Evaporative fuel handling apparatus

• US 20070023015A1
• Filed: 07/28/2006
• Published: 02/01/2007
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Nakamura, Hiroshi, Uchida, Akikazu, Kobayashi, Yasunori
• Granted Patent: US 7,216,637 B2
• Time in Patent Office: Days
• US Class Current: 123/520
• CPC Class Codes: F02M 25/0818 having means for pressurising the evaporative emission space
• CPC Class Codes: F02M 25/089 Layout of the fuel vapour installation

Abstract

A fuel handling apparatus with a purge system, a first communication passage, and a second communication passage with a greater pressure loss than the first communication passage. A check device is coupled to the second communication passage for checking a leak of evaporative fuel from the purge system. A pump is included, and a selector device is included for switching fluid communication of the pump between one of the first communication passage and the second communication passage. A controller controls the selector device to allow fluid communication between the first communication passage and the pump and then controls the pump to produce the pressure difference for forcible purging. The controller further controls the selector device to allow fluid communication between the second communication passage and the pump, and then controls the pump to produce the pressure difference and controls the check device for leak checking.

Claims

1. An evaporative fuel handling apparatus for a vehicle with an air intake system of an engine and a fuel tank, the evaporative fuel handling apparatus comprising:

a purge system for purging evaporative fuel from the fuel tank into the air intake system, wherein the purge system defines an inside and an outside;

a first communication passage fluidly coupled with the purge system;

a second communication passage fluidly coupled with the purge system and having a greater loss of pressure of flowing fluid than the first communication passage;

a check device coupled to the second communication passage for checking a leak of evaporative fuel from the purge system;

a pump for producing a pressure difference between the inside and the outside of the purge system;

a selector device for switching fluid communication of the pump between one of the first communication passage and the second communication passage; and

a controller that controls the selector device to allow fluid communication between the first communication passage and the pump and then controls the pump to produce the pressure difference to thereby perform forcible purge of evaporative fuel; and

wherein the controller is further operable for controlling the selector device to allow fluid communication between the second communication passage and the pump, and then controls the pump to produce the pressure difference and controls the check device to check for a leak of evaporative fuel.

2. The evaporative fuel handling apparatus as claimed in claim 1, further comprising a restrictor fluidly coupled to the second communication passage, wherein an axial cross sectional area of the restrictor is less than an axial cross sectional area of the second communication passage.

3. The evaporative fuel handling apparatus as claimed in claim 1, wherein the purge system has a canister for adsorbing evaporative fuel from the fuel tank and purges evaporative fuel desorbed from the canister, and wherein the first communication passage and the second communication passage are fluidly coupled to the canister.

4. The evaporative fuel handling apparatus as claimed in claim 3, further comprising an open passage that is fluidly coupled to the pump and is open to the atmosphere, wherein the purge system has a purge passage fluidly coupled to the air intake system and the canister, and wherein the controller, to perform the forcible purge, controls the selector device to allow fluid communication between the first communication passage and the pump and then controls the pump to pressurize the first communication passage.

5. The evaporative fuel handling apparatus as claimed in claim 4, wherein the controller, to check for a leak, controls the selector device to allow fluid communication between the second communication passage and the pump and then controls the pump to depressurize the second communication passage.

6. The evaporative fuel handling apparatus as claimed in claim 4, wherein the controller, to check for a leak, controls the selector device to allow for fluid communication between the second communication passage and the pump and then controls the pump to pressurize the second communication passage.

7. The evaporative fuel handling apparatus as claimed in claim 3, further comprising a first open passage and a second open passage that are each open to the atmosphere;

wherein the purge system has a purge passage that is fluidly coupled to the air intake system and the canister;

wherein the selector device includes a first selection part that switches to allow fluid communication of the pump between one of the first communication passage and the first open passage;

wherein the selector device includes a second selection part that switches to allow fluid communication of the pump between one of the second communication passage and the second open passage;

wherein the controller, to perform the forcible purge, controls the first selection part and the second selection part to allow for fluid communication between the first communication passage and pump and to allow for fluid communication between the second communication passage and the pump, and then controls the pump to pressurize the first communication passage.

8. The evaporative fuel handling apparatus as claimed in claim 7, wherein the controller, to check for a leak, controls the first selection part and the second selection part to allow for fluid communication between first open passage and the pump and to allow for fluid communication between the second communication passage and the pump, and then controls the pump to depressurize the second communication passage.

9. The evaporative fuel handling apparatus as claimed in claim 7, wherein the controller, to check for a leak, controls the first selection part and the second selection part to allow for fluid communication between the first open passage and the pump and to allow for fluid communication between the second communication passage and the pump, and then controls the pump to pressurize the second communication passage.

10. The evaporative fuel handling apparatus as claimed in claim 3, wherein the first communication passage is in directly fluidly coupled to the canister.

11. The evaporative fuel handling apparatus as claimed in claim 3, wherein the purge system includes an introduction passage for introducing evaporative fuel from the fuel tank into the canister, and wherein the first communication passage is fluidly coupled to the introduction passage, such that fluid communication between the first communication passage and the canister occurs through the introduction passage.

12. The evaporative fuel handling apparatus as claimed in claim 3, wherein the purge system includes an introduction passage for introducing evaporative fuel from the fuel tank into the canister, and wherein the first communication passage is fluidly coupled to the fuel tank, such that fluid communication between the first communication passage and the canister occurs through the fuel tank and the introduction passage.

13. The evaporative fuel handling apparatus as claimed in claim 3, further comprising an open passage that is open to the atmosphere;

wherein the purge system has a purge passage fluidly coupled with the air intake system;

wherein the selector device includes a first selection part that switches for allowing fluid communication of the pump between one of the first communication passage and the second communication passage;

wherein the selector device further includes a second selection part that switches to allow fluid communication of the pump between one of the open passage and the purge passage;

and wherein the controller, to perform the forcible purge, controls the first selection part to allow for fluid communication between the first communication passage and the pump, controls the second selection part to allow for fluid communication between the purge passage and the pump, and then controls the pump to depressurize the first communication passage and to pressurize the purge passage.

14. The evaporative fuel handling apparatus as claimed in claim 13, wherein the controller, to check for a leak, controls the first selection part to allow for fluid communication between the second communication passage and the pump, controls the second selection part to allow for fluid communication between the open passage and the pump, and then controls the pump to depressurize the second communication passage.

15. The evaporative fuel handling apparatus as claimed in claim 13, wherein the controller, to check for a leak, controls the first selection part to allow for fluid communication between the second communication passage and the pump, controls the second selection part to allow for fluid communication between the open passage and the pump, and then controls the pump to pressurize the second communication passage.