JPH0519542Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine cooling system, and particularly to an engine cooling system in which at least two engine cooling systems are arranged around an engine combustion chamber.

[Conventional technology]

If the temperature of the engine combustion chamber is too high, many knocks will occur, and the efficiency of filling intake air will decrease, leading to a decrease in output. On the other hand, since the valve train in the cylinder head generates frictional heat, it is generally desirable to cool the upper side of the combustion chamber by keeping it at a relatively low temperature. On the other hand, it is generally considered desirable to cool the side portions of the combustion chamber and the lower engine cylinder side by keeping them at a high temperature. This is because frictional heat is generated on the sliding surfaces between the combustion chamber wall and the piston, and on the sliding surfaces of the crankshaft bearings, depending on the fit and oil film formation. This is because it is considered a good idea to keep the engine at a high temperature to reduce frictional resistance and suppress a drop in output.

Therefore, a system is known in which the cylinder head side and the cylinder block side are cooled separately using relatively low temperature cooling water and relatively high temperature cooling water.

[Problem that the invention attempts to solve]

However, cooling water usually begins to boil at around 100°C and generates bubbles, so even if such cooling water can be used to keep the sides of the cylinder block relatively high, there is a limit to its temperature. .

The present invention was developed to solve these problems, and by using oil, it is possible to maintain the side peripheral wall of the engine combustion chamber at a relatively high temperature and cool it. An object of the present invention is to provide an engine cooling device that can prevent a decrease in cooling capacity due to air bubbles mixed in.

[Means for solving problems]

Therefore, the engine cooling device of the present invention cools the engine combustion chamber formed by the cylinder head, the cylinder block superimposed on the cylinder head, and the piston sliding inside the engine cylinder of the cylinder block. In order to separate the head side and cylinder block side,
an upper cooling system that cools the cylinder head side;
A lower oil circulation system that cools the cylinder block side is provided separately, and the lower oil circulation system is formed around the engine cylinder and receives cooling oil from one side of the engine cylinder. An oil jacket is provided to allow the cooling oil to flow out from the other side of the engine cylinder, and the oil jacket part on the oil outflow side of the oil jacket is provided with an oil outflow passage in the center in the longitudinal direction of the engine. In order to discharge air bubbles accumulated at the ends of the jacket part, air bubbles are discharged between the upper part of both ends of the oil jacket part on the oil outflow side and the part communicating with the oil pan connected to the lower part of the cylinder block. It is characterized by an intervening passageway.

[Effect]

In the engine cooling system of the present invention described above, the engine cylinder is cooled while being maintained at a relatively high temperature by the cooling oil in the oil jacket. In addition, in the oil jacket part on the oil spill side of the oil jacket, the oil outlet is only in one part in the center, so the resistance in the oil discharge passage is large, and the cooling oil fills up to the top of the discharge passage before exiting. The effect is that cooling can be performed up to the top of the side oil jacket. Furthermore, since there are bubble discharge passages at both ends, even if the engine is tilted due to whether the vehicle is running or stopped, the bubbles at the outlet end of the oil jacket can be reliably discharged.

〔Example〕

Below, an engine cooling system as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a side view thereof, Fig. 2 is a horizontal sectional view thereof, Fig. 3 is an exploded perspective view of its main parts, and Fig. 4 is an exploded perspective view of its main parts. 5 is an explanatory diagram of the three-part cooling system, and FIG. 6 is a side view showing a modification thereof corresponding to FIG. 1.

Now, this embodiment relates to a cooling system for a 4-cycle DOHC in-line 4-cylinder engine. As shown in FIGS. 3 and 4, the main body of this engine includes a cylinder block 1 and its upper side. It consists of a cylinder head 2, a cylinder head upper 3 above it, a cylinder head cover 4 above it, a crank cover 5 below the cylinder block 1, and an oil pan 6.

A crankshaft 7 which is long in the longitudinal direction of the engine (perpendicular to the plane of the paper in FIG. 4) is housed in the center of the lower part of the cylinder block 1. Therefore, a plurality of crankshafts 7 for pivotally supporting the crankshaft 7 are housed in this part. A crank bearing 8 is provided, the upper part 8a of which is integrally formed at the bottom of the cylinder block 1.

The lower portion 8b of the crank bearing 8 is integrally formed within the crank cover 5, which overlaps the upper portion 8a on the cylinder block 1 side from below. The crank cover 5 has a ladder shape consisting of left and right skirt parts 5a, 5b and lower parts 8b of a plurality of crank bearings 8 arranged in tandem between them (see Fig. 3). The peripheral portion of the cylinder block 1 is tightened by a plurality of bolts 9, and has an upper portion 8a and a lower portion 8b.
The crank bearing 8 consisting of both members is tightened with a plurality of through bolts 10, respectively.

Further, the downward opening of the crank cover 5 is closed by an oil pan 6, and an oil pump 11 for supplying lubricating oil in the oil pan 6 to various parts of the engine is housed in a part of the oil pan 6. Note that this oil pump 11 is driven by the crankshaft 7 via a chain or the like.

On the side peripheral wall of the cylinder block 1, four liner parts 13 are formed in tandem as an inner peripheral wall member that accommodates a piston 12 that slides up and down, and a separate liner part 13 is formed to cover these liner parts 13. A plate-shaped cover 14 as a formed outer peripheral wall member
A, 14B, 14C, and 14D are attached, and these liner portions 13 and covers 14A to 14D constitute an oil jacket 15 sealed therebetween. That is, as shown in FIG. 3, this liner part 13 has pillar parts 16 at the four corners, and four pillar parts 16 on the front, rear, left and right sides are connected to these four pillar parts 16 and the upper and lower flange parts 13a through packings (not shown). Plate-shaped covers 14A to 14D are bolted. In this way, the liner section 13 and the covers 14A to 14
The annular space between D and the oil jacket 15
is formed as.

In FIG. 4, a horizontal protrusion 13b that is long in the longitudinal direction of the engine is formed at the lower end of the liner part 13 forming the left side peripheral wall, and the tip of this protrusion 13b comes into close contact with the inner wall surface of the cover 14A. An oil jacket 15 is formed above the protrusion 13b, and an oil gear gallery 17 is formed below the protrusion 13b. These oil jackets 15
The oil gear gallery 17 is located in the lower oil circulation system 43 (see FIG. 5), and the oil gear gallery 17 is connected to a high pressure oil passage 18 formed in the lower wall of the cylinder block 1.
It is connected to the discharge port of the oil pump 11 via an oil cleaner 19 attached to the outside of the lower part of the cylinder block 1, a high pressure oil pipe 20, etc. Also,
Projection 13b which becomes the upper wall of this oil gear rally 17
A check valve 22 as a pressure regulating means is provided at a predetermined position.The check valve 22 lowers the hydraulic pressure of the high pressure oil in the oil gear gallery 17 by a predetermined amount, and also lowers the oil pressure in the low pressure oil in the oil jacket 15. The oil can flow into the oil jacket 15 which is long in the longitudinal direction of the engine.

Further, on the outside of the cover 14B forming the outer wall of the oil spill side oil jacket portion 15B drawn on the right side in FIG. 4, a return path 23 (this return path 23 (which constitutes a bubble discharge passage as described later) are integrally formed. The return path 23 and the oil jacket 15 are integrated with the cover 14B and are connected to the oil outlet side oil jacket portion 1.
Three openings 2 formed at the upper edge of the full plate 14B-1 that partitions the return path 23 and the return path 23.
It communicates with 4A, 24B, and 24C.

And, the opening 24A is the full plate 14B.
There is a large gap in the center of -1 in the longitudinal direction,
As a result, the openings 24B and 24C function as oil overflow holes, and the openings 24B and 24C
There are small openings at both longitudinal ends of B-1, which function as air bubble discharge ports for discharging air bubbles that remain near the top surface of both ends of the oil jacket portion 15B on the oil outflow side.

Further, the lower end of the wide return path 23 on the outside of the cover 14B is connected to an oil gear rally 26 through a plurality of communication holes 14B-2. Note that this oil gear rally 26 is connected to the crank chamber 25.
It has a return port 26A open at the top. Also,
A curved plate 27 is arranged in the crank chamber 25 below the return port 26A, so that the oil from the return port 26A can smoothly flow down into the oil pan 6 below. Therefore, oil is oil gear 17
The amount supplied into the oil jacket 15 from the overflow hole 24A and air bubble discharge ports 24B, 2
The oil overflows from the oil tank 4C and returns to the oil pan 6, and a predetermined amount of oil is always held in the oil jacket 15 as it circulates.

Furthermore, double annular grooves 29a and 30a are formed at the upper end edge of the cylinder block 1 to annularly surround the engine combustion chamber 28 formed by the cylinder head 2, cylinder block 1, and piston 12. Of these, the inner annular groove 29a
is formed to extend downward from the upper end by an extension amount H.

On the other hand, the cylinder head 2 forming the upper peripheral wall of the combustion chamber 28 is connected to the intake port 31 of each combustion chamber 28.
is connected to the intake manifold 32, and the exhaust port 33 is connected to the exhaust manifold 34, respectively, and intake and exhaust valves 35 and 36 are housed therein. In addition, a downward annular groove 29 opening downward is provided at the lower end of the groove.
b, 30b, which oppose the double upward annular grooves 29a, 30a on the cylinder block 1 side to constitute the water jacket 29 and the water gear gallery 30 outside thereof. Note that the water jacket 29 is formed to extend upward so as to surround the intake port 31 and the exhaust port 33.

Both the water gear 30 and the water jacket 29 are in the cooling water circulation system 44 (see FIG. 5), and the water gear 30 receives the cooling water discharged from the water pump (not shown) and diverts it toward the water jacket 29. Supply evenly. That is, the water gear gallery 30 and the water jacket 29 communicate with each other through communication holes 37 having different inner diameters at a plurality of locations. Further, an outlet (not shown) is formed at a predetermined position of the water jacket 29, and the cooling water discharged from this outlet is returned to the water pump (not shown) via a cooling water pipe (not shown). It's getting old.

The cylinder head asper 3 superimposed on the upper side of the cylinder head 2 is the upper part of the cylinder head in a broad sense, and carries the intake camshaft 38, exhaust camshaft 39, intake valve spring 40, exhaust valve spring 41, etc. that make up the valve train. accommodate. Also, this cylinder head opening 3
A plurality of through holes for through bolts 10 are formed in the bottom wall of the cylinder, and these through bolts 10 integrally connect the cylinder head upper 3, the cylinder head 2, the cylinder block 1, and the crank cover 5. Here, a cylindrical guide column 102 as shown in FIG. 3 is provided at the portion of each through bolt 10 that passes through the oil jacket 15, and each through bolt 10 passes through each cylindrical guide column 102. Penetrating.

In addition, the valve train in the camshaft chamber 42 surrounded by the cylinder head upper 3 and the cylinder head cover 4 is connected to an upper cooling system 45 separate from the crank chamber 25 side.
(see Figure 5) and cooled. That is, an oil pump (not shown) is attached to the end of the intake camshaft 38, and operates to supply oil on the bottom wall of the camshaft chamber 42 to the sliding surfaces in the valve system.

With the above-mentioned configuration, when such an engine cooling system is operated, the upper circumferential wall of the combustion chamber 28, the cylinder head 2, and the portion of the cylinder block 1 extending downward from the upper end thereof to the extent H are covered with water jackets 29. Cooled by circulating cooling water. At the same time, the main part of the engine cylinder, which is the side peripheral wall of the combustion chamber 28 (excluding the upper end from the upper end to the extension amount H), and the crank chamber 25 side are:
Cooled by cooling oil in the lower oil circulation system 43 including the oil jacket 15 and oil pan 6,
Or be lubricated. Further, the valve train side is cooled and lubricated by oil in the upper cooling system 45.

In this way, when the engine body shown in Fig. 4 is driven, the engine cooling system, which is divided into three parts, operates independently, and by keeping the upper circumferential wall of the combustion chamber 28 at a relatively low temperature, the occurrence of knocks is suppressed. , the expansion of the intake air is suppressed to improve the filling efficiency, and the oil film is formed while keeping the sliding surfaces between the liner section 13 and the piston 12 and the crank bearing 8 at a relatively high temperature. It is possible to significantly reduce the frictional resistance of the parts and improve the output. In particular, compared to water, the oil in the oil jacket 15 can suppress the generation of bubbles even at high temperatures, and uneven cooling of the liner section 13 is less likely to occur.

Also, when oil is introduced into the oil jacket part 15A and goes around the oil jacket part 15B on the oil spill side, both ends of the oil jacket part 15B on the oil spill side (represented by symbols A and B in FIG. 2) Even if air bubbles remain in the oil jacket (see section 15B), the air bubbles are discharged along with a small amount of oil to the return path 23 side through the air bubble discharge ports 24B and 24C, so that air bubbles do not accumulate at both ends of the oil jacket part 15B. . Therefore, even if the engine is tilted due to the running or stopped state of the vehicle, the air bubbles in the oil jacket on the outlet side can be reliably discharged through either of the air bubble discharge ports, and the cooling performance is improved by these air bubbles. The decline can be prevented. This provides sufficient cooling performance.

Note that the air bubbles and the oil discharged together with the air bubbles are discharged from the return path 23 through the communication hole 14B-2, through the oil gear gallery 26, and toward the oil pan 6 side.

That is, the return path 23 also functions as a bubble discharge path.

Furthermore, the oil in the oil jacket 15 overflows from the overflow hole 24A at the highest position in the oil jacket 15 and returns to the oil pan 6 side through the return path 23, the communication hole 14B-2, and the oil gear gallery 26. ,
For example, even if bubbles occur in the oil jacket 15, they are not only effectively removed by the bubble discharge ports 24B and 24C, but also quickly flowed out from the oil jacket 15 by the overflow hole 24A. be able to.

Overflow hole 24A is oil jacket 1
5, the resistance of the oil discharge passage is large, and cooling oil fills up to the top of the discharge passage and cools down to the top of the outlet side oil jacket 15B. It can be done.

In addition, by maintaining a sufficient volume of the oil jacket 15, the oil pan 6 side only needs to contain the minimum amount of oil necessary, and as a result, the total height of the engine body can be reduced by downsizing the oil pan 6. It also has the advantage of being able to reduce

Note that an oil drain hole communicating with the oil pan 6 may be provided at the substantial lower end of the oil jacket portion 15B, and this oil drain hole may be closed by a drain plug so as to be openable and closable. The oil accumulated in the oil pan 6 can be quickly drained from the oil drain hole by removing the drain plug.

In addition, as shown in FIG. 6, the communication hole 14B-2 between the return path 23 and the oil gear rally 26 is located at one location in the center, and the air bubbles discharged from the air bubble discharge ports 24B and 24C are directed toward the center of the cover 14B and collected. The overflow oil may be discharged through one communication hole 14B-2 together with the overflow oil from the overflow hole 24A.

[Effect of idea]

As detailed above, the engine cooling device of the present invention provides the following effects and advantages.

(1) The engine combustion chamber is cooled separately on the cylinder head side and cylinder block side, so
The cooling oil in the oil jacket allows the engine cylinder to be cooled while being kept at a relatively high temperature, thereby contributing to improved output.

(2) The resistance of the oil discharge passage is large, so that the cooling oil fills up to the top of the discharge passage and can cool the oil jacket up to the top of the outlet side oil jacket.

(3) Since there are bubble discharge passages at both ends, it is possible to achieve the effect that the bubbles at the end of the oil jacket on the outlet side can be reliably discharged even if the engine is tilted due to whether the vehicle is running or stopped. (4) The air bubbles accumulated in the oil jacket part on the oil outflow side can be efficiently discharged to the oil pan side, thereby sufficiently preventing the air bubbles from reducing the cooling capacity.

[Brief explanation of the drawing]

The figures show an engine cooling system as an embodiment of the present invention, in which Fig. 1 is a side view thereof, Fig. 2 is a horizontal sectional view thereof, Fig. 3 is an exploded perspective view of its main parts, and Fig. 4 5 is a longitudinal sectional view thereof, FIG. 5 is an explanatory diagram of its three-part cooling system, and FIG. 6 is a side view showing a modification thereof corresponding to FIG. 1. 1... Cylinder block, 2... Cylinder head, 3... Cylinder head upper, 4... Cylinder head cover, 5... Crank cover, 6...
Oil pan, 7...Crankshaft, 8...Crank bearing, 8a...Top portion of crank bearing, 8b...
...Lower part of crank bearing, 9...Bolt, 10...
...Through bolt, 11...Oil pump, 12...
Piston, 13...liner part, 13a...flange part, 13b...projection, 14A-14D...cover, 14B-1...buttful plate, 14B-
2...Communication hole, 15...Oil jacket, 15
A...Oil inflow side oil jacket part, 15B...
... Oil jacket part on oil spill side, 16 ... Pillar part, 17 ... Oil gear gallery, 18 ... High pressure oil path, 19 ... Oil cleaner, 20 ... High pressure oil pipe, 21 ... Drain plug, 22 ... Check Valve, 23...Return passage that also serves as a bubble discharge passage, 24A...Overflow hole, 24B, 2
4C...Bubble outlet, 25...Crank chamber, 26
...Oil gear gallery, 26A...Return port, 27...
... Curved plate, 28 ... Engine combustion chamber, 29 ... Water jacket, 29a, 29b ... Annular groove,
30...Water gear rally, 30a, 30b...
Annular groove, 31...Intake port, 32...Intake manifold, 33...Exhaust port, 34...Exhaust manifold, 35...Intake valve, 36...Exhaust valve,
37...Communication hole, 38...Intake camshaft, 39...
Exhaust camshaft, 40...Intake valve spring, 41...Exhaust valve spring, 42...Camshaft chamber, 43...Lower oil circulation system, 44...Cooling water circulation system, 45...Upper cooling system, 102... Cylindrical guide column.

Claims (1)

[Scope of utility model registration request] Cooling of the engine combustion chamber formed by the cylinder head, the cylinder block superimposed on the cylinder head, and the piston sliding inside the engine cylinder of the cylinder block is separated between the cylinder head side and the cylinder block side. In order to achieve this, an upper cooling system that cools the cylinder head side and a lower oil circulation system that cools the cylinder block side are provided separately. An oil jacket is provided to allow cooling oil to flow in from one side of the engine cylinder and to flow out from the other side of the engine cylinder, and the oil jacket part on the oil outflow side of the oil jacket is located along the length of the engine. An oil spill passage is provided in the center of the direction, and in order to discharge air bubbles that accumulate at the end of the oil jacket part on the oil spill side, an oil spill passage is provided in the upper part of both ends of the oil jacket part on the oil spill side and in the lower part of the cylinder block. An engine cooling device characterized in that a bubble discharge passage is interposed between the part communicating with the connected oil pan.