JP2004225582A - Engine cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine cooling structure for restraining an excessive rise in a contact fire surface temperature of a combustion chamber opposed part opposed to inter-port clearance by making cooling water flow to the inter-port clearance of intake-exhaust ports. <P>SOLUTION: Intake-exhaust valves are arranged by sandwiching the cylinder head center line LO, and at least one of the intake-exhaust valves is juxtaposed by two in the axial direction X to one cylinder. A cooling water passage is provided for making the cooling water flow in the axial direction X. A cylinder head has a port wall part for forming the intake-exhaust ports 22 and 23 for communicating a combustion chamber C with the cylinder head outside via at least one valve of the intake-exhaust valves. The cooling water passage has a central waterway r1 for making the cooling water flow to the other end side from the axial directional one end side, intake-exhaust side waterways r2 and r3 and a sucking-out passage rs passing between the two valves, and a projecting part 27 is formed from an axial directional other end side wall surface in the port wall part positioned on the axial directional one end side among the port wall part. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
[Industrial application fields]
The present invention relates to an engine cooling device, and more particularly to a cooling device having a cooling water passage formed in an axial direction in a cylinder head of a water-cooled engine.
[0002]
[Prior art]
In a conventional cooling device for a water-cooled internal combustion engine, a water jacket is formed in a cylinder block or a cylinder head which is an engine body, and cooling water is circulated in the water jacket using a water pump. Cooling water is cooled by installing a radiator in an external circulation path connecting between the water outlet and the cooling water inlet.
[0003]
By the way, the cylinder head forming a part of the engine main body closes the upper opening of the cylinder liner on the cylinder block side so that the combustion chamber is formed. It is necessary to cool this part effectively. Therefore, the water jacket on the cylinder head side is disposed so as to face the combustion chamber facing portion, and the combustion chamber facing portion is positively cooled with cooling water.
[0004]
In particular, the spark plug mounting boss, the intake / exhaust valve seat, and the intake / exhaust port extending from it are integrally cast on the opposite part of the combustion chamber. A water jacket is formed, and the shape of the water jacket, which is the flow path of the cooling water, has a relatively complicated shape.
[0005]
For example, in the case of an in-line multiple cylinder cylinder head, intake / exhaust ports are sequentially arranged along the axial direction, and an ignition plug mounting cylindrical portion is provided in the middle of the intake / exhaust ports. A large number of projecting members are provided on the road to restrict the flow of the cooling water.
In particular, as shown in FIG. 6, if the valve operating system of one cylinder is an intake 2 valve exhaust 2 valve type, a pair of intake ports 110 and exhaust ports 120 are arranged along the axial direction X in the cylinder head. Arranged in parallel, a spark plug mounting cylinder 130 is disposed in the center of the four intake and exhaust ports 110 and 120.
[0006]
In the case of such a layout, the water jacket 140 provided so as to avoid interference with the protruding members is located below the central flow path n1 extending in series in the axial direction X and the intake / exhaust port at the center of the cylinder head. It comprises an intake / exhaust flow path n2. Here, the central flow path n1 can flow in the axial direction X while ensuring a relatively large amount of cooling water, although the mounting tube portion 130 for the spark plug protrudes. Furthermore, the suction / discharge side flow channel n2 located on the left and right sides of the central flow channel n1 has a relatively narrow flow channel cross section, but, like the central flow channel, extends substantially in series in the axial direction X. It is possible to flow in the axial direction X by securing a predetermined amount of flow.
[0007]
On the other hand, the central flow path n1 and the intake / exhaust flow path n2 are communicated with the gap 160 between the ports of the air supply port 110 and the exhaust port 120 arranged in parallel in a pair along the axial direction X. The cooling water flowing through the intake / exhaust side n2 is joined to the central flow path n1 through the gap 160 between the ports. However, if the flow of the cooling water in the central flow path n1 is strong, the flow of the cooling water in the central flow path n1 affects the flow of the cooling water in the communication path so that the gap 160 between the ports is not affected. Cooling water stays and cooling between ports cannot be performed well.
[0008]
Therefore, in order to eliminate the retention of the cooling water between the ports, for example, a sufficient flow rate of the cooling water in the water jacket of the cylinder head is ensured, or the contact surface temperature of the portion between the ports in the combustion chamber facing portion is reduced. In order to suppress the rise, the longitudinal flow in the axial direction of the cylinder head is enhanced.
[0009]
Incidentally, Japanese Utility Model Publication No. 7-34197 (Patent Document 1) discloses a forced air cooling type cylinder head, in which cooling air from a cooling air inlet side passage is formed to protrude upstream of an exhaust port. A structure is disclosed in which the cooling air is divided into left and right portions and the cooling air is surely flowed down to the left and right cooling air outlet side passages to prevent heating of the exhaust port and the liquid cooling chamber in the vicinity thereof.
[0010]
[Patent Document 1]
Japanese Utility Model Publication No. 7-34197 [0011]
[Problems to be solved by the invention]
As described above, the combustion chamber facing portion of the lower wall of the cylinder head tends to be heated, and among these, the cooling water stays in the downstream portion of the intake / exhaust port in the flow direction of the cooling water, in particular, between the port gaps. The tendency to do is high. Conventionally, in order to eliminate the retention of the cooling water, the longitudinal flow in the axial direction of the cylinder head has been strengthened. However, a sufficient retention preventing function cannot be obtained, and the pump discharge amount may be increased. Furthermore, as disclosed in Patent Document 1, when measures such as branching the cooling medium to the cooling target portion side and making it flow in are taken, the flow rate of the main flow channel that originally maintained a sufficient flow rate is reduced. In this case, there are the following problems.
[0012]
That is, a spark plug cylinder or the like protrudes on the main flow path, and its boss portion is easily heated to a comparatively high temperature, and the central facing wall side of the valve seat of the intake / exhaust valve is located in the vicinity of the boss portion. For this reason, it is necessary to sufficiently cool the contact surface temperature of these parts so as to eliminate the difference between the cylinders, and there is a demand that it is not preferable to reduce the amount of cooling water in the main flow path.
[0013]
The present invention has been made on the basis of the above problems, and allows cooling water to flow between the port gaps of the intake and exhaust ports without reducing the flow rate of the main flow path in the water jacket of the cylinder head. It is an object of the present invention to provide a cooling structure for an engine that prevents an excessive increase in the temperature of the contact surface of the combustion chamber facing portion facing the cylinder.
[0014]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention of claim 1 is characterized in that an intake valve is disposed on one side and an exhaust valve is disposed on the other side with an axis parallel to the crankshaft interposed therebetween, and the intake air is applied to one cylinder. An engine having at least one of a valve and two exhaust valves arranged in parallel in the axial direction, the engine having a cooling water passage that is formed in a cylinder head of the engine and distributes cooling water in the axial direction. In the cooling structure, the cylinder head has a port wall portion that forms a port that communicates between the combustion chamber and the outside of the cylinder head via the at least one valve, and the cooling water channel is formed on the axis line with the cooling water. A first water channel that circulates from one end side to the other end side in the axial direction, a second water channel that circulates the cooling water from one end side to the other end side in the axial direction below the port wall, and the few A port located on one end side in the axial direction of the port wall portion, having a communication passage that connects the first water passage and the second water passage through two valves constituting one of the valves. The wall portion is characterized in that a protruding portion is formed on the wall surface on the other end side in the axial direction so as to protrude toward the other end side in the axial direction.
[0015]
As described above, at least one of the intake valve or the exhaust valve, that is, the intake / exhaust port is arranged in parallel in the axial direction, and the cooling water is circulated in the axial direction, and upstream of at least one of the intake / exhaust ports. Since the projecting portion projects from the port wall portion on the side toward the wall surface of the other downstream port wall portion, a part of the cooling water flowing through the first water channel flows into the gap between the ports. The cooling water in the gap between the wall surface of the downstream port wall portion and the tip end portion of the protruding portion is suppressed from affecting the flow of the cooling water of the cooling water flowing in the axial direction in the first water channel. The suction action due to the flow velocity causes the suction flow to the first water channel side, the flow of cooling water can be generated between the port gaps, and the cooling between the ports, that is, between the valve gaps, can be surely promoted. There will be no major fluctuations in the flow rate on the side.
[0016]
According to a second aspect of the present invention, there is provided a cooling structure for an engine, wherein the cylinder head according to the first aspect is formed with a central wall portion for disposing an ignition plug or a fuel injection valve at a center portion of the cylinder, The axial side surface is formed so as to follow the shape of the central wall portion.
As described above, the axial side surface, which is the opposing wall surface of the protrusion, is formed along the shape of the central wall portion with respect to the central wall portion of the cylinder central portion, so that the flow of cooling water in the first water channel is greatly affected. Is not given.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The engine cooling apparatus shown in FIGS. 1 to 4 is mounted on an engine 1 of a vehicle (not shown) and performs forced water cooling on the engine body. In this engine 1, a cylinder head 3 and an oil pan 4 are integrally coupled to the upper and lower sides of a cylinder block 2 to constitute an engine body, a radiator 5 is disposed in front of the engine body, and a water pump 8 is integrally formed with the cylinder block 2. Install.
As shown in FIGS. 3 and 4, the cylinder block 2 has four cylinder liners 11 arranged in series in the longitudinal direction of the cylinder block 2 in a state where the axis Ls is vertically oriented.
[0018]
The cylinder block 2 is provided with a crankshaft (not shown) in the lower part thereof. 1 and 2 disclose an axis L0 parallel to the crankshaft (not shown) together with the cylinder head 3 above the cylinder block 2.
In a plan view of the cylinder head 3, a pair of intake ports 22 that are opened and closed by an intake valve (not shown) are disposed on one side (upper side in FIGS. 1 and 2) across an axis L 0 parallel to the crankshaft, and the other ( An exhaust port 23 that is opened and closed by an exhaust valve (not shown) is disposed on the lower side in FIGS.
[0019]
The cylinder block 2 forms a cylinder block side water jacket 12 (hereinafter simply referred to as a lower jacket) between the outer wall 9 and the four cylinder liners 11 in an annular shape. A plurality of cooling water introduction holes 14 are formed in the upper wall 13 of the lower jacket 12, and a discharge port 15 is formed in the outer wall 9 on the front end side. In some cases, the upper wall 13 may not be formed in the cylinder block 2, and the cooling water introduction hole 14 may be arranged by the gasket 16.
[0020]
The lower jacket 12 is connected to the cooling water circuit A. The discharge port 15 communicates with the radiator 5 through the lower pipe 7.
As shown in FIG. 3, the cylinder head 3 has a lower wall 17 that is overlapped with an upper wall 13 of the cylinder block 2 via a gasket 16, an annular outer wall 18 that extends vertically from the peripheral edge thereof, and an outer wall 18. And an upper head wall 19 integrally coupled to the upper end side of the head. The lower wall 17 of the cylinder head 3 is formed with a combustion chamber facing portion B facing the combustion chamber C facing each cylinder liner 11 on the cylinder block 2 side so as to protrude upward.
[0021]
A cylinder head-side water jacket 21 (hereinafter simply referred to as an upper jacket) is formed on the lower wall 17 of the cylinder head 3 without interfering with a valve system and ignition system members (not shown). It is connected to the water circuit A.
As shown in FIG. 2, the lower wall 17 of the cylinder head 3 sequentially arranges combustion chamber facing portions B facing the cylinder liners 11 in the axial direction X that is the direction of the axis L0 parallel to the crankshaft. .
[0022]
A base end side of each pair of intake port 22 and exhaust port 23 is integrally attached to each combustion chamber facing portion B, and a cylinder for fitting a spark plug (not shown) at the center of the cylinder at the center thereof. A central wall portion 24 to which the member 26 is fitted is formed.
Here, as shown in FIG. 3, annular valve seats 221 and 231 are formed on the inner lower surfaces of the base ends of the intake and exhaust ports 22 and 23. A downward surface in the vicinity of the seats 221 and 231 forms a flaming surface f. Each intake / exhaust port 22, 23 is formed by a substantially cylindrical port wall portion, and the port wall portion is curved and formed so that its extended end is integrally coupled to the outer wall 18, and the outside of the connecting portion An intake / exhaust manifold (not shown) is connected to. Here, the curved port wall portions are provided with intake and exhaust side water channels r2 and r3 as second water channels, which will be described later, below the downward surface df below the port wall.
[0023]
Further, as shown in FIG. 3, a jacket upper wall 20 is provided at a predetermined amount above the combustion chamber facing portion B, and the jacket upper wall 20 is provided with intake and exhaust ports 22 and 23 and a center wall portion 24. It is cast so as to be integrally coupled with each other at the contact portion.
For this reason, an upper jacket 21 is formed between the lower wall 17 of the cylinder head and the jacket upper wall 20, and a valve system or ignition plug (not shown) is formed in the space between the jacket upper wall 20 and the head upper wall 19. The upper part of the cylinder member 26 is accommodated.
[0024]
Here, the upper jacket 21 between the lower wall 17 of the cylinder head 3 and the jacket upper wall 20 faces the central water channel r1 and its left and right end sides in the axial direction X, which is the direction of the axis L0 parallel to the crankshaft. The intake / exhaust water channels r2, r3 are formed in parallel.
Among these, the central water channel r1 of the upper jacket 21 is a water channel through which cooling water flows down along the central part of the combustion chamber facing part B, the central side wall part of the intake / exhaust port, and the central wall part 24. The flow resistance is small, a relatively large flow rate can be secured, and a large cooling water speed can be secured.
[0025]
The intake and exhaust side water channels r2 and r3 are water channels that sequentially flow cooling water along the side of the combustion chamber facing part B, the downward surface df of the intake and exhaust ports 22 and 23, and the vertical outer wall 18. Although the target channel cross-sectional area is small, a relatively large cooling water speed can be secured.
As shown in FIG. 1, the intake / exhaust ports 22 and 23 are respectively arranged in parallel in the upper jacket 21 along the upstream side and the downstream side along the axial direction X of the central water channel r <b> 1 whose central side wall portion is the axial direction X. Are deployed sequentially.
[0026]
Here, the upstream exhaust port 23u and the downstream exhaust port 23d have a gap e between the opposing wall surfaces, and the gap e communicates with the central water channel r1 and the exhaust side channel r3. Similarly, the upstream intake port 22u and the downstream intake port 22d have a gap e between the opposing wall surfaces, and the gap e communicates with the central water channel r1 and the intake side flow channel r2.
Here, in the vicinity of the central side wall portions of the upstream exhaust port 23u and the upstream intake port 22u, the projecting portions 27 are formed in the axial direction X toward the wall surface of the other end side port (downstream exhaust port 22d, downstream exhaust port 23d). Protrusions are formed.
[0027]
Each projecting portion 27 is a vertically-facing piece that ensures a relatively thick state at the joint with the upstream side wall and each central side wall portion of the intake ports 23u, 22u, and thins the thickness toward the projecting end. It is formed. In particular, each tip portion is formed so as to face each central side wall portion of the downstream exhaust port 23d and the downstream intake port 22d with a predetermined width, and a suction port m is formed in the same portion.
[0028]
Here, each protrusion 27 of the upstream exhaust port 23u and the upstream intake port 22u is formed such that a central vertical surface fa which is a side surface of each axial line is formed along the flow line of the cooling water in the central water channel r1, and each vertical clearance surface fb. Is formed in a shape along each opposing wall surface f1 of the downstream exhaust port 23d or the downstream intake port 22d.
Here, the central vertical surface fa which is the axial side surface of each protrusion 27 is formed along the streamline of the central water channel r1 and along the shape of the central wall 24 of the combustion chamber facing portion B. By providing the flow resistance to the cooling water passing through this portion by the portion, it is possible to reliably prevent the flow rate from being greatly affected.
[0029]
Further, each gap vertical surface fb of each protrusion 27 is formed in a shape along the opposing wall surfaces of the downstream exhaust port 23d or the downstream intake port 22d with a predetermined interval. Here, each gap vertical surface fb takes the shape of a suction path rs that can easily guide the cooling water of the intake side flow path r2 and the exhaust side flow path r3 to the suction port m.
Here, each suction port m faces the central water channel r1, and is formed so as to keep an acute angle with respect to the flow line of the cooling water. For this reason, when cooling water having a flow rate of a predetermined amount or more flows in the central water channel r1, the cooling water in the suction channel rs is sucked out from the suction port m into the cooling water flow in the central water channel r1, and the jet pump function can be exhibited.
[0030]
The operation of the engine cooling apparatus having such a configuration will be described.
When the engine 1 is driven, the water pump 8 is driven, and the cooling water sucked from the main pipe 34 is discharged to the upper jacket 21.
In this case, when the engine 1 is in a cold state, the thermostat 10 on the outlet side of the upper jacket 21 closes the first inlet 31 on the radiator side, opens the second inlet 32 on the upper jacket 21 side, and cools the cooling water of the upper jacket 21. Through the outlet 33, the main pipe 34, the water pump 8 and the warming-up cycle R1 to promote warming-up.
[0031]
When the temperature of the cooling water reaches a predetermined high temperature range, the thermostat 10 closes the second inlet 32, opens the first inlet 31, and causes the cooling water on the radiator side to flow through the main pipe 34.
That is, when the temperature of the cooling water is within a predetermined high temperature range, the cooling water in the upper jacket 21 flows into the lower jacket 12 around the cylinder row through the plurality of cooling water introduction holes 14, and after cooling the cylinder row, the outer wall 9. Reaches the discharge port 15. The cooling water at the discharge port 15 flows through the lower pipe 7 and the radiator 5 to the second inlet 31, the main pipe 34, and the water pump 8 of the thermostat 10, and the cooling water flows along the cooling cycle R2.
[0032]
Thus, when the cooling water flows in the upper and lower jackets 21 and 12 of the engine 1, in particular, the cooling water always flows in the axial direction X in the upper jacket 21, that is, the central water channel r1 and the intake and exhaust side water channels r2 and r3. The cooling water flows along.
[0033]
Projections 27 are formed in the upstream exhaust ports 23u and the upstream intake ports 22u among the plurality of supply / exhaust ports arranged in the upper jacket 21, thereby forming the suction port m and the suction path rs. ing. For this reason, when the cooling water flows in the central water channel r1 in the axial direction with a predetermined flow rate, the suction port m works to suck the action of the jet pump, thereby cooling the intake side flow path r2 and the exhaust side flow path r3. Water can be sucked out from the suction path rs between the ports through the suction port m to the central water channel r1 side which is a main flow path, and a flow of cooling water can be generated between the port gaps. Further, the protruding portion 27 can prevent a part of the cooling water flowing through the central water channel r1 from flowing into the gap between the ports, and the cooling water flowing through the central water channel r1 can flow into the cooling water in the suction channel rs. There is no adverse effect. At this time, the heat generated on the contact surface f in the vicinity of the annular valve seats 221 and 231 to which the respective intake and exhaust valves (not shown) contact and separate can be reliably cooled by the cooling water flowing through the suction passage rs, The cooling between the valve gaps can be surely promoted, and the reliability and the anti-knock property can be improved. At this time, the flow rate on the central water channel r1 side, which is the main channel, does not change greatly.
[0034]
In the above description, the central wall portion 24 for the spark plug is formed in the center of the combustion chamber facing portion B. Instead, the central wall portion for the fuel injection valve is formed. In this case, the same effect as the engine cooling structure of FIG. 1 can be obtained.
As described above, in the engine cooling structure of FIG. 1, the plurality of upstream exhaust ports 23u and upstream intake ports 22u provided in the upper jacket 21 are formed with protrusions 27. The protrusion 27 may be provided only on the upstream exhaust port 23u side where the surface temperature is particularly likely to rise, thereby simplifying the configuration.
[0035]
【The invention's effect】
As described above, the invention of claim 1 is the one in which at least one of the intake valve or the exhaust valve, that is, the intake / exhaust port is arranged in parallel in the axial direction, and the cooling water is circulated in the axial direction. Since the projecting portion protrudes from the port wall portion on the upstream side of at least one of the intake and exhaust ports toward the wall surface of the port wall portion on the other downstream side, the wall surface and the projecting portion of the downstream port wall portion are formed. Cooling water in the gap with the tip is sucked by the flow rate of cooling water flowing in the axial direction through the main flow path between the intake and exhaust valves, flows into the main flow path, and flows between the port gaps. The flow between the ports, that is, between the valve gaps can be surely promoted, and at this time, the flow rate of the main flow path does not change greatly.
[0036]
According to the second aspect of the present invention, the axial side surface, which is the opposing wall surface of the projecting portion, is formed along the shape of the central wall portion with respect to the central wall portion of the cylinder central portion. There is no impact.
[Brief description of the drawings]
FIG. 1 is a cutaway plan view of a main part in a state where an upper jacket wall is removed from an engine cylinder head to which an engine cooling structure according to an embodiment of the present invention is applied.
2 is an overall plan view of the cylinder head in a state where a jacket upper wall is excluded from the cylinder head of FIG. 1. FIG.
FIG. 3 is a cutaway cross-sectional view of a main part of the cylinder head and cylinder block of FIG. 1;
4 is an overall schematic side view of an engine including the cylinder head of FIG. 1;
5 is a perspective view of the cylinder head of FIG. 1 with the upper jacket wall removed, (a) is a schematic cutaway perspective view of the main part from the upstream side of the flow path, and (b) is from the downstream side of the flow path. It is a principal part notch schematic perspective view.
FIG. 6 is a cutaway plan view of a main part in a state in which a jacket upper wall is excluded from a cylinder head having a conventional engine cooling structure.
[Explanation of symbols]
1 Engine 3 Cylinder Head 20 Jacket Upper Wall 21 Upper Jacket 22 Intake Port 23 Exhaust Port 27 Projection L0 Center Line (Axis Parallel to Crankshaft)
X axis direction (crank axis direction)
c Combustion chamber m Suction port r1 Central waterway (first waterway)
r2, r3 Intake / exhaust water channel (second water channel)
rs Suction path (communication path)

Claims (2)

An intake valve is disposed on one side and an exhaust valve is disposed on the other side of an axis parallel to the crankshaft, and at least one of the intake valve or the exhaust valve is aligned in the axial direction with respect to one cylinder. An engine to be installed,
In the engine cooling structure having a cooling water passage formed in the cylinder head of the engine and circulating the cooling water in the axial direction,
The cylinder head has a port wall portion that forms a port for communicating the combustion chamber and the outside of the cylinder head through the at least one valve.
The cooling water channel includes a first water channel that circulates the cooling water from one axial end side to the other end side on the axial line, and the cooling water from the one axial end side to the other end side below the port wall portion. A second water channel that circulates to and a communication passage that communicates between the first water channel and the second water channel through two valves constituting the at least one valve,
The port wall portion located on the one axial end side of the port wall portion is formed with a protruding portion formed on the wall surface on the other axial end side so as to project toward the other axial end side. An engine cooling structure characterized by that. The cylinder head is formed with a central wall portion for disposing an ignition plug or a fuel injection valve at the center of the cylinder.
The engine cooling structure according to claim 1, wherein the axial side surface of the projecting portion is formed along the shape of the central wall portion.

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