JP2013204460A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve responsiveness of a thermostat valve device for coolant water control while restraining cost.SOLUTION: A thermostat valve device 14 is disposed in a hollow part 5 provided in a cylinder head 3. The thermostat valve device 14 has a temperature sensing part 32 so that a valving element 34 is moved by thermal expansion and thermal contraction of a temperature sensing material stored in the temperature sensing part 32. Coolant water is sent from a heater return port 24 to the hollow part 5 so as to be discharged to a main water supply port 41. A guide means is provided in a portion of an inner surface of the hollow part 5 surrounding the temperature sensing part 32 for guiding the coolant water for smooth flow around an axis of the temperature sensing part 32 such as a stepwise part 42 and a circular arc surface 43. Since the temperature sensing part 32 is exposed strongly to the coolant water, the responsiveness of the thermostat valve device 14 is improved.

Description

  The present invention relates to a liquid-cooled internal combustion engine in which a cylinder head or a cylinder block is provided with a thermostat valve device for controlling the flow of coolant.

  Internal combustion engines mounted on vehicles such as passenger cars and trucks are generally water-cooled. Cooling water that has become hot is cooled by a radiator, but if the temperature of the cooling water is below a certain level, it is cooled by a radiator. The engine body is circulated without any problems. For this reason, for example, a thermostat valve device with a valve body is provided in the cylinder head to control the flow of the cooling water according to the temperature of the cooling water.

  As an example, Patent Document 1 discloses that when a thermostat valve device is mounted in a hollow portion formed in a cylinder head, a hook-shaped plug that partially covers the thermostat valve device is mounted in the hollow portion of the cylinder head. In addition, it is disclosed to provide a guide wall portion that guides cooling water to a temperature sensing portion of a thermostat valve device.

JP-A-8-319828

  In Patent Document 1, the cooling water for operating the thermostat valve device flows from the direction orthogonal to the axis of the thermostat valve device and flows out in the axial direction of the thermostat valve device. By the guide action, the cooling water can be guided so as to hit the temperature sensitive part accurately.

  However, if a saddle-shaped plug is provided, not only the cost for manufacturing the same is increased, but also processing for attaching the saddle-shaped plug to the hollow portion of the cylinder head or the like must be performed, which also increases the cost. Further, cooling water for operating the thermostat valve device may flow across the temperature sensing part of the thermostat valve device, but this type also has a problem that Patent Document 1 is difficult to apply.

  The present invention has been made to improve the current situation.

  According to the present invention, a thermostat valve device in which a valve element moves in accordance with the amount of heat received by the temperature sensing portion is disposed in a hollow portion provided in the cylinder head or the cylinder block, and a coolant for operating the thermostat valve device flows in. The operating coolant inlet and the exiting operating coolant outlet are arranged so that the coolant from the operating coolant inlet to the operating coolant outlet crosses the temperature sensing portion of the thermostat valve device, and the thermostat valve device This is intended for an internal combustion engine configured such that the flow of the other coolant passage is controlled by the movement of the valve body.

  In the invention of claim 1, the thermostat valve device is arranged concentrically with the temperature sensing portion and has a central axis with the valve body attached to one end, while being hollow from the working coolant inlet. The coolant that has flowed into the portion is set to change direction around the central axis of the thermostat valve device toward the working coolant outlet, and the coolant that has flowed into the cavity from the working coolant inlet. Guide means is integrally formed to guide the liquid so that the liquid smoothly changes direction toward the temperature sensing portion of the thermostat valve device.

  According to a second aspect of the present invention, in the first aspect, the hollow portion is formed in the cylinder head, and the cylinder head has an EGR passage having a circular cross section for returning a part of the exhaust gas to the intake system. A portion is formed so as to be close to the cavity, and a recess having an inner surface extending around the axis of the EGR passage is formed in a portion of the inner surface of the cavity close to the EGR passage. ing.

  In the present invention, the flow of the coolant flowing into the cavity from the working coolant inlet is guided to hit the temperature sensing portion of the thermostat valve device by the guide action of the guide means formed in the cavity itself. Therefore, even when the coolant flows in a direction that crosses the temperature sensing portion of the thermostat valve device while changing the flow direction, the coolant can be brought into contact with the temperature sensing portion at a high rate. Thus, the flow of the coolant can be accurately controlled.

  And since a guide means is formed in cavity part itself and it is not necessary to give a special process to a cavity part, manufacturing cost and processing cost do not increase. Therefore, the responsiveness of the thermostat valve device can be improved while the cost is suppressed.

  In recent internal combustion engines, a part of exhaust gas is recirculated to the intake system in order to improve fuel efficiency. In this case, an EGR passage through which the recirculated exhaust gas passes is formed in the cylinder head. It has been broken. According to the invention of claim 2 of the present application, since the concave portion having the inner side surface around the axis of the EGR passage is formed in the hollow portion, the heat of the exhaust gas passing through the EGR passage is transferred from the location of the concave portion to the coolant. Is transmitted efficiently. For this reason, the cooling efficiency of the exhaust gas (EGR gas) which recirculates can be improved.

It is a mimetic diagram in the plane view of the internal-combustion engine concerning an embodiment. It is the side view of the cylinder head seen from the II-II view direction of FIG. 3A is a cross-sectional view taken along line III-III in FIG. 2, and FIG. 3B is a partial view in a communication state in which a thermostat is operated. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2. FIG. 5 is a cross-sectional view taken along the line V-V in FIG. 2. FIG. 6 is a sectional view taken along line VI-VI in FIG. 3. FIG. 7 is a sectional view taken along line VII-VII in FIG. 3.

  Next, an embodiment of the present invention will be described with reference to the drawings. The present invention is applied to a multi-cylinder (3-cylinder) internal combustion engine for a vehicle.

(1) Outline First, an outline will be described with reference to FIG. The internal combustion engine includes a cylinder block 1 in which a cylinder bore 2 is formed and a cylinder head 3 fixed on the upper surface thereof. The cylinder block 1 and the cylinder head 3 constitute an engine body. Cooling water passages 4 a and 4 b are formed in the cylinder block 1 and the cylinder head 3, and inlets and outlets of the cooling water passages 4 a and 4 b are connected to a cavity 5 provided on one side of the cylinder head 3. Yes. For convenience, reference numeral 4 a is attached to the forward path portion in which the cooling water flows out of the cavity 5 in the cooling water passage, and reference numeral 4 b is attached to the return path portion where the cooling water returns to the cavity 5.

  The internal combustion engine further includes a water pump 6 and a radiator 7. An input port of the water pump 6 is connected to the cavity portion 5 by a first pipe line 8, and an output port of the water pump 6 is a cooling water passage. It is connected to the starting end of the forward path 4a. The water receiving port (upper tank) of the radiator 7 is connected to the end of the return path 4 b of the cooling water passage via the second pipe 9, and the water supply port (lower tank) of the radiator 7 is connected via the third pipe 10. It is connected to the cavity 5. The water pump 6 is fixed to the cylinder block 1 through a bracket 6a and is driven by an auxiliary machine drive belt.

  Furthermore, the internal combustion engine is accompanied by a heater 11 for heating the interior of the vehicle, and cooling water that has passed through the engine body is sent to the heater 11 from the forward passage portion 4b of the cooling water passage through the fourth pipe 12; The cooling water heat-exchanged by the heater 11 is sent to the cavity 5 by the fifth pipe 13.

  A thermostat valve device 14 is disposed in the cavity 5 of the cylinder head 3, and the cooling water circulates only to the cooling water passages 4 a and 4 b and the heater 11 according to the temperature of the cooling water after passing through the heater 11. Or the flow is switched so as to circulate through the cooling water passages 4a and 4b, the heater 11 and the radiator 7.

  An intake manifold 16 and an exhaust manifold 17 are connected to the cylinder head 3, and an intake passage 18 is connected to the intake manifold 16. The intake passage 18 has a surge tank 19, and fuel is supplied to the intake passage 18 from an injector (not shown) provided on the downstream side of the surge tank 19.

  An exhaust passage 20 is connected to the exhaust manifold 17, and an exhaust purification device, an exhaust turbocharger (both not shown) and the like are interposed in the middle of the exhaust passage 20, and the end portion is a silencer It has become. An EGR passage 21 is branched from the middle of the exhaust passage 20, and the EGR passage 21 is connected to a portion of the intake passage 18 upstream of the surge tank 18. A part of the EGR passage 21 is formed in the cylinder head 3. The part constituted by the cylinder head 3 in the EGR passage 21 is denoted by reference numeral 21a.

  Further, an EGR valve 22 that controls the amount of exhaust gas is inserted in the EGR passage 21. In FIG. 1, the EGR valve 22 is fixed to the cylinder head 3, but it may be inserted in a portion exposed from the cylinder head 3. In addition, when fixing to the cylinder head 3, it may be fixed to a portion on the downstream side of the EGR passage 21.

(2). Cavity and Thermostat Valve Device Next, details of the cavity 5 and the thermostat valve device 14 will be described with reference to FIG. The cavity 5 opens toward the one side surface 3 a of the cylinder head 3. Also, on one side surface 3 a of the cylinder head 3, the heater feed port 23 that sends the coolant to the heater 11, the heater return port 24 that receives the coolant returned from the heater 11, and the coolant to the upper tank of the radiator 7 The fourth feed line 12 is connected to the heater feed port 23, the fifth pipe 13 is connected to the heater return port 24, and the second pipe is connected to the radiator feed port 25. Road 9 is connected.

  The first pipe 8 that supplies water to the water pump 6 is connected to a main water supply port 41 that communicates with the cavity 5. The main water supply port 41 is provided on the peripheral surface of the cylinder head 3 intersecting with the one side surface 3a, but may be disposed on the one side surface 3a. The heater return port 24 communicates with the cavity 5, and the heater feed port 23 and the radiator feed port 25 are connected to the cooling water passage 4 b without communicating with the cavity 5.

  3 to 5, the cylinder head 3 is provided with a radiator return port 26 having a case 26 a that covers the cavity 5 from the outside, and a third pipe line is connected to the radiator feed port 26. 10 is connected. As shown in FIG. 5, an L-shaped joint 27 constituting the fifth pipe line 13 is connected to the heater return port 24.

  For example, as shown in FIG. 3, the thermostat valve device 14 has a relief shaft 30 in a posture substantially orthogonal to the one side surface 3 a of the cylinder head 3, and a disc-shaped relief valve element 31 at the back end of the relief shaft 30. Is attached. Further, a temperature sensing part 32 concentric with the relief shaft 30 is arranged on the front side of the relief shaft 30, and the temperature sensing part 32 is located concentrically with the relief shaft 30 and on the opposite side of the relief shaft 30. It is attached to the central shaft 33. The relief shaft 30 and the central shaft 33 are arranged concentrically, but each has a relationship capable of sliding independently in the axial direction.

  The thermostat valve device 14 has a diaphragm-like valve body 34 that overlaps one side 3 a of the cylinder head 3 from the outside, and a central shaft 33 is fixed to the valve body 34 so as not to slide. In addition, a single character-like front frame 35 that supports the front end of the central shaft 33 is fixed to the valve body 34. Therefore, the central shaft 33, the valve body 34, and the front frame 35 can be moved back and forth integrally. When the central shaft 33 moves back and forth, the valve body 34 comes into close contact with or separates from the one side surface 3a of the cylinder head 3. Or

  A case 26a constituting the radiator return port 26 has a cup shape, and the case 26a is fixed to one side surface 3a of the cylinder head 3 so as to surround the valve body 34 and the front frame 35 from the outside.

  The temperature sensing part 32 has a fixed case, and a spring receiver 36 is fixed to the inner part of the fixed case. The spring receiver 36 is fixed to the rear end of the inner frame 38, and the front end of the inner frame 38 overlaps one side 3 a of the cylinder head 3 from the outside. Therefore, the fixed case of the temperature sensing unit 32 is held so as not to move back and forth.

  The central shaft 33 is fixed to a slider (not shown) built in the temperature sensing unit 32, and when a wax-like temperature sensitive material (not shown) expands or contracts due to heat, the slider moves in the axial direction. When the central shaft 33 moves in the axial direction integrally with the slider, the valve body 34 moves back and forth, whereby the valve body 34 comes into close contact with the cylinder head 3 and closes, and the valve body 34 separates from the cylinder head 3. The opening degree in the communication state is proportional to the temperature of the cooling water (the valve body 34 is fully opened when the temperature is raised to a certain level, so that the valve body 34 is fully opened regardless of the water temperature). . The inner frame 38 extends in the axial direction and does not hinder the flow of cooling water.

  A coiled main spring 37 that urges the valve body 34 in the opening direction is disposed between the spring receiver 36 and the valve body 34. The pressure of the return cooling water passage from the radiator 7 acts on the valve body 34, but when the cooling water is heated to a certain level, the sum of the pressing force due to the expansion of the temperature sensing member and the elastic restoring force of the main spring 37. Overcomes the pressure of the return cooling water from the radiator 7, the valve body 34 is separated from the outer surface of the cylinder head 3, and the third pipe line 13 communicates with the cavity 5. As a result, the cooling water is connected to the radiator 7. Circulates with the engine body 1.

  A relief spring 39 is interposed between the temperature sensing part 32 and the relief valve element 31. A communication port 40 where the relief valve body 31 overlaps is opened at the back of the cavity portion 5. When the communication port 40 is closed by the valve body 31, the cavity portion 5 and the cooling water passage 4 b can communicate with each other. In addition, the cooling water is not circulated in the engine body 1. The rotational speed of the water pump 6 is proportional to the rotational speed of the internal combustion engine. When the rotational speed of the internal combustion engine becomes higher than a set value, the discharge pressure of the water pump 6 overcomes the elastic restoring force of the relief spring 39 and the relief valve body. 31 retreats, and the cooling water passage 4b and the cavity 5 communicate with each other. Thereby, the cooling water circulates through the engine body 1.

  As shown in FIGS. 5 and 6, the heater return port 24 opens downward toward the cavity 5. To be precise, the heater return port 24 is located on the opposite side of the main water supply port 41 with the thermostat valve device 14 interposed therebetween as shown in FIG. 6, and the thermostat valve device 14 as shown in FIG. When viewed from the side perpendicular to the axis of the thermostat valve device 14, the outlet thereof is directed to the temperature sensing portion 32 of the thermostat valve device 14. In the present embodiment, the heater return port 24 corresponds to the working coolant inlet, and the main water supply port 41 corresponds to the working coolant outlet.

  Then, as shown in FIG. 6, as an example of the guide means described in the claims, cooling water is supplied to the temperature sensing portion 32 of the thermostat valve device 14 in a portion of the inner peripheral surface of the cavity portion 5 below the heater return port 24. A stepped portion 42 is formed to guide the direction. Similarly, as an example of the guide means, an arcuate surface 43 extending around the axis of the thermostat valve device 14 is formed in a portion of the bottom surface of the cavity 5 that is close to the main water supply port 41. As indicated by a one-dot chain line 44 in FIG. 6, a portion of the hollow portion 5 below the heater return port 24 may also be an arcuate curved surface extending around the axis of the thermostat valve device 14.

  As shown in FIG. 7, a stepped portion 42 is also formed in a portion of the hollow portion 5 where the relief shaft 30 of the thermostat valve device 14 is located. On the other hand, the main water supply port 41 is provided with a downward rib 45 so that only the lower portion thereof serves as a passage at the relief shaft 30 of the thermostat valve device 14. For this reason, the cooling water discharged from the heater return port 24 is guided so as to flow toward the temperature sensing portion 32 without flowing much toward the relief shaft 30. Therefore, the temperature sensing part 32 of the thermostat valve device 14 is intensively exposed to the flow from the heater return port 24 toward the main water supply port 41. For this reason, the responsiveness of the temperature sensing part 32 can be improved significantly. The rib 45 can be said to be an example of the guide means described in the claims.

  As shown in FIGS. 4 and 5, the EGR passage 21 a is disposed below the front portion of the cavity portion 5. As shown in FIGS. 2 and 5, an inner side surface 46 a around the axis of the EGR passage 21 a is disposed on a portion of the bottom surface of the cavity 5 that is closer to the heater return port 24 than the axis of the thermostat valve device 14. The recessed part 46 which has is formed. By forming the recess 46 in this way, the cross-sectional area between the EGR passage 21a and the cavity 5 can be made as small as possible, and the heat dissipation from the EGR passage 21a can be improved. As a result, for example, it may be possible to cool the exhaust gas accurately without the EGR cooler.

(3). Others The present invention can be embodied in various ways other than the above embodiment. For example, the structure of the thermostat valve device is not limited to the illustrated type, and various types can be adopted. Moreover, the specific structure of the cavity can be arbitrarily set. In the embodiment, the cooling water that flows in the circulation path to the heater is adopted as the cooling liquid that operates the thermostat valve device. However, it goes without saying that the cooling water that flows in other flow paths may be used. The flow path controlled by the thermostat valve device can also be selected as necessary.

  The present invention is actually applicable to internal combustion engines such as gasoline engines and diesel engines. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Cylinder block 3 Cylinder head 4a, 4b Cylinder head and cylinder block cooling water passage 5 Cavity 6 Water pump 7 Radiator 11 Heater 14 Thermostat valve device 21, 21a EGR passage 23 Heater feed port 24 Heater return port (working coolant inlet) )
25 Radiator feed port 26 Radiator return port 30 Central shaft 31 Valve body 32 Temperature sensing part 40 Communication port 41 Main water supply port (working coolant outlet)
42 Stepped portion as an example of guide means 43 Arc surface as an example of guide means 45 Arc surface as an example of guide means 46 Recessed portion 46a Inner side surface

Claims (2)

An operating coolant inlet in which a thermostat valve device in which a valve body moves in accordance with the amount of heat received by the temperature sensing portion is disposed in a cavity provided in the cylinder head or the cylinder block, and a coolant for operating the thermostat valve device flows in And the outlet of the operating coolant flowing out from the operating coolant inlet to the outlet of the operating coolant so that the coolant crosses the temperature sensing portion of the thermostat valve device. The flow of the other coolant passage is controlled by movement,
While the thermostat valve device is arranged concentrically with the temperature sensing part and has a central axis with the valve body attached to one end,
The coolant flowing into the cavity from the working coolant inlet is set to change direction around the central axis of the thermostat valve device toward the working coolant outlet. A guide means for guiding the coolant flowing from the coolant inlet to the temperature sensing portion of the thermostat valve device while changing the direction smoothly is formed integrally.
Internal combustion engine. The hollow portion is formed in the cylinder head, and an EGR passage having a circular cross section for returning a part of the exhaust gas to the intake system is provided in the cylinder head so that a part thereof is close to the hollow portion. A recess having an inner surface extending around the axis of the EGR passage is formed in a portion of the inner surface of the cavity portion close to the EGR passage.
The internal combustion engine according to claim 1.

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