Patent Publication Number: US-9416699-B2

Title: Heating device of a PCV valve

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Japanese Patent Application No. 2014-023354 filed on Feb. 10, 2014, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to a heating device for heating a positive crankcase ventilation (PCV) valve mounted to an oil separator made from resin. 
     BACKGROUND OF THE INVENTION 
     Blowby gas includes gas leaking from a clearance between a cylinder and a piston to a crankcase of an engine. Fuel economy is improved by leading the blowby gas to an intake passage. Further, since a pressure inside the crankcase can be made to a negative pressure, a pumping loss of a piston can be decreased. An engine oil mist is included in the blowby gas and the oil is separated from the blowby gas by an oil separator. The blowby gas from which the oil is separated is caused to flow to the intake passage. The amount of the blowby gas flowing to the intake passage is regulated by a PCV valve. 
     For decreasing manufacturing costs, the oil separator is made from resin. Therefore, when the PCV valve is mounted to the oil separator, a heat from the engine is more difficult to be transmitted to the PCV valve via the oil separator than in a case where the oil separator is made from metal. As a result, when an ambient temperature is low, a water component contained in the blowby gas may freeze whereby a blowby gas passage in the PCV valve may be blocked by ice. 
     Japanese Patent Publication 2009-150351 discloses that a portion of the oil separator to which the PCV valve is mounted is made from metal having a high coefficient of thermal conductivity so that the heat from the engine is efficiently transmitted to the PCV valve. 
     RELATED ART DOCUMENT 
     Patent Document 
     Patent Document 1: JP2009-150351 
     BRIEF SUMMARY 
     One object of the invention is to provide a heating device of a PCV valve which heats a PCV valve not by a heat transferred from an engine but by an engine cooling water (warmed water). 
     The present invention for achieving the above object is as follows: 
     (1) A heating device of a PCV valve comprises a PCV valve, a conduit and a bush each of which is made from metal. 
     The PCV valve is mounted to an oil separator made from resin via the bush. 
     The conduit includes an outside surface and an internal passage through which an engine cooling water flows. 
     The bush includes an inside surface, a portion of which contacts the PCV valve, and an outside surface, a first portion of which contacts the oil separator and a second portion of which contacts the outside surface of the conduit. 
     The bush includes an outward protrusion protruding outwardly in a radial direction of the bush and having a curved surface extending along the outside surface of the conduit in a circumferential direction of a cross section of the conduit so that the curved surface of the outward protrusion of the bush contacts a portion of the outside surface of the conduit, opposing the curved surface of the outward protrusion in a manner of a surface-to-surface contact, the curved surface of the outward protrusion defining the second portion of the outside surface of the bush. 
     (2) A heating device of a PCV valve according to item (1) above, wherein the bush and the conduit are welded to each other. 
     (3) A heating device of a PCV valve according to item (2) above, wherein the conduit includes a longitudinally bent portion extending along a portion of the outside surface of the bush in a circumferential direction of the bush and contacting the outside surface of the bush. The bush and the longitudinally bent portion of the conduit are welded to each other.
 
(4) A heating device of a PCV valve according to item (3) above, wherein the longitudinally bent portion extends by a half of a circumference of the bush.
 
(5) A heating device of a PCV valve according to item (3) above, the heating device of a PCV valve further comprises a cover made from resin. A portion of the bush and the longitudinally bent portion of the conduit are covered with the cover.
 
(6) A heating device of a PCV valve according to item (5) above, wherein the cover is fixed to the oil separator.
 
(7) A heating device of a PCV valve according to item (1) above, wherein the PCV valve includes a valve body including an outside surface. The inside surface of the bush contacts a portion of the outside surface of the valve body in a manner of a surface-to-surface contact.
 
(8) A heating device of a PCV valve according to item (1) above, wherein the oil separator includes a chamber, a gas inlet, an oil separating portion, a drain and a gas outlet. The gas inlet is provided so as to introduce blowby gas into the chamber. The oil separating portion is provided so as to separate oil from the blowby gas. The drain is provided so as to drain the oil separated from the blowby gas by the oil separating portion. The gas outlet is provided so as to cause the blowby gas from which the oil is separated by the oil separating portion to flow out from the chamber. The bush is pressed into the gas outlet.
 
     Technical Advantages 
     According to the heating device of a PCV valve of items (1)-(8) above, the PCV valve contacts the bush. The bush includes the outward protrusion. The outward protrusion has the curved surface contacting the outside surface of the conduit in the manner of a surface-to-surface contact. Therefore, the following technical advantages can be obtained: 
     When the conduit is heated by an engine cooling water, the bush contacting the conduit in the manner of a surface-to-surface contact is heated and the PCV valve contacting the bush is heated. Therefore, the PCV valve can be heated by the engine cooling water. Since the bush contacts the conduit in the manner of a surface-to-surface contact, the bush is heated more efficiently than in a case where the bush does not contact the conduit in the manner of a surface-to-surface contact. 
     According to the heating device of a PCV valve of item (2) above, since the bush and the conduit are welded to each other, heat transfer from the conduit to the bush is conducted efficiently. 
     According to the heating device of a PCV valve of item (5) above, since the bush and the conduit are covered with the cover, radiation of heat from the bush and the conduit is more suppressed than in a case where the bush and the conduit are not covered with the cover. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an oblique view of a heating device of a PCV valve according to the present invention. 
         FIG. 2  is an enlarged plane view of the PCV valve and its vicinity of the heating device of a PCV valve according to the present invention. 
         FIG. 3  is an enlarged side view of the PCV valve and its vicinity of the heating device of a PCV valve according to the present invention. 
         FIG. 4  is an enlarged cross-sectional view taken along line A-A of  FIG. 2 . 
         FIG. 5  is a schematic view of an oil separator to which the PCV valve of the heating device of a PCV valve according to the present invention is mounted. 
     
    
    
     DETAILED DESCRIPTION 
     A heating device of a PCV valve according to an embodiment of the present invention will be explained below with reference to the drawings. 
     As illustrated in  FIG. 1 , the heating device  10  of a PCV valve according to an embodiment of the present invention is a device heating a PCV valve  20  mounted to an oil separator  1  made from resin. 
     As illustrated in  FIG. 5 , the oil separator  1  is provided so as to separate oil  61  from a blowby gas  60  leaking to a crankcase (not shown) of a vehicle engine (not shown). The oil  61  separated from the blowby gas is caused to flow to the crankcase. As illustrated in  FIG. 1 , the oil separator  1  includes an upper casing  1   a  and a lower casing  1   b . The upper casing  1   a  and the lower casing  1   b  are manufactured separately from each other and fixed to each other. The upper casing  1   a  and the lower casing  1   b  are fixed to each other by vibration welding or an adhesive. 
     As illustrated in  FIG. 5 , the oil separator  1  includes a chamber  2 , a gas inlet  3 , an oil separating portion  4 , a drain  5  and a gas outlet  6 . 
     The chamber  2  is a space including an interior of the oil separator  1 . The gas inlet  3  is provided so as to introduce the blowby gas  60  from an exterior of the oil separator  1  to the chamber  2 . The oil separating portion  4  is provided so as to separate the oil  61  from the blowby gas  60 . The drain  5  is provided so as to drain the oil  61  separated from the blowby gas  60  by the oil separating portion  4  to the exterior of the oil separator  1 . The gas outlet  6  is provided so as to cause the blowby gas  60 , from which the oil  61  is separated by the oil separating portion  4 , to flow out from the chamber  2  to the exterior of the oil separator  1 . 
     The single gas inlet  3 , the single drain  5  and the single gas outlet  6  are provided one by one, respectively. The gas inlet  3  and the drain  5  are tubular and are provided at the lower casing  1   b . The gas inlet  3  extends in a horizontal direction or a downward direction. The drain  5  extends in a downward direction. The gas outlet  6  is tubular and is provided at the upper casing  1   a . The gas outlet  6  extends in an upward direction. As illustrated in  FIG. 4 , a flange  6   a  is formed at a downstream end portion of the gas outlet  6  in the blowby gas flow direction. The flange  6   a  is formed integral with the gas outlet  6 . The flange  6   a  extends outwardly in a radial direction of the gas outlet  6 . 
     The oil separator  1  may be (i) an inertia collision-type separator as shown in  FIG. 5 , 
     (ii) a cyclone-type separator (not shown) or (iii) a labyrinth-type separator (not shown). 
     (i) When the oil separator  1  is an inertia collision-type separator, a baffle  4   a  to which the blowby gas  60  collides is provided and the oil  61  included in the blowby gas  60  adheres to the baffle  4   a  whereby the oil  61  is separated from the blowby gas  60 . 
     (ii) When the oil separator  1  is a cyclone-type separator, the blowby gas  60  is caused to flow circularly and a centrifugal force is generated whereby the oil  61  is separated from the blowby gas  60 . 
     (iii) When the oil separator  1  is a labyrinth-type separator, a partition (not shown) forming a portion of the interior of the chamber  2  into a labyrinth passage is provided whereby a flow passage of the blowby gas  60  in the chamber  2  is lengthened so that the oil  61  easily falls down by a self gravity of the oil  61  and so that a flow speed of the blowby gas  60  is caused to be higher and the oil  61  included in the blowby gas  60  easily contacts on a wall of the oil separator  1 . As a result, the oil  61  is easily separated from the blowby gas  60 . 
     As illustrated in  FIG. 4 , the heating device  10  of a PCV valve includes the PCV valve  20 , a conduit (a pipe)  30  having an outside surface  33 , a bush  40  and a cover  50 . 
     The PCV valve  20  is provided so as to regulate the amount of the blowby gas flowing from the chamber  2  to the exterior of the oil separator  1 . The PCV valve  20  is made from metal, and the metal is, for example, iron, steel, copper or aluminum. As illustrated in  FIG. 4 , the PCV valve  20  includes a plunger (a movable valve element)  21 , a spring  22  and a valve body  23 . The plunger  21  moves relative to the valve body  23  whereby a cross-sectional area of an internal passage  23   a  of the valve body  23  is changed. Therefore, the amount of the blowby gas flowing through the internal passage of the PCV valve  20  is controlled by the PCV valve  20 . 
     The valve body  23  is made from metal, and the metal is, for example, iron, steel, copper or aluminum. The valve body  23  includes an outside surface  23   b . The outside surface  23   b  of the valve body  23  includes a small-diameter portion  23   b   1 , a large-diameter portion  23   b   3  and a second large-diameter portion  23   b   5 . The large-diameter portion  23   b   3  is located downstream of the small-diameter portion  23   b   1  in a blowby gas flow direction. The large-diameter portion  23   b   3  and the small-diameter portion  23   b   1  are connected via a step  23   b   2 . A diameter of the large-diameter portion  23   b   3  is larger than a diameter of the small-diameter portion  23   b   1 . The second large-diameter portion  23   b   5  is located downstream of the large-diameter portion  23   b   3  in the blowby gas flow direction. The second large-diameter portion  23   b   5  and the large-diameter portion  23   b   3  are connected via a second step  23   b   4 . A diameter of the second large-diameter portion  23   b   5  is larger than the diameter of the large-diameter portion  23   b   3 . 
     The valve body  23  is mounted to the gas outlet  6  of the oil separator  1  via the bush  40  contacting the valve body  23 . 
     The bush  40  is made from metal, and the metal is, for example, iron, steel, copper or aluminum. The bush  40  is pressed into the gas outlet  6 . The bush  40  is tubular. The bush  40  includes an inside surface  41  and an outside surface  42 . 
     A portion of the inside surface  41  of the bush  40  contacts the PCV valve  20 . The inside surface  41  of the bush  40  includes a small-diameter portion  41   a  and a large-diameter portion  41   c . The large-diameter portion  41   c  is located downstream of the small-diameter portion  41   a  in the blowby gas flow direction. The large-diameter portion  41   c  and the small-diameter portion  41   a  are connected via a step  41   b . A diameter of the large-diameter portion  41   c  is larger than a diameter of the small-diameter portion  41   a.    
     A male screw  70  is formed at the small-diameter portion  23   b   1  of the outside surface  23   b  of the valve body  23 . A female screw  71  is formed at the small-diameter portion  41   a  of the inside surface  41  of the bush  40 . The male screw  70  is threaded into the female screw  71  whereby the valve body  23  (PCV valve  20 ) is coupled to the small-diameter portion  41   a  of the inside surface  41  of the bush  40 . The step  41   b  of the bush  40  axially opposes the step  23   b   2  of the valve body  23 . The large-diameter portion  41   c  of the inside surface  41  of the bush  40  contacts the large-diameter portion  23   b   3  of the outside surface  23   b  of the valve body  23  in a manner of a surface-to-surface contact. The surface-to-surface contact between the large-diameter portion  23   b   3  of the outside surface  23   b  of the valve body  23  and the large-diameter portion  41   c  of the inside surface  41  of the bush  40  is sealed by an O-ring  43 . A thickness of the bush  40  at the large-diameter portion  41   c  of the inside surface  41  is substantially equal to a step amount of the second step  23   b   4  of the valve body  23 . 
     The outside surface  42  of the bush  40  includes a first portion  42   a  and a second portion  42   b  axially separate from the first portion  42   a . The first portion  42   a  of the outside surface  42  contacts an inside surface  6   b  of the gas outlet  6  of the oil separator  1  in a manner of a surface-to-surface contact. The second portion  42   b  of the outside surface  42  contacts the outside surface  33  of the conduit  30  in a manner of a surface-to-surface contact. The surface-to-surface contact between the outside surface  42  of the bush  40  and the inside surface  6   b  of the gas outlet  6  of the oil separator  1  is sealed by an O-ring  44 . 
     The bush includes an outward protrusion  45 . The outward protrusion  45  is formed integral with the bush  40 . The outward protrusion  45  is formed at an intermediate portion of the bush  40  in an axial direction of the bush (i.e., in the blowby gas flow direction). The outward protrusion  45  protrudes outwardly in a radial direction of the bush  40 . The outward protrusion  45  radially outwardly protrudes to a space S formed axially between the conduit  30  and the flange  6   a  of the gas outlet  6 . The outward protrusion  45  has a curved surface extending along the outside surface  33  of the conduit  30  in a circumferential direction of a cross section of the conduit  30 , and the curved surface defines the second portion  42   b  of the outside surface  42  of the bush  40 . The curved surface (i.e., the second portion  42   b  of the outside surface  42  of the bush  40 )  42   b  contacts a portion  33   a  of the outside surface  33  of the conduit  30 , opposing the curved surface  42   b  in a manner of a surface-to-surface contact. A surface  45   b  of the outward protrusion  45  axially opposing the flange  6   a  of the gas outlet  6  contacts a portion of the flange  6   a  opposing the surface  45   b  in a manner of a surface-to-surface contact. Since the bush  40  includes the outward protrusion  45  and the outward protrusion  45  includes the curved surface  42   b , the bush  40  contacts the outside surface  33  of the conduit  30  at the portion  33   a  in a manner of a surface-to-surface contact. 
     The conduit  30  includes an internal passage  31 . An engine cooling water (not shown, warmed water) for cooling the engine (not shown) flows through the internal passage  31 . The conduit  30  is made from metal, and the metal is, for example, iron, stainless-steel, copper or aluminum. As illustrated in  FIG. 2 , the conduit  30  includes a longitudinally bent portion  32  extending along a portion of the outside surface  42  of the bush  40  in a circumferential direction of the bush  40 . The longitudinally bent portion  32  extends by a half of a circumference of the bush  40 . As illustrated in  FIG. 4 , the longitudinally bent portion  32  is located outside the oil separator  1 . The longitudinally bent portion  32  contacts the outside surface  42  of the bush  40 . The amount of heat transfer from the conduit  30  to the bush  40  is proportional to a size of the contact area of the conduit  30  and the bush  40 . Since the longitudinally bent portion  32  extends by a half of the circumference of the bush  40 , the size of the contact area of the conduit  30  and the bush  40  is kept large. 
     The longitudinally bent portion  32  of the conduit  30  and the bush  40  may be welded to each other. In order to weld the conduit  30  and the bush  40  to a deep position of the coupling of the conduit  30  with the bush  40 , it is desirable that the weld of the conduit  30  and the bush  40  is conducted by brazing. According to brazing, a size of the contact area between the conduit  30  and the bush  40  can be large. However, the weld the conduit  30  and the bush  40  may be conducted by TIG welding or laser beam welding. 
     At least a portion of the longitudinally bent portion  32  of the conduit  30  not covered with the gas outlet  6  (located outside the gas outlet  6 ) and at least a portion of the bush  40  not covered with the gas outlet  6  (located outside the gas outlet  6 ) are covered with the cover  50  made from resin. Therefore, radiation of heat from the longitudinally bent portion  32  and the bush  40  can be suppressed by the cover  50 . 
     The cover  50  is located outside the oil separator  1 . The cover  50  is located outside the bush  40  in the radial direction of the bush. An inner end surface  51  of the cover  50  radially opposes the outside surface  42  of the bush  40 . The inner end surface  51  of the cover  50  opposes a downstream end portion of the outside surface  42  of the bush  40 . The cover  50  extends outwardly in the radial direction of the bush  40  from the inner end surface  51 . A portion of the cover  50  extends along the outside surface  33  of the conduit  30  in the circumferential direction of the cross section of the conduit  30 . A step  52   a  is formed at an outside surface of a radially outer end portion  52  of the cover  50 . The radially outer end portion  52  of the cover  50  is fixed to the flange  6   a  of the gas outlet  6 . 
     The cover  50  is fixed to the flange  6   a  of the gas outlet  6  by ultrasonic bonding or an adhesive. The cover  50  may or may not contact the longitudinally bent portion  32  of the conduit  30 . The inner end surface  51  of the cover  50  may or may not contact the outside surface  42  of the bush  40 . 
     Next, operation and technical advantages of the embodiment of the present invention will be explained. 
     The PCV valve  20  contacts the bush  40 . The bush  40  includes the outward protrusion  45 . The outward protrusion  45  has the curved surface  42   b  contacting the outside surface  33  of the conduit  30  in the manner of a surface-to-surface contact. Therefore, the following technical advantages are obtained: 
     When the conduit  30  is heated by the engine cooling water, the bush  40  contacting the conduit  30  in the manner of a surface-to-surface contact is heated and the PCV valve  20  contacting the bush  40  is heated. Therefore, the PCV valve  20  can be heated by the engine cooling water. 
     Since the bush  40  contacts the conduit  30  in the manner of a surface-to-surface contact, the bush  40  is heated more efficiently than in a case where the bush  40  does not contact the conduit  30  in the manner of a surface-to-surface contact. 
     Since the PCV valve  20  contacts the bush  40  in the manner of a surface-to-surface contact, the PCV valve  20  is heated more efficiently than in a case where the PCV valve  20  does not contact the bush  40  in the manner of a surface-to-surface contact. 
     Since the bush  40  and the conduit  30  are welded to each other, heat transfer from the conduit  30  to the bush  40  is conducted efficiently. 
     Since the bush  40  and the conduit  30  are covered with the cover  50 , escape of heat due to radiation from the bush  40  and the conduit  30  is more suppressed than in a case where the bush  40  and the conduit  30  are not covered with the cover  50 . 
     Since the cover  50  is fixed to the oil separator  1 , the bush  40  pressed into the gas outlet  6  of the oil separator  1  is suppressed from dropping off from the oil separator  1 . 
     The longitudinally bent portion  32  of the conduit  30  not covered with the gas outlet  6  (located outside the gas outlet  6 ) and the bush  40  not covered with the gas outlet  6  (located outside the gas outlet  6 ) are covered with the cover  50  made from resin. Therefore, heat transfer from the conduit  30  to the PCV valve  20  via the bush  40  can be completely (including substantially completely) conducted inside the resin members (gas outlet  6  and the cover  50 ) having a high-insulating ability as a heat insulator. As a result, heat transfer from the conduit  30  to the PCV valve  20  is conducted efficiently. 
     EXPLANATION OF REFERENCE NUMERALS 
     
         
           1  oil separator 
           1   a  upper casing 
           1   b  lower casing 
           2  chamber 
           3  gas inlet 
           4  oil separating portion 
           4   a  baffle 
           5  drain 
           6  gas outlet 
           6   a  flange 
           10  heating device of a PCV valve 
           20  PCV valve 
           21  plunger 
           22  spring 
           23  valve body 
           23   a  internal passage of the valve body 
           23   b  outside surface of the valve body 
           30  conduit 
           31  internal passage of the conduit 
           32  longitudinally bent portion 
           33  outside surface of the conduit 
           40  bush 
           41  inside surface of the bush 
           42  outside surface of the bush 
           42   a  first portion 
           42   b  second portion 
           43 , 44  O-ring 
           45  outward protrusion 
           50  cover 
           60  blowby gas 
           61  oil