Evaporation leakage checking system and checking method of evaporation leakage using the same

Patent metadata

Field	Value
Publication number	US-10234356-B2
Application number	US-201715592671-A
Country	US
Kind code	B2
Filing date	May 11, 2017
Priority date	May 13, 2016
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

An evaporation leakage checking system includes a pump, a pump passage unit, a tank passage unit, a specified passage unit, an atmosphere passage unit, a flow-passage area changing unit, an atmosphere valve unit, a pressure sensing unit, and a control unit. The control unit includes a calculating unit that calculates a leakage threshold, based on a first pressure, a first area, an Nth pressure, an Nth area, and a reference area that is predetermined, and a leakage checking unit that activates the pump, closes the atmosphere passage unit by changing the flow-passage area of the atmosphere passage unit by using the atmosphere valve unit, and checks the existence of the evaporation leakage based on the leakage threshold and a checking pressure that is the pressure sensed by the pressure sensor in a case where a communication between the tank passage unit and the pump passage unit is allowed.

First claim

What is claimed is:

1. An evaporation leakage checking system comprising:
a pump including an inlet and an outlet;
a pump passage unit having a first end that is connected with the inlet or the outlet, and a second end;
a tank passage unit having a first end that is connected with a fuel tank storing a fuel, and a second end;
a specified passage unit having a first end that is connected with the second end of the pump passage unit, and a second end that is connected with the second end of the tank passage unit;
an atmosphere passage unit having a first end that is connected with the second end of the tank passage unit or the second end of the specified passage unit, and a second end that is exposed to the atmosphere;
a flow-passage area changing unit changing a flow-passage area of the specified passage unit to a plurality of areas including a first area and an Nth area, N being a value greater than one;
an atmosphere valve unit changing a flow-passage area of the atmosphere passage unit;
a pressure sensing unit sensing a pressure in the pump passage unit; and
a control unit controlling operations of the pump, the flow-passage area changing unit, and the atmosphere valve unit, wherein
the control unit includes
a calculating unit that calculates a leakage threshold that is a threshold used to check an existence of an evaporation leakage that is a leakage of an evaporation that is an evaporated fuel, based on a first pressure that is relative to a pressure sensed by the pressure sensing unit in a case where the pump is activated and the flow-passage area changing unit changes the flow-passage area of the specified passage unit to the first area, the first area, an Nth pressure that is relative to the pressure sensed by the pressure sensing unit in a case where the pump is activated and the flow-passage area changing unit changes the flow-passage area of the specified passage unit to the Nth area, the Nth area, and a reference area that is predetermined, and
a leakage checking unit that activates the pump, closes the atmosphere passage unit by changing the flow-passage area of the atmosphere passage unit by using the atmosphere valve unit, and checks the existence of the evaporation leakage based on the leakage threshold and a checking pressure that is the pressure sensed by the pressure sensing unit in a case where a communication between the tank passage unit and the pump passage unit is allowed.

2. The evaporation leakage checking system according to claim 1 , wherein
the leakage checking unit determines that the evaporation leakage occurs, in a case where an absolute value of the checking pressure is less than an absolute value of the leakage threshold.

3. The evaporation leakage checking system according to claim 1 , wherein
the calculating unit calculates the leakage threshold, based on dimension variations of the first area and the Nth area in manufacturing, a dimension variation generated due to a temperature variation and a humidity variation, and sensing errors of the first pressure and the Nth pressure.

4. The evaporation leakage checking system according to claim 1 , further comprising:
an orifice member arranged in the specified passage unit and including an opening, wherein
the orifice member has at least one of characteristics that the linear expansion coefficients are less than that of a member constituting the specified passage unit, the variations of dimension generated due to the water absorbing are less than that of the member constituting the specified passage unit, the variations of dimension generated due to the fuel that is exposed are less than that of the member constituting the specified passage unit, and the variations of opening areas generated due to the magnesium chloride solution, the calcium chloride solution, or the natrium chloride solution that is exposed are less than that of the member constituting the specified passage unit.

5. The evaporation leakage checking system according to claim 1 , wherein
the atmosphere valve unit includes a switching valve that switches between a first state and a second state,
the first state is a state where a communication between the tank passage unit and the atmosphere passage unit is allowed, and the communication between the tank passage unit and the pump passage unit is interrupted, and
the second state is a state where the communication between the tank passage unit and the atmosphere passage unit is interrupted, and the communication between the tank passage unit and the pump passage unit is allowed.

6. The evaporation leakage checking system according to claim 5 , wherein
the switching valve includes at least a part of the specified passage unit, and the orifice member that is arranged in the part of the specified passage unit.

7. The evaporation leakage checking system according to claim 1 , wherein
the flow-passage area changing unit includes an opening variable valve that changes an opening position of the opening variable valve to change the flow-passage area of the specified passage unit, and
the flow-passage area changing unit changes the flow-passage area of the specified passage unit to a plurality of areas including the first area and the Nth area, by changing the opening position of the opening variable valve.

8. The evaporation leakage checking system according to claim 1 , wherein
the flow-passage area changing unit changes a flow-passage area of the atmosphere passage unit, by changing an opening position of the atmosphere valve unit, and
the flow-passage area changing unit changes a substantial flow-passage area of the specified passage unit to a plurality of areas including the first area and the Nth area, by changing the opening position of the atmosphere valve unit.

9. The evaporation leakage checking system according to claim 1 , wherein
the control unit further includes a malfunction determining unit that determines that a malfunction occurs in the evaporation leakage checking system in a case where the first pressure or the second pressure becomes out of a range that is obtained based on a variation of a characteristic of the pump and is also obtained based on the first area and the Nth area.

10. The evaporation leakage checking system according to claim 9 , wherein
the leakage checking unit interrupts the checking operation of the evaporation leakage in a case where the malfunction determining unit determines that the malfunction occurs in the evaporation leakage checking system.

11. The evaporation leakage checking system according to claim 10 , wherein
the calculating unit interrupts a calculation of the leakage threshold in a case where the malfunction determining unit determines that the malfunction occurs in the evaporation leakage checking system.

12. The evaporation leakage checking system according to claim 1 , wherein
the first end of the pump passage unit is connected with the inlet of the pump, and
the pump decreases the pressure in the pump passage unit.

13. The evaporation leakage checking system according to claim 1 , wherein
the pump is a vane pump that includes a casing,
a rotor rotatably arranged in the casing and on an outer wall of which a groove portion is arranged, and
a vane being a plate and reciprocating in the groove portion in a radial direction of the rotor.

14. A checking method of an evaporation leakage for an evaporation leakage checking system including a pump including an inlet and an outlet; a pump passage unit having a first end that is connected with the inlet or the outlet, and a second end; a tank passage unit having a first end that is connected with a fuel tan

Assignees

• Denso Corp

Inventors

• Kaneko Makoto
• Kato Yasuo

Classifications

• F02M25/0818 Primary

  having means for pressurising the evaporative emission space · CPC title

• B60K2015/03514

  with vapor recovery means · CPC title

• F02M37/045

  Arrangements for driving rotary positive-displacement pumps · CPC title

• F02M25/0854

  Details of the absorption canister · CPC title

• B60K2015/03328

  Arrangements or special measures related to fuel tanks or fuel handling · CPC title