Evaporated fuel processing device

Patent metadata

Field	Value
Publication number	US-2016298577-A1
Application number	US-201415036278-A
Country	US
Kind code	A1
Filing date	Sep 1, 2014
Priority date	Nov 25, 2013
Publication date	Oct 13, 2016
Grant date	—

Abstract

An evaporated fuel processing device has a canister, a vapor passage, a purge passage, a shutoff valve, a storage device and a control device. The canister includes an adsorbent material that adsorbs evaporated fuel generated in a fuel tank. The vapor passage connects the canister and the fuel tank. The purge passage connects the canister and an intake passage of an engine. The shutoff valve is provided in the vapor passage, and adjusts flow rate of gas flowing through the vapor passage. The storage device stores in advance a reference value for the shutoff valve corresponding to internal pressure of the fuel tank. The shutoff valve is controlled based on the reference value, which is obtained from the internal pressure of the fuel tank, and pressure release control is performed on the fuel tank.

First claim

1 . An evaporated fuel processing device comprising:
a canister including an adsorbent material that adsorbs evaporated fuel generated in a fuel tank; a vapor passage configured to connect the canister and the fuel tank; a purge passage configured to connect the canister and an intake passage of an engine; a shutoff valve provided in the vapor passage, and configured to adjust flow rate of gas flowing through the vapor passage; a storage device configured to store in advance a reference value for the shutoff valve corresponding to an internal pressure of the fuel tank; and a control device configured to perform a pressure release control by controlling the shutoff valve based on the reference value which is obtained from the internal pressure of the fuel tank.

2 . The evaporated fuel processing device of claim 1 wherein the control device is configured to determine whether or not a reduction amount in the internal pressure of the fuel tank within a prescribed time is smaller than a predetermined value; and
wherein the control device is configured to control the shutoff valve based on an addition value obtained through addition of a correction value to the reference value when the reduction in the internal pressure of the fuel tank is smaller than the predetermined value.

3 . The evaporated fuel processing device of claim 2 wherein the control device is configured to determine whether or not the reduction amount of the internal pressure of the fuel tank within the prescribed time is larger than or equal to the predetermined value in a state in which the shutoff valve is being controlled based on the addition value, and
wherein the control device is configured to control the shutoff valve based on the reference value in a case where the reduction amount of the internal pressure of the fuel tank is greater than or equal to the predetermined value.

4 . The evaporated fuel processing device of claim 3 wherein the control device is configured so as to obtain the reduction amount of the internal pressure of the fuel tank by detecting the internal pressure of the fuel tank every predetermined period of time to compute a pressure difference between a previous detection pressure and a current detection pressure;
wherein the control device is configured to control the shutoff valve based on the reference value in a case where the pressure difference is greater than or equal to a predetermined value; and
wherein the control device is configured to control the shutoff valve based on the addition value in a case where the pressure difference is less than the predetermined value.

5 . The evaporated fuel processing device of claim 1 wherein the reference value for the shutoff valve is set in the storage device such that a flow rate of gas flowing through the vapor passage does not exceed a flow rate of gas flowing through the purge passage.

6 . The evaporated fuel processing device of claim 1 wherein the control device is configured to determine whether or not an amount of fuel with respect to an amount of air supplied to the engine per unit time is greater than or equal to a predetermined value;
wherein the control device is configured such that, when the amount of fuel is greater than or equal to the predetermined value, it obtains a subtraction value by subtracting a subtraction correction value from the reference value; and
wherein the control device is configured to control the shutoff valve based on the subtraction value.

7 . The evaporated fuel processing device of claim 6 wherein the control device is configured to control the shutoff valve based on the reference value when the amount of fuel is less than the predetermined value in a state in which the shutoff valve is being controlled based on the subtraction value.

8 . The evaporated fuel processing device of claim 2 wherein the control device is configured to determine whether or not an amount of fuel with respect to an amount of air supplied to the engine per unit time is greater than or equal to a predetermined value;
wherein the control device is configured to obtain a subtraction value through subtraction of a subtraction correction value from the addition value when the amount of fuel is greater than or equal to the predetermined value; and
wherein the control device is configured to control the shutoff valve based on the subtraction value.

9 . The evaporated fuel processing device of claim 8 wherein the control device is configured to control the shutoff valve based on the addition value when the amount of fuel is less than the predetermined value in a state in which the shutoff valve is being controlled based on the subtraction value.

10 . The evaporated fuel processing device of claim 1 , wherein the shutoff valve includes a valve seat, and a movable valve configured to move in an axial direction with respect to the valve seat, and wherein the reference value for the shutoff valve is a reference stroke amount, which is a movement amount of the movable valve.

11 . The evaporated fuel processing device of claim 10 wherein the shutoff valve has a feed screw mechanism, and an electric motor configured to operate the feed screw mechanism to move the movable valve.

12 . The evaporated fuel processing device of claim 10 wherein the movable valve includes:
a valve guide formed so as to be capable of contacting the valve seat;
a valve body connected to the valve guide so as to be capable of relative movement by a fixed dimension in an axial direction thereby the valve body contacts with and moves away from the valve seat; and
a biasing member configured to bias the valve body toward the valve seat.

Assignees

• Aisan Ind

Inventors

• Kimoto Junya
• Miyabe Yoshikazu
• Tagawa Naoyuki

Classifications

• F02M25/0854

  Details of the absorption canister · CPC title

• F02M25/0872

  Details of the fuel vapour pipes or conduits · CPC title

• F02M25/089

  Layout of the fuel vapour installation · CPC title

• F02M25/0836 Primary

  Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold · CPC title

• F02D41/0045

  Estimating, calculating or determining the purging rate, amount, flow or concentration · CPC title