Abstract:
Provided is a fuel tank control valve for a vehicle that appropriately and actively controls a loading pipe of an evaporation gas which is connected from a fuel tank to a canister, and prevents internal pressure of the fuel tank from excessively increasing or decreasing, by basically preventing the evaporation gas from being loaded from the fuel tank to the canister when the engine is turned off, allowing the evaporation gas to be loaded from the fuel tank to the canister when the engine is turned on, and allowing the evaporation gas to be loaded from the fuel tank to the canister, even if the engine is turned off, when the vehicle is filled with fuel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority to Korean Patent Application Number 10-2010-0122044 filed Dec. 2, 2010, the entire contents of which application is incorporated herein for all purposes by this reference. 
       BACKGROUND OF INVENTION 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to a fuel tank control valve for a vehicle, and more particularly, to a control valve that controls an evaporation gas from fuel moving from a fuel tank to a canister, between the fuel tank and the canister. 
         [0004]    2. Description of Related Art 
         [0005]    A canister of vehicles is a device that prevents an evaporation gas from fuel from leaking to the atmosphere by collecting an evaporation gas from fuel stored in a fuel tank and purges the evaporation gas to the intake system of the engine to be burned, when the engine operates. 
         [0006]    Recently, in hybrid vehicles or plug-in hybrid vehicles, the operational ratio of an electric motor when a vehicle travels largely increases in comparison to common vehicles of the related art and the amount of an evaporation gas that can be purged to the engine greatly decreases, such that the collective capacity of a canister is insufficient and the evaporation gas is likely to be discharged to the atmosphere. 
         [0007]    Therefore, control for limit or preventing an evaporation gas from being loaded from the fuel tank to the canister when the engine is turned off, except for when fuel is injected, is required, and it is required to limit the evaporation gas to be loaded to the canister only while the engine is turned on. 
         [0008]    Further, when the evaporation gas that is loaded from the fuel tank to the canister is limited, the fuel tank may be closed and the pressure excessively increases or negative pressure may occur, such that measures for appropriately removing the pressure are required. 
         [0009]    The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
       SUMMARY OF INVENTION 
       [0010]    Various aspects of the present invention provide for a fuel tank control valve for a vehicle that appropriately and actively controls a loading pipe of an evaporation gas which is connected from a fuel tank to a canister, and prevents internal pressure of the fuel tank from excessively increasing or decreasing, by basically preventing the evaporation gas from being loaded from the fuel tank to the canister when the engine is turned off, allowing the evaporation gas to be loaded from the fuel tank to the canister when the engine is turned on, and allowing the evaporation gas to be loaded from the fuel tank to the canister, even if the engine is turned off, when the vehicle is filled with fuel. 
         [0011]    Various aspects of the present invention provide for a fuel tank control valve for a vehicle, including a housing having a first port connected to a fuel tank and a second port connected to a canister; a pressure valve spool disposed to be able to slide straight in the housing, connects or disconnects the first port and the second port, and has a through-hole; a solenoid actuator having a plunger that moves straight to close the through-hole and press the pressure valve spool in the disconnection direction of the first port and the second port; a pressure spring elastically supporting the pressure valve spool in the connection direction of the first port and the second port; and a balance spring pressing the plunger, opposite to the pressure spring. 
         [0012]    According to various aspects of the present invention, it is possible to appropriately and actively control a loading pipe of an evaporation gas which is connected from a fuel tank to a canister, and prevent internal pressure of the fuel tank from excessively increasing or decreasing, by basically preventing the evaporation gas from being loaded from the fuel tank to the canister when the engine is turned off, allowing the evaporation gas to be loaded from the fuel tank to the canister when the engine is turned on, and allowing the evaporation gas to be loaded from the fuel tank to the canister, even if the engine is turned off, when the vehicle is filled with fuel. Therefore, it is possible to protect the fuel tank and prevent the evaporation gas from the fuel from leaking to the atmosphere, thereby minimizing environmental pollution and satisfying various rules. 
         [0013]    The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a view showing the outer shape of a fuel tank control valve for a vehicle. 
           [0015]      FIG. 2  is a cross-sectional view taken along the line II-II of  FIG. 1 . 
           [0016]      FIG. 3  is a cross-sectional view taken along the line III-III of  FIG. 1 . 
           [0017]      FIG. 4  is a view illustrating the first open position of the control valve, relative to  FIG. 3 . 
           [0018]      FIG. 5  is a view illustrating the second open position of the control valve, relative to  FIGS. 3 and 4 . 
           [0019]      FIG. 6  is a view showing a relief valve and a vacuum valve in a normal state. 
           [0020]      FIG. 7  is a cross-sectional view showing the state of  FIG. 6  at another angle. 
           [0021]      FIG. 8  is a view illustrating the operation of the relief valve when the pressure of a fuel tank is excessively high. 
           [0022]      FIG. 9  is a cross-sectional view showing the state of  FIG. 8  at another angle. 
           [0023]      FIG. 10  is a view illustrating the operation of the relief valve when the pressure of a fuel tank is excessively low. 
           [0024]      FIG. 11  is a cross-sectional view showing the state of  FIG. 10  at another angle. 
       
    
    
       [0025]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
         [0026]    In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
       DETAILED DESCRIPTION 
       [0027]    Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0028]    Referring to  FIGS. 1 to 3 , various embodiments of the present invention includes a housing  5  having a first port connected to a fuel tank and a second port  3  connected to a canister; a pressure valve spool  9  disposed to be able to slide straight in housing  5 , connects or disconnects first port  1  and second port  3 , and has a through-hole  7 ; a solenoid actuator  13  having a plunger  11  that moves straight to close through-hole  7  and press pressure valve spool  9  in the disconnection direction of first port  1  and second port  3 ; a pressure spring  15  elastically supporting pressure valve spool  9  in the connection direction of first port  1  and second port  3 ; and a balance spring  17  pressing plunger  11 , opposite to pressure spring  15 . 
         [0029]    That is, pressure valve spool  9  is disposed in housing  5  to be able to slide straight up/down in the drawings, with the lower portion elastically supported by pressure spring  15  and the upper portion allowing plunger  11  to close and pressure through-hole  7 , and plunger  11  is elastically supported to press down pressure valve spool  9  through balance spring  17 , such that plunger  11  is moved up while pressing balance spring  17  by electric force applied to solenoid valve actuator  13  and pressure valve spool  9  correspondingly moves up to switch the positions where first port  1  and second port  3  are fully connected and disconnected, and continuously make the state between them, thereby linearly and variably controlling the open area. 
         [0030]    As described above, by linearly and variably controlling the open area between first port  1  and second port  3  in accordance with changes in electric force applied to solenoid actuator  13 , it is possible to accurately control the pressure of the fuel tank and pressure of an evaporation gas which is applied from the fuel tank to the canister, in accordance with the pressure of the fuel tank. 
         [0031]    Further, housing  5  has a bypass channel  19  that bypasses pressure valve spool  9  disconnecting first port  1  and second port  3  and connects first port  1  with second port  3 . Bypass channel  19  is provided with a relief valve  21  that opens bypass channel  19  when the pressure of the fuel tank becomes first reference pressure or more and a vacuum valve  23  that opens bypass channel  19  when the pressure of the fuel tank becomes second reference pressure or less. 
         [0032]    That is, when first port  1  and second port  3  are fully disconnected by pressure spool valve  9  and plunger  11 , the fuel tank is substantially completely sealed from the outside, such that relief valve  21  and vacuum valve  23  are provided to ensure safety by appropriately removing the internal pressure of the fuel tank, when the internal pressure becomes excessively high or low. 
         [0033]    Relief valve  21  can remove the internal pressure of the fuel tank to the canister by opening bypass channel  19  when the first reference pressure, for example, at about 35 KPa, is applied from first port  1  and vacuum valve  23  can remove negative pressure of the fuel tank by opening bypass channel  19 , when the second reference pressure, for example, at about −15 Kpas, is applied to first port  1 . 
         [0034]    Through-hole  7  of pressure valve spool  9  can connect first port  1  with second port  3  through pressure valve spool  9 , when plunger  11  is spaced apart. 
         [0035]    Pressure valve spool  9  includes a spool body  25  formed in a flat plate shape with through-hole  7  and a plurality of guide protrusions  27  protruding from both edges of spool body  25 , perpendicular to the flat plate shape of spool body  25 , to guide spool body  25  to slide straight in housing  5 . 
         [0036]    Although balancing spring  17  elastically supports plunger  11  toward pressure valve spool  9  in solenoid actuator  13  in various embodiments, it may support plunger  11  at the outside of solenoid actuator  13 . 
         [0037]    Relief valve  21  and vacuum valve  23  are arranged in a row in bypass channel  19 . 
         [0038]    That is, a relief body  29  is inserted in a space where bypass channel  19  is formed in housing  5 , and relief valve  21  and vacuum valve  23  are disposed in parallel in relief body  29 . 
         [0039]    A relief valve spool  21  of relief valve  21  is inserted to be able to slide straight in relief body  29  and a relief spring  33  elastically supporting relief valve spool  31  is disposed against pressure applied from first port  1 . 
         [0040]    Further, vacuum valve  23  is disposed at relief body  29  to open bypass channel  19  by means of self-deformation due to the pressure applied from second port  3 . 
         [0041]    Vacuum valve  23  may be composed of an insertion protrusion  35  that is inserted through relief body  29 , at the center, and an elastic plate  39  integrally connected with insertion protrusion  35  in an umbrella shape and closing a connection hole  37  formed in relief body  29  by using its elastic force. That is, as shown in the figures, a rubber part in which insertion protrusion  35  and elastic plate  39  are integrally connected in an umbrella shape. One will appreciate that the insertion protrusion and elastic plate may be monolithically formed. 
         [0042]    The operation of a fuel tank control valve for a vehicle of the present invention, which has the above configuration, is described hereafter. 
         [0043]    The operations for connection and disconnection between first port  1  and second port  3  by pressure valve spool  9  and plunger  11  are described with reference to  FIGS. 3 to 6 .  FIG. 3  shows when pressure valve spool  9  is pressed down by plunger  11  and through-hole  7  is closed, such that first port  1  and second port  3  are completely disconnected, in which an evaporation gas from the fuel tank is not loaded to the canister by keeping the above state, with the engine off. 
         [0044]    Obviously, when the pressure of the fuel tank increases above the first reference pressure in this state, relief valve  21  is automatically opened and the pressure of the fuel tank is removed. 
         [0045]    A first step where the control valve opens from the state shown in  FIG. 3  is shown in  FIG. 4 . 
         [0046]    That is, as electricity is supplied to solenoid actuator  13  and plunger  11  moves up while pressing balance spring  17 , pressure valve spool  9  cannot immediately move up and maintains the position by the pressure from the fuel tank in the earlier moving-up stage, such that first port  1  and second port  3  are instantaneously connected only by through-hole  7 . 
         [0047]    This is for preventing malfunction of various valves in the fuel tank and noise and vibration, when the pressure of the fuel tank is suddenly removed, and the pressure of the fuel tank is reduced from 35 KPa to about 1 KPa, for example, by the first open operation described above. 
         [0048]    Thereafter, as the pressure difference between first port  1  at the fuel tank and second port  3  at the canister is removed, as described above, pressure valve spool  9  is moved up along plunger  11  by the elastic force of pressure spring  15 , such that first port  1  and second port  3  can be completely connected. 
         [0049]    Obviously, the movement stroke of pressure valve spool  9  described above can be controlled by electric force applied to solenoid actuator  13 . As described above, it is possible to more accurately control the pressure by controlling the area that is open between first port  1  and second port  3  by pressure valve spool  9 . 
         [0050]      FIGS. 6 to 11  compare operations for ensuring safety of the fuel tank by automatically removing excessive positive pressure or excessive negative pressure in the fuel tank, with pressure valve spool  9  closed. 
         [0051]    Referring to  FIGS. 6 and 7 , when the pressure in the fuel tank is above the second reference pressure and under the first reference pressure, that is, it is in a range where it can be considered as normal pressure, bypass channel  19  is closed by relief valve  21  and vacuum valve  23 . 
         [0052]    Referring to  FIGS. 8 and 9 , when the pressure in the fuel tank has increase at the first reference pressure or more, the pressure supplied from first port  1  is applied to relief valve spool  31  and relief valve spool  31  moves while compressing relief spring  33 , such that bypass channel  19  is opened, in which the excessive pressure of the fuel tank is removed by connecting the fuel tank to the canister, and after the pressure is removed, relief valve spool  31  is automatically returned by the elastic force of relief spring  33  and closes bypass channel  19 . 
         [0053]    Referring to  FIGS. 10 and 11 , as the internal pressure of the fuel tank drops under the second reference pressure and excessive negative pressure is generated, elastic plate  39  of vacuum valve  23  deforms and opens connection hole  37  of relief body  29 , such that bypass channel  19  is connected and the negative pressure in the fuel tank is removed. 
         [0054]    For convenience in explanation and accurate definition in the appended claims, the terms upper or lower, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
         [0055]    The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.