JPH05156939A - Partially liquid-cooled and forced air-cooling system of cylinder block for multicylinder overhead-valve engine - Google Patents

Abstract

PURPOSE:To heighten a cooling capacity in a cylinder block as a whole as well as to control a thermal strain by setting a spot the higher in a cooling effect by a coolant, the lower in the cooling effect by cooling air. CONSTITUTION:Cooling air produced by a cooling fan is blown through from the front to the rear of a cylinder block 3. A cylinder 15 is formed in space between cylinders themselves. Each of jackets 18a, 18b is formed in two thick wall part 17 between the cylinders and each of bush rod chambers 16a, 16b. A coolant being circulated by a pump 10 enters from the jacket 18b at the final side, flowing into a jacket 15 at the one front side in order, and afterward it goes out of the jacket 18a at the forefront.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid cooling device for a part of a cylinder block of a forced air cooling multi-cylinder overhead valve engine, in which a part of the cylinder block is cooled with cooling air and the remaining part is cooled with a cooling liquid fed under pressure. Regarding

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. Hei.
As disclosed in Japanese Patent Laid-Open No. 115516, a cooling liquid pumped by a pump is passed from a pressure feeding path to a jacket between cylinders and a cooling path between intake and exhaust valves, and then to a sub combustion chamber jacket and a radiator. A configuration is known in which the materials are passed in order, returned to the pressure feeding path and circulated.

[0003]

In the above-mentioned conventional structure, the cylinder wall portion between the cylinder and the push rod chamber existing between each cylinder and the push rod chamber is liable to be insufficiently cooled, and the cylinder portion is not easily cooled. Thermal distortion may occur due to the temperature difference in the circumferential direction. Also, because the cooling air from the cooling fan provided on the front side of the engine is blown through the cylinder block from the front to the rear, the cylinder located on the rear side can receive the air cooling effect more sufficiently than the cylinder located on the front side. However, thermal strain due to the temperature difference between the front and rear of the cylinder block was also likely to occur.

An object of the present invention is to make it possible to suppress the generation of thermal strain in the cylinder block by improving the cooling liquid supply structure in a part of the liquid cooling device.

[0005]

In order to achieve the above object, the present invention provides a cooling fan 6 and a fan case 7 on the front side of a multi-cylinder overhead valve engine 1, and a cooling air generated by the cooling fan 6. Is guided by the fan case 7 to blow through the cylinder block 3 from the front to the rear, and the plurality of cylinders 3 arranged in front of and behind the cylinder block 3 are arranged.
A cylinder-to-cylinder jacket 15 is formed between a and 3b, and the cylinder-to-cylinder jacket 15 and the radiator 8 are formed.
In the partially liquid-cooled forced air cooling device of the cylinder block of the multi-cylinder overhead valve engine configured to circulate the cooling liquid with the pump 10, the cylinders 3a and 3b and the push rod chambers 16a on the side thereof. 16b, the cylinder-push rod jackets 18a, 18b are formed in the cylinder-push-rod wall portion 17 between them, and the cooling liquid inlet a is opened in the cylinder-push rod jacket 18b on the rearmost side, and the frontmost side is formed. Cylinder
The cooling liquid outlet b is opened in the inter-push rod jacket 18a, and the cylinder-to-push rod jacket 18b on the rearmost side to the front cylinder-to-cylinder jacket 1
After 5, the structure is such that the cylinder-push rod jacket 18a on the front side is communicated with each other in order.

[0006]

According to the structure of the present invention, the cooling liquid introduced into the jacket between the cylinders and the push rods on the rearmost side first cools the wall of the wall between the cylinders and the pushrod chambers on the rearmost side, and then the cylinders on the front side are cooled. Then, the meat wall between the cylinders is cooled by entering the jacket between cylinders, and then the meat wall between the cylinder and push rod chambers on the front side is cooled by entering the jacket between the cylinders and push rods on the front side.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a partially cutaway side surface of a two-cylinder diesel engine which is an example of a forced air-cooled multi-cylinder overhead valve engine of the present invention, FIG. 2 shows a vertical rear surface of an engine, and FIG. 3 shows a cylinder. The planes in which a part of the head is cut away are shown. The engine 1 includes a cooling system that combines cooling of the crankcase 2 by forced air cooling and cooling of the cylinder block 3 and the cylinder head 4 by partial liquid cooling (oil cooling).

That is, cooling air is generated by a cooling fan 6 also serving as a flywheel, which is attached to the front end of a crank shaft 5 penetratingly supported by the crank case 2, and this cooling air is guided by a spiral case 7 to guide the cooling air to the upper part of the crank case 2. The cylinder block 3 and the cylinder head 4 connected to the upper surface of the cylinder block 4 are guided to the outer periphery of the cylinder block 3 to cool them, and at the same time, the radiator 8 of the pressure-feed type partial cooling device is cooled by a part of the cooling air drawn from the upper part of the spiral case 7. It has a structure that

Cylinder block 3 and cylinder head 4
The configuration of the partial liquid cooling device for the above is shown in FIGS. 2 and 3. In other words, the lubricating oil that also serves as the cooling fluid is stored in the oil pan 9 formed at the bottom of the crankcase 2, and the oil is passed through the strainer 11 by the trochoid type pump 10 that is driven by being gear-linked to the crankshaft 5. Part of the oil sucked by the pump 10 and pumped by the pump 10 is supplied to the lubricating oil passage 13 at a predetermined pressure regulated by the regulating valve 12 and sent to the lubrication necessary portion of the engine 1, The oil returned to the pan 9 and passing through the regulating valve 12 is used as a cooling liquid for the partial liquid cooling device of the cylinder block 3 and the cylinder head 4.

That is, the cylinder-to-cylinder jacket 15 is formed in the vertical direction on the cylinder-to-cylinder wall portion 14 between the cylinders 3a and 3b provided side by side on the cylinder block 3, and the cylinders 3a and 3b and the cylinders 3a and 3b are arranged in the vertical direction. Cylinder-push rod chamber jackets 18a, 18b are formed in the same manner in the cylinder-push rod chamber wall portion 17 existing between the lateral push rod chambers 16a, 16b, respectively. A jacket 18b between the cylinder and the push rod is provided with a coolant inlet a which is connected to an oil pressure feed passage 19 passing through the regulating valve 12.

Further, one end of the jacket 15 between the cylinders and the jackets 18a, 1 between the cylinders and the push rods are provided.
Communication passages 20a and 20b are provided to communicate with 8b. The communication passages 20a and 20b are provided in the cylinder block 3
The groove formed on the upper surface of the cylinder head 4 is covered with the lower surface of the cylinder head 4. Communication passages 20a, 20b
Can also be formed.

Further, each suction / removal for each cylinder 3a, 3b is performed.
Intervalve cooling passages 23a and 23b running laterally are formed in the wall portion between the exhaust valves 21 and 22, respectively.
The starting ends of a and 23b and the upper ends of the cylinder-push rod jackets 18a and 18b are communication passages 24a and 2b, respectively.
4b, and the inter-valve cooling paths 23a, 23
an auxiliary combustion chamber jacket 26a surrounding the auxiliary combustion chambers 25a, 25b corresponding to the cylinders 3a, 3b at the end of b,
26b are connected to each other.

Then, each auxiliary combustion chamber jacket 26a, 2
One discharge passage 27 connected to 6b is connected to the inlet 8a of the radiator 8 by piping, and the outlet 8b of the radiator 8 is also provided.
And a return hole 28 provided in the cylinder head 4 are connected by piping, and the return hole 28 communicates with an oil pan 9 in the crankcase 2 via a return passage 29 in the cylinder block 3.

That is, the oil sent into the cylinder block 3 through the regulating valve 12 first flows into the rear cylinder-push rod jacket 18b to cool the push rod side of the rear cylinder 3b, and then the oil. Part of the gas reaches the rear side auxiliary combustion chamber jacket 26b through the communication passage 24b and the intervalve cooling passage 23b,
During this period, the inter-valve wall portion and the auxiliary combustion chamber 25b are cooled.

Further, another part of the oil in the rear cylinder-push rod jacket 18b enters the cylinder-to-cylinder jacket 15 through the rear communication passage 20b to cool the cylinder-to-cylinder wall portion 14, and Front passage 20a
Through the inter-cylinder push rod jacket 18a on the front side to cool the push rod side of the front cylinder 3a. Further, the oil in the front cylinder-push rod jacket 18a flows into the front auxiliary combustion chamber jacket 26a through the communication passage 24a and the inter-valve cooling passage 23a, during which the intervalve wall and the front auxiliary combustion chamber 25a
Cooling.

After that, the front and rear auxiliary combustion chamber jackets 26
The high temperature oil discharged from a and 26b enters the radiator 8 through the discharge passage 27 and is forcibly cooled, and the oil whose temperature has dropped is collected in the oil pan 9 through the return hole 28 and the return passage 29.

Incidentally, the return hole 28 and the front valve-to-valve cooling passage 23a.
A relief valve 30 is interposed between the start end of the
When the oil pressure on the inter-valve cooling passage 23a side becomes equal to or higher than the set pressure, the oil is discharged to the return hole 28 side to prevent the high pressure from acting on the radiator 8.

[0018]

According to the present invention, the following effects can be obtained. (1) By providing the jacket between the cylinder and the push rod, it is possible to suppress the overheating in the wall portion of the cylinder on the push rod side and improve the cooling performance of the cylinder block.

(2) Since the cooling liquid is supplied from the rear cylinder side which is located on the lower side of the cooling air passage and is less susceptible to the air cooling effect, part of the liquid cooling is performed more strongly toward the rear side. The temperature difference between the front and rear of the cylinder block is reduced, and thus the thermal strain of the cylinder block can be reduced.

[Brief description of drawings]

FIG. 1 is a side view in which a part of a multi-cylinder overhead valve engine including a partial liquid cooling device according to the present invention is cut away.

FIG. 2 is a vertical cross-sectional rear view of an upper portion of an engine showing a configuration of a liquid cooling device around a front cylinder.

FIG. 3 is a plan view showing a configuration of a liquid cooling device with a cylinder head partially cut away.

FIG. 4 is a schematic perspective view showing a cooling liquid flow path configuration of a liquid cooling device. 1 ... Multi-cylinder overhead valve engine, 3 ... Cylinder block,
3a, 3b ... Cylinder, 6 ... Cooling fan, 7 ... Fan case, 8 ... Radiator, 9 ... Oil pan, 10 ...
Pump, 15 ... Jacket between cylinders, 16a
16b ... Push rod chamber, 17 ... Cylinder-push rod chamber inner wall portion, 18a-18b ... Cylinder-push rod jacket, a ... Coolant inlet,
b ... Coolant outlet.

Claims (1)

[Claims] 1. A cooling fan (6) and a fan case (7) are provided in front of a multi-cylinder overhead valve engine (1), and cooling air generated by the cooling fan (6) is guided by the fan case (7). Then, the cylinder block (3) is configured to be blown from front to back, and between the plurality of cylinders (3a) (3b) arranged in front of and behind the cylinder block (3),
A cylinder of a multi-cylinder overhead valve engine, in which a jacket (15) between cylinders is formed, and a cooling liquid is circulated by a pump (10) between the jacket (15) between cylinders and the radiator (8). In the partly liquid-cooled forced air cooling device of the block, the cylinder push rod inter-wall walls (17) between the cylinders (3a) (3b) and the push rod chambers (16a) (16b) on the side of the cylinders (3a) (3b), respectively. Jacket between cylinder and push rod (18a) (1
8b), the cooling liquid inlet (a) is opened in the jacket (18b) between the cylinder and push rod on the rear side, and the cooling liquid outlet (b) is formed in the jacket (18a) between the cylinder and push rod on the front side. Open and from the cylinder-pushrod jacket (18b) on the last side,
Through the jacket (15) between Linda on the front side of this,
Front jacket between cylinder and push rod (18
A partly liquid-cooled forced air cooling device for a cylinder block of a multi-cylinder overhead valve engine, characterized in that it is configured to communicate with each other in sequence up to a).