JPH0988582A - Cooling device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce limitation of arrangement of various auxiliary machines and prevent the occurrence of cavitation of a water pump, in a cooling device for an intake advance cooling type internal combustion engine. SOLUTION: By driving a water pump to feed cooling water by a cam shaft, limitation on arrangement of other auxiliary machines to be drive from a crankshaft through a belt and a chain is reduced. Further, the water pump 7 is attached to a cylinder head 2, the delivery port of the water pump 7 is connected to the inlet 3a of a cooling water passage 3 on the suction side of a cylinder head 2, and a cooling water passage 3 on the intake side forms the delivery side of the water pump 7. This constitution increases the negative pressure on the suction side of the water pump 7 even when passage resistance of the cooling water passage 3 on the intake side is high and prevents cavitation from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for an internal combustion engine, and more particularly to a cooling system for an internal combustion engine of a pre-intake cooling type.

[0002]

2. Description of the Related Art In a general automobile internal combustion engine cooling device, as shown in FIG. 6 (a), cooling water that has passed through a radiator 45 is passed through a thermostat valve 46 and a water pump 47 to a cylinder block 41. Of the cylinder block 41 to flow into the cooling water passage 44 of the cylinder head 42, and from its outlet 44a to the radiator 45.
8 is provided, and a bypass passage 49 and a heater circuit 50 are branched from the cooling water passage outlet 44a of the cylinder head 42 toward the thermostat valve 46.

Further, in the intake-air pre-cooling type internal combustion engine disclosed in Japanese Utility Model Laid-Open No. 2-63052, FIG.
As shown in FIG. 7B and FIG. 7, the cooling water passage of the cylinder head 42 is connected to the intake side cooling water passage 51 and the exhaust side cooling water passage 5.
The cooling water that has been divided into two is passed through the radiator 45 through the intake side cooling water passage 51 of the cylinder head 42, and is sent to the cooling water passage 43 of the cylinder block 41 by the water pump 47 through the thermostat valve 46. A main circulation passage 53 is provided, which allows the cooling water passage 43 of the cylinder block 41 to flow into the exhaust side cooling water passage 52 of the cylinder head 42 and sends it out to the radiator 45 from the outlet 52a thereof.
Further, a bypass passage 49 and a heater passage 50 are branched from the exhaust side cooling water passage outlet 52a toward the thermostat valve 46.

According to the intake pre-cooling method, the cooling water having a low water temperature returned from the radiator 45 is caused to flow near the intake side squish area of the combustion chamber 55 and near the intake port 56, thereby suppressing knocking and intake. There is an advantage that the filling efficiency can be improved by reducing the temperature.

The water pump 47 is configured to be driven by a crankshaft pulley at the front of the cylinder block 41 via a belt. In FIG. 7, 57 is an exhaust port, 58 is a partition wall that divides the intake side cooling water passage 51 and the exhaust side cooling water passage 52, and 59 is a boss for fastening and fixing the cylinder head 42 to the cylinder block 41 by bolts. The partition wall 58 is formed so as to connect the boss portion 59 and the upper wall of the combustion chamber 55.

[0006]

However, even in the cooling system of the intake pre-cooling system, the water pump 47 is used.
Is driven by transmitting rotation from a crankshaft by means of a pulley and a belt, which poses a problem of restricting the arrangement of other auxiliary equipment such as an alternator and an air conditioner.

The intake side cooling water passage 51 of the cylinder head 42 serves as the intake side passage of the water pump 47.
Since the intake-side cooling water passage 51 has many irregularities and it is difficult to take a sufficient water-flow cross-sectional area in terms of space, negative pressure becomes large on the intake side of the water pump 47 and cavitation easily occurs, resulting in pump discharge. There is a problem that the performance may be reduced and the impeller may be damaged.

The cooling water passages for cooling the squish area on the intake side are the cooling water passages 51 on the intake side and the exhaust side.
It is divided by a partition wall 58 between 52, and the intake side cooling water passage 51 portion and the exhaust side cooling water passage 52 portion are cooled by different cooling water, so that it is difficult to be uniformly cooled, and knocking does not occur. There is a problem that the suppression effect becomes insufficient.

In view of such conventional problems, the present invention can reduce restrictions on the arrangement of various accessories, can prevent cavitation in the water pump, and can uniformly cool the squish area on the intake side. It is an object of the present invention to provide a cooling device for an internal combustion engine of an intake air pre-cooling system that can reliably suppress knocking.

[0010]

SUMMARY OF THE INVENTION The present invention relates to an internal combustion engine of an intake-advance cooling type in which cooling water flows from a cooling water passage on the intake side of a cylinder head to a cooling water passage on the cylinder head through a cooling water passage of a cylinder block. In the cooling device of
By driving the water pump that supplies the cooling water with the camshaft, the restrictions on the arrangement of other auxiliary equipment that is driven from the crankshaft via the belt and the chain are reduced.

In the cooling system for an internal combustion engine of the intake pre-cooling type, a water pump is attached to a cylinder head, and a discharge port of the water pump is connected to an inlet of a cooling water passage on the intake side of the cylinder head. By making the cooling water passage on the discharge side of the water pump, even if the passage resistance of the intake side cooling water passage is large, it is possible to prevent the negative pressure on the suction side of the water pump from becoming large and to prevent cavitation.

In the cooling system for an internal combustion engine of the intake pre-cooling type, the discharge port of the water pump is connected to the inlet of the intake side cooling water passage, and the partition wall of the intake side cooling water passage and the exhaust side cooling water passage is separated. By providing a through hole for guiding the cooling water to the cooling water passage of the cylinder block in the vicinity of, the low temperature cooling water flowing from the water pump into the intake side cooling water passage is made to flow toward the through hole near the partition wall, and the intake side The part of the squish area near the partition wall is also reliably cooled, and the entire area of the squish area on the intake side is uniformly and effectively cooled.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
~ It demonstrates with reference to FIG.

1 and 2, 1 is a cylinder block, 2 is a cylinder head, and a cooling water passage of the cylinder head 2 is divided into an intake side cooling water passage 3 and an exhaust side cooling water passage 4. Then, the cooling water passing through the radiator 5 is sent to the inlet 3a of the intake side cooling water passage 3 of the cylinder head 2 by the water pump 7 via the thermostat valve 6, and the outlet 3b of the cooling water passage of the cylinder block 1 is supplied. 8 through the cooling water passage 8 of the cylinder block 1 through the through hole 9 to the exhaust side cooling water passage 4 of the cylinder head 2.
Is provided and a main circulation passage 10 for discharging the same to the radiator 5 from its outlet 4a is provided, and a heater passage passing through the bypass passage 11 and the heater 13 from the exhaust side cooling water passage outlet 4a of the cylinder head 2 toward the thermostat valve 6. 12
Is branched. Reference numeral 14 is a reservoir tank for cooling water.

The water pump 7 is arranged at the rear end of the cylinder head 2 opposite to the camshaft driving side. That is, as shown in detail in FIGS. 3 and 4,
The pump casing 17 of the water pump 7 is attached to the rear end of the cylinder head 2 so that the impeller shaft 18 and the cam shaft 15 are concentric. The rear end portion 15 a of the camshaft 15 has an engagement pin 1 for the impeller shaft 18.
An engagement groove 16 is formed which engages with 8a and engages in the rotational direction. The impeller shaft 18 has an intermediate portion rotatably supported by a bearing portion 19 made of a bush, and an impeller 20 is fixed to the other end portion of the pump casing 17. 80 is an oil seal. Pump casing 1
At the tip of the spiral discharge passage 21 of No. 7, the cylinder head 2
Outlet 2 connected to the inlet 3a of the intake side cooling water passage 3 of
2 is formed, and the thermostat valve 6 is built in outside the suction port 23. Further, in the pump casing 17, an inlet 24 for introducing cooling water from the radiator 5 to the thermostat valve 6 and an outlet 4a of the exhaust side cooling water passage 4 of the cylinder head 2 are provided.
Bypass passage 11 for bypassing to and heater passage 12
Connection port 25 of

As shown in FIG. 5, the intake side cooling water passage 3 and the exhaust side cooling water passage 4 in the cylinder head 2 are formed by partitioning the upper walls of the combustion chambers 26, 26 with a partition wall 27. The partition wall 27 is disposed closer to the center of the combustion chamber 26 than the conventional case shown in FIG. 7, and the intake side cooling water passage 3 is a boss for fastening and fixing the cylinder head 2 to the cylinder block 1. It is formed so as to pass through both sides of the portion 29. A through hole 30 for guiding cooling water to the cooling water passage 8 of the cylinder block 1 is formed near the partition wall 27. The through hole 30 serves as an inlet 3 of the intake side cooling water passage 3.
The a side has a small diameter and the outlet 3b side has a larger diameter. In FIG. 5, 31 is an intake hole that opens into the combustion chamber 26, 32 is an exhaust hole, 33 is an intake port, and 34 is an intake port.
Is the exhaust port.

The operation of the above-described structure will be described. When the camshaft 15 rotates in accordance with the operation of the internal combustion engine, the impeller 20 of the water pump 7 rotates and the radiator 5 moves.
The low-temperature cooling water from is supplied to the inlet 3a of the intake side cooling water passage 3 of the cylinder head 2 by the water pump 7 via the thermostat valve 6. Thus, the low-temperature cooling water flows through the intake-side cooling water passage 3 so that the intake port 3
The third part and the vicinity of the squish area on the intake side of the combustion chamber 26 are effectively cooled, the intake efficiency is reduced by the decrease of the intake temperature, and knocking is prevented. In particular, since the partition wall 27 between the combustion chambers 26, 26, which is partitioned from the exhaust side cooling water passage 4, is arranged near the center of the combustion chamber 26 and the cooling water passes through both sides of the boss portion 29, the intake side squish area Since the entire region can be effectively cooled and the through hole 30 is formed near the partition wall 27 to allow the cooling water to flow to the cooling water passage 8 of the cylinder block 1, the cooling water flows in. Cooling water surely flows in the vicinity of the difficult partition wall 27, and the entire region of the squish area on the intake side can be cooled uniformly, so that knocking can be reliably prevented.

The cooling water discharged from the outlet 3b of the intake side cooling water passage 3 passes through the cooling water passage 8 of the cylinder block 1 to cool the outer periphery of the cylinder, and then passes through the through hole 9 to exhaust side cooling water of the cylinder head 2. The gas flows into the passage 9, flows through the exhaust side cooling water passage 9, cools the exhaust port 34, flows out from the outlet 4 a toward the radiator 5, is cooled by the radiator 5, and is returned to the water pump 7.

In the above construction, the discharge port 22 of the water pump 7 is connected to the inlet 3a of the intake side cooling water passage 3 of the cylinder head 2 so that the intake side cooling water passage 3 is connected to the discharge side of the water pump 7. Since the intake side cooling water passage 3 has a large number of irregularities and has a small flow cross-sectional area because of the connection, even if the passage resistance is large, there is no risk of cavitation in the water pump 7, and the pump discharge capacity decreases. In addition, there is no inconvenience such as damage to the impeller 20.

Further, since the water pump 7 is arranged at the rear end of the cylinder head 2 and is driven by the camshaft 15, it is arranged at the front of the cylinder block 1 so that a belt or a chain is used. The layout of the auxiliary equipment in the front part of the internal combustion engine can be made compact without restricting the arrangement of other auxiliary equipment such as an alternator and an air conditioner that are linked to the crankshaft. Further, since the impeller shaft 18 of the water pump 7 is directly connected to the cam shaft 15, the structure is simple and the cost can be reduced. Furthermore, the rotation speed of the camshaft 15 is 2 times that of the crankshaft.
Since the number of rotations of the impeller 20 is small, the number of rotations of the impeller 20 is small, so that it is possible to use a bush in place of the bearing in the bearing portion 19, the cost can be reduced, and the mechanical seal has a long life. Note that the water pump 7 may not be arranged concentrically with the camshaft 15, but the camshaft 15 and the impeller shaft 18 of the water pump 7 may be interlockingly connected by a belt or a chain. There is no risk of breakage, and pump drive reliability is improved.

[0021]

According to the cooling device for an internal combustion engine of the present invention,
In the intake-preceding cooling type cooling device, the water pump that feeds the cooling water is driven by the camshaft, so there are less restrictions on the arrangement of other auxiliary equipment that is driven from the crankshaft via a belt or chain. This makes it possible to make the auxiliary equipment arrangement at the front of the internal combustion engine compact.

In the cooling system of the intake pre-cooling system, the water pump is attached to the cylinder head, and the discharge port of the water pump is connected to the inlet of the cooling water passage on the intake side of the cylinder head. Since the water passage is on the discharge side of the water pump, cavitation can be prevented from occurring in the water pump even if the passage resistance is large due to the unevenness of the intake side cooling water passage and the small passage cross-sectional area.

Further, in the cooling system of the intake preceding cooling system, the discharge port of the water pump is connected to the inlet of the intake side cooling water passage, and the cylinder is provided in the vicinity of the partition wall of the intake side cooling water passage and the exhaust side cooling water passage. Since the cooling water passage of the block is provided with a through hole for guiding the cooling water, the low-temperature cooling water flowing from the water pump into the intake side cooling water passage flows toward the through hole near the partition wall, and the intake side squish area. It is possible to reliably cool the portion in the vicinity of the partition wall, and to uniformly and effectively cool the entire area of the squish area.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cooling device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a flow of cooling water in the cooling device of the same embodiment.

FIG. 3 is a cross-sectional plan view of the water pump in the cooling device of the same embodiment.

FIG. 4 is a side view showing the water pump in the cooling device of the same embodiment with a cover removed.

FIG. 5 is a cross-sectional plan view of a cooling water passage of a cylinder head in the cooling device of the same embodiment.

6A and 6B show a schematic configuration of a cooling device for an internal combustion engine of a conventional example, FIG. 6A is a configuration diagram of a general cooling device, and FIG. 6B is a configuration diagram of a cooling device of an intake preceding cooling system.

FIG. 7 is a cross-sectional plan view of a cooling water passage of a cylinder head in a cooling apparatus of an intake air preceding cooling system of a conventional example.

[Explanation of symbols]

 1 Cylinder Block 2 Cylinder Head 3 Inlet-side Cooling Water Passage 3a Inlet 4 Exhaust-side Cooling Water Passage 7 Water Pump 8 Cooling Water Passage 15 Camshaft 22 Discharge Port 27 Partition Wall 30 Through Hole

Claims (3)

[Claims] 1. A cooling device for an internal combustion engine of an intake pre-cooling type, wherein cooling water is flown from an intake side cooling water passage of a cylinder head to a cooling water passage of a cylinder block through a cooling water passage of a cylinder block. A cooling device for an internal combustion engine, wherein a water pump for feeding is driven by a cam shaft. 2. A cooling system for an internal combustion engine of an intake pre-cooling type, wherein cooling water is supplied from an intake side cooling water passage of a cylinder head to a cooling water passage of a cylinder block through a cooling water passage of a cylinder block. A cooling device for an internal combustion engine, wherein the cooling device is attached to a cylinder head, and a discharge port of a water pump is connected to an inlet of a cooling water passage on an intake side of the cylinder head. 3. A cooling apparatus for an internal combustion engine of an intake pre-cooling type, wherein cooling water is flown from an intake side cooling water passage of a cylinder head to a cooling water passage of a cylinder block through a cooling water passage of a cylinder block. The discharge port is connected to the inlet of the intake side cooling water passage, and a through hole for introducing the cooling water to the cooling water passage of the cylinder block is provided near the partition wall of the intake side cooling water passage and the exhaust side cooling water passage. A cooling device for an internal combustion engine, which is characterized.