JP3994273B2 - Fuel tank level detection valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is attached to the upper end wall of the fuel tank and normally discharges the vapor in the fuel tank to the outside of the fuel tank. At the time of refueling, the fuel level rise is detected and the valve is automatically closed. Use a liquid level detection valve that intentionally increases the pressure.
[0002]
[Prior art]
Conventionally, vapor (fuel vapor) emitted from fuel (gasoline) contained in a fuel tank of an automobile is collected and supplied to an engine as fuel, so that the fuel can be used without waste. Recently, vapor generated during refueling is also collected and used as fuel.
[0003]
In this case, a sensor is installed outside the tip of the fuel injection gun used for refueling to stop fuel discharge when the fuel level comes into contact. The fuel level is detected by this sensor and the lubrication is automatically stopped. However, if the vapor generated during refueling is discharged from the tank and recovered as described above, The inside air will also be discharged, and even if the fuel level rises due to refueling, the tank internal pressure will not rise, and the fuel injection gun will not be able to detect a full tank.
[0004]
For this reason, as shown in FIG. 5, a liquid level detection valve c is conventionally provided on the inner surface of the upper end of the fuel tank a to which the vapor recovery pipe b is connected. It is detected and the valve is closed, and when the tank is full, the tank internal pressure is increased to stop fuel injection.
[0005]
In this case, since a large amount of fuel is discharged and injected from the fuel injection gun d at a very high speed, the liquid level detection valve c is closed with a certain margin before the tank is almost completely filled, and the tank is rapidly increased. Generally, the internal pressure is set so as to prevent the fuel from rapidly flowing back through the fuel supply pipe e and overflowing. However, when the liquid level detection level for closing the valve c is set to be low in this way, it is impossible to inject fuel even though there is still room to accommodate the fuel.
[0006]
Therefore, the liquid level detection level of the liquid level detection valve c is set in two stages, and when the fuel liquid level reaches the first liquid level detection level, the exhaust pressure speed is limited and the tank internal pressure is temporarily increased. Once the fuel injection is stopped, the fuel is injected little by little at a speed at which the internal pressure can be discharged, and when the fuel level reaches the second liquid level detection level that is almost full, the liquid level detection valve c Is completely closed and fuel injection is stopped.
[0007]
Conventionally, as a liquid level detection valve having two levels of liquid level detection, the valve shown in FIGS. 6 to 8 is disclosed in Japanese Patent Publication No. 10-500088. As shown in FIG. 6, this valve is provided with a bottomed cylindrical valve housing g in which a float body h is accommodated inside a short shaft cylindrical skirt body 52 having an upper end wall. is there.
[0008]
A discharge port i is provided in the upper end wall of the skirt body f, and a pipe connecting pipe j communicating with the discharge port i is integrally provided, and a flange portion k is formed from the outer peripheral edge of the upper end wall. The valve is fixed to the fuel tank a by being integrally formed and fixing the flange portion k to the outer peripheral edge of the through hole provided in the fuel tank a.
[0009]
The valve housing g has a long cylindrical shape having a lower end wall, and its upper end is fixed in a state of being inserted into the discharge port i of the skirt body f, and its lower half is the skirt. A vapor inflow port u is formed between the outer peripheral surface of the valve housing g and the lower end inner peripheral surface of the skirt body f. The valve housing g is provided with a valve seat portion m whose inner wall surface is inclined obliquely and gradually decreases in diameter on the inner surface of the upper end of the valve housing g, and a plurality of flow ports are provided in the peripheral wall adjacent to the valve seat portion m. In addition, a liquid inflow window p for allowing the fuel r to flow into the valve housing g is formed in the lower peripheral wall protruding from the lower end surface of the skirt body f.
[0010]
Further, the float body h has a cylindrical shape whose upper end surface is closed by a hemispherical wall body, and the hemispherical upper end wall serves as a valve head s. The float body h is assisted by a coil spring q disposed therein, and moves upward due to its buoyancy as the liquid level of the fuel r rises.
[0011]
As indicated by the arrows in FIG. 6, this valve is normally passed through the inlet u, the outlet n, the valve seat m, the outlet i and the pipe connecting pipe j in this order, and the vapor in the tank a. (Fuel vapor) is discharged out of the tank a.
[0012]
At the time of refueling, the tank internal pressure that rises as the fuel level t rises is discharged out of the tank a through the same path as the vapor discharge path, thereby facilitating fuel injection.
[0013]
As shown in FIG. 7, when the fuel level t rises and reaches the lower end surface of the skirt body f, the lower end surface of the skirt body 5 is closed by the fuel r, and the tank internal pressure is discharged by the skirt body f. Only from the fuel level inside, the exhaust pressure speed is greatly limited. For this reason, the tank internal pressure rises due to the rise of the fuel level due to the rapid injection of a large amount of fuel, and as shown in FIG. 7 (A), the fuel r flows back into the fuel supply pipe e. The fuel comes into contact with a sensor provided at the tip of the fuel injection gun d, and the fuel discharge is temporarily stopped. Then, the tank internal pressure is gradually released to the outside from the fuel liquid level in the skirt body f, and as shown in FIG. 7B, the fuel that has flowed back into the fuel supply pipe e returns to the tank a. Then, the fuel can be supplied from the fuel injection gun d again.
[0014]
In this state, the fuel is further supplied by slowly injecting the fuel little by little so that the pressure can be discharged from the fuel level in the skirt body f. As a result, when the fuel level t in the tank a rises to a predetermined full tank level, the float body h rises due to its buoyancy as shown in FIG. 8, and the valve head s of the float body h becomes the valve. The valve g at the upper end of the housing g is brought into contact with and close to the outlet i. As a result, the release of pressure stops, the internal pressure of the tank a rises, and as shown in FIG. 8A, the fuel r flows back into the fuel supply pipe e, and the fuel flows to the tip of the fuel injection gun d. The fuel injection is stopped by contacting a sensor provided in the section. As a result, fuel can be injected reliably and safely up to a predetermined full tank level.
[0015]
[Problems to be solved by the invention]
However, in this conventional liquid level detection valve,
(1) The stability of the opening / closing operation is not always satisfactory, and the reliability is poor.
(2) When changing and adjusting the paper and pressure discharge capacity, a large design change is required.
There is a problem.
[0016]
That is, as shown in FIG. 6, the valve housing g in which the float body h is accommodated protrudes downward from the lower end surface of the skirt body f, and the fuel level t is the first level detection level. Since the float body h is immersed in the fuel r before reaching the lower end surface of the skirt body f, the float body h may also move up and down when the fuel level t swings greatly. is there. In this case, the valve head s of the float body h is attracted to the valve seat m by the negative pressure generated by the airflow flowing out of the tank through the valve seat m, and the fuel level t becomes the first level detection level or the first level. There is a risk that the valve may be completely closed before reaching the two liquid level detection level.
[0017]
Further, it is necessary to change the discharge capability of the vapor and the tank internal pressure during normal and refueling for each vehicle type according to various factors such as the shape and size (capacity) of the fuel tank a and the type of fuel. The discharge capacity of the vapor and the tank internal pressure is almost determined by the area of the inlet u and the circulation port n and the area ratio of the inlet u and the circulation port n. Is provided in the valve housing g, while the inflow port u is designed to be provided between the skirt f and the valve housing g. Therefore, the areas of the inflow port u and the flow port n are changed. In order to achieve this, the design of both the skirt body f and the valve housing g must be changed. When the outer diameter of the valve housing g is changed, the float body h accommodated therein is also newly designed. It will be necessary to redo. As described above, in the conventional valve shown in FIGS. 6 to 8, when the vapor and tank internal pressure discharge capacity is changed according to the vehicle type or the like, it is almost necessary to change the design of the entire valve.
[0018]
The present invention has been made in view of the above circumstances, and can achieve a reliable opening / closing operation without causing a problem that the valve closes before the fuel level reaches a predetermined level. An object of the present invention is to provide a fuel tank level detection valve that can be easily and inexpensively adapted without changing the design of the vapor and the tank internal pressure.
[0019]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a liquid level detection valve that is attached to the upper end wall of the fuel tank and detects the liquid level of the fuel when refueling, and closes the valve. A case body having a discharge port formed at the upper end surface, a valve seat provided inside the case body, a valve seat communicating with the discharge port at the upper end, and a flow port provided at the upper end of the peripheral wall A float body having a valve head at the upper end, which is accommodated in the valve chamber in a vertically movable manner, a flow passage provided between the valve chamber and the case body peripheral wall, and a bottom of the case body A bottom wall portion that closes the end surface to form a horizontal bottom surface, and a cylindrical partition wall that forms the peripheral wall of the valve chamber is provided on the bottom wall portion, and communicates with the flow passage. A bottom lid body having an inflow port formed therein, It is a liquid level detection valve in which an opening for introducing fuel into the valve chamber is only the inflow port formed in the bottom wall portion of the bottom lid body, and the vapor in the fuel tank is normally connected to the inflow port and the flow path. When the fuel level reaches the lower end surface of the valve, the inlet is blocked by the liquid level when the fuel level reaches the lower end surface of the valve. When the tank internal pressure is temporarily increased and the fuel level rises further, the float body rises due to its buoyancy, and the valve head of the float body comes into contact with and close to the valve seat to close the valve. Provided is a fuel tank level detection valve configured to intentionally increase the pressure inside.
[0020]
That is, the liquid level detection valve of the present invention is attached to the upper end wall of the fuel tank as described above, and the vapor in the fuel tank is normally connected to the inlet, the passage, the circulation port, the valve seat, and the outlet. When the fuel level reaches the lower end surface of the valve, the inflow port is blocked by the liquid level to temporarily increase the tank internal pressure. When the surface rises, the float body rises due to its buoyancy, and the valve head of the float body comes into close contact with the valve seat and closes the valve to intentionally increase the pressure in the fuel tank. is there.
[0021]
In this case, in the valve of the present invention, the lower end surface of the valve is a horizontal bottom surface formed by the bottom wall portion of the bottom lid body, and the first liquid level detection level at which the fuel level closes the inlet. The float body is not soaked in the fuel before reaching the fuel level. Therefore, the float body moves up and down by the oscillation of the fuel liquid level, and the float body valve before reaching the predetermined liquid level. There is no malfunction that the head is sucked by the valve seat and the valve is closed.
[0022]
Further, in the valve of the present invention, a partition body that forms a valve chamber in the case body is erected integrally with the bottom lid body, and the flow inlet is formed in the partition body, and the inlet is also provided. Since it is formed on the bottom lid, when changing the area of the inlet and outlet and changing and adjusting the discharge capacity of vapor and tank internal pressure, only the bottom lid is redesigned and manufactured. The other parts can be used as they are without requiring any change, and even when the discharge capacity of the vapor and the tank internal pressure is changed and adjusted, it is possible to easily cope with it.
[0023]
Thus, according to the liquid level detection valve of the present invention, it is possible to achieve a reliable opening / closing operation without causing a problem that the valve closes before the fuel liquid level reaches a predetermined level. In addition, even when the vapor and tank internal pressure discharge capacity is changed in accordance with the vehicle type or the like, it can be easily and inexpensively handled without requiring a significant design change.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described more specifically by showing examples of the present invention.
FIG. 1 shows a liquid level detection valve according to an embodiment of the present invention. The liquid level detection valve includes a case body 1 fixed to a fuel tank a, and a valve provided in the case body 1. A float body 3 accommodated in the chamber 2 and a bottom lid body 4 for closing the lower end surface of the case body 1 are provided.
[0025]
The case body 1 has a cylindrical shape having an upper end wall. A discharge port 11 is provided at the center of the upper end wall, and a short shaft protrudes downward from an inner peripheral edge of the discharge port 11. A cylindrical valve seat 12 is formed, and a pipe connecting pipe 13 is integrally connected to the outer peripheral edge of the discharge port 11. Further, a flange portion 14 that protrudes outward is formed on the outer peripheral edge of the upper end of the case body 1.
[0026]
The bottom lid 4 is formed by integrally forming a peripheral wall 42 at the peripheral edge of a disc-shaped bottom wall 41 and a cylindrical partition wall 43 integrally standing at the center. The bottom lid 4 is attached to the lower portion of the case body 1 so as to cover the lower end portion of the case body 1, and the bottom wall portion 41 closes the lower end surface of the case body 1 to form a horizontal bottom surface. In addition, the upper end of the partition wall 43 reaches the upper end wall of the case body 1, the valve chamber 2 is formed inside the partition body 43, and the partition wall 43 and the peripheral wall of the case body 1 A flow passage 47 is formed between the two.
[0027]
An inlet 44 communicating with the flow passage 47 is formed in the bottom wall portion 41 of the bottom lid body 4, and a fuel r flows into the valve chamber 2 at the lower end portion of the partition wall body 43. A liquid inlet 45 is formed, and a communication port 46 is formed at the upper end of the partition wall 43 to communicate the flow passage 47 with the upper portion of the valve chamber 2.
[0028]
The float body 3 accommodated in the valve chamber 2 has a cylindrical shape having an upper end wall, is assisted by a coil spring 5 disposed therein, and moves up and down the fuel level t by its buoyancy. It moves up and down in the valve chamber 2. Further, an elastic material such as rubber is disposed on the outer surface (upper surface) of the upper end wall of the float body 3, and this elastic material serves as the valve head 31.
[0029]
As shown in FIG. 1, this valve is inserted into a through hole provided in the fuel tank a from the outside of the tank, the flange portion 14 is welded to the fuel tank a, and the upper end wall of the fuel tank a Fixed to. And normally, the vapor | steam (fuel vapor | steam) in the tank a goes out of the tank a through the said inflow port 44, the flow path 47, the flow port 46, the valve seat 12, the discharge port 11, and the pipe connection pipe 13 one by one. It comes to discharge.
[0030]
Next, at the time of refueling, the tank internal pressure that rises as the fuel level t rises is discharged out of the tank a through the same path as the vapor discharge path, facilitating fuel injection, as shown in FIG. As described above, when the fuel level t rises and reaches the lower end surface of the bottom wall portion 41 of the bottom lid 4 that forms the bottom surface of the valve, the inlet 44 is closed by the fuel r, and the discharge of the tank internal pressure is reduced. Only from the fuel liquid level in the case body 1, the exhaust pressure speed is greatly limited. For this reason, the tank internal pressure rises due to the rise in the fuel level t due to the rapid injection of a large amount of fuel, and as shown in FIG. 2 (A), the fuel r flows back into the fuel supply pipe e, The fuel comes into contact with a sensor provided at the tip of the fuel injection gun d, and the fuel discharge is temporarily stopped. Then, the tank internal pressure is gradually released to the outside from the fuel liquid level in the case body 1, and as shown in FIG. 2 (B), the fuel that has flowed back into the fuel supply pipe e returns into the tank a. Then, the fuel can be supplied from the fuel injection gun d again.
[0031]
In this state, the fuel is further supplied by slowly injecting the fuel little by little so that the pressure can be discharged from the fuel level in the case body 1. As a result, when the fuel level t in the tank a rises to a predetermined full tank level, the float body 3 rises due to its buoyancy as shown in FIG. 3, and the valve head 31 of the float body 3 The lower end of the seat 12 is brought into contact with and tightly closed, and the discharge port 11 is closed. As a result, the pressure release stops, the internal pressure of the tank a rises, and as shown in FIG. 3A, the fuel r flows backward into the fuel supply pipe e, and the fuel flows to the tip of the fuel injection gun d. The fuel injection is stopped by contacting a sensor provided in the section. As a result, fuel can be injected reliably and safely up to a predetermined full tank level.
[0032]
In the liquid level detection valve, as described above, the lower end surface of the valve is a horizontal bottom surface formed by the bottom wall portion 41 of the bottom cover body 4, and the fuel level r closes the inlet 44. The float body 3 is not immersed in the fuel r before reaching the first liquid level detection level. Therefore, the float body 3 is moved up and down by the swinging of the fuel liquid level r, and a predetermined level is reached. There is no malfunction that the valve head 31 of the float body 3 is sucked by the valve seat 12 before the liquid level is reached and the valve is closed.
[0033]
Further, in this valve, a partition body 43 that forms the valve chamber 2 in the case body 1 is erected integrally with the bottom lid body 4, and a flow port 46 is formed in the partition body 43. Since the inflow port 44 is also formed in the bottom wall portion 41 of the bottom cover body 4, when changing the area of the inflow port 44 and the flow port 46 to change or adjust the discharge capacity of the vapor and the tank internal pressure. Only the bottom lid 4 needs to be redesigned and remanufactured, and other parts can be used as they are without any changes, and even when changing and adjusting the vapor and tank internal pressure discharge capacity, It can be easily handled.
[0034]
Thus, according to the liquid level detection valve, a reliable opening / closing operation can be achieved without causing a problem that the valve closes before the fuel level reaches a predetermined level. Even when the discharge capacity of the vapor and the tank internal pressure is changed according to the vehicle type or the like, it can be easily and inexpensively handled without requiring a significant design change.
[0035]
The liquid level detection valve of the present invention is not limited to the above embodiment, and the configuration of each part may be changed as appropriate without departing from the gist of the present invention. For example, as shown in FIG. 4, the valve of the above embodiment can be provided with a high return pressure valve for preventing the occurrence of malfunction due to the suction of the float body 3 during the valve opening operation. That is, the valve of FIG. 4 is provided with a second valve chamber 15 in the case body 1 and a second valve seat 52 communicating with the pipe connecting pipe 13 (discharge passage) is formed at the upper end of the second valve chamber 15. In addition, the second float body 6 that opens and closes the second valve seat 52 is disposed in the valve chamber 15, and the above-described valve opening operation is performed more than the valve opening operation by the float body 3 of the main valve having the same configuration as the above embodiment. A high return pressure valve configured to perform the valve opening operation of the second valve seat 52 by the two float body 6 first is provided. According to the valve of FIG. 4, when the fuel level drops and the valve is opened, the high return pressure valve is first opened to release the strong negative pressure, and the negative pressure causes the float body of the main valve to open. It is possible to more reliably prevent the occurrence of malfunction due to the suction of 3 to the valve seat 12. In FIG. 4, 51 is an inlet for introducing the fuel r into the second valve chamber 15, 61 is a coil spring for assisting the operation of the second float body 3, and other configurations, operations, and effects are as described above. Since it is the same as that of the valve | bulb of FIGS. 1-3, the same referential mark is attached | subjected and the description is abbreviate | omitted.
[0036]
【The invention's effect】
As described above, according to the liquid level detection valve of the present invention, a reliable opening / closing operation is achieved without causing the disadvantage that the valve closes before the fuel level reaches a predetermined level. In addition, even when the discharge capacity of the vapor and the tank internal pressure is changed, it can be easily and inexpensively handled without requiring a significant design change.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing a liquid level detection valve according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing when the fuel level has reached the lower end surface of the liquid level detection valve. FIG. 2 (A) is an explanatory view showing the state of the fuel supply pipe at this time, and FIG. It is explanatory drawing which shows the state of the oil supply pipe after passing for a while from.
FIG. 3 is a schematic cross-sectional view showing the same liquid level detection valve when the fuel level reaches a predetermined full tank level, and FIG. 3 (A) is an explanatory view showing the state of the fuel supply pipe at this time.
FIG. 4 is a schematic cross-sectional view showing a liquid level detection valve according to another embodiment of the present invention.
FIG. 5 is a schematic view showing an example of a fuel tank provided with a liquid level detection valve.
FIG. 6 is a cross-sectional view showing a conventional liquid level detection valve.
FIG. 7 is a schematic cross-sectional view showing the same liquid level detection valve when the fuel liquid level reaches the first liquid level detection level, (A) is an explanatory view showing the state of the fuel supply pipe at this time; B) is an explanatory view showing the state of the oil supply pipe after a lapse of time from this time.
FIG. 8 is a schematic cross-sectional view showing the same liquid level detection valve when the fuel liquid level reaches the second liquid level detection level, and (A) is an explanatory view showing the state of the fuel supply pipe at this time. .
[Explanation of symbols]
1 Case body 11 Discharge port 12 Valve seat 13 Pipe connection pipe (discharge path)
14 Flange portion 15 Second valve chamber 2 Valve chamber 3 Float body 31 Valve head 4 Bottom lid body 41 Bottom wall portion 42 Peripheral wall portion 43 Partition body 44 Inlet port 45 Inlet port 46 Inlet port 47 Inlet channel 5, 61 Coil spring 52 First 2 valve seat 6 second float body

Claims (2)

A liquid level detection valve that is attached to the upper end wall of the fuel tank and detects the fuel level during refueling and closes the valve.
A case body in which a lower end surface is opened and a discharge port is formed on an upper end surface;
A valve chamber provided on the inner side of the case body, provided with a valve seat communicating with the discharge port at an upper end, and provided with a circulation port at an upper end portion of the peripheral wall;
A float body accommodated in the valve chamber so as to be movable up and down and having a valve head at an upper end;
A flow passage provided between the valve chamber and the peripheral wall of the case body,
The case body has a bottom wall portion that closes the lower end surface of the case body to form a horizontal bottom surface, and a cylindrical partition wall body that forms a peripheral wall of the valve chamber is erected on the bottom wall portion. A bottom lid formed with an inflow port communicating with the flow path, and the inflow port having an opening for introducing fuel into the flow path and the valve chamber formed in a bottom wall portion of the bottom lid body. It is only a liquid level detection valve,
Normally, the vapor in the fuel tank is discharged out of the fuel tank through the above inlet, flow passage, distribution port, valve seat and discharge port in sequence, and the fuel level reaches the lower end surface of the valve when refueling Occasionally, the tank inlet pressure is temporarily increased by the liquid level being blocked, and when the fuel level rises further, the float body rises due to its buoyancy, and the valve head of the float body moves to the valve A fuel tank level detection valve configured to intentionally increase the pressure in the fuel tank by closing the valve in contact with the seat.   A high return pressure valve having a second valve seat communicating with the discharge passage connected to the discharge port and a second float body for opening and closing the second valve seat is provided. 2. The liquid level detection valve according to claim 1, wherein the valve opening operation of the second valve seat by the two float body is performed before the valve opening operation of the valve seat by the float body according to claim 1.

Images