Abstract:
The present invention relates to a crankcase ventilation device for a vehicle and, more specifically, to a crankcase ventilation device for a vehicle, which: prevents a back flow of blow-by gas to a new air inflow valve according to a rise in pressure and a rise in a flow rate inside a crankcase; prevents deterioration in the inside of an engine due to unburned fuel contained in the blow-by gas and minute particles of engine oil, generation of sludge, and an engine failure; and minimizes contamination of an intake system by providing a new air inflow control valve having a nozzle and a diaphragm, so as to block a back flow of the blow-by gas to a new air inflow hose due to an excessive rise in pressure inside the crankcase during a process for re-circulating and re-burning the blow-by gas discharged from the crankcase of the vehicle.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a crankcase ventilation device for a vehicle, and more particularly to a crankcase ventilation device for a vehicle that includes a fresh air inflow control valve that includes a nozzle and a diaphragm therein in order to prevent a blow-by gas discharged from a crankcase of the vehicle from flowing backwards to a fresh air hose due to an excessive rise in the pressure in the interior of the crankcase in a process of recirculating and re-burning the blow-by gas. 
       BACKGROUND ART 
       [0002]    Most internal combustion engines mounted on vehicles has a cycle of an intake stroke, a compression stroke, an explosion stroke, and an exhaust stroke, and in particular, a very small amount of mixed air is leaked through an aperture between a wall of a cylinder and a piston during the compression and explosion strokes. 
         [0003]    The phenomenon is called a blow-by phenomenon, and the mixed air is called a blow-by gas. 
         [0004]    Theoretically, if the space between the wall of the cylinder and the piston is sealed, the blow-by gas will not generated, but the blow-by phenomenon occurs in all vehicles because it is practically impossible to completely eliminate an aperture between the wall of the cylinder and the piston. 
         [0005]    Most of the components of the blow-by gas is unburned fuels (HC), and the remaining components are burned gases, partially oxidized mixed gases, and a very small amount of engine oil. 
         [0006]    Because the blow-by gas significantly contaminates the atmospheric environment, the recent vehicles have been required to recirculate the blow-by gas into the crankcase, and re-burn and discharge the blow-by gas. 
         [0007]    Accordingly, the methods of ventilating the interior of a crankcase include positive crankcase ventilation (PCV), and Korean Patent No. 1163786 discloses a method of recirculating and re-burning a blow-by gas by mounting a PCV valve that may control flow rate according to a pressure difference between an intake manifold and a crankcase, in which because the amount of generated blow-by gas increases as the load of an engine rises, an intake system including an air cleaner, an air inflow part, and an intake manifold is contaminated as the blow-by gas flows backwards to a fresh air inflow hose, and the engine deteriorates, sludge is generated, and in severe cases, an engine failure can be generated as the viscosity of the engine oil lowers and smooth lubrication is hampered. 
         [0008]    (Patent Document 1) KR 1163786 B1 
       DISCLOSURE 
     Technical Problem 
       [0009]    The present invention has been made in an effort to solve the above-mentioned problems, and an object of the present invention is to solve contamination problems of an intake system as well as deterioration of an engine, generation of sludge, and an engine failure that are generated when a blow-by gas of a crankcase ventilation device flows backwards. 
       Technical Solution 
       [0010]    In order to achieve the above objects, the present invention provides a crankcase ventilation device for a vehicle including: a crankcase ( 400 ); a cam cover ( 300 ) situated on the upper side of the crank case ( 400 ); a fresh air inflow control valve ( 310 ) one side of which is connected to the cam cover ( 300 ) and an opposite side of which is connected to a fresh air inflow hose ( 220 ) so that fresh air is introduced into the crank case ( 400 ); and a pressure control valve ( 320 ) situated on the upper side of the cam cover  300  to control a pressure in the crankcase ( 400 ). 
         [0011]    It may be preferable that a nozzle ( 311 ) is situated in the interior of the fresh air inflow hose ( 220 ) of the fresh air inflow control valve ( 310 ), and the nozzle ( 311 ) controls inflows of the fresh air into the crankcase ( 400 ) according to a control of the pressure in the crankcase ( 400 ) of the pressure control valve ( 320 ). 
         [0012]    It may be preferable that a diaphragm ( 312 ) is situated on the lower side of the nozzle ( 311 ) to prevent backward flows of a blow-by gas to the fresh air inflow hose ( 220 ). 
         [0013]    It may be preferable that the crankcase ventilation device further includes: an oil separator ( 330 ) communicated with the pressure control valve ( 320 ) to separate oil particles from the blow-by gas discharged from the crank case ( 400 ). 
         [0014]    It may be preferable that the pressure control valve ( 320 ) is any one of an orifice valve, a pressure reducing valve, and a solenoid valve electrically connected to an ECU. 
         [0015]    It may be preferable that in a low-speed/middle-speed of an engine provided with the crankcase ventilation device for a vehicle, the pressure control valve ( 320 ) is opened according to the amount of generated blow-by gas in the crankcase ( 400 ) such that the blow-by gas in the crankcase ( 400 ) flows into the intake manifold ( 500 ) and is mixed with the fresh air supplied from the air inflow hose  210  to be reintroduced into the crankcase ( 400 ) and burned again, and the fresh air is introduced into the crankcase ( 400 ) through the fresh air inflow control valve ( 310 ). 
         [0016]    It may be preferable that in a high-speed condition of an engine provided with the crankcase ventilation device for a vehicle, the amount of the blow-by gas in the crankcase ( 400 ) increases so that when the blow-by gas is introduced into the fresh air inflow hose ( 220 ), the blow-by gas is prevented from being introduced into the fresh air inflow hose ( 220 ) through the fresh air inflow control valve ( 310 ). 
       Advantageous Effects 
       [0017]    As described above, in the crankcase ventilation device for a vehicle according to the present invention, because a fresh air inflow control valve is installed, deterioration of the interior of the engine, generation of sludge, and an engine failure phenomenon can be prevented by preventing backward flows of a blow-by gas into the fresh air inflow valve due to rises in the pressure of the crankcase and flow rate, and contamination of an intake system can be minimized. 
     
    
     
       DESCRIPTION OF THE INVENTION 
         [0018]      FIG. 1  is a perspective view illustrating the entire external appearance of a crankcase ventilation device  1000  for a vehicle according to an embodiment of the present invention. 
           [0019]      FIG. 2  is a sectional view of the crankcase ventilation device  1000  for a vehicle taken along line A-A of  FIG. 1 . 
           [0020]      FIG. 3  is a view illustrating generation of a blow-by gas in the interior of a crankcase  400 . 
           [0021]      FIG. 4  is a sectional view of a fresh air inflow control valve  310 . 
           [0022]      FIG. 5  is a view illustrating flows of a fresh air and a blow-by gas of the crankcase ventilation device  1000  under a low-speed/middle-speed condition. 
           [0023]      FIG. 6  is a view illustrating flows of a fresh air and a blow-by gas of the crankcase ventilation device  1000  under a high-speed condition. 
       
    
    
     BEST MODE 
       [0024]    The elements constituting the crankcase ventilation device for a vehicle according to the present invention may be integrally used or separately used as occasion demands. Further, some elements may be omitted according to an in-use form. 
         [0025]    A preferred embodiment of the crankcase ventilation device for a vehicle according to the present invention will described with reference to the accompanying drawings. It should be noted that the drawings are not to precise scale and may be exaggerated in thickness of lines or size of components for descriptive convenience and clarity. In addition, terms used herein are defined by taking functions of the present invention into account and can be changed according to user or operator custom or intention. Therefore, definition of the terms should be made according to the overall disclosure set forth herein. 
         [0026]    Hereinafter, an embodiment of the crankcase ventilation device  1000  for a vehicle according to the present invention will be described with reference to the accompanying drawings. 
         [0027]    As illustrated in  FIG. 1 , the crankcase ventilation device  1000  for a vehicle according to an embodiment of the present invention includes an air cleaner  100  (see  FIGS. 5 and 6 ), a crankcase  400 , a cam cover  300  coupled to an upper side of the crankcase  400 , an intake manifold  500  (see  FIG. 2 ) coupled to a lateral side of the crankcase  400 , and an air inflow part  200  one side of which is connected to the air cleaner  100  and an opposite side of which is connected to the intake manifold  500 . 
         [0028]    A turbo charger that compresses and introduces air to increase engine efficiency may be situated between the air cleaner  100  and the air inflow part  200  (the turbo charger is not illustrated). 
         [0029]    The air cleaner  100  purifies air such that the air mixed with dust and the like is not introduced into the crankcase  400 , and introduces the air into the crankcase  400 . 
         [0030]    The air inflow part  200  includes an air inflow hose  210  and a fresh air inflow hose  220 . 
         [0031]    One side of the air inflow hose  210  is connected to the air cleaner  100  and an opposite side of the air inflow hose  210  is connected to the intake manifold  500  so that the air purified by the air cleaner  100  is introduced into the intake manifold  500 . 
         [0032]    Accordingly, the air purified in the intake manifold  500  is mixed with a blow-by gas and is introduced into the crankcase  400 . 
         [0033]    One side of the fresh air inflow hose  220  is connected to an outer peripheral surface of the air inflow hose  210  and an opposite side of the fresh air inflow hose  220  is connected to the fresh air inflow control valve  310  so that the air that is not mixed with the blow-by gas, that is, the fresh air is introduced into the crankcase  400 . 
         [0034]    As illustrated in  FIG. 3 , a cylinder  410  is situated in the interior of the crankcase  400 , and a cycle of an intake stroke, a combustion stroke, an explosion stroke, and an exhaust stroke is performed while a piston  420  is moved upwards and downwards in the cylinder  410 , and then a blow-by gas produced at an upper portion of the cylinder  410  is leaked through an aperture between a wall of the cylinder  410  and the piston  420  and is introduced into the crankcase  400 . 
         [0035]    The cam cover  300  is coupled to an upper portion of the crankcase  400  to seal the interior of the crankcase  400 , and includes a fresh air inflow control valve  310 , a pressure control valve  320 , and an oil separator  330 . 
         [0036]    One side of the fresh air inflow control valve  310  is connected to the fresh air inflow hose  220  and an opposite side of the fresh air inflow control valve  310  is connected to the cam cover  300  so that the fresh air from the fresh air inflow hose  220  is introduced into the interior of the crank case  400 . 
         [0037]    As illustrated in  FIG. 4 , the fresh air inflow control valve  310  includes a nozzle  311  and a diaphragm  312  therein. 
         [0038]    The nozzle  311  is situated inside the fresh air inflow control valve  310  to introduce a suitable amount of fresh air into the crank case  400 . 
         [0039]    The diaphragm  312  has a thin plate that may be opened and closed according to pressure in order to allows air to flow only in one direction and is situated below the nozzle  311 , and is closed if a pressure in the crankcase  400  rises to prevent the blow-by gas in the crank case  400  from flowing backwards to the air inflow part  200  through the fresh air inflow hose  220 . 
         [0040]    The pressure control valve  320  is situated on the upper side of the cam cover  300  and is communicated between the crank case  400  and the intake manifold  500  so that a change in the internal pressure of the crank case  400  is controlled according to a turbo charging pressure of the compressed air introduced from the turbo charger (not illustrated) according to a pressure difference between opposite sides of the pressure control valve  320  and a load of the engine. 
         [0041]    Accordingly, the pressure control valve  320  is opened and closed according to the change in the internal pressure of the intake manifold  500  to allow the blow-by gas in the crank case  400  to be introduced into the intake manifold  500 . 
         [0042]    The pressure control valve  320  may be an orifice valve, a pressure reducing valve, or a solenoid valve that is electrically connected to an electronic control unit (ECU) that detects a change in pressure. 
         [0043]    The oil separator  330  is communicated with the pressure control valve  320  to separate engine oil particles mixed with the blow-by gas introduced into the crank case  400 . 
         [0044]    As illustrated in  FIG. 1 , two pipes are provided at an upper portion of the crankcase ventilation device such that a recirculation hose  331  is connected to one of the pipes to introduce the blow-by gas, from which engine oil is separated, into the air inflow part  200  so that the introduced blow-by gas is mixed with fresh air and is introduced into the intake manifold  500  and a bypass hose  332  is connected to the other of the pipes to directly introduce the blow-by gas into the intake manifold  500 . 
         [0045]    Furthermore, when the turbo charger (not illustrated) is installed, the blow-by gas introduced from the recirculation hose  331  into the air flow part  200  is mixed with the compressed air introduced from the turbo charger and is introduced into the intake manifold  500 . 
         [0046]    Hereinafter, the flows of the fresh air and the blow-by gas in the crankcase ventilation device  100  according to an engine condition will be described with reference to  FIGS. 5 and 6 . 
         [0047]    First, the flows of the fresh air and the blow-by gas in a low-speed/middle-speed condition will be described with reference to  FIG. 5 . 
         [0048]    Here, the “low-speed/middle-speed condition” refers to a state in which a partial load is applied to the engine, and means a state in which a throttle that adjusts an amount of the fuel supplied to the engine is partially opened, that is, a partial throttle state and does not mean that the speed of the vehicle itself is a low speed or a middle speed. 
         [0049]    In this condition, because the amount of generated blow-by gas is not large, the pressure in the crankcase  400  does not significantly rise so that the pressure control valve  320  is slightly opened, and the blow-by gas in the crankcase  400  flows to the intake manifold  500  and is mixed with the fresh air introduced from the air inflow hose  210  in the intake manifold  500  to be reintroduced into the crankcase  400  and burned again. 
         [0050]    The fresh air is introduced into the crankcase  400  through the fresh air inflow control valve  310 . 
         [0051]    Next, the flows of the fresh air and the blow-by gas at a high-speed condition will be described with reference to  FIG. 6 . 
         [0052]    Here, the “high-speed condition” refers to a state in which a full load is applied to the engine, and means a state in which the throttle is completely opened, that is, a full throttle state. 
         [0053]    In this condition, because the amount of the blow-by gas increases, the pressure in the crankcase  400  significantly rises, and the pressure control valve  320  is opened by a large degree and the flow rate of the blow-by gas introduced into the intake manifold  500  increases in the crankcase  400 . 
         [0054]    Accordingly, the blow-by gas in the crankcase  400  is not entirely introduced into the intake manifold  400 , but flows backwards to the fresh air inflow hose  220 . 
         [0055]    Then, the diaphragm  312  in the interior of the fresh air inflow control valve  310  situated in the cam cover  300  prevents the backward flow phenomenon so that the blow-by gas is introduced only to the intake manifold  500 . 
         [0056]    Although the embodiment of the present invention illustrated in the drawings has been described so that those skilled in the art can easily reproduce and implement the present invention, it is merely exemplary and it will be understood by those skilled in the art that various modifications and equivalent embodiments can be made. Therefore, the scope of the present invention should be determined according to the claims.