JPH0437227Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Fields> The present invention relates to a partial liquid cooling system for the cylinder head of an engine, which can effectively prevent thermal distortion of the headblock, and which can effectively prevent the cooling liquid passage provided in the headblock. In addition to being easy to form, the increase in the number of parts can be minimized.

<Prior Art> The forced air cooling system has a relatively simple configuration as a cooling system and is advantageous in reducing the weight of the engine, so it is widely adopted in relatively inexpensive engines. However, when such a cooling system is adopted for an overhead valve type pre-chamber engine, such as an overhead valve type pre-chamber diesel engine, or a gasoline engine with a pre-chamber for achieving lean combustion, the formation of the headblock becomes difficult. It is difficult to uniformly air-cool the headblock because of the complexity. As a result, thermal distortion occurs in the cylinder head,
Problems such as loss of engine performance and durability arise.

In order to solve this problem, for example, as shown in Japanese Patent Application Laid-Open No. 57-81113, a liquid cooling method is adopted in which the entire headblock is liquid-cooled, and the headblock is configured to have a uniform temperature. has already been proposed. However, such a liquid cooling system in which the entire headblock is liquid cooled requires a relatively large amount of coolant, which is disadvantageous in terms of reducing the weight of the engine.

Therefore, it is conceivable to cool only the portions of the headblock that tend to reach high temperatures with a liquid such as water or oil to make the temperature distribution of the headblock uniform and prevent the occurrence of thermal distortion.

Conventionally, as a technology to partially cool the high-temperature parts of the engine using an oil cooling method, for example,
As disclosed in Japanese Patent No. 47621, it is known to cool the area around the exhaust hole of a horizontally opposed engine using lubricating oil that naturally flows.

<Problems to be Solved by the Invention> However, the above-mentioned conventional technology is applied to a two-stroke engine in which the exhaust hole is formed on the circumferential surface of the cylinder, and cannot be applied generally.

The present invention was devised in consideration of the above circumstances, and can effectively prevent thermal distortion of the headblock. Moreover, it can easily form the coolant passage provided in the headblock, and it also requires an increase in the number of parts. It is an object of the present invention to provide a partial liquid cooling device for a cylinder head of an engine, which is constructed so as to be able to minimize the amount of liquid cooling.

<Means for Solving the Problems> As a means for achieving the above object, the present invention is constructed as follows, as shown in FIGS. 1 to 4, for example.

That is, a coolant jacket 32 is formed in the headblock 3, a liquid rising passage 34 and a liquid falling passage 33 are formed side by side and extend in the vertical direction in the headblock 3, and the liquid rising passage 34 is formed side by side from the side of the headblock 3.
A through hole 36 passes through the liquid drop passage 33 and reaches the coolant jacket 32 formed in the head block 3.
and the terminal end of the external piping 38 led out from the cooling liquid jacket 32 to the outside of the head block 3,
The through hole 36 is connected to the liquid drop passage 33 via a joint 39 attached to the outer end thereof, and this joint 39 is extended into the partition wall 41 that partitions the liquid rise passage 34 and the liquid fall passage 33. This joint 39 is characterized in that the through hole 36 is divided into a coolant introduction path 42 which communicates the liquid riser path 34 with the coolant jacket 32, and a droplet path 33.

<Function of the device> The coolant flows through the riser passage 34, the coolant introduction passage 42, the coolant jacket 32, the external piping 38, and the droplet passage 3.
Cycle through 3. As a result, head block 3
In this case, the high-temperature part is liquid-cooled, making the temperature distribution uniform and preventing the occurrence of thermal distortion.

In addition, the coolant introduction path 42 of the head block 3
and a joint 3 that connects the external pipe 38 to the droplet path 33.
9 is formed as one through-hole 36, so by forming this through-hole 36 using one core during casting or by drilling it with a drill after casting, it is possible to The passage for the cooling liquid inside the tube can be easily formed.

Furthermore, the joint 39 is extended into the partition wall 41 that partitions the liquid rising path 34 and the liquid falling path 33, and the through hole 36 is
is divided into a coolant introduction path 42 on the rising liquid path 34 side and a liquid descent path 33 by this joint 39, and the joint 39 is also used as a plug that partitions the cooling liquid introduction path 42 and the liquid descent path 33. Therefore, the increase in the number of parts can be minimized.

Note that water, oil such as circulating oil, or an aqueous ethylene glycol solution should be used as the coolant circulating in the rising liquid passage 34, the cooling liquid introduction passage 42, the cooling liquid jacket 32, the external piping 38, and the liquid falling passage 33. By the way,
This coolant may be circulated by natural convection or may be forced to circulate using a pump.

Further, the through hole 36 is connected to a partition wall 4 that partitions the liquid rising path 34 and the liquid falling path 33 from the outer end surface of the head block 3.
1 may be a straight line, but in order to reduce costs, it is advantageous for the entire length from the outer end surface of the head block 3 to the coolant jacket 32 to be a straight line.

There is no problem in interposing the coolant cooler 37 in the external piping 38, but when lubricating oil that lubricates various parts of the engine is used as the coolant, the heat of the lubricating oil used for cooling inside the oil pan may If sufficient diffusion is achieved, the coolant cooler may be omitted.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

FIG. 1 is a vertical cross-sectional rear view of the main parts of a partial liquid cooling system for a forced air-cooled overhead valve pre-compartment engine according to an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional side view of the engine. 3 is a rear view of the engine, and FIG. 4 is a cross-sectional plan view taken along the line A--A in FIG. 1.

The forced air-cooled overhead valve pre-chamber type diesel engine shown in FIGS. 1 to 4 includes a crankcase 1 and a cylinder block 2 that are integrally cast from aluminum alloy, and an aluminum alloy head block 3 is coupled to the upper side of the crankcase 1 and cylinder block 2. Ru. A crankshaft 4, a balancer shaft 5, and a valve drive camshaft 6 are each pivotally supported on the crankcase 1. A front end 4a of the crankshaft 4 projects forward of the crankcase 1, and a cooling fan 7 is fixed to the front end 4a of the crankshaft 4. The cooling fan 7 and the front of the engine are covered with a wind guide case 8, and the air taken in by the cooling fan 7 from the air intake port 9 formed at the front of the wind guide case 8 is guided to the wind guide case 8 as cooling air. It is then supplied to the cylinder block 2 and head block 3 of the engine. Further, a trochoid type lubricating oil pump 10 is incorporated into the rear wall 1a of the crankcase 1. This lubricating oil pump 1
0 is interlocked with the crankshaft 4 through a gear device 11, pumps lubricating oil from oil pans 12 and 47 formed at the bottom of the crankcase 1 through an oil strainer 13, and pumps up lubricating oil through an oil strainer 13 to the rear wall 1 of the crankcase 1.
a. It is configured to supply lubricating oil to each part of the engine via a lubricating oil supply path 14 formed inside the crankshaft 4 and the like.

From the middle of this lubricating oil supply path 14 to the cooling oil outgoing path 1
5 is branched, and this cooling oil outgoing path 15 passes through the rear wall 1a of the crankcase 1 and is led to the lower part of one side of the cylinder block 2. cylinder block 2
There is a push rod chamber 18 on one side of the
An oil lifting passage 17 extending in the vertical direction is formed in the partition wall 16 that partitions the push rod chamber 18 and the main combustion chamber 43. Inserted into the push rod chamber 18 are the upper part of the tappet 20 that moves up and down according to the cam 19 of the valve drive camshaft 6, and the push rod 21 that comes into contact with the upper end of the tappet 20 and moves up and down following the tappet 20. be done. The liquid raising path 17 and the push rod chamber 18 extend to the joint surface between the cylinder block 2 and the head block 3. An oil return hole 22 communicating with the crank case 1 is formed in the bottom wall of the push rod chamber 18. An oil return hole and blazer passage 26 is formed in the front side of the cylinder block 2 to communicate the crank room 23 in the crank case 1 with the rocker arm chamber 25 in the head cover 24.

The head block 3 assembled on the upper end surface of the cylinder block 2 of this engine has a subchamber 27 on one side and intake valve seats 28 arranged front and rear in the center.
and an exhaust valve seat 29, and an intake valve seat 2.
8 to head block 3 through the front side of subchamber 27.
An intake port 30 extending to one side of the exhaust valve seat 2
9 and an exhaust port 31 extending rearward. A cooling liquid jacket 3 is installed around the subchamber 27.
A push rod insertion passage 33 is formed on the other side of the head block 3 as a liquid drop passage that extends in the vertical direction and communicates with the push rod chamber 18. Further, a liquid elevating path 34 is formed on one side of the push rod insertion passage 33, communicating with the liquid elevating path 17 of the cylinder block 2 and extending in the vertical direction. Also, it penetrates the push rod insertion passage 33 and the liquid rising passage 34 from the other side of the headblock 3,
In addition, a through hole 36 is formed which passes through the wall portion 35 between the intake port 30 and the exhaust port 31 and reaches the coolant jacket 32. An external piping 38 with an oil cooler 37 interposed therein is led out from one side of the cooling liquid jacket 32, and this external piping 3
The terminal end of 8 is connected to the push rod insertion passage 33 via a joint 39 attached to the outer end of the through hole 36. The inner end 40 of this joint 39 is extended into the partition wall 41 that partitions the liquid riser passage 34 and the push rod insertion passage 33, and the through hole 36 is connected to the liquid riser passage 34 side with the inner end 40 of this joint 39. It is divided into a coolant introduction path 42 and a push rod insertion path 33. The oil cooler 38 is cooled by a portion of the cooling air supplied from the cooling fan 7 and guided by the air guide case 8, for example.

Note that if the amount of oil supplied to the coolant jacket 32 is sufficiently large and the temperature rise of the lubricating oil is relatively small, or if the total amount of lubricating oil is sufficiently large and the heated lubricating oil is mixed with other lubricating oils. If the oil cooler 37
can be omitted. Also, the relatively low temperature part of the headblock 3, that is, the intake port 30
The peripheral wall of the exhaust port 31, the upper wall of the main combustion chamber 43 having the intake valve seat 28 and the exhaust valve seat 29, etc. are forced by cooling air supplied from the cooling fan 7 and guided by the air guide case 8. Air cooled. Furthermore, the crankcase 1 of this engine is fixed to the upper surface of a hollow box-shaped engine stand 44 as required. In this case, if necessary, a pair of front and rear communication holes 46 are formed across the bottom wall 1b of the crankcase 1 and the upper wall 45 of the engine stand 44, so that the internal space 47 of the engine stand 44 is connected to the inside of the crank room 23. It is used as an auxiliary oil pan to increase the capacity of the oil pan 12 formed at the bottom. The crankcase side portion and the engine stand side portion of each communication hole 46 are inserted between the engine mounting surface 48 that is originally machined and the engine mounting surface 49 of the engine stand 44 that is machined opposite thereto. They are connected in an oil-tight manner by a packing 50. In this way, when connecting the crankcase 1 side of the communication hole 46 and the engine stand 44 side via the packing 50, the machining accuracy of the communication hole 46 on the crankcase 1 side and the engine stand 44 side is determined by, for example, as-cast. This means that the processing cost can be reduced to a certain extent.

In the above structure, the head block 3 and the cylinder block 2 as a whole are connected to the cooling fan 7.
Forced air cooling is performed by cooling air supplied by the air guide case 8 and guided by the air guide case 8.

By the way, the partition wall 16 directly receives the combustion heat in the main combustion chamber 43, and also receives the combustion heat in the push rod chamber 18.
Since the cylinder 21 is isolated from the cooling air passage by a cooling method using only forced air cooling, the cylinder 21 essentially constitutes a high temperature section, and the temperature distribution in the circumferential direction of the cylinder 21 becomes uneven. In addition, the area around the subchamber 27 of the head block 3 is directly overheated by combustion in the subchamber 27, and the cooling air is blocked by the intake port 30, resulting in a small amount of cooling air. , 31 is the exhaust valve seat 28.
In addition to being overheated by high-temperature exhaust gas passing through the exhaust port 31 and the exhaust port 31, the cooling air is blocked by the intake port 30, so the temperature increases in a cooling method using only forced air cooling.

However, by cooling these high-temperature parts with lubricating oil that is forcibly circulated, they are prevented from increasing in temperature, and the temperature distributions of the cylinder block 2 and cylinder head 3 are made uniform.

That is, after the lubricating oil in the oil pan 12 is filtered by an oil strainer 13, it is supplied to various parts of the engine by the lubricating oil pump 10 via a lubricating oil supply path 14 on the one hand, and a cooling oil outgoing path 15 on the other hand.
is guided to the partition wall 16 through the. and liquid rising path 17
While passing through from bottom to top, the heat stored in the partition wall 16 is taken away, and while passing through the coolant introduction path 42, the wall portion 35 between the intake and exhaust ports 30 and 31 is cooled, and furthermore, the coolant jacket is cooled. While passing through the oil cooler 32 , the peripheral wall of the auxiliary chamber 27 is cooled and the oil is sent to the oil cooler 37 . Then, the oil pan 12 is cooled by the cooling air supplied from the cooling fan 7 and guided by the air guide case 8 in the oil cooler 37.
will be returned to. In this oil pan 12, the heat of the lubricating oil returned to the oil pan 12 is diffused to the internal space 47 of the engine stand 44 as an auxiliary oil pan and the lubricating oil inside the oil pan 12, and the lubricating oil is cooled to a predetermined temperature. I will do it. In this way, the heat accumulated in the high-temperature parts of the cylinder block 2 and head block 3 is absorbed by the lubricating oil and removed, thereby preventing the cylinder block 2 and head block 3 from becoming locally heated, thereby improving the temperature distribution of the cylinder block 2 and head block 3. will be held uniformly. As a result, occurrence of thermal distortion in the cylinder block 2 and head block 3 is prevented, and deterioration in output and durability due to thermal distortion of the cylinder block 2 and head block 3 is prevented.

In addition, the coolant introduction path 42 of the head block 3
The through hole 3 has one hole for mounting a joint 39 for connecting the external piping 38 to the push rod insertion passage 33.
6, the coolant in the head block 3 can be formed by using one core (not shown) during casting, or by drilling it with a drill (not shown) after casting. A passageway can be easily formed.

Furthermore, the inner end 40 of the joint 39 is extended into the partition wall 41 that partitions the liquid lifting path 34 and the push rod insertion path 33, and the through hole 36 is connected to the liquid lifting path 34 side with the inner end 40 of the joint 39. The joint 39 is divided into a coolant introduction path 41 and a push rod insertion path 33.
The coolant introduction passage 42 and the push rod insertion passage 33
Since the stopper also serves as a partition between the two parts, the increase in the number of parts can be minimized.

The through hole 36 is connected to the coolant introduction passage 42 and the push rod insertion passage 33 from the outer end surface of the cylinder head 3.
It suffices if the distance to the partition wall 42 that separates the
It is advantageous if it is straight over the entire length up to 2.

In addition, the liquid rising passages 17 and 34, the cooling liquid introduction passage 41,
The coolant that circulates in the coolant jacket 32, external piping 38, push rod insertion passage 33, and push rod chamber 18 includes lubricating oil that is shared with the engine's lubrication system, as well as oil that is circulated independently of the engine's lubrication system. Oil such as lubricating oil, water, ethylene glycol aqueous solution (antifreeze), etc. may be used, and this coolant may be forced to circulate or may be circulated by natural convection.

<Effects of the Invention> The present invention is configured and operates as described above, and thus has the following effects.

Since the coolant is circulated only to the high-temperature parts of the cylinder head and the high-temperature parts are liquid-cooled, the temperature distribution of the cylinder head can be made uniform with a relatively small amount of coolant, which improves performance and durability due to thermal distortion of the cylinder head. It is possible to prevent a decrease in performance and is also advantageous in terms of reducing the weight of the engine.

In addition, the coolant introduction path of the headblock and the hole for installing the joint that connects the external piping to the downflow path are
Since it is formed as a single through hole, this through hole can be formed using a single core during casting, or by drilling it after casting, making it easy to create a passage for the coolant inside the headblock. It can be formed easily and inexpensively.

Furthermore, the joint that connects the external piping and the downfall path,
Since it is also used as a stopper that divides the coolant inlet passage and the droplet passage on the liquid riser side in the headblock, the increase in the number of parts can be minimized, which is even more advantageous in terms of cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional rear view of the main parts of a partial liquid cooling system for a cylinder head of an engine according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional side view of the engine, and FIG. 3 is a rear view of the engine. Figure 4 is A- in Figure 1.
It is an A-line cross-sectional plan view. 2...Cylinder block, 3...Head block, 27...Subchamber, 30...Intake port, 31...
...Exhaust port, 32...Cooling fluid jacket, 33
...Liquid descending path, 34...Liquid rising path, 35...Fall wall portion,
36...Through hole, 38...External piping, 39...Joint, 41...Partition wall, 42...Cooling liquid introduction path.

Claims (1)

[Claims for Utility Model Registration] 1. A cooling liquid jacket 32 is formed in the headblock 3, a liquid rising passage 34 and a liquid falling passage 33 extending in the vertical direction are formed side by side in the headblock 3, and Liquid path 3
A through hole 36 is formed that passes through the cooling liquid jacket 4 and the liquid drop passage 33 and reaches the cooling liquid jacket 32 formed in the head block 3, and the terminal end of an external piping 38 led out from the cooling liquid jacket 32 to the outside of the head block 3 is formed. , connected to the liquid descending path 33 via a joint 39 attached to the outer end of the through hole 36, and extending this joint 39 into the partition wall 41 that partitions the liquid rising path 34 and the liquid descending path 33; A partial liquid supply system for a cylinder head of an engine characterized in that the through hole 36 is divided by the joint 39 into a coolant introduction passage 42 that communicates the liquid riser passage 34 with the coolant jacket 32, and a liquid drop passage 33. refrigeration equipment. 2. Utility model registration claim 1, characterized in that the cooling liquid jacket 32 is formed around the auxiliary chamber 27 disposed in the head block 3.
Partial liquid cooling system for the cylinder head of the engine described in 2. 3 The coolant introduction path 42 is connected to the head block 3.
A cylinder of an engine according to claim 1 or 2 of the utility model registration claim, characterized in that the engine cylinder is formed to pass through a wall portion 35 between an intake port 30 and an exhaust port 31 in the engine cylinder. Head partial liquid cooling system.