JPH0631144Y2 - Engine cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an engine cooling device.

(Prior Art and Problems Thereof) In recent years, the thermal load on the cylinder has tended to increase with the increase in output of the engine, and high cooling performance around the combustion chamber is required.

Therefore, conventionally, cooling water is circulated between the radiator and the cylinder block and the cylinder head,
It has been proposed to circulate engine lubricating oil in an oil jacket formed around the cylinder liner to achieve uniform cooling around the cylinder (for example, JP-A-61-553).
51, Japanese Utility Model Publication 56-117038, Japanese Utility Model Publication 62-28021).

However, in a multi-cylinder engine in which cooling water cooled by a radiator is sucked in by a water pump and flows sequentially from the water jacket of the cylinder closest to the water pump, the temperature difference between the cylinders at both ends increases, so Therefore, there is a problem in that the piston clearance varies and the friction and oil consumption increase.

The present invention focuses on these conventional problems and aims to make the cooling of each cylinder uniform.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a liner is fitted to a cylinder block having a plurality of cylinders, and an oil jacket for circulating engine lubricating oil around the liner is provided in the cylinder block. , Forming a water jacket for circulating cooling water around the oil jacket, and distributing the lubricating oil to the oil jacket of each cylinder, the flow of the lubricating oil in the oil gallery and the flow of the cooling water in the water jacket are mutually in line with each other. Reversely along the direction, the passage cross-sectional area of the branch passage for allowing the lubricating oil from the oil gallery to flow into the oil jacket is made larger in the order of increasing distance from the inlet for allowing the cooling water to flow into the water jacket.

(Operation) Based on the above configuration, for example, in the water jacket around the cylinder far from the water pump, cooling water having a relatively high temperature due to heat radiation from each cylinder circulates, and the amount of heat radiation from the liner to this cooling water decreases. On the other hand, in the oil jacket formed around this cylinder, a relatively low temperature lubricating oil is introduced from the oil gallery, and this lubricating oil is relatively proportional to the passage cross-sectional area of the branch flow passage. Since it circulates around the liner at high speed, the cooling performance of each cylinder can be made uniform even in an engine with a large number of cylinders so that the amount of heat released from the liner to the lubricating oil is increased and sufficient cooling performance can be secured.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the cylinder block 1 has a liner 2
A water jacket 9 is formed so as to surround each cylinder formed by inserting. A water jacket 14 is formed in the cylinder head 4 around the intake / exhaust ports 15 and 16 and the spark plug 17, and the water jacket 14 is attached to the water jacket 9 of the cylinder block 1 through a plurality of through holes (not shown). Communicate.

As shown in FIG. 2, the water pump 21 is provided at the front end of the cylinder block 1.
Is a pipe 21 for cooling water cooled by a radiator (not shown).
An inlet 9A is formed at the front end of the cylinder block 1 through which the cooling water discharged from the water pump 21 flows into the water jacket 9. The cooling water supplied through this inflow port 9A is sent to the water jacket 14 of the cylinder head 4 while circulating in the order of # 1, # 2, # 3, and # 4 cylinders, as indicated by arrows in the figure.

An oil jacket 6 for circulating engine lubricating oil between an inner wall (bore portion) 11 of the cylinder block 1 and the liner 2.
Is formed.

The cylinder block 1 is formed with an oil gallery 20 that distributes lubricating oil to the oil jackets 6 of the respective cylinders, and a branch passage 5 that allows the lubricating oil from the oil gallery 20 to flow into the oil jacket 6.

Lubricating oil stored in the oil pan is sucked up by an oil pump 22 (not shown), cooled by an oil cooler 24, and then is passed through an inflow port 20A of the oil gallery 20.
Sent to.

The inflow port 20A of the oil gallery 20 is formed at the rear end of the cylinder block 1, and the lubricating oil from the oil pump is
As indicated by the arrow in the figure, the cooling water in the water jacket 9 is circulated in the reverse direction, and the water is cooled through # 4, # 3, and # 4 via the respective branch channels 5.
The oil is introduced into each oil jacket 6 in the order of # 2 and # 1 cylinders.

The passage cross-sectional area of each branch passage 5 of each cylinder # 1, # 2, # 3, # 4 increases in the order of S ₁ <S ₂ <S ₃ <S ₄ as the distance to the inlet 9A of the water jacket 9 increases. Form.

The oil jacket 6 is defined by a plurality of lateral grooves 12 extending in the circumferential direction of the liner 2 and a plurality of vertical grooves (not shown) orthogonal to the lateral grooves 12, and a few lubricating oils flowing from the oil gallery 20. Every time it makes a half turn through the horizontal groove 12, it rises through the vertical groove, flows out from the outlets 7 and 8 formed in the upper part of the cylinder block 1, and is returned to the oil pan (not shown) through the return passages 22 and 23, respectively. Will be returned.

With such a configuration, the liner 2 is directly radiated to the lubricating oil circulating around the liner 2 and indirectly radiated to the cooling water circulating in the water jacket 9 of the cylinder block 1.

The relatively low temperature cooling water cooled by the radiator is sucked by the water pump 21 as shown by the arrow in the figure,
It flows into the water jacket 9 from the inflow port 20A, and in the process of flowing from the front to the rear in the water jacket 9, the heat of each cylinder is absorbed and the temperature becomes high in the order of flowing to the # 1, # 2, # 3, and # 4 cylinders. Go.

On the other hand, the relatively low temperature lubricating oil that flows into the oil gallery 20 through the oil cooler 24 absorbs heat of each cylinder in the process of flowing from the rear to the front in the oil gallery 20, and then from each shunt channel 5. The lubricating oil branched to each oil jacket 6 becomes high temperature in the order of # 4, # 3, # 2, and # 1 cylinders.

Further, the flow velocity of the lubricating oil circulating around the liner 2 in each oil jacket 6 increases in the order of # 4, # 3, # 2, and # 1 cylinders in proportion to the passage cross-sectional area of the branch passage 5, and increases in this order. Cooling performance can be obtained.

Therefore, for example, in the case of the # 4 cylinder at the rear end, the temperature of the cooling water circulating around it is higher than that of the other cylinders, and the heat radiation amount decreases, but the heat radiation amount to the lubricating oil circulating in the oil jacket 6 increases. Therefore, each cylinder can be cooled uniformly so that the same cooling performance as that of the other cylinders can be obtained.

(Effects of the Invention) As described above, according to the present invention, the liner is fitted to the cylinder block of the multi-cylinder engine, and the cylinder block has an oil jacket for circulating engine lubricating oil around the liner and the periphery of the oil jacket. A water jacket that circulates the cooling water is formed in each cylinder, and the flow of the lubricating oil of the oil gallery that distributes the lubricating oil to the oil jacket of each cylinder and the flow of the cooling water of the water jacket are made opposite to each other, and the lubrication from the oil gallery is performed. Since the passage cross-sectional area of the shunt channel that allows oil to flow into the oil jacket is formed to be large as it becomes farther from the inlet that allows cooling water to flow into the water jacket, the amount of insufficient heat radiation from the liner to the cooling water is transferred to the lubricating oil. This is compensated for by increasing heat dissipation, and even in engines with many cylinders, the cooling performance of each cylinder is evenly distributed. On the other hand, the piston clearance can be reduced to reduce friction and oil consumption, and the cylinder can be easily overheated so that the compression ratio is not limited and high output can be achieved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an engine showing an embodiment of the present invention,
FIG. 2 is a cross-sectional view showing the path of lubricating oil. 1 ... Cylinder block, 2 ... Liner, 3 ... Piston, 4 ... Cylinder head, 5 ... Dividing channel, 6 ... Oil jacket, 9 ... Water jacket, 20 ... Oil gallery, 21 ... Water pump.

Claims (1)

[Scope of utility model registration request] 1. A liner is fitted to a cylinder block having a plurality of cylinders, an oil jacket for circulating engine lubricating oil around the liner, and a water jacket for circulating cooling water around the oil jacket on the cylinder block. Respectively, and the flow of the lubricating oil of the oil gallery that distributes the lubricating oil to the oil jacket of each cylinder and the flow of the cooling water of the water jacket are made to run backwards along the cylinder row direction, and the lubricating oil from the oil gallery is formed. A cooling device for an engine, characterized in that a passage cross-sectional area of the shunt passage through which the oil flows into the oil jacket is formed in order of increasing distance from an inlet through which the cooling water flows into the water jacket.