JP3208295B2 - 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 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 cooling device for an internal combustion engine for a vehicle, as shown in FIG. 6A, a cooling water passing through a radiator 45 is supplied to a cylinder block 41 by a water pump 47 through a thermostat valve 46. The main circulation passage 4 is supplied to the cooling water passage 43 of the cylinder block 41, flows into the cooling water passage 44 of the cylinder head 42 from the cooling water passage 43 of the cylinder block 41, and is sent to the radiator 45 from the outlet 44a.
A bypass passage 49 and a heater circuit 50 are branched from a cooling water passage outlet 44a of the cylinder head 42 toward the thermostat valve 46.

[0003] In the internal combustion engine of the prior intake cooling system 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 cooling water passage 51 and the exhaust cooling water passage 5.
The cooling water passing through the radiator 45 passes through the cooling water passage 51 on the intake side of the cylinder head 42 and is supplied to the cooling water passage 43 of the cylinder block 41 by the water pump 47 via the thermostat valve 46. There is provided a main circulation passage 53 that flows from the cooling water passage 43 of the cylinder block 41 into the exhaust-side cooling water passage 52 of the cylinder head 42 and sends out from the outlet 52a to the radiator 45.
In addition, 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 system, the cooling water having a low water temperature returned from the radiator 45 is caused to flow in the vicinity of the intake side squish area of the combustion chamber 55 and in the vicinity of the intake port 56, thereby suppressing knocking. There is an advantage that the charging efficiency can be improved by reducing the temperature.

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

[0006]

However, even in the above-mentioned cooling device of the pre-intake air cooling system, the water pump 47 is also required.
Is driven by transmitting rotation from a crankshaft by a pulley and a belt or the like, so that there is a problem that the arrangement of other auxiliary machines such as an alternator and an air conditioner is restricted.

The intake-side cooling water passage 51 of the cylinder head 42 serves as the suction-side passage of the water pump 47.
Since the intake-side cooling water passage 51 has many irregularities and it is difficult to obtain a sufficient water-passing cross-sectional area in terms of space, negative pressure increases on the suction side of the water pump 47, and cavitation is likely to occur. There is a problem that the performance may be reduced or the impeller may be damaged.

The cooling water passage for cooling the squish area on the intake side includes cooling water passages 51 on the intake side and the exhaust side.
52, the cooling water passages 51 and 52 are cooled by different cooling water in the intake-side cooling water passage 51 and the exhaust-side cooling water passage 52. There is a problem that the suppression effect becomes insufficient.

In view of the above 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 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 attaching the water pump to the cylinder head, connecting the discharge port of the water pump to the inlet of the cooling water passage on the intake side of the cylinder head, and making this intake side cooling water passage the discharge side of the water pump, the intake side cooling water Even if the passage resistance of the passage is large, the negative pressure on the suction side of the water pump is prevented from being increased to prevent cavitation. In addition, in addition to the above configuration, the present invention has a configuration in which a thermostat valve is built in the casing of the water pump and a bypass passage is provided in the casing so that cooling water is bypassed from the outlet of the exhaust-side cooling water passage of the cylinder head to the thermostat valve. And

[0011]

In the cooling device for an internal combustion engine of the intake precooling type, the discharge port of the water pump is connected to an inlet of the intake-side cooling water passage, and a partition wall of the intake-side cooling water passage from the exhaust-side cooling water passage. Is provided with a through-hole for guiding the cooling water to the cooling water passage of the cylinder block in the vicinity of the cylinder block, so that 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. The portion of the squish area near the partition is also cooled reliably, and the entire area of the squish area on the intake side is uniformly and effectively cooled.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIGS.

1 and 2, reference numeral 1 denotes a cylinder block, and 2 denotes a cylinder head. The 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. The cooling water that has passed through the radiator 5 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, and the cooling water passage of the cylinder block 1 is discharged from the outlet 3b. 8 through the cooling water passage 8 of the cylinder block 1 through the through hole 9.
A main circulation passage 10 is provided for inflow to the radiator 5 from an outlet 4a thereof, and a heater passage passing through a bypass passage 11 and a heater 13 from the exhaust-side cooling water passage outlet 4a of the cylinder head 2 to the thermostat valve 6. 12
Is branched. 14 is a reservoir tank for cooling water.

The water pump 7 is disposed at the rear end of the cylinder head 2 opposite to the camshaft driving side. That is, as shown in detail in FIGS.
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 is concentric with the camshaft 15. At the rear end 15a of the camshaft 15, an engaging pin 1 of the impeller shaft 18 is provided.
An engagement groove 16 is formed in which the engagement grooves 8a engage in the rotational direction. The impeller shaft 18 has an intermediate portion rotatably supported by a bearing 19 formed of a bush, and an impeller 20 is fixed to the other end in the pump casing 17. 80 is an oil seal. Pump casing 1
7 has a cylinder head 2 at the tip of the spiral discharge passage 21.
Outlet 2 connected to inlet 3a of intake-side cooling water passage 3
2 are formed, and the thermostat valve 6 is incorporated outside the suction port 23. The pump casing 17 has an inlet 24 for introducing cooling water from the radiator 5 to the thermostat valve 6, and a thermostat valve 6 from the outlet 4 a of the exhaust-side cooling water passage 4 of the cylinder head 2.
Passage 11 and heater passage 12
Connection port 25 is provided.

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 has 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 is provided at the inlet 3 of the intake-side cooling water passage 3.
The a side is formed so as to have a small diameter and the outlet 3b side to have a large diameter. In FIG. 5, reference numeral 31 denotes an intake hole opening to the combustion chamber 26, 32 denotes an exhaust hole, 33 denotes an intake port,
Is an exhaust port.

The operation of the above configuration will be described. When the camshaft 15 rotates with the operation of the internal combustion engine, the impeller 20 of the water pump 7 rotates and the radiator 5 rotates.
Is supplied to the inlet 3 a of the intake-side cooling water passage 3 of the cylinder head 2 by the water pump 7 via the thermostat valve 6. In this way, the low-temperature cooling water flows through the intake-side cooling water passage 3 so that the intake port 3
The three sections and the vicinity of the squish area on the intake side of the combustion chamber 26 are effectively cooled, and the charging efficiency is improved by reducing the intake air temperature, and knocking is prevented from occurring. In particular, a partition wall 27 between the combustion chambers 26, 26, which is partitioned from the exhaust-side cooling water passage 4, is disposed near the center of the combustion chamber 26, and the cooling water passes through both sides of the boss portion 29. The entire area can be cooled effectively, and the cooling water flows into the cooling water passage 8 of the cylinder block 1 by forming the through hole 30 near the partition wall 27 so that the cooling water flows in. Cooling water flows reliably also in the vicinity of the partition wall 27, which is difficult, so that the entire squish area on the intake side can be uniformly cooled, and knocking can be reliably prevented.

The cooling water flowing out of 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 cool the exhaust-side cooling water of the cylinder head 2. It flows into the passage 9, flows through the exhaust-side cooling water passage 9, cools the exhaust port 34, flows out of the outlet 4 a toward the radiator 5, is cooled by the radiator 5, and returns to the water pump 7.

In the above configuration, 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, and the intake-side cooling water passage 3 is connected to the discharge side of the water pump 7. Because of the connection, the intake-side cooling water passage 3 has many irregularities and a small flow cross-sectional area, so that even if the passage resistance is large, there is no danger of cavitation occurring in the water pump 7 and the pump discharge performance is reduced. Also, there is no inconvenience such as damage to the impeller 20.

Further, since the water pump 7 is disposed at the rear end of the cylinder head 2 and is driven by the camshaft 15, it is disposed at the front of the cylinder block 1 and is driven by a belt or a chain. The layout of the auxiliary equipment at 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 camshaft 15, the configuration is simplified and the configuration can be made at low cost. Further, the number of revolutions of the camshaft 15 is two times that of the crankshaft.
Since the number of rotations is one-half, the number of rotations of the impeller 20 is small, so that a bush can be used in place of the bearing for the bearing portion 19, so that the configuration can be made inexpensively and the life of the mechanical seal is prolonged. Note that the water pump 7 may not be arranged concentrically with the camshaft 15 and the camshaft 15 and the impeller shaft 18 of the water pump 7 may be linked and connected by a belt or a chain. There is no danger of breakage, and the reliability of pump drive is improved.

[0021]

[0022]

According to the cooling device for an internal combustion engine of the present invention,
In the cooling device of the intake pre-cooling method, 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 an intake side of the cylinder head,
In addition, since the thermostat valve is built in the casing of the water pump, and the casing is provided with a bypass passage for bypassing the cooling water from the outlet of the exhaust-side cooling water passage of the cylinder head to the thermostat valve, the intake-side cooling water passage is provided. Because it is on the discharge side of the water pump,
Even if the passage resistance is large due to the unevenness of the intake-side cooling water passage or the small passage cross-sectional area, the water pump can be prevented from generating cavitation.

In the cooling device of the pre-intake cooling system, a discharge port of a water pump is connected to an inlet of an intake-side cooling water passage, and a cylinder is provided near a partition wall of the intake-side cooling water passage from the exhaust-side cooling water passage. Since the cooling water passage of the block is provided with a through-hole that guides cooling water, low-temperature cooling water that has flowed from the water pump into the intake-side cooling water passage flows toward the through-hole near the partition wall, and the squish area on the intake side Of the squish area can be uniformly and effectively cooled.

[Brief description of the 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 embodiment.

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

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

6A and 6B show a schematic configuration of a conventional cooling device for an internal combustion engine, in which FIG. 6A is a configuration diagram of a general cooling device, and FIG.

FIG. 7 is a cross-sectional plan view of a cooling water passage of a cylinder head in a conventional cooling device of an intake pre-cooling system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 3 Intake 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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01P 3/02 F01P 5/10 F01P 5/12

Claims (2)

(57) [Claims] In a cooling device for an internal combustion engine of a preceding intake cooling type, cooling water flows from a cooling water passage of an intake side of a cylinder head to a cooling water passage of a cylinder block through a cooling water passage of a cylinder block. Attach it to the cylinder head, connect the discharge port of the water pump to the inlet of the cooling water passage on the intake side of the cylinder head, and
When the thermostat valve is built into the casing of the tap pump
In both cases, the cooling water is exhausted from the cylinder head to the casing.
From the outlet of the cooling water passage to the thermostat valve
A cooling apparatus for an internal combustion engine, characterized in that a bypass passage to scan. 2. A cooling system for an internal combustion engine of a preceding intake cooling type in which cooling water flows from a cooling water passage on an intake side of a cylinder head through a cooling water passage of a cylinder block to a cooling water passage on an exhaust side of a cylinder head. The discharge port is connected to the inlet of the intake-side cooling water passage, and a through-hole for introducing cooling water to the cooling water passage of the cylinder block is provided near the partition wall of the intake-side cooling water passage with the exhaust-side cooling water passage. A cooling device for an internal combustion engine.