JP2810373B2 - Engine cooling system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine cooling device.

(Prior art and its problems) In recent years, with an increase in the output of an engine, the thermal load on the cylinder tends to increase, and the cylinder is required to have high cooling performance around the combustion chamber.

Therefore, for example, in Japanese Utility Model Laid-Open Publication No. 62-128142, a coolant formed around a cylinder head is circulated through a passage formed between a cylinder block and a liner inserted therein to uniformly cool the cylinder. Things have been suggested.

However, in this case, since the same flow rate of the coolant circulates almost all over the outer periphery of the liner, at a low engine load, the lower portion of the liner below the combustion chamber is excessively cooled, resulting in a reduction in engine cooling loss. In addition to the increase, there is a problem that the viscosity of oil for lubricating the piston increases to increase friction.

In Japanese Utility Model Application Laid-Open No. 60-190934, cooling is performed by circulating around the liner according to the temperature of the cooling water in a cooling water circulation path that cools around the liner from a water gallery provided in the cylinder block and flows into the cylinder head. A thermostat that regulates the flow of water has been proposed, but in this case, there is a portion where cooling is insufficient due to the opening and closing of the thermostat, and the water flow resistance increases and the load on the water pump increases. There was a point.

The present invention focuses on such conventional problems, and has as its object to ensure sufficient cooling performance of the upper portion of the liner and prevent overcooling of the lower portion of the liner.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, a plurality of lateral grooves are provided around a liner inserted into a cylinder block and located above the liner to guide cooling water in a circumferential direction. And a circulating chamber formed by a plurality of vertical grooves intersecting with these horizontal grooves and arranged around the liner, and a communication groove located below the circulating chamber and facing the lowermost horizontal groove. A convection chamber that communicates only with the circulation chamber is formed at the upper part thereof, and the communication groove is formed at a plurality of locations so as not to coincide with the vertical groove in the circumferential direction, and the cooling water flows into the circulation chamber. The inlet and the outlet for allowing the cooling water to flow out of the circulation chamber were each formed above the convection chamber.

The circulation chamber may be configured to communicate with the circulation chamber of another adjacent cylinder, and the convection chamber may be configured to communicate with the convection chamber of another cylinder.

(Operation) Based on the above configuration, in the circulation chamber, the cooling water circulates in the circumferential direction of the liner due to the flow between the inlet and the outlet, thereby reliably preventing the upper portion of the high-temperature liner that directly receives the combustion heat from being overheated. Therefore, seizure of the piston and gas leakage are prevented, and the induction of knocking is suppressed, so that the output of the engine can be increased.

In the convection chamber not directly communicating with the inlet with respect to the flow of the cooling water in the circulation chamber, the cooling water stays in the convection chamber, and the heat in the lower portion of the liner is taken away mainly by the convection of the cooling water. This prevents overcooling of the lower part of the liner, which is lower than that of the upper part, thus reducing engine cooling loss and maintaining low oil viscosity, improving piston lubrication performance and achieving higher efficiency. Is done.

In particular, since the vertical groove forming the circulation chamber and the communication groove communicating the circulation chamber with the convection chamber are located at positions that do not coincide in the liner circumferential direction, the low-temperature cooling water from the upper part of the liner excessively flows into the convection chamber. Cooling water vapor generated in the convection chamber rises from the communication groove to the lateral groove of the circulation chamber and condenses, thereby promoting convection of the cooling water in the convection chamber, while overcooling is reliably avoided. Therefore, appropriate cooling is stably performed in the lower part of the liner.

(Example) Hereinafter, an example of the present invention is described based on an accompanying drawing.

As shown in FIG. 1, FIG. 2, and FIG. 3, a water jacket 9 is formed in the cylinder block 1 so as to surround each cylinder formed by inserting the liner 2, and an inner wall (bore) of the cylinder block 1 is formed. Part) 11 and liner 2
A circulating chamber 6 for guiding the cooling water in the circumferential direction at the upper side and a convection chamber 7 below the circulating chamber 6 are formed therebetween.

In this case, most of the cooling water sent from the water pump 8 to the water jacket 9 is sent to the water jacket 14 of the cylinder head 13 through the through hole 12 and then sent to a radiator (not shown), After the part flows into each circulation chamber 6 as shown by an arrow in FIG. 2, it is sucked into the water pump 8 through a bypass passage 10 that bypasses the radiator.

The circulation chamber 6 includes three lateral grooves 21, 22, 23 formed in the upper part of the liner 2 and extending in the circumferential direction at a predetermined interval, and these lateral grooves
It is formed by two longitudinal grooves 24, 25 which are orthogonal to 21, 22, 23, and in this case symmetrically arranged with respect to the center of the main shaft.

The convection chamber 7 is defined below the circulation chamber 6 between the inner wall 11 of the cylinder block 1 and the liner 2 as an annular space or a number of vertical groove-shaped spaces, and only the upper part thereof is connected via the communication groove 28. It communicates with the lowermost horizontal groove 23. The communication groove 28 is a vertical groove
It is provided at a plurality of places so that the positions in the circumferential direction do not coincide with 24, 25.

As shown in FIG. 1, two O-rings 15 are interposed on the outer periphery of the lower end of the liner 2 to seal the convection chamber 7.

The inlet 3 penetrating the water jacket 9 is formed on the inner wall 11 of the cylinder block 1 immediately below one vertical groove 24, and the outlet 4 is formed facing the upper part of the other vertical groove 25.

In the figure, reference numeral 16 denotes a water pump 8 which cools water passing through a radiator or a thermostat bypass hole (not shown).
The bypass passage 10 communicating with each of the outlets 4 is connected to the middle of the circulation passage 16.

It is configured in this way, and its operation will now be described.

First, the cooling water that has flowed in from the inlet 3 is
The water is diverted to 21, 22, and 23 and flows around the liner 2 half way, and is sucked into the water pump 8 through the outlet 4 and the bypass passage 10 from the vertical groove 25 on the opposite side.

As described above, since the cooling water flows forcibly and at a high speed in the circumferential direction of the liner 2 into the circulation chamber 6, the heat received from the combustion chamber 17 at the upper part of the liner 2 is sufficiently absorbed, and the piston 18 at a high load is Is reliably prevented, and gas leakage due to thermal expansion of the liner 2 is also prevented. In addition, since the temperature of the combustion chamber wall of the liner 2 does not locally rise, the induction of knocking is suppressed, thereby enabling a high output.

The circulation chamber 6 is connected to a water pump 8 through a bypass passage 10.
The flow rate of the cooling water circulating in the circulation chamber 6 can be arbitrarily set according to the passage diameter and the like. Further, by setting the ratio of the cooling water passing through the bypass passage 10 to the cooling water passing through the radiator, for example, about 1/4, the cooling performance by the radiator is sufficiently ensured.

On the other hand, the convection chamber 7 is located below the inlet 3 and the outlet 4 and has a blind-path-like structure that communicates with the circulation chamber 6 only through the communication groove 28 above. The convection chamber 7 is symmetrical to the circulation chamber 6 in which the cooling water circulates.
The cooling water inside is in a stagnant state. For this reason, in the convection chamber 7, as the cooling water heated by the heat transfer from the liner 2 rises, the relatively low-temperature cooling water forcibly circulating in the circulation chamber 6 falls. Cooling water moves by the action of natural convection. As a result, the amount of heat taken by the cooling water in the lower part of the liner 2 at a relatively low temperature facing the piston 18 is reduced, and the temperature drop is suppressed. As a result, the viscosity of the oil lubricating between the piston 18 and the cylinder is maintained at a moderately low level, so that friction is reduced and a fuel reduction effect is obtained.

When the amount of heat received by the liner 2 increases under a high load, the cooling water around the liner 2 boils in the convection chamber 7, deprives the latent heat of vaporization, and the steam generated by the boiling rises, and the communication groove 28
Through the circulation chamber 6. At this time, the steam is condensed by touching the relatively low-temperature cooling water forcibly circulating in the circulation chamber 6, whereby the convection action in the convection chamber 7 is promoted, and the appropriate cooling effect is stably maintained. Become.

Although the above embodiment shows an example in which the circulation chamber 6 and the convection chamber 7 are provided independently for each cylinder, the present invention is not limited to this, and as shown in FIGS. 4 and 5, The configuration may be such that the circulation chambers 6 and the convection chambers 7 of the adjacent cylinders communicate with each other. By doing so, in addition to shortening the overall length of the engine, the movement of the cooling water in the circulation chamber or the convection chamber between the cylinders is facilitated, so that a more uniform and stable cooling effect can be expected for each cylinder. .

(Effect of the Invention) As described above, according to the present invention, the cooling water is forcibly circulated in the upper part of the liner and the cooling water held in the lower part of the liner 2 is naturally convected. While the output performance can be improved by sufficiently securing the cooling performance of the upper part of the liner which is directly received, the effect of preventing the lower part of the liner from being overcooled and improving fuel efficiency can be obtained.

Further, by making the circulation chambers and the convection chambers of the adjacent cylinders communicate with each other, it is possible to obtain the effect of reducing the size of the engine and stabilizing the cooling performance.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an engine showing one embodiment of the present invention,
FIG. 2 is a transverse sectional view of the same, and FIG. 3 is a detailed view of a main part of FIG. FIGS. 4 and 5 are a longitudinal sectional view and a transverse sectional view, respectively, of an engine showing another embodiment of the present invention. 1 ... cylinder block, 2 ... liner, 3 ... inlet,
4 ... outlet, 6 ... circulation chamber, 7 ... convection chamber, 8 ... water pump, 9 ... water jacket, 10 ... bypass passage, 21, 22, 23 ... horizontal groove, 24, 25 ... vertical groove.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoichi Shimizu 2-1-13 Shinmeicho, Okaya-shi, Nagano Imperial Piston Ring Co., Ltd. (72) Inventor Kenichi Harashina 2-1 Shinmeicho, Okaya-shi, Nagano Prefecture -13 Inside Imperial Piston Ring Co., Ltd. (56) References JP-A-49-96142 (JP, A) JP-A 56-166771 (JP, U) JP-A 62-28021 (JP, U) JP-A 62-28021 59-126155 (JP, U) Fully open 1986-110826 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02F 1/14 F02F 1/16 F01P 3/02

Claims (2)

(57) [Claims] 1. A plurality of lateral grooves, which are located above the liner and guide the cooling water in a circumferential direction, around the liner inserted into the cylinder block, intersect with the lateral grooves, and are arranged around the liner. A circulation chamber formed by a plurality of vertical grooves, and a convection chamber located below the circulation chamber and communicating only with the circulation chamber at an upper portion thereof through a communication groove facing the lowermost horizontal groove. And the communication groove is formed at a plurality of locations so as not to coincide with the vertical groove in the circumferential direction, and has an inlet through which cooling water flows into the circulation chamber and an outlet through which cooling water flows out from the circulation chamber. An engine cooling device characterized by being formed above a convection chamber. 2. The engine according to claim 1, wherein the circulation chamber communicates with the circulation chamber of another adjacent cylinder, and the convection chamber communicates with the convection chamber of another cylinder. Cooling system.