JPH0517377Y2 - - 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 a combustion chamber.

<Prior art> If the temperature of the combustion chamber of an engine is too high, knocks will occur frequently, and the filling efficiency of 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 surface between the combustion chamber wall and the piston, the sliding surface of the crankshaft bearing, etc., depending on the fitting condition and oil film formation. kept at a relatively high temperature,
This is because it is considered a good idea to reduce the frictional resistance and suppress the drop in output.

Based on this intention, 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 seeks to solve> However, since cooling water usually begins to boil at around 100°C and generates bubbles, it is difficult to keep the sides of the cylinder block at a relatively high temperature with such cooling water. However, there is a limit to that temperature.

The present invention solves these problems by using oil to cool the side peripheral wall of the combustion chamber by keeping it at a relatively high temperature, and also to make it easier to drain the oil. The purpose is to provide engine cooling equipment.

<Means for Solving the Problems> To achieve this objective, the engine cooling system according to the present invention has a structure including a cylinder in which a piston is slidably housed, and a cooling device formed around the cylinder. An oil jacket for holding oil, an overflow hole formed at the substantially top of the oil jacket, and an overflow hole disposed at the substantially bottom of the engine to flow out of the oil jacket through the overflow hole. an oil pan in which the coolant oil held in the oil pan is held; a cooling oil pressure sending means for force-feeding the coolant oil held in the oil pan to the oil jacket; The oil drain hole communicates with the oil jacket and the oil pan, and the oil drain hole is operated from the outside of the cylinder to move between a first position where the oil drain hole is closed and a second position where the oil drain hole is opened. It is characterized by comprising a drain plug disposed in the cylinder.

<Operation> The cooling oil in the oil jacket cools the engine cylinder while keeping it at a relatively high temperature. Furthermore, when the drain plug is removed during an oil change, the oil drain hole opens and the oil in the oil jacket is drained from there into the oil pan.

<Example> Hereinafter, an example in which the present invention is applied to a 4-cycle DOHC engine will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of an engine cooling system according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the main parts of the same device, and FIG. 3 is an explanatory diagram of the three-part cooling system of the same device. There is.

As shown in FIGS. 1 and 2, this engine body includes a cylinder block 1, a cylinder head 2 above it, a cylinder head upper 3 above it,
It consists of a cylinder head cover 4 on the upper side, a crank cover 5 on the lower side of the cylinder block 1, and an oil pan 6.

A crankshaft 7 that is long in the longitudinal direction of the engine (perpendicular to the plane of the paper in FIG. 1) is housed in the center of the lower part of the cylinder block 1, and therefore, a plurality of cranks for pivotally supporting the crankshaft 7 are accommodated therein. A bearing 8 is provided, and its upper portion 8a is integrally formed with the lower portion 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 crankshafts 8 arranged between them (see Fig. 2). The peripheral portion of the 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.

A liner section 13 as an inner circumferential wall member housing a piston 12 that slides up and down is formed on the side circumferential wall of the cylinder block 1, and an outer circumferential wall member formed separately to cover the liner section 13. A plate-shaped cover 14 is attached, and the liner portion 13 and cover 14 constitute an oil jacket 15 sealed therebetween. That is, this liner section 13, as shown in FIG.
Pillar portions 16 are provided at the four corners, and four plate-shaped covers 14 on the front, rear, left and right sides are bolted to these four pillar portions 16 and the upper and lower flange portions 13a via gaskets (not shown).

In FIG. 1, a long horizontal protrusion 13b extending in the longitudinal direction of the engine is formed at the lower end of the liner portion 13 forming the left side peripheral wall, and the tip of the protrusion 13b comes into close contact with the inner wall surface of the cover 14. The projecting rim 13b defines an oil jacket 15 on the upper side and an oil gear rally 17 on the lower side. These oil jackets 1
5 and the oil gear rally 17 are located in the lower oil circulation system 43 (see Fig. 3), and the oil gear rally 17 includes a high pressure oil passage 18 formed in the lower wall of the cylinder block 1, and an oil cleaner installed on the outside of the lower part of the cylinder block 1. 19, is connected to the discharge port of the oil pump 11 via a high pressure oil pipe 20 and the like. In addition, a plurality of throttle holes 22 are formed at predetermined positions of the protrusion 13b that forms the upper wall of the oil gear rally 17, and these throttle holes 22 serve as pressure regulating means. It is formed so as to lower the oil pressure by a predetermined amount, cause it to flow into the low pressure oil in the oil jacket 15, and evenly flow into the oil jacket 15 which is long in the longitudinal direction of the engine.

Here, the left and right oil jackets 15 have gaps in the longitudinal direction of the engine between each liner part 13,
It communicates through front and rear oil jackets (not shown). A vertically long return path 23 is integrally formed in a part of the cover 14 forming the right oil jacket 15. The return passage 23 communicates with an overflow hole 24 opening toward the upper edge of the oil jacket 15 and a return port 26 at the upper part of the crank chamber 25. Further, a curved plate 27 is disposed in the crank chamber 25 below the return port 26,
The oil from the return port 26 is allowed to smoothly flow down into the oil pan 6 below. Therefore, the oil is transferred from the oil gear rally 17 to the oil jacket 1.
The amount of oil supplied into the oil jacket 15 overflows from the overflow hole 24 and is returned into the oil pan 6, and a predetermined amount of oil is always held in the oil jacket 15 while circulating.

Furthermore, an oil drain hole 15a communicating with the oil pan 6 is provided at the substantially lower end of the oil jacket 15, and the oil drain hole 15a is connected to the drain plug 21.
It is closed so that it can be opened and closed freely. In this example,
The oil drain hole 15a is formed in the cover 14 constituting the outer wall of the oil jacket 15 and communicates the oil jacket 15 with the return path 23, and the drain plug 21 is screwed onto the outer wall of the cover 14 and has an oil drain hole at its tip. It is fitted into 15a. Therefore, tighten the drain plug 21 and insert its tip into the oil drain hole 15.
Although the oil drain hole 15a is closed when the drain plug 21 is inserted into the drain plug 21 (the first movement position of the drain plug 21),
As shown in FIG. 4, when the drain plug 21 is turned and its tip is removed from the oil drain hole 15a (the second movement position of the drain plug 21), the oil in the oil jacket 15 is drained from there to the return path 23 and the return path. mouth 26
and flows down into the oil pan 6.

Further, a double annular groove 29 annularly surrounding the combustion chamber 28 is provided on the upper edge of the cylinder block 1.
a, 30a are formed, and among these, the inner annular groove 29a is formed to extend downward by an extension amount H from the upper end.

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.
communicates with the intake manifold 32 and the exhaust port 33 communicates with the exhaust manifold 34, respectively, and accommodates intake and exhaust valves 35 and 36. 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 gear bracket 29 and the water gear rally 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 rally 30 and the water jacket 29 are in the cooling water circulation system 44 (see FIG. 3), and the water gear rally 30 receives the cooling water discharged from the water pump (not shown) and directs it to the water jacket 29 side. Supply evenly without bias. That is, the water gear rally 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 up 3, which is superimposed on the upper side of the cylinder head 2, is the upper part of the cylinder head in a broad sense, and houses the intake camshaft 38, exhaust camshaft 39, intake valve spring 40, exhaust valve spring 41, etc. that make up the valve train. do. Also, this cylinder head opening 3
A plurality of through holes for through bolts 10 are formed in the lower wall of the cylinder head, 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, each through bolt 10 is placed with its center portion exposed inside the oil jacket 15,
All other parts are inserted into the bolt holes. In this way, by arranging the through bolt 10 at a position where its central portion penetrates the oil jacket 15, this exposed portion will not deteriorate due to rust, and there is no need to cover it with a cover. Further, unlike a conventional water jacket (not shown), there is no need to curve the shape and provide a through bolt on the outside of the jacket.

The valve train in the camshaft chamber 42 surrounded by the cylinder head upper 3 and the cylinder head cover 4 is connected to the upper oil circulation system 45 (third oil circulation system) separate from the crank chamber 25 side.
(see figure) and cooled. That is, an oil pump (not shown here) is attached to the end of the intake camshaft 38, and this is connected to the camshaft chamber 4.
It operates to supply oil on the bottom wall of No. 2 to the sliding surfaces in the valve train.

When such an engine cooling system operates, the upper peripheral wall cylinder head 2 of the combustion chamber 28,
A portion of the cylinder block 1 extending downward from its upper end to an extent H is cooled by cooling water circulating within the water jacket 29. At the same time, the main part of the engine cylinder which is the side peripheral wall of the combustion chamber 28 (the part excluding the upper end from the upper end to the extension amount H)
and the crank chamber 25 side means the oil jacket 1.
It is cooled or lubricated by the cooling oil in the lower oil circulation system 43 including the inside of the oil pan 5 and the oil pan 6.
Further, the valve train side is cooled and lubricated by oil in the upper oil circulation system 45.

In this way, when the engine body shown in Fig. 1 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. The frictional resistance of the parts can be significantly reduced, and the output can be improved. In particular, compared to water, the oil in the oil jacket 15 can suppress the generation of bubbles even at high temperatures, and the occurrence of uneven cooling of the liner 13 is reduced. In addition, the oil in the oil jacket 15 overflows from the overflow hole 24 at the highest position in the oil jacket 15 and returns to the oil pan 6, so that even if air bubbles are generated in the oil jacket 15, This can also be quickly flowed out from inside the oil jacket 15. Furthermore, 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 by downsizing the oil pan 6, the overall height of the engine body can be reduced. There is also the advantage of being able to do so.

On the other hand, when changing oil, oil jacket 1
The oil accumulated in the oil pan 5 is discharged from the oil drain hole 15a into the oil pan 6 by removing the drain plug 21.

Further, FIGS. 5 and 6 each show a sectional view of a main part of another embodiment of the present invention. In the above-mentioned embodiment, an overflow hole 24 is provided in the oil jacket 15, and oil is allowed to overflow from the overflow hole 24, thereby maintaining a predetermined amount of oil in the oil jacket 15 while keeping the oil in the oil jacket 15 constantly flowing. However, the one illustrated in FIGS. 5 and 6 is configured to hold a predetermined amount of oil in the oil jacket 15 using a relief valve.
That is, the one shown in FIG.
An inlet relief valve 46 is provided in the hole that communicates the oil jacket 15 and the return port 26 to allow oil to flow into the return port 26. valve 47
is provided so that oil is supplied from the inlet relief valve 46 into the oil jacket 15 and discharged from the outlet relief valve 47.
By setting the relief pressure of 7 lower than that of the inlet relief valve 46, the oil jacket 15
A predetermined amount of oil that circulates inside the tank is retained. Furthermore, in the system shown in FIG. 6, instead of providing the inlet relief valve 46, the oil pressure depending on the size of the throttle hole 22 and the relief pressure of the outlet relief valve 47 are appropriately balanced. The oil is held in the oil jacket 15 while adjusting the flow rate of the oil. In FIGS. 5 and 6, an oil drain hole 15a communicating with the oil pan 6 via a return port 26 is provided at the substantially lower end of the oil jacket 15, respectively.
A drain plug 21 is inserted so as to close the oil drain hole 15a.
is screwed onto the cover 14. That is, if the drain plug 21 is tightened, the oil drain hole 15a
Although the drain plug 21 is turned and the tip is removed from the oil drain hole 15a, the oil in the oil jacket 15 flows down into the oil pan 6 through the oil hole 15a.

<Effects of the invention> As described above in detail with reference to embodiments, according to the invention, the cooling oil in the oil jacket can cool the engine cylinder while keeping it at a relatively high temperature, thereby improving output. I can do it. Further, the oil in the oil jacket can be easily drained by operating the drain plug, making it possible to easily perform oil exchange work.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an engine cooling system according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the main parts of the same device, FIG. 3 is an explanatory diagram of a three-part cooling system of the same device, and FIG. The figure is a sectional view of the main part of the drain plug in an open state, and FIGS. 5 and 6 are sectional views of the main part of other embodiments of the present invention. In the drawings, 1 is a cylinder block, 2 is a cylinder head, 6 is an oil pan, 15 is an oil jacket, 15a is an oil drain hole, and 21 is a drain plug.

Claims (1)

[Scope of utility model registration request] a cylinder in which the piston is slidably housed;
An oil jacket formed around the cylinder and holding cooling oil; an overflow hole formed at the substantially top of the oil jacket; and an overflow hole disposed substantially at the bottom of the engine. an oil pan that retains the cooling oil that has flowed out of the oil jacket through the oil pan; a cooling hydraulic pressure sending means that force-feeds the cooling oil held in the oil pan to the oil jacket; an oil drain hole that is bored substantially at the lower end and communicates the oil jacket with the oil pan; a first position that is operated from the outside of the cylinder to close the oil drain hole; and a second position that opens the oil drain hole; and a drain plug disposed in the cylinder so as to be movable between positions.