JP2745872B2 - Internal combustion engine cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for an internal combustion engine, and more particularly to a cooling device for cooling an internal combustion engine by providing an annular groove around an outer periphery of a cylinder liner to flow a refrigerant.

[0002]

2. Description of the Related Art A cylinder block in which several cylinders are arranged, and a cylinder head located on the upper surface of the cylinder block and having a depression on the lower surface form a combustion chamber of an internal combustion engine. Further, an outer peripheral surface of the cylinder liner is fitted to an inner peripheral surface of the bore of the cylinder block. Therefore, high-temperature heat generated in the combustion chamber by the operation of the engine is transmitted to the cylinder liner and the like through the cylinder block and the cylinder head.

In order to cool the wall surface of the cylinder liner and prevent the refrigerant from boiling, a refrigerant passage is formed between the inner peripheral surface of the bore of the cylinder block and the outer peripheral surface of the cylinder liner. 2. Description of the Related Art A cooling device for an internal combustion engine by so-called groove cooling in which air flows is conventionally known (for example, Japanese Utility Model Application Laid-Open No. 63-168242).
No.).

FIG. 5 shows a structural diagram of an example of the above-mentioned conventional cooling device for an internal combustion engine, wherein FIG. 5A is a plan view and FIG.
Shows a vertical cross-sectional view along the line BB in FIG. FIG.
(A), (B), the the outer circumferential surface of the cylinder liner 2 is fitted to the cylinder block 1 is for example 3 ₁ to 3 ₄
As shown in the figure, four annular grooves having a rectangular cross section are formed in the axial direction of the cylinder liner 2. The annular groove 3 ₁ to 3 ₄ when fitted to the cylinder liner 2 into the bore portion of the cylinder block 1, to form a refrigerant passage of an annular between the inner circumferential surface 4 of the bore portion.

The plurality of annular grooves 3 _{1 to} 3 are positioned at positions where the cylinder liner 2 and the cylinder block 1 face each other and in the axial direction (longitudinal direction) of the cylinder liner 2.
Vertical grooves 5 and 6 communicating between the _four are formed. Also,
At the position of the cylinder block 1 closest to the cylinder head, a refrigerant inlet 7 communicating with the vertical groove 5 is formed, and a refrigerant outlet 8 communicating with the vertical groove 6 is formed.

[0006] Further, it is generated in the combustion chamber, and the cylinder liner 2
The heat transmitted to the cylinder liner increases the temperature of the cylinder liner wall surface as it approaches the combustion chamber (upper part of the cross-sectional view of FIG. 4B), and cools the cylinder liner 2 so that the wall surface temperature becomes uniform. to, and is about the annular groove close to the cross-sectional area of the annular groove combustion chamber, that is, _{3 4 → 3 3 → 3 2} → 3 1 small in the order.

According to the conventional cooling device of the above, the refrigerant introduced from the refrigerant inlet port 7, the longitudinal grooves 5 in FIG. 4 (B), the annular groove 3 ₁ to 3 ₃ while flowing downward from the top the refrigerant that has reached the bottom of the distributed longitudinal grooves 5 flows into the annular groove 3 ₄ the bottom. In FIG. 4 (B) a plurality of annular grooves 3 ₁ to 3 _4, the refrigerant respectively pass through the X-direction, while absorbing heat of the outer peripheral wall surface of the cylinder liner 2 in this case, and, as the upper part of the annular groove 3 Since the cross-sectional area is small, it flows at a high speed to reach the vertical groove 6, where it is assembled, and then led out of the refrigerant outlet 8 through an external radiator to a circulation pump (neither is shown).
Thereafter, the refrigerant reaches the refrigerant inlet 7 again.

As described above, according to the above-described conventional apparatus, the heat generated in the combustion chamber and transmitted to the cylinder liner 2 is transferred at a speed (the higher the temperature, the higher the temperature) according to the heat input distribution on the wall surface of the cylinder liner 2. By circulating the refrigerant at (fast), the wall surface of the cylinder liner 2 can be made substantially uniform.

[0009]

However, in the above-mentioned conventional apparatus, as shown in FIG. 5, the refrigerant flowing into the refrigerant introduction port 7 has the uppermost annular shape with almost no bending of the flow path through the vertical groove 5. whereas flowing into the groove 3 _1, for the top of the second and subsequent annular groove 3 _2, 3 ₃ a, the flow path as indicated by b flows bent at a right angle. However, since the refrigerant flows through the vertical groove 5 at a relatively high speed, it is difficult to change the flow path at right angles due to inertia. For this reason, the annular grooves 3 ₂ , 3
In the second and subsequent annular groove from the top is, such as ₃ stagnation occurs upstream position of the refrigerant inlet portion of the annular groove 3 _2, 3 ₃ As shown respectively in c and d in FIG. This stagnation is the largest as shown by c in the second annular groove 3 ₂ from the top tend to be relaxed as the lower part of the annular groove 3 _3, 3 _4. This is because the flow velocity of the refrigerant in the vertical groove 5 becomes lower toward the lower part as the flow rate decreases, so that the inertia effect is greatest at the upper position indicated by a, and decreases below the lower part.

When such stagnation occurs in the upper portion of the cylinder liner 2 having a large amount of heat input, the refrigerant boils, and the resulting air in the refrigerant stays in the circulation pump to reduce the output flow rate of the circulation pump. As a result, the radiator may malfunction due to cooling, which may cause overheating.

[0011] The present invention has been made in view of the above points,
An object of the present invention is to provide a cooling device for an internal combustion engine that solves the above-mentioned problem by forming a depth in a width direction of a communication passage in which stagnation is likely to occur in a tapered shape closer to a refrigerant upstream position.

[0012]

According to the present invention, there is provided a cylinder liner formed between a cylinder block and a cylinder liner fitted to the cylinder block along a circumferential direction of the cylinder liner. A plurality of annular passages formed in the axial direction, and first and second annular passages extending in the axial direction of the cylinder liner and provided to communicate between the plurality of annular passages at positions different from each other. Internal combustion having a communication passage, a refrigerant inlet for supplying refrigerant to the first communication passage, and a refrigerant outlet for discharging refrigerant passing through the plurality of annular passages and the second communication passage. In the cooling device for the engine, the width of each of the plurality of annular passages, in which the refrigerant passing through the first communication passage is divided and introduced in a direction substantially orthogonal to the extending direction of the first communication passage. Direction depth, People who refrigerant flow upstream position of the first communication path is one that was formed to be deeper.

[0013]

According to the present invention, each of the annular passages into which the refrigerant passing through the first communication passage is diverted in a direction substantially perpendicular to the direction in which the first communication passage extends is introduced into the annular passage with respect to the first communication passage. More refrigerant is introduced because the upstream position of the opening of the passage is deeper than the downstream position of the opening.

[0014]

1 is a sectional view of a main part of a first embodiment of the present invention, and FIG. 2 is a plan view of one embodiment of a cooling device for an internal combustion engine according to the present invention. 1 and 2, on the outer circumferential surface of the cylinder liner 12 is fitted in the cylinder block 11, a plurality of annular grooves as shown in FIG. 1 _{131-134 3} are formed at equal intervals, for example. FIG. 1 shows three of the plurality of annular grooves. This cylinder liner 12
The by fitted into the bore portion of the cylinder block 11, an annular passage is formed by a bore in the peripheral surface 11a of the annular groove _{131-134 3} and the cylinder block 11. Reference numeral 12a denotes the inner peripheral surface of the bore of the cylinder liner 12.

Further, the cylinder block 11 and the cylinder liner 12, longitudinal grooves 14 communicating the plurality of annular grooves, such as _{131-134 3} in the axial direction of the cylinder liner 12 is formed as the first communication path, also as shown in the plan view of FIG. 2, also annular grooves 13 ₁ to the longitudinal grooves 14 and 180 ° positions different
13 ₃ etc. flutes 15 communicating with the axial direction of the cylinder liner 12 a is formed as the second communication path.

Furthermore, on substantially the same plane as the annular groove 13 ₁ positioned closest to the cylinder head of the plurality of annular grooves,
A refrigerant inlet 16 communicating with the vertical groove 14 is formed, and a refrigerant outlet 17 communicating with the vertical groove 15 is formed. Thus, the annular groove 13 ₁ is positioned on the extending direction of the refrigerant inlet 16, also annular groove 13 _2, 13 _3, etc. at the bottom of the second and subsequent stages from the top is rolled Zaikata improved coolant inlet 16 Instead, the refrigerant is divided and introduced in a direction substantially perpendicular to the extending direction of the vertical groove 14.

The present embodiment in the cooling device of such a structure, as shown in FIG. 1, the refrigerant is diverted in a direction extending direction substantially orthogonal longitudinal groove 14 of the plurality of annular grooves, such as _{131-134 3} Annular grooves 13 ₂ , 13 _{3 in the second} and subsequent stages introduced
Is formed so that the depth d in the width direction of the refrigerant flow upstream of the vertical groove 14 becomes deeper. Further, the taper angle theta ₁ of the cross-section annular groove 13 ₂ is tapered groove shape, 13 ₃ as shown in FIG. 1, theta ₂ to θ _1> θ ₂ (i.e., as the annular groove of the position away from the cylinder liner 12 The taper angle is set to be small). Cylinder liner 1
The taper angle is smaller as the annular groove is farther away from 2
This is because the stagnation that occurs in the lower annular groove is smaller.

Next, the operation of this embodiment will be described. The refrigerant introduced into the refrigerant inlet 16 advances to the right as shown by the solid line I in FIG. 1 and is supplied to the longitudinal groove 14, and further proceeds straight with almost no bending in the flow path as shown by II. 1
4 while being introduced into the annular groove 13 from _1, part of the refrigerant goes downward as shown within the vertical groove 14 in III, part of which is distributed in an annular groove 13 ₂ as indicated by IV, the rest is at V being dispensed into the annular groove 13 ₃ through the vertical groove 14 as shown proceeds flutes 14 downward.

The annular groove _{131-134 3} all refrigerant distributed in the annular groove of the like, absorbing heat of the outer peripheral wall surface of the cylinder liner 12 while flowing in a direction as shown by the solid line arrows VI and VII in Fig. 2, Then, after merging in the vertical groove 15, as shown by an arrow VIII, it is led out from the refrigerant outlet 17 in the direction of the circulation pump.

[0020] Here, conventionally, as described above refrigerant to be distributed to an annular groove 13 ₂ in FIG. 1 is bent in a direction in which the flow passage of the refrigerant by the inertia due to the particularly high flow velocity is perpendicular to the axial direction of the cylinder liner 12 since no Kira, stagnation occurs as shown by c in FIG. 5 to the coolant inlet upstream position of the annular groove 13 _2.

On the other hand, according to the present embodiment, the annular groove 1
3 ₁ refrigerant particularly fast flow rates are in the vicinity of the opening for longitudinal groove 14, annular groove 13 ₂ as indicated by solid line arrow IV in FIG. 1
Especially, since a large amount flows into the upstream position of the refrigerant inlet, the stagnation c does not occur. Similarly, the refrigerant inlet upstream position of the annular groove _{13. 3,} since the positively refrigerant flows, stagnation as shown in d in FIG. 5 does not occur.

Thus, according to the present embodiment, the occurrence of stagnation can be prevented, and thereby the boiling and overheating of the refrigerant which may occur due to stagnation can be prevented.

In this embodiment, the annular grooves 13 ₂ , 13 _{2
Since 3} has a tapered groove shape, the rigidity can be improved as compared with a conventional annular groove having a tapered angle of zero, and thus the reliability as a cooling device can be improved.

Further, in this embodiment, the annular grooves 13 ₂ , 13
_{By making} the taper angle of ₃ or the like smaller at the lower part of the cylinder liner 12, the groove passage cross-sectional area becomes smaller at the lower part of the cylinder liner 12, so that the flow rate of the refrigerant becomes smaller at the annular groove farther from the cylinder head.

As a result, according to the present embodiment, it is possible to obtain a flow distribution between the annular grooves corresponding to the heat input distribution in which the temperature is higher as the wall surface of the cylinder liner 12 is closer to the cylinder head. Can be cooled so as to make the temperature uniform.

Next, another embodiment of the present invention will be described. FIG. 3 is a sectional view showing a main part of a second embodiment of the present invention. In the figure, the same components as those of FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, the water jacket of the cylinder head 21 located on the upper surface of the cylinder block 11 communicates with the refrigerant inlet 22.

Further, the longitudinal groove 23 which communicates the annular groove 13 ₁ ', 13 _2, 13 _3, etc. in the axial direction of the cylinder liner 12,
The annular groove 13 ₁ ′ located closest to the cylinder head 21 extends further in the direction of the cylinder head 21, and the refrigerant introduction port 22 communicates with the extending portion.

In the cooling device having such a structure, the refrigerant introduced into the refrigerant inlet 22 through the water jacket flows downward in the vertical groove 23 in FIG. Annular grooves 13 ₁ ′, 13 ₂ , 13 ₃
Are sequentially distributed and supplied to

Therefore, in the case of this embodiment, the annular groove 1
Since the largest stagnation may occur at 3 ₁ ',
As shown in FIG. 3, the annular groove 13 ₁ ′ has a tapered groove shape such that its depth in the width direction becomes deeper at the refrigerant flow upstream position of the vertical groove 23 and the taper angle of the annular groove 13 ₁ ′. the theta ₀ formed larger than the taper angle theta ₁ of the annular groove 13 _1.

Thus, the refrigerant from the vertical groove 23 flows into the annular groove 13 ₁ ′ at a position upstream of the refrigerant introduction portion in a larger amount than at the position downstream of the refrigerant, so that generation of stagnation can be prevented. Stagnation can be similarly prevented from occurring in the other annular grooves 13 ₂ and 13 ₃ .

Also in the case of the present embodiment, the larger the flow rate of the refrigerant can be made to flow in the annular groove closer to the cylinder head 22 side, so that the cooling corresponding to the heat input distribution of the cylinder liner 12 can be performed.

The present invention is not limited to the above embodiment, but can be applied to a cooling device in which a refrigerant inlet is provided at a position farthest from a cylinder head. In this case, the refrigerant introduced from the refrigerant introduction port is distributed to the plurality of annular grooves while flowing in the vertical groove in the direction of the cylinder head, and is the furthest to the cylinder head among the annular grooves that are not on the extension of the refrigerant introduction port. The refrigerant is bent at a right angle to the axial direction of the vertical groove in the annular groove at the position, and flows at a large flow velocity, so that stagnation is most likely to occur. Therefore, even in such a cooling device, the occurrence of the above-mentioned stagnation can be prevented by setting the depth of the annular groove in the width direction to be deeper at the refrigerant flow upstream position of the vertical groove.

[0033]

As described above, according to the present invention, the cross-sectional shape of the annular passage is such that the refrigerant is positively introduced into the cooling introduction portion of the annular passage where stagnation is likely to occur in the flow path of the refrigerant. The stagnation can be prevented from occurring, so that the refrigerant can be prevented from boiling due to stagnation, and overheating can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a first embodiment of the apparatus of the present invention.

FIG. 2 is a plan view of one embodiment of a cooling device for an internal combustion engine according to the present invention.

FIG. 3 is a sectional view of a main part of a second embodiment of the apparatus of the present invention.

FIG. 4 is a structural diagram of an example of a conventional cooling device for an internal combustion engine.

FIG. 5 is an explanatory diagram of a problem to be solved by the invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Cylinder block 12 Cylinder liner 13 ₁ 13 ₂ , 13 ₃ , 13 ₁ 'Annular groove 14 Vertical groove (first communication path) 15 Vertical groove (second communication path) 16 Refrigerant inlet 17 Refrigerant outlet

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-78518 (JP, A) JP-A-1-167448 (JP, A) Fully open 63-168242 (JP, U) Really open 1959 60366 (JP, U)

Claims (1)

(57) [Claims] An annular passage formed between a cylinder block and a cylinder liner fitted to the cylinder block along a circumferential direction of the cylinder liner, and a plurality of annular passages formed in an axial direction of the cylinder liner. A first and a second communication passages extending in the axial direction of the cylinder liner and provided to communicate with the plurality of annular passages at different positions from each other; And a refrigerant outlet for discharging the refrigerant that has passed through the plurality of annular passages and the second communication passage. The width in the width direction of each of the annular passages into which the refrigerant passing through the first communication passage is divided and introduced in a direction substantially perpendicular to the extending direction of the first communication passage is set to the first depth. Upstream position of refrigerant flow in communication path A cooling apparatus for an internal combustion engine, characterized in that the deeper as formed.