JP4356690B2 - Water jacket spacer - Google Patents

Description

  The present invention relates to a water jacket spacer installed in a water jacket of an engine.

  Conventionally, in a cylinder block of a water-cooled engine, a water channel called a water jacket is formed in the outer peripheral portion of the cylinder, and the engine is cooled by cooling water flowing through the water jacket. The water jacket, for example, is adjacent to a cylindrical cylinder so as to surround the outer peripheral side of the cylindrical surface thereof, and extends in the direction of the cylindrical axis, and has a shape capable of cooling substantially the entire outer periphery of the cylinder. As such an engine cooling structure, the one described in Patent Document 1 is known.

  By the way, in a general engine, a crankcase that covers the crankshaft is provided on the lower side of the cylinder block, and an intake valve, an exhaust valve, a spark plug, and the like are installed on a cylinder head that is mounted adjacent to the upper side of the cylinder block. Is done. Focusing on the combustion stroke of the engine, the air-fuel mixture introduced into the cylinder starts to combust on the cylinder head side in the cylinder and expands while pushing the piston down to the crankcase side.

  For this reason, the amount of heat generated by combustion is not uniformly distributed in the cylinder axial direction of the cylinder surface on the cylinder surface, and the upper side (top dead center side) is hotter than the lower side (bottom dead center side). There is a tendency to become. Therefore, even if the cooling capacity (for example, cooling water temperature and flow rate) required for the cooling water flowing in the water jacket is calculated based on the total heat generated in the cylinder, the cooling cylinder is unevenly generated in the cylinder axis direction. There is a possibility that the upper side of the surface cannot be sufficiently cooled and that the lower side of the cylinder surface is overcooled.

For such a problem, for example, a cooling structure as shown in FIG. 6 has been proposed. That is, in a cylinder block 24 of a water-cooled engine provided with a cylinder 26, a water jacket 23 as a cooling water flow path is provided on the outer periphery of the cylinder 26, and the lower side of the water jacket 23 (bottom dead center side, The open-cell type sponge material 21 is inserted into the end of the crankcase side). The open cell sponge material 21 is a porous sponge having pores connected to each other, and functions so as to delay the flow of cooling water on the lower side of the water jacket 23. Thereby, the overcooling of the lower side of the cylinder 26 can be suppressed, and the upper side can be effectively cooled.
JP 2003-262155 A

However, the flow of cooling water is suppressed, so that the amount of heat hardly moves and the lower side of the cylinder 26 is not cooled too much. On the other hand, once the temperature is raised, the heat is hardly cooled. For this reason, for example, when the high load state of the engine continues, a sufficient cooling effect cannot be obtained, and the temperature on the lower side of the cylinder 26 may gradually increase.
As described above, in the conventional cooling structure, uniform cooling performance can be obtained due to the difference in the characteristics of the ease of heating and the ease of cooling (in other words, the heat capacity) between the upper side and the lower side in the water jacket 23. There is a problem that temperature control becomes difficult.

  The present invention has been devised in view of such problems, and provides a water jacket spacer capable of obtaining good cooling performance with a simple configuration and improving durability, output, and fuel consumption. With the goal.

In order to achieve the above object, a water jacket spacer according to the present invention (Claim 1) is installed in a water jacket provided as a cooling water flow path on the outer peripheral portion of a cylinder that reciprocally slides a piston on an inner peripheral surface. A water jacket spacer, which is inserted into an end of the piston at the bottom dead center side inside the water jacket, and a porous member (sponge) through which cooling water can flow, and an inner wall surface of the water jacket It interpolated one end to the porous member with a gap, comprising: a bracket you transfer heat the porous member to the other end side by the heat conduction, and the bracket is in the water jacket A guide member for rectifying the cooling water, and the water jacket is continuously formed so as to surround the outer peripheral portions of the plurality of cylinders; Guide member, the flow of the cooling water from the adjacent side of the partition wall between the plurality of the cylinders in the interior of the water jacket is characterized in that it is oriented in a direction away from the cylinder outer wall.

Here, the porous member functions to suppress supercooling by the cooling water on the bottom dead center side (crankcase side) of the piston. Further, the bracket serves to conduct heat of the porous member the top dead center side (cylinder head side).
The porous member is an open cell type porous material in which adjacent pores are connected to each other, and includes, for example, rubber sponge, synthetic resin sponge, and the like. The bracket is a fixture made of a material having thermal conductivity, and includes, for example, a metal or a thermally conductive ceramic.
The guide member has an orientation in which the gap between the guide member and the cylinder outer wall of the water jacket becomes wider as the distance from the adjacent portion increases.

Further, it is preferable that the other end of the bracket is fixed to the top dead center side end of the piston (that is, the cylinder head side) inside the water jacket. In this case, the bracket has rigidity and strength capable of fixing the porous member .

Further, the guide member is preferably oriented in a direction in which the flow of the cooling water is guided to an adjacent portion (inter-cylinder portion) with the partition wall between the plurality of cylinders inside the water jacket (claims). 3 ). In other words, the guide member has an orientation in which the gap between the guide member and the cylinder outer wall becomes narrower as it approaches the adjacent portion.

  According to the water jacket spacer of the present invention (Claim 1), since the porous member is inserted into the water jacket, the bottom dead center side (lower side) end of the piston in the combustion and expansion strokes of the engine Overcooling can be suppressed. In addition, since the heat inside the porous member is conducted to the cooling water on the upper side by the bracket inserted into the porous member at one end, the excessive temperature rise at the bottom dead center side of the piston is suppressed. it can. Thereby, it becomes easy to make the temperature distribution from the upper side to the lower side substantially uniform on the outer periphery of the cylinder.

In particular, since the bracket is not in contact with the inner wall surface of the water jacket, the transmitted heat of the porous member can be directly transmitted to the cooling water, and the amount of heat can be efficiently dispersed. Thus, good cooling performance can be obtained with a simple configuration, and durability, output, and fuel consumption can be improved.
Moreover, the flow path of the cooling water in the water jacket can be arbitrarily changed and set, and the cooling efficiency can be adjusted according to the arrangement and orientation of the guide members.
Further, by controlling the cooling performance by separating the cooling water from the cylinder outer wall at portions other than the inter-cylinder portion, the temperature distribution between the inter-cylinder portion where heat tends to be trapped and the portion other than the inter-cylinder portion can be made substantially uniform. .
Further, according to the water jacket spacer of the present invention (Claim 2), the position of the bracket can be easily fixed, and the positional displacement of the porous member and the bracket itself within the water jacket can be effectively prevented. can do.

Also, according to the water jacket spacer of the present invention (claim 3), together a plurality of cylinders can raise the cooling performance of the unit between the adjacent heat tends confined to the cylinders. Thereby, the durability of the cylinder block can be improved, and the engine output and fuel consumption can be ensured.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 4 show a water jacket spacer as one embodiment of the present invention, and FIG. 1 is a longitudinal sectional configuration diagram schematically showing the configuration of a cylinder block in which the water jacket spacer is housed. FIG. 3 is a horizontal sectional view of the cylinder block [A-A sectional view of FIG. 1], FIG. 3 is a sectional configuration view of a bracket of the water jacket spacer, and FIG. 4 is a schematic perspective view of the bracket.

[Constitution]
(1) Overall Configuration The water jacket spacer according to the present invention is applied to the water-cooled engine 15 shown in FIG. The engine 15 includes a cylinder block 4 and a cylinder head 5 attached adjacent to the cylinder block 4 and the upper portion thereof. A crankcase (both not shown) for supporting the crankshaft is provided on the lower side of the cylinder block 4.
The cylinder head 5 includes an ignition plug 8, an intake valve 10 interposed on the intake passage 11, and an exhaust valve 12 interposed on the exhaust passage 13, while the cylinder block 4 includes A cylinder bore (cylinder, hereinafter simply referred to as a cylinder) 6 in which the piston 14 reciprocally slides on the inner peripheral surface is formed. The cylinder 6 is a hole formed in a substantially cylindrical shape with its outer periphery surrounded by a cylinder outer wall 7 in a cylindrical shape. Inside the cylinder 6, its upper end and lower end are closed by the cylinder head 5 and the piston 14, respectively, to form a combustion chamber.

  For example, a mixture of fuel and air introduced from the intake passage 11 is ignited and burned by the plug 8 in the combustion chamber in the combustion and expansion strokes of the engine 15, and the piston 14 is moved in the direction toward the crankcase (in FIG. 1). It is downward and is pushed down to the lower side of the cylinder block 4). The combusted air-fuel mixture is pushed up by the piston 14 that moves to the cylinder head 5 side (upward in FIG. 1 and the upper side of the cylinder block 4) due to inertia, and is discharged from the combustion chamber through the exhaust passage 13. It has become so. Although detailed description is omitted here, the piston 14 is connected to the crankshaft via a connecting rod, and the engine 15 converts the reciprocating sliding of the piston 14 in the cylinder 6 into the rotational motion of the crankshaft. A known structure is provided.

In the cylinder block 4, a water jacket 3 as a cooling water flow path for cooling the engine 15 is formed on the outer periphery of the cylinder 6. Here, the water jacket 3 is adjacent to the cylinder 6 so as to surround the outer peripheral side of the cylinder surface, and extends in the direction of the cylindrical axis, so that substantially the entire outer periphery of the cylinder 6 can be cooled. That is, the water jacket 3 is formed as a cavity drilled as a cooling water passage adjacent to the cylinder 6 through the cylinder outer wall 7.
As shown in FIG. 2, the engine 15 has a structure in which three cylinders 6 are arranged in series.

(2) Water Jacket Spacer Configuration The water jacket spacer of the present invention is housed in the water jacket 3. First, as shown in FIG. 1, the sponge 1 is formed as a porous member at the bottom dead center side of the piston 14, that is, at the lower end side (crankcase side) of the cylinder block 4 in the water jacket 3. Has been inserted. The sponge 1 is an open cell material in which pores are connected to each other, and is, for example, an NBR (nitrile rubber) sponge, other rubber sponge, a synthetic resin sponge, or the like. Even if the cooling water tries to pass through the pores inside the sponge 1, the circulation of the cooling water is delayed and the flow of water is slowed down. As a result, the lower side of the water jacket 3 in which the sponge 1 is inserted is given a property that the temperature is less likely to fluctuate (the amount of heat is less likely to move) than the upper side. That is, the sponge 1 functions to suppress overcooling by the cooling water on the lower side of the cylinder block 4.

  In addition, a bracket 2 is provided inside the water jacket 3 with one end 2a inserted into the sponge 1 with a predetermined gap with respect to the inner wall surface 3a of the water jacket 3. That is, the bracket 2 is disposed so that its plate surface is substantially parallel along the inner wall surface 3a (note that the bracket 2 is curved in an arc shape following the cylindrical surface shape of the inner wall surface 3a as shown in FIG. 4). And is not in contact with the inner wall surface 3a.

  The bracket 2 is a plate-shaped fixture made of a material having thermal conductivity, and is made of, for example, metal or thermal conductive ceramics. The other end 2 b of the bracket 2 is immersed in cooling water and is fixed to the upper end of the water jacket 3 via a fixing member 9. Thereby, the position of the bracket 2 can be easily fixed, and the positional deviation of the sponge 1 and the positional deviation of the bracket 2 itself in the water jacket 3 can be effectively prevented.

In the present embodiment, as shown in FIG. 1, a plate-like sponge 1 is inserted and fixed to the lower side of the water jacket 3 in a state where the sponge 1 is folded at the tip of the one end 2 a of the bracket 2.
As shown in FIG. 2, the water jacket 3 is continuously formed so as to surround the outer periphery of the three cylinders 6 arranged side by side. The cylinder outer wall 7 surrounding the outer periphery of each cylinder 6 is integrally formed by joining together. Hereinafter, of the cylinder outer wall 7, a wall body whose both wall surfaces face the cylinder 6 is referred to as a partition wall 7 a between the cylinders 6, and only one wall surface faces the cylinder 6 cylinder (that is, The wall body (the other surface constitutes the inner peripheral surface of the water jacket 3) is referred to as a side wall 7b.
In FIG. 2, the flow direction of the cooling water in the water jacket 3 is a direction from the lower part to the upper part in FIG. 2, and the bracket 2 moves each cylinder 6 from the left and right sides in FIG. They are arranged symmetrically in pairs so as to sandwich them.

(3) Guide Member Configuration As shown in FIG. 2, the bracket 2 is provided with two types of guide members 2 c and 2 d for rectifying cooling water flowing through the water jacket 3. As shown in FIG. 4, these guide members 2c and 2d are cut so as to form three rectangular sides with respect to the plate-like bracket 2, and the cut portions are slightly inclined with respect to the plate surface. It has a bent shape.

  As shown in FIG. 2, one guide member 2c is disposed upstream of the inter-cylinder part (adjacent part to the partition wall 7a) 3b in the water jacket 3, and as shown in FIG. Is oriented in such a direction as to guide the flow to the inter-cylinder portion 3b. That is, the guide member 2c has an orientation in which the gap between the guide member 2c and the side wall 7b becomes narrower as it approaches the inter-cylinder portion 3b.

Further, as shown in FIG. 2, the other guide member 2d is disposed on the downstream side of the inter-cylinder part 3b inside the water jacket 3, and as shown in FIG. 3, the cooling water from the inter-cylinder part 3b. Is oriented in a direction away from (isolating) the flow of the liquid from the side wall 7b. That is, the guide member 2c has an orientation that becomes wider as the distance from the inter-cylinder portion 3b increases.
In FIG. 2, the guide members 2c and 2d are oriented so that the pair of brackets 2 sandwiching each cylinder 6 from the left and right are symmetrical with each other including the guide members 2c and 2d. These guide members 2c and 2d are formed only on the substantially upper half side of the bracket 2 as shown in FIG. This is because the bracket 2 is fixed in the water jacket 3 with only the substantially upper half side immersed in the cooling water, as shown in FIG.

[Action]
The water jacket spacer is configured as described above and operates as follows.
(1) During normal operation of the engine The engine 15 has a spark plug 8 on its upper side, and acts to push the piston 14 downward in the combustion and expansion strokes. For this reason, the upper side of the cylinder outer wall 7 is given a characteristic that it tends to be hotter than the lower side.

On the other hand, the sponge 1 is inserted into the lower side of the water jacket 3, and the temperature of the lower side of the water jacket 3 into which the sponge 1 is inserted is less likely to fluctuate than the upper side (the amount of heat is less likely to move). Nature is given.
For this reason, the upper side of the water jacket 3 where the temperature rises relatively quickly is effectively cooled by the cooling water, while the lower side of the water jacket 3 where the temperature is relatively difficult to rise is more excessive. Cooling is performed gently without being cooled. That is, overcooling on the lower side is suppressed without impairing the cooling effect on the upper side of the water jacket 3.

(2) During high-load operation of the engine Since the amount of heat hardly moves on the lower side of the water jacket 3, when the high-load operation of the engine 15 continues, the temperature of the sponge 1 gradually increases. . On the other hand, since one end 2a of the bracket 2 having thermal conductivity is inserted into the sponge 1, the heat of the sponge 1 is transmitted to the upper side through the bracket 2 by thermal conduction. Here, since the bracket 2 is not in contact with the inner peripheral surface 3a of the water jacket 3, and the other end 2b of the bracket 2 is immersed in the cooling water, the conduction heat is directly transmitted to the cooling water and diffused. The In addition, since the bracket 2 is not in contact with the inner peripheral surface 3a of the water jacket 3, in the state (1), the amount of heat on the lower side of the water jacket 3 is prevented from escaping to the inner wall surface 3a via the bracket 2. This can further suppress the subcooling on the lower side.

(3) Action by the guide member Since the flow of the cooling water is guided to the inter-cylinder part 3b by the guide member 2c on the upper side of the water jacket 3, the low-temperature cooling water is sufficiently supplied to the inter-cylinder part 3b. . That is, the flow of the cooling water flowing outside the bracket 2 is directed toward the inside of the bracket 2 along the surface of the guide member 2c.

  Further, since the inter-cylinder portion 3b is more likely to accumulate heat than the side wall 7b other than the inter-cylinder portion 3b, the flow of cooling water is directed to the outside of the bracket 2 by the guide member 2d. Thereby, the flow rate of the cooling water inside the bracket 2 (the portion sandwiched between the side wall 7b and the bracket 2) is reduced, and the heat radiation amount is suppressed. Therefore, uneven temperature distribution between the inter-cylinder portion 3b and the vicinity of the side wall 7a is suppressed.

[effect]
The present water jacket spacer has the following effects.
(1) During normal operation of the engine Cooling suitable for each of the upper and lower portions of the water jacket 3 is performed, so that cooling unevenness does not occur on the outer periphery of the cylinder 6 and it is easy to make the temperature distribution substantially uniform. It becomes.

(2) During high-load operation of the engine Since the heat of the sponge 1 is directly transferred to the cooling water via the bracket 2, the amount of heat can be efficiently dispersed. Thereby, even if the high load operation of the engine 15 is continued, the cooling capacity on the lower side of the water jacket 3 is not insufficient, and the excessive temperature rise can be suppressed. Thus, a favorable cooling performance can be obtained by a simple configuration including the sponge 1 and the bracket 2, and the durability, output, and fuel consumption of the engine 15 can be improved.

  In addition, as described above, in the conventional cooling structure, it is difficult to obtain uniform cooling performance due to the difference in the characteristics of easiness of heating and cooling between the upper side and the lower side in the water jacket 23. According to this, it is possible to easily cool the characteristics on the lower side. Therefore, there is an advantage that uniform cooling performance is easily obtained and temperature control is easy.

(3) Effect by the guide member Since the low-temperature cooling water is sufficiently supplied to the inter-cylinder portion 3b that tends to be relatively high in the water jacket 3, the heat generated from the cylinder can be effectively cooled, Cooling performance can be increased. In addition, it is possible to increase the cooling performance in the inter-cylinder part where heat is easily trapped, and to suppress the uneven temperature distribution between the inter-cylinder part 3b and the side wall 7b, thus ensuring durability, output and fuel consumption. can do.

(4) Other effects In addition, in the water jacket 3, since the lower end part of the bracket 2 is fixed to the end part on the top dead center side of the piston 14, the positional deviation of the sponge 1 and the positional deviation of the bracket 2 itself are prevented. It can be effectively prevented.
Further, since two types of guide members 2c and 2d are provided on the surface of the bracket 2, the flow path of the cooling water in the water jacket 3 can be arbitrarily changed and set. Thereby, as above-mentioned, cooling efficiency can be adjusted according to arrangement | positioning and orientation of the guide members 2c and 2d.

[Others]
Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the guide members 2c and 2d are provided on the bracket 2. However, the guide member is not an essential component and may be appropriately provided according to the shape of the water jacket 3 and the required cooling performance. Good. Further, the shape, orientation, mounting position, and quantity of the guide member are also arbitrary. By providing the guide member according to these various conditions, the flow path of the cooling water can be arbitrarily changed and set, and the cooling efficiency can be adjusted. It should be noted that the bracket 2 does not have to be arranged symmetrically so as to sandwich each cylinder 6 as in the above embodiment.

  In the above-described embodiment, the engine 15 including the three cylinders 6 is applied with the water jacket spacer of the present invention. However, the applicable types of the engine 15 are not limited thereto. In the above-described embodiment, the water jacket 3 is a so-called open deck jacket formed continuously so as to surround the outer peripheral portions of a plurality of cylinders. However, the present invention can also be applied to a closed jacket. .

Moreover, in the above-mentioned embodiment, although the bracket 2 has comprised plate shape, the shape is arbitrary if it has the function to transmit the heat | fever of sponge 1 to an upper side.
Further, in the above-described embodiment, the cooling water is formed to flow on both sides of the cylinder outer wall 7 from one end of the cylinder block 4 to the other end in a plan view (a top view as shown in FIG. 2). Although the case of the water jacket 3 has been described in detail, a cooling water flow path different from this may be considered.

  For example, as shown in FIG. 5, a coolant flow path that flows from one end side of the cylinder block 4 to one side surface of the cylinder 6 is folded back at the other end side of the cylinder block 4, and the other side surface of the cylinder 6 is circulated. Even in the water jacket 3 formed so as to make a U-turn to one end portion of the cylinder 4 (that is, in which the cooling water circulates around the cylinder block 4), the same effect as the above-described embodiment can be obtained. Can do. In this case, as shown in FIG. 5, all the guide members 2 have the same shape (in FIG. 5, a shape that coincides with a 180 ° rotation).

It is a longitudinal section lineblock diagram showing typically the composition of the cylinder block as one embodiment of the present invention. FIG. 2 is a horizontal cross-sectional view (cross-sectional view taken along the line AA in FIG. 1) of the cylinder block. It is a section lineblock diagram of a bracket concerning this cylinder block. It is a typical perspective view of the bracket concerning this cylinder block. It is a horizontal sectional view of the cylinder block of another embodiment concerning the present invention. It is a longitudinal cross-sectional view which shows the structural example of the conventional cylinder block.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sponge 2 Bracket 2a One end part 2b Other end part 2c, 2d Guide member 3 Water jacket 3a Inner wall surface 3b Inter-cylinder part 4 Cylinder block 5 Cylinder head 6 Cylinder (cylinder, cylinder bore)
7 Cylinder outer wall 7a Bulkhead 7b Side wall 8 Spark plug 9 Fixing member 14 Piston 15 Engine

Claims (3)

A water jacket spacer provided in a water jacket provided as a cooling water flow path on the outer periphery of a cylinder that reciprocally slides the piston on the inner peripheral surface,
Inside the water jacket, a porous member inserted into the end of the bottom dead center side of the piston and capable of circulating cooling water;
With a gap to the inner wall surface of the water jacket interpolated one end to the porous member comprises a bracket you transfer heat the porous member to the other end side by the heat conduction, and
The bracket has a guide member that rectifies the cooling water in the water jacket,
The water jacket is continuously formed so as to surround the outer peripheral portions of the plurality of cylinders,
The guide member is oriented so that the flow of the cooling water from the side adjacent to the partition between the plurality of cylinders is separated from the outer wall of the cylinder inside the water jacket. A featured water jacket spacer. 2. The water jacket spacer according to claim 1, wherein the other end of the bracket is fixed to an end of the piston at the top dead center side in the water jacket. The guide member is characterized in that it is oriented in the direction of the adjacent portion of the partition wall between the plurality of the cylinder directing the flow of the cooling water inside of the water jacket, according to claim 1 or 2, wherein Water jacket spacer.

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