which the fuel tank is closed off; a second closed system forming device that forms a second closed system in which the canister and the fuel tank form a combined space that is closed off; a first closed system leak diagnostic unit that executes a leak diagnostic on the first closed system based on the tank internal pressure detected by the tank internal pressure detecting device, while the first closed system is formed with the first closed system forming device and an ignition switch is off, after a temperature that reflects a state of the internal combustion engine has reached a reference temperature; and a second closed system leak diagnostic unit that introduces pressure in the first closed system into the second closed system by forming the second closed system with the second closed system forming device, and executes a leak diagnostic on the second closed system after the leak diagnostic by the first closed system leak diagnostic unit, the second closed system leak diagnostic unit executes the leak diagnostic based on the tank internal pressure detected by the tank internal pressure detecting device while the ignition switch is off.
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Specification