Device and method for diagnosing evaporated fuel processing device

Patent metadata

Field	Value
Publication number	US-9494481-B2
Application number	US-201314380787-A
Country	US
Kind code	B2
Filing date	Mar 5, 2013
Priority date	Mar 9, 2012
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

An evaporated fuel processing apparatus includes a valve between a canister and a fuel tank, and maintains the fuel tank in hermetic state by closing the valve while a vehicle is stationary, and adsorbs evaporated fuel by the canister by opening the valve during fuel filling, wherein the evaporated fuel occurs in the fuel tank. A diagnostic apparatus includes: a pump connected to a canister-side region with respect to the valve, and configured to pressurize a system of the canister and the fuel tank; and a pressure sensor for sensing an internal pressure of the system. The diagnostic apparatus starts pressurization by the pump with the valve closed; brings the system into a pressurized state by opening the valve with a delay after the start of pressurization; and performs a leakage diagnosis based on a change in the internal pressure of the system from the pressurized state.

First claim

The invention claimed is:

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 maintains the fuel tank in hermetic state by closing the blocking valve while a vehicle is stationary, and adsorbs evaporated fuel by the canister by opening the blocking valve during fuel filling, wherein the evaporated fuel occurs in the fuel tank, the diagnostic apparatus comprising:
a pump connected to a canister-side region with respect to the blocking valve, and configured to pressurize an inside of a system, wherein the system includes the canister and the fuel tank; and
at least one pressure sensor configured to sense an internal pressure of the system;
wherein the diagnostic apparatus is configured to:
start pressurization by the pump with the blocking valve closed;
bring the inside of the system into a pressurized state by opening the blocking valve with a delay of a predetermined period after the start of pressurization; and
perform a leakage diagnosis based on a change in the internal pressure of the system from the pressurized state.

2. The diagnostic apparatus as claimed in claim 1 , wherein the diagnostic apparatus is configured to open the blocking valve in response to a condition where a pressure of the canister-side region becomes higher than or equal to a pressure of a fuel-tank-side region after the start of pressurization by the pump.

3. The diagnostic apparatus as claimed in claim 2 , wherein the diagnostic apparatus is configured to open the blocking valve in response to a condition where the pressure of the canister-side region becomes higher than the pressure of the fuel-tank-side region by a predetermined pressure difference.

4. The diagnostic apparatus as claimed in claim 1 , wherein the diagnostic apparatus is configured to open the blocking valve in response to a condition where a predetermined time has elapsed after the start of pressurization by the pump.

5. 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.

6. The diagnostic apparatus as claimed in claim 1 , wherein the diagnostic apparatus is configured to maintain an inside of the fuel tank pressurized, by closing the blocking valve after termination of the diagnosis.

7. The diagnostic apparatus as claimed in claim 1 , wherein:
the at least one pressure sensor includes a pressure sensor provided in the canister-side region with respect to the blocking valve, and a pressure sensor provided in the fuel-tank-side region with respect to the blocking valve; and
the diagnostic apparatus is configured to:
close the blocking valve after the inside of the entire system has been made pressurized by opening the blocking valve; and
perform a leakage diagnosis for each of the canister-side region and the fuel-tank-side region.

8. 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 maintains the fuel tank in hermetic state by closing the blocking valve while a vehicle is stationary, and adsorbs evaporated fuel by the canister by opening the blocking valve during fuel filling, wherein the evaporated fuel occurs in the fuel tank, the diagnostic method comprising:
bringing an inside of a system into hermetic state, wherein the system includes the canister and the fuel tank;
starting pressurization by a pump via a canister-side region with respect to the blocking valve, with the blocking valve closed;
opening the blocking valve with a delay of a predetermined period after the start of pressurization;
stopping the pressurization in response to a condition where the inside of the entire system has been brought into a predetermined pressurized state; and
performing a leakage diagnosis based on a change in internal pressure of the system from the pressurized state.

9. The diagnostic method as claimed in claim 8 , comprising opening the blocking valve in response to a condition where a pressure of the canister-side region becomes higher than or equal to a pressure of a fuel-tank-side region after the start of pressurization by the pump.

10. The diagnostic method as claimed in claim 8 , comprising opening the blocking valve in response to a condition where a predetermined time has elapsed after the start of pressurization by the pump.

Assignees

• Nissan Motor

Inventors

• Takakura Shinsuke

Classifications

• G01M3/26

  by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors · CPC title

• F02M25/0818 Primary

  having means for pressurising the evaporative emission space · CPC title

• G01M3/3236

  by monitoring the interior space of the containers · CPC title

• G01M3/04 Primary

  by detecting the presence of fluid at the leakage point · CPC title

• F02M2700/05

  Miscellaneous constructional elements; Leakage detection · CPC title