JPH08177483A - Cooling device of multi-cylinder engine - Google Patents

Abstract

PURPOSE: To prevent excessive cooling of a cylinder block as well as to improve cooling performance of a cylinder head. CONSTITUTION: An inlet part 8 for cooling water is provided on the end in the cylinder line direction of a cylinder head 1, an outlet part 9 is provided on a cylinder block 2 on the end opposite side to it, through holes 10, 11 for communicating a cylinder head cooling jacket 1A with a cylinder block cooling jacket 2A are provided on the upstream side and the downstream side, and cooling water is allowed to flow from the cylinder head 1 to the cylinder block 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved cooling system for a multi-cylinder engine.

[0002]

2. Description of the Related Art Conventionally, as a cooling device for a multi-cylinder engine of an automobile or the like, there is a cooling device as shown in FIG.
MA engine maintenance manual (1982) Nissan Motor Co., Ltd. reference).

In the figure, 1 is a cylinder head, 2 is a cylinder block, and cooling water from the water pump 3 enters a cylinder block cooling jacket 2A from an inlet 5 provided at one end of the cylinder block 2 and further the cylinder head. 1 and the cylinder block 2 through a plurality of through holes 4 provided in the gasket, and flows into the upper cylinder head cooling jacket 1A.

The cooling water thus cooling the cylinder head 1 from the cylinder block 2 flows out from the outlet 6 provided at the end of the cylinder head 1 on the side opposite to the inlet 5, and is cooled by the radiator 7. Then, the water pump 3 circulates the engine again.

[0005]

By the way, in this cooling device, the cooling water flows from the cylinder block 2 to the cylinder head 1, and the cooling water temperature is lower on the cylinder block side than on the cylinder head side. .

However, considering the cooling characteristics required for the cylinder head 1 and the cylinder block 2 separately, cooling water having a lower temperature is supplied to the cylinder head 1 in order to prevent knocking, and the cylinder block 2 is provided with a piston slide. Cooling water at a relatively high temperature should be supplied in order to reduce dynamic friction and exhaust emissions.

An object of the present invention is to improve the cooling efficiency of the engine by allowing the cooling water to flow from the cylinder head to the cylinder block in consideration of such required cooling characteristics.

[0008]

A first aspect of the present invention is an engine cooling device in which cooling water from a radiator is circulated in a cooling jacket of a cylinder head and a cooling jacket of a cylinder block. An inlet for cooling water is provided at one end in the row direction, an outlet is provided at the cylinder block cooling jacket located at the opposite end, and the cylinder head cooling jacket and the cylinder block cooling jacket are cooled. Through holes were provided to communicate with each other on the upstream side and the downstream side of water.

In a second aspect based on the first aspect, the upstream through hole is formed near the inlet portion, and the downstream through hole is formed near the outlet portion.

In a third aspect based on the first or second aspect, the cylinder block cooling jacket is formed below the through hole on the upstream side to form a deep bottom portion deeper than other portions.

In a fourth aspect based on the third aspect, the side wall rising from the deep bottom portion is inclined obliquely toward the downstream side.

In a fifth aspect based on the first to fourth aspects, the cylinder bore wall located upstream of the cylinder block is formed thicker than the other bore wall thicknesses.

[0013]

In the first aspect of the invention, the cooling water cooled by the radiator and lowered in temperature is introduced into the cylinder head cooling jacket, and a part of the cooling water cools the cylinder head to flow to the outlet on the downstream side. The rest flows into the cylinder block cooling jacket through the through hole on the upstream side, cools the cylinder block, and reaches the outlet.

Therefore, the cooling water having a low temperature flows through the cylinder head, while the warmed cooling water is introduced into the cylinder block via the cylinder head, so that the cooling water on the cylinder block side can be compared with that on the cylinder head side. Supercooling is prevented. Therefore, the knocking resistance of the engine is improved, the sliding friction of the piston is reduced, and the exhaust emission is improved.

In the second aspect of the invention, since the upstream and downstream through holes are located near the inlet and outlet, respectively, the cooling water is circulated to all the cylinders of both the cylinder head and the cylinder block. It is possible to control the temperature distribution to be uniform.

In the third aspect of the invention, the flow of the cooling water flowing into the cylinder block cooling jacket from the through hole on the upstream side is
By inverting it at the deep bottom and directing it upward while guiding it by the side wall, most of the cooling water can be guided above the cylinder bore, and the upper side of the cylinder bore having a high temperature can be efficiently cooled.

In the fourth aspect of the invention, since the side wall for guiding the flow of the cooling water upward is inclined to the downstream side, the cooling water reversed at the deep bottom can be made to flow smoothly and the flow resistance can be reduced.

In the fifth aspect of the present invention, since the wall thickness of the upstream cylinder bore is made thicker than that of the downstream cylinder bore, the temperature drop of the upstream cylinder bore, which is easily subjected to excessive cooling, is prevented, and uniform cooling is possible. .

[0019]

1 is a first embodiment of the present invention, in which 1 is a cylinder head, 2 is a cylinder block, and a cylinder head 1
An inlet 8 for introducing cooling water into the cylinder head cooling jacket 1A is provided at one end of the cylinder block cooling jacket 1A, and above the end of the cylinder block 2 on the opposite side from the cylinder block cooling jacket 2A. An outlet 9 for discharging the cooling water is provided.

In the vicinity of the cooling water inlet portion 8, there is formed a through hole 10 for guiding the cooling water through the gasket vertically from the cylinder head cooling jacket 1A to the cylinder block cooling jacket 2A, and in the vicinity of the outlet portion 9. In the same manner, a through hole 11 that connects the cooling jacket 1A and the cooling jacket 2A is provided. Therefore, the cylinder head cooling jacket 1A and the cylinder block cooling jacket 2A communicate with each other in the longitudinal direction of the cylinder arrangement of the engine by vertically extending through holes 10 and 11 at the most upstream portion and the most downstream portion.

Cooling water is sent from the water pump 3 to the inlet 8, and cooling water discharged from the outlet 9 is circulated to the water pump 3 after being cooled by the radiator 7.

The operation will be described next.

The cooling water from the water pump 3 enters the cylinder head cooling jacket 1A from the inlet portion 8 provided in the cylinder head 1, and the component 12 flowing through the cooling jacket 1A as it is toward the through hole 11 on the downstream side, and the cylinder head. From the through hole 10 upstream of the cooling jacket 1A, it is split into the component 13 flowing into the cylinder block cooling jacket 2A.

The main flow of the cooling water flowing into the cylinder block cooling jacket 2A from the through hole 10 flows downward as it reaches the bottom of the jacket, then reverses and changes its direction upward, and the outlet 9 at the downstream side. Flow to.

In this way, the cooling water having a low temperature is positively introduced into the cylinder head cooling jacket 1A to effectively cool the high temperature cylinder head 1, while the cylinder block having a low required cooling capacity. Cooling water having a raised temperature is caused to flow through the cylinder head 1 through 2, and
By inflowing only through the upstream through-hole 10,
Component 13 flowing through the cylinder block cooling jacket 2A
Reduce the flow rate to prevent excessive cooling.

As a result, the knocking resistance of the engine can be improved, the sliding friction of the piston can be reduced, and the exhaust emission can be improved.

Next, the embodiment shown in FIG. 2 will be described. In each of the following embodiments, the description will focus on the parts that differ from the embodiment of FIG.

In this embodiment, a deep bottom portion 14 is formed in the cylinder block cooling jacket 2A below the through hole 10, and the cooling water flowing downward from the through hole 10 is inverted at the deep bottom portion 14. At the same time, the vertical side wall 15 guides the flow of the cooling water directly upward.

In this way, most of the components 13 flowing in the cylinder block cooling jacket 2A do not flow along the bottom portion but pass from the upstream side to the downstream side cylinder near the boundary with the cylinder head 1, and only that much. Coolability above each cylinder is enhanced.

The temperature distribution of the cylinder block 2 becomes higher at the upper portion of each cylinder bore wall, so that by increasing the amount of cooling water introduced to the portion near the boundary with the cylinder head 1 in the cylinder block cooling jacket 2A. Therefore, the cylinder block 2 can be cooled more efficiently.

In the embodiment shown in FIGS. 3 and 4, the side wall 16 rising diagonally from the deep bottom portion 14 is formed to more smoothly guide the flow of the cooling water and reduce the flow resistance.

Further, in this embodiment, the wall thickness of the cylinder bore 21 of the cylinder 20A located at the most upstream position with respect to the cooling water flowing through the cylinder block cooling jacket 2A and immediately after passing through the through hole 10 has the highest flow velocity. L1 is made thicker than the wall thickness L2 of the other cylinders 20B, 20C, 20D.

The cooling water temperature when passing around the upstream cylinder 20A is higher than that of the downstream cylinders 20B, 20C and 20D, and the flow velocity is high, so that the cooling water is cooled excessively. Will be lower than. Therefore,
By increasing the wall thickness of the cylinder bore 21, the temperature difference between the cylinders is eliminated, and uniform cooling performance is obtained in all the cylinders.

[0034]

According to the first aspect of the present invention, the cooling water cooled by the radiator and lowered in temperature is introduced into the cylinder head cooling jacket, and a part of the cooling water is directly cooled to the outlet portion on the downstream side. And the rest flows into the cylinder block cooling jacket from the through hole on the upstream side, cools the cylinder block and reaches the outlet,
Cooling water with a low temperature flows to the cylinder head, while part of the cooling water is guided to the cylinder block via the cylinder head and through holes, preventing overcooling on the cylinder block side compared to the cylinder head side. As a result, the knocking resistance of the engine is improved, the sliding friction of the piston is reduced, and the exhaust emission is improved.

According to the second aspect of the present invention, since the through holes on the upstream side and the through hole on the downstream side are near the inlet portion and the outlet portion, respectively, both the cylinder head and the cylinder block are cooled for all cylinders. Water can be circulated, and the temperature distribution between the cylinders can be controlled as uniformly as possible.

According to the third aspect of the invention, the flow of the cooling water that has flowed into the cylinder block cooling jacket from the through hole on the upstream side is reversed at the deep bottom portion and is directed right above while being guided by the side wall. It is possible to guide most of the above to above the cylinder bore and efficiently cool above the cylinder bore having a high temperature.

According to the fourth aspect of the invention, since the side wall for guiding the flow of the cooling water upward is inclined to the downstream side, the cooling water inverted at the deep bottom can smoothly flow, and the cooling water in the cylinder block cooling jacket can be smoothly flowed. The distribution resistance of can be reduced.

According to the fifth aspect of the invention, the wall thickness of the upstream cylinder bore is made thicker than that of the downstream cylinder bore.
It is possible to prevent a temperature drop on the upstream side, which is easily subjected to excessive cooling, and to perform uniform cooling among all cylinders.

[Brief description of drawings]

FIG. 1 is a cooling system diagram showing a first embodiment of the present invention.

FIG. 2 is a cooling system diagram similarly showing a second embodiment.

FIG. 3 is a cooling system diagram similarly showing a third embodiment.

FIG. 4 is a sectional view of the same taken along line XX.

FIG. 5 is a cooling system diagram of a conventional example.

[Explanation of symbols]

 1 Cylinder Head 1A Cylinder Head Cooling Jacket 2 Cylinder Block 2A Cylinder Block Cooling Jacket 3 Water Pump 7 Radiator 8 Inlet 9 Outlet 10 Through Hole 11 Through Hole 14 Deep Bottom 15 Side Wall 16 Side Wall

Claims (5)

[Claims] 1. A cooling device for an engine, wherein cooling water from a radiator is circulated through a cooling jacket of a cylinder head and a cooling jacket of a cylinder block, wherein the cooling water is sent to one end of the cylinder head cooling jacket in the cylinder row direction. An inlet portion is provided, an outlet portion is provided at the cylinder block cooling jacket located at the opposite end, and the cylinder head cooling jacket and the cylinder block cooling jacket are connected to each other on the upstream side and the downstream side of the cooling water, respectively. A cooling device for an engine, which is provided with a through hole that allows the cooling. 2. The engine cooling device according to claim 1, wherein the upstream through hole is formed near the inlet portion, and the downstream through hole is formed near the outlet portion. 3. The engine cooling device according to claim 1, wherein the cylinder block cooling jacket has a deep bottom portion that is located below the upstream through hole and is deeper than other portions. 4. The engine cooling device according to claim 3, wherein the side wall rising from the deep bottom portion is inclined obliquely toward the downstream side. 5. The engine cooling device according to claim 1, wherein a wall thickness of the cylinder bore located on the upstream side of the cylinder block is thicker than wall thicknesses of other bores.