Evaporated fuel processing device and method for diagnosing evaporated fuel processing device

• US 9,341,538 B2
• Filed: 12/26/2013
• Issued: 05/17/2016
• Est. Priority Date: 12/27/2012
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Horiba, Ayumu
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Shabman, Mark A
• Application Number:
  US14/140,696
• Publication Number:
  US 20140182360A1
• Time in Patent Office: 873 Days
• US Class Current: 1/1
• CPC Class Codes: G01M 3/2876 for valves G01M3/30 takes precedence

Abstract

A evaporated fuel processing device includes a seal valve that seals off the fuel tank from the atmosphere, a canister, a changeover valve that allows or inhibits communication of the canister with the atmosphere, the canister internal pressure sensor, a controller that sends an open/close command to the seal valve and the changeover valve, a diagnosis unit that performs leak diagnosis of an evaporated fuel sealing system, and a negative pressure pump that generates pressure in the evaporated fuel sealing system. The diagnosis unit performs leak diagnosis of the entirety of the evaporated fuel sealing system before performing leak diagnosis of a canister side section. The diagnosis unit performs function diagnosis of the seal valve with the seal valve closed and the changeover valve at a shut-off position based on whether the detection value of the tank internal pressure sensor varies beyond a predetermined range of the generated pressure.

Claims

1. An evaporated fuel processing device comprising:

a seal valve disposed in a communication passage communicating a fuel tank with atmosphere, the fuel tank being mounted in a vehicle including an internal-combustion engine, the seal valve sealing off the fuel tank from the atmosphere;

a canister disposed in the communication passage between the seal valve and the atmosphere, the canister collecting evaporated fuel vented from the fuel tank via the communication passage;

a changeover valve disposed in the communication passage between the canister and the atmosphere, the changeover valve allowing or inhibiting the canister from communicating with the atmosphere;

a canister internal pressure detecting unit disposed in a canister side section of the communication passage, the canister side section being one of two sections of the communication passage divided at a position of the seal valve and including the canister, the canister internal pressure sensor detecting a canister internal pressure of the canister,

a tank internal pressure detecting unit configured to detect a tank internal pressure of the fuel tank;

a controller configured to send a command to open or close the seal valve and a command to switch the changeover valve between an atmosphere communication position and an atmosphere shut-off position;

a diagnosis unit configured to perform a leak diagnosis of an evaporated fuel sealing system including the fuel tank, the canister, and the seal valve; and

a pressure generating unit configured to generate pressure in the evaporated fuel sealing system via the changeover valve,

wherein the diagnosis unit performs a leak diagnosis of the entirety of the evaporated fuel sealing system using the pressure generating unit and the canister internal pressure detecting unit with the seal valve in open state and with the changeover valve at the atmosphere shut-off position in response to the command from the control unit, and

wherein when the control unit closes the seal valve and, thereafter, sets the changeover valve at the atmosphere shut-off position, the diagnosis unit performs a function diagnosis of the seal valve by determining whether a detection value of the tank internal pressure detected by the tank internal pressure detecting unit varies beyond a predetermined range while the pressure generating unit generates pressure on condition that the seal valve is closed and the changeover valve is at the atmosphere shut-off position.

2. The evaporated fuel processing device according to claim 1, wherein the function diagnosis of the seal valve is started after a predetermined wait time elapses from the time the control unit closes the seal valve.

3. The evaporated fuel processing device according to claim 2, wherein the control unit stops the pressure generating unit for the predetermined wait time from the time the seal valve is closed until the leak diagnosis of the seal valve starts.

4. The evaporated fuel processing device according to claim 1, wherein, by closing the seal valve, the seal valve separates the fuel tank from the canister side section of the communication passage, and wherein the pressure generating unit changes the pressure in the canister side section of the communication passage.

5. The evaporated fuel processing device according to claim 4, wherein the seal valve divides the communication passage into the canister side section and a tank side section connected to the fuel tank such that the canister side section communicates with the tank side section through the seal valve in open state.

6. The evaporated fuel processing device according to claim 1, wherein the pressure generating unit is connected to the canister side section via the changeover valve.

7. A method for diagnosing an evaporated fuel processing device, the evaporated fuel processing device including:

a seal valve disposed in a communication passage communicating a fuel tank with atmosphere, the fuel tank being mounted in a vehicle including an internal-combustion engine, and the seal valve configured to seal off the fuel tank from the atmosphere,

a canister disposed in the communication passage between the seal valve and the atmosphere and configured to collect evaporated fuel vented from the fuel tank via the communication passage,

a changeover valve disposed in the communication passage between the canister and the atmosphere and configured to allow or inhibit the canister from communicating with the atmosphere,

a canister internal pressure detecting unit disposed in a canister side section of the communication passage, where the canister side section is one of two sections of the communication passage divided at a position of the seal valve and includes the canister, and configured to detect a canister internal pressure of the canister,

a tank internal pressure detecting unit configured to detect a tank internal pressure of the fuel tank,

a controller configured to send a command to open or close the seal valve and a command to switch the changeover valve between an atmosphere communication position and an atmosphere shut-off position,

a diagnosis unit configured to perform a leak diagnosis of an evaporated fuel sealing system including the fuel tank, the canister, and the seal valve, and

a pressure generating unit configured to generate pressure in the evaporated fuel sealing system via the changeover valve, the method comprising;

performing a leak diagnosis of the entirety of the evaporated fuel sealing system using the diagnosis unit that uses the pressure generating unit and the canister internal pressure detecting unit with the seal valve in open state and with the changeover valve at the atmosphere shut-off position in response to the command from the control unit; and

performing, after performing the leak diagnosis of the entirety of the evaporated fuel sealing system, a leak diagnosis of the canister side section of the evaporated fuel sealing system using the diagnosis unit that uses the pressure generating unit and the canister internal pressure detecting unit with the seal valve closed and with the changeover valve at the atmosphere shut-off position in response to the command from the control unit,

wherein in performing the leak diagnosis of the canister side section of the evaporated fuel sealing system, the control unit closes the seal valve and, thereafter, sets the changeover valve at the atmosphere shut-off position, and the diagnosis unit performs a function diagnosis of the seal valve by determining whether a detection value of the tank internal pressure detected by the tank internal pressure detecting unit varies beyond a predetermined range while the pressure generating unit generates pressure.

8. The method according to claim 7, wherein the function diagnosis of the seal valve is started after a predetermined wait time elapses from the time the control unit closes the seal valve.

9. The method according to claim 8, wherein the control unit stops the pressure generating unit for the predetermined wait time from the time the seal valve is closed to the time the leak diagnosis of the seal valve starts.

10. The method according to claim 7, wherein, by closing the seal valve, the seal valve separates the fuel tank from the canister side section of the communication passage, and wherein the pressure generating unit changes the pressure in the canister side section of the communication passage.

11. The method according to claim 10, wherein the seal valve divides the communication passage into the canister side section and a tank side section connected to the fuel tank such that the canister side section communicates with the tank side section through the seal valve in open state.

12. The method according to claim 7, wherein the pressure generating unit is connected to the canister side section via the changeover valve.