DEVICE AND METHOD FOR DIAGNOSING EVAPORATED FUEL PROCESSING DEVICE

• US 20150040645A1
• Filed: 03/05/2013
• Published: 02/12/2015
• Est. Priority Date: 03/09/2012
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Takakura, Shinsuke, Otsu, Isao
• Granted Patent: US 9,476,793 B2
• Time in Patent Office: Days
• US Class Current: 73/47
• CPC Class Codes: F02M 25/0818 having means for pressurising the evaporative emission space
• CPC Class Codes: G01M 3/025 Details with respect to the testing of engines or engine parts
• CPC Class Codes: G01M 3/04 by detecting the presence of fluid at the leakage point
• CPC Class Codes: G01M 3/2876 for valves G01M3/30 takes precedence
• CPC Class Codes: G01M 3/3236 by monitoring the interior space of the containers

Abstract

An evaporated fuel processing apparatus includes a valve between a canister and a fuel tank, and adsorbs evaporated fuel by the canister during fuel filling, and introduces into an intake air line of an internal combustion engine and processes the evaporated fuel while the internal combustion engine is operating. A diagnostic apparatus includes: a pump for pressurizing a system including the fuel tank and the canister; and a pressure sensor for sensing an internal pressure of the system. The diagnostic apparatus diagnoses whether or not leakage is present, based on a change in the internal pressure of the system from a pressurized state, wherein the pressurized state is a state pressurized to a predetermined pressure for diagnosis that is higher than a tank pressure at start of diagnosis; and maintains the fuel tank in the pressurized state by closing the valve after termination of the diagnosis.

Claims

1. A diagnostic apparatus for an evaporated fuel processing apparatus, wherein the evaporated fuel processing apparatus includes a blocking valve configured to selectively allow and shut off communication between a canister and a fuel tank, and adsorbs evaporated fuel by the canister during fuel filling, wherein the evaporated fuel occurs in the fuel tank, and introduces into an intake air line of an internal combustion engine and processes the evaporated fuel while the internal combustion engine is operating, the diagnostic apparatus comprising:

a pump configured to pressurize an inside of a system, wherein the system includes the fuel tank and the canister; and

at least one pressure sensor configured to sense an internal pressure of the system;

wherein the diagnostic apparatus is configured to;

diagnose whether or not leakage is present, based on a change in the internal pressure of the system from a pressurized state, wherein the pressurized state is a state pressurized to a predetermined pressure for diagnosis that is higher than a tank pressure at start of diagnosis; and

maintain an inside of the fuel tank in the pressurized state by closing the blocking valve after termination of the diagnosis.

2. The diagnostic apparatus as claimed in claim 1, wherein the canister includes a first end and a second end in a flow direction, wherein a charge port and a purge port is arranged at the first end, and a drain port is disposed at the second end, wherein the second end is connected to the pump.

3. The diagnostic apparatus as claimed in claim 1, wherein the diagnostic apparatus is configured to:

perform a leakage diagnosis with the blocking valve opened, after pressurization of the inside of the system; and

close the blocking valve after termination of the diagnosis.

4. The diagnostic apparatus as claimed in claim 1, wherein:

the pressure sensor is disposed in a fuel tank side closer to the fuel tank at least with respect to the blocking valve; and

the diagnostic apparatus is configured to perform a leakage diagnosis for the fuel tank side with the blocking valve closed, after pressurization of the inside of the system.

5. The diagnostic apparatus as claimed in claim 1, wherein:

the pressure sensor is disposed in a canister side closer to the canister at least with respect to the blocking valve; and

the diagnostic apparatus is configured to perform a leakage diagnosis for the canister side with the blocking valve closed, after pressurization of the inside of the system.

6. The diagnostic apparatus as claimed in claim 1, wherein:

the blocking valve is a normally closed electromagnetic valve; and

the diagnostic apparatus is configured to leave the blocking valve in closed state until a next fuel filling operation.

7. A diagnostic method for an evaporated fuel processing apparatus, wherein the evaporated fuel processing apparatus includes a blocking valve configured to selectively allow and shut off communication between a canister and a fuel tank, and adsorbs evaporated fuel by the canister during fuel filling, wherein the evaporated fuel occurs in the fuel tank, and introduces into an intake air line of an internal combustion engine and processes the evaporated fuel while the internal combustion engine is operating, the diagnostic method comprising:

bringing an inside of a system into hermetic state, wherein the system includes the fuel tank and the canister;

pressurizing the inside of the system into a pressurized state by a pump, wherein the pressurized state is a state pressurized to a predetermined pressure for diagnosis that is higher than a tank pressure at start of diagnosis;

diagnosing whether or not leakage is present, based on a change in an internal pressure of the system after termination of the pressurization; and

maintaining an inside of the fuel tank in the pressurized state by maintaining the blocking valve in closed state after termination of the diagnosis.

8. The diagnostic method as claimed in claim 7, comprising performing the pressurization by the pump via a drain port side of the canister.

9. The diagnostic method as claimed in claim 7, comprising:

performing a leakage diagnosis with the blocking valve opened, after pressurization of the inside of the system; and

closing the blocking valve after termination of the diagnosis.

10. A diagnostic apparatus for an evaporated fuel processing apparatus, wherein the evaporated fuel processing apparatus includes a blocking valve configured to selectively allow and shut off communication between a canister and a fuel tank, and adsorbs evaporated fuel by the canister during fuel filling, wherein the evaporated fuel occurs in the fuel tank, and introduces into an intake air line of an internal combustion engine and processes the evaporated fuel while the internal combustion engine is operating, the diagnostic apparatus comprising:

a pump configured to pressurize an inside of a system via a canister side of the system closer to the canister with respect to the blocking valve, wherein the system includes the fuel tank and the canister; and

a canister side pressure sensor configured to sense a pressure of the canister side of the system with respect to the blocking valve;

a fuel tank side pressure sensor configured to sense a pressure of a fuel tank side of the system closer to the fuel tank with respect to the blocking valve;

wherein the diagnostic apparatus is configured to;

start the pressurization by the pump with the blocking valve closed;

bring the entire system into a pressurized state by opening the blocking valve, in response to a condition that the pressure of the canister side with respect to the blocking valve becomes higher than the pressure of the fuel tank side with respect to the blocking valve;

diagnose whether or not leakage is present, based on a change in an internal pressure of the system from the pressurized state; and

maintain an inside of the fuel tank in the pressurized state via the blocking valve after termination of the diagnosis.