JP2658630B2 - Internal combustion engine cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, for example,
In JP-A-117038, cooling water is circulated between a radiator and a cylinder block and a cylinder head, and engine lubricating oil is circulated through an oil jacket formed around the cylinder to achieve uniform cooling around the cylinder. However, in this case, since the lubricating oil constantly circulates around the cylinder during the operation of the engine, it takes a lot of time for the temperature of the cylinder to rise when the engine is cold, and at this time, the exhaust is discharged. Unburned HC
The volume has increased and there is room for improvement in this regard.

Japanese Utility Model Application Laid-Open No. 60-58840 proposes a cylinder block and a cylinder head in which cooling water is circulated between a radiator and an air layer around a cylinder. However, in this case, there is a possibility that the cooling of the cylinder may be insufficient during operation with a high heat load.

The present invention has been made in view of the above points, and has as its object to improve the cooling performance of a cylinder.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a cooling system for an internal combustion engine, which includes an oil jacket for circulating engine lubricating oil around a cylinder and a water jacket for circulating cooling water around the oil jacket. , An inlet opening at the upper part of the oil jacket, an outlet opening at the lower part of the oil jacket, an oil gallery for guiding the lubricating oil to the moving part of the engine, a lubricating oil introduction passage branched from the oil gallery, and one end of the oil gallery. An air introduction passage, a valve means for selectively communicating the lubricating oil introduction passage and the air introduction passage with the inlet of the oil jacket, and a control means for switching the valve means according to the temperature state of the engine. Prepare each.

The control means switches the valve means so that air is introduced into the oil jacket during warm-up and lubricating oil is introduced into the oil jacket after warm-up.

[0007]

When the lubricating oil introduction passage is connected to the inlet of the oil jacket via valve means, a part of the lubricating oil diverted from the oil gallery circulates in the oil jacket. As a result, the cylinder radiates heat to the lubricating oil and promotes heat radiation to the cooling water circulating through the water jacket formed therearound, thereby preventing insufficient cooling of the cylinder during operation with a high heat load.

When the air introduction passage is connected to the inlet of the oil jacket via valve means, the lubricating oil in the oil jacket is discharged from the outlet by gravity. Thereby, the oil jacket forms an air layer around the cylinder, and suppresses heat radiation from the cylinder to the cooling water circulating through the water jacket.

The control means introduces air into the oil jacket during warm-up, and introduces lubricating oil into the oil jacket after warm-up, thereby forming an air layer in the oil jacket from a cold start to increase the temperature of the cylinder. Promotes unburned H
The amount of C discharged can be reduced, and the cooling performance of the cylinder can be sufficiently ensured after warm-up.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a water jacket 9 is formed in the cylinder block 1 so as to surround each cylinder formed by inserting the liner 2 therein. A water jacket 34 is formed around the intake / exhaust ports 35 and 36 and the ignition plug 37 in the cylinder head 4.
Cooling water cooled by a radiator flows into the water jacket 9 via a water pump (not shown), and is sent to the water jacket 34 through a plurality of through holes.

In FIG. 1, reference numeral 10 denotes an oil gallery. Oil is distributed from the oil gallery 10 to a main motion section system of the crankshaft 47, the piston 3, the connecting rod 48, and a valve system on a cylinder head (not shown). As shown in FIG. 2, oil stored in an oil pan 25 is sucked up by an oil pump 23 via a strainer 22 and oil discharged from the oil pump 23 is supplied to a relief valve 3.
The oil is supplied to the oil gallery 10 through the filter 24 while being adjusted to a set pressure or less at 1.

An oil jacket 6 for circulating engine lubricating oil is formed between the inner wall (bore portion) 11 of the cylinder block 1 and the liner 2. One inlet 7 is formed in the upper part of the oil jacket 6 of each cylinder, and the inlets 7 communicate with each other via a branch passage 16. A lubricating oil introduction passage 14 that communicates the branch passage 16 with the oil gallery 10 is provided so that lubricating oil diverted from the oil gallery 10 is introduced.

The lubricating oil introduction passage 14 is provided in the cylinder block 1
Is configured by a pipe 39 and the like disposed outside the
It is also possible to integrally form the inside of the cylinder block 1.

The oil jacket 6 is defined by a groove 12 that is spirally formed on the outer periphery of the liner 2. The lubricating oil that has flowed in from the inlet 7 turns around the liner 2 through the groove 12, then flows out of the plurality of outlets 8 that open at the lower part of the oil jacket 6, and returns to the oil pan 25.

In order to selectively introduce lubricating oil and air into the oil jacket 6, an air introducing passage 15 having one end communicating with a rocker chamber 38 on the cylinder head 4 is provided. Passage 14 and air introduction passage 1
An electromagnetic rotary switching valve 17 is provided as valve means for selectively communicating the valve 5. The switching valve 17 is held in a position that connects the lubricating oil introduction passage 14 to each of the oil jackets 6 of each cylinder when energized, and is held in a position that communicates the air introduction passage 15 to each oil jacket 6 when it is not energized. Is done.

A control unit 18 provided as control means for switching the position of the switching valve 17 inputs a signal of an ignition switch 19 and a signal of a wall temperature sensor 20 for detecting the wall temperature of the liner 2. The control unit 18 determines
Air is introduced into the oil jacket 6 from when the engine is stopped to when it is warmed up, and the wall temperature of the liner 2 is set to a predetermined value (for example, 80 °).
C) The configuration is such that the position of the switching valve 17 is switched so that lubricating oil is introduced into the oil jacket 6 after the warm-up that has been performed as described above.

Next, the operation will be described.

A switching valve 1 is provided at the inlet 7 of each oil jacket 6.
7, when the lubricating oil introduction passage 14 is connected via
Lubricating oil separated from the oil gallery 10 flows into each oil jacket 6. Thus, the liner 2 radiates heat to the lubricating oil circulating through the oil jacket 6 and radiates heat to the cooling water circulating through the water jacket 9 formed around the oil jacket 6. Therefore, it is possible to prevent insufficient cooling of the liner 2 during operation with a high heat load.

A switching valve 1 is provided at the inlet 7 of each oil jacket 6.
When the air introduction passage 15 is connected via the, the lubricating oil in the oil jacket 6 is discharged from the outlet 8 to the oil pan 25 by gravity, and the oil jacket 6 forms an air layer around the liner 2. With this air layer, heat radiation from the liner 2 to the cooling water circulating through the water jacket 9 is suppressed.

The control unit 18 introduces air into the oil jacket 6 from when the engine is stopped to when the engine is warmed up, and introduces lubricating oil into the oil jacket 6 after the engine is warmed up. Is formed to promote the temperature rise of the liner 2 to reduce the amount of unburned HC emissions, and to ensure sufficient cooling of the liner 2 after warming up.

Next, in another embodiment shown in FIG. 3, the lubricating oil introduction passage 14 is used as a valve means for selectively communicating the lubricating oil introduction passage 14 and the air introduction passage 15 with the branch passage 16.
And an electromagnetic on-off valve 26 is provided in the middle of the air introduction passage 15.

A control unit 29 for controlling the opening and closing of the on-off valve 27 receives a signal from an ignition switch 19, opens the air introduction passage 15 when the engine stops, introduces air into the oil jacket 6, and supplies air when the engine is operating. The introduction passage 15 is closed.

A control unit 28 for controlling the opening and closing of the on-off valve 26 receives a signal from a temperature sensor 30 for detecting the temperature of a catalyst provided in the middle of an exhaust pipe (not shown), and adjusts the catalyst temperature to a predetermined value (for example, 300 ° C.). C) The lubricating oil passage 14 is closed when the temperature is lower than a predetermined value, and the lubricating oil introduction passage 14 is opened after warming up to a predetermined value or more, and the position of the switching valve 17 is adjusted so that the lubricating oil is introduced into the oil jacket 6. Is switched.

In this case as well, air is introduced into the oil jacket 6 from when the engine is stopped until the engine is warmed up, and lubricating oil is introduced into the oil jacket 6 after the engine is warmed up. Liner 2 with layer
, The amount of unburned HC discharged is reduced, and sufficient cooling of the liner 2 after warm-up can be ensured.

Further, instead of the wall temperature sensor 20 and the catalyst temperature sensor 30 of the liner 2 in each of the above embodiments, the temperature of the cooling water or the like may be detected to determine the cylinder temperature accurately.

Next, in another embodiment shown in FIG. 4, in the upper part of the liner 2, lateral grooves 41, 42 extending circumferentially at predetermined intervals.
And two vertical grooves 43 orthogonally and symmetrically arranged with the horizontal grooves 41 and 42, respectively, and a plurality of vertical grooves 44 extending linearly in the axial direction below these. Are formed at equal intervals.

In another embodiment shown in FIG. 5, lateral grooves 41, 42 extending in the circumferential direction at predetermined intervals are provided on the upper portion of the liner 2.
And two vertical grooves 43 orthogonally and symmetrically arranged to the horizontal grooves 41 and 42, respectively, and a plurality of vertical grooves extending helically curved below them. 45 are formed at equal intervals.

In any case, the lubricating oil introduced into the oil jacket 6 is guided to the periphery of the liner 2 through the lateral grooves 41 and 43, thereby improving the cooling performance of the upper part of the liner 2 and the vertical grooves 44 and 45. As a result, the lubricating oil flows down quickly, thereby preventing the lower part of the liner 2 from being supercooled.

[0030]

As described above, the present invention provides a cooling system for an internal combustion engine having an oil jacket for circulating engine lubricating oil around a cylinder and a water jacket for circulating cooling water around the oil jacket. The apparatus includes valve means for selectively communicating the lubricating oil introduction passage and the air introduction passage with the inlet of the oil jacket, and control means for switching the valve means in accordance with the temperature state of the engine. By sufficiently circulating the lubricating oil, the cooling performance of the cylinder can be sufficiently ensured, and by introducing air into the oil jacket, the heat radiation to the cooling water can be suppressed and the cylinder can be prevented from being overcooled.

In addition, by introducing air into the oil jacket during warm-up and introducing lubricating oil into the oil jacket after warm-up, the temperature of the cylinder can be increased during a cold period to reduce the emission of unburned HC. , Can improve the warm-up performance.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an engine showing an embodiment of the present invention.

FIG. 2 is a block diagram similarly.

FIG. 3 is a longitudinal sectional view of an engine showing another embodiment.

FIG. 4 is a perspective view of a liner showing still another embodiment.

FIG. 5 is a perspective view of a liner showing still another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Liner 6 Oil jacket 7 Inlet 8 Outlet 9 Water jacket 10 Oil gallery 14 Lubricating oil introduction passage 15 Air introduction passage 17 Switching valve 18 Control unit 19 Ignition switch 20 Wall temperature sensor

Claims (2)

(57) [Claims] 1. A cooling system for an internal combustion engine, comprising: an oil jacket for circulating engine lubricating oil around a cylinder; and a water jacket for circulating cooling water around the oil jacket. An inlet, an outlet opening at a lower portion of the oil jacket, an oil gallery for guiding lubricating oil to a moving part of the engine, a lubricating oil introduction passage branched from the oil gallery, and an air introduction passage one end of which is released to the atmosphere. A valve means for selectively communicating the lubricating oil introduction passage and the air introduction passage with the inlet of the oil jacket, and a control means for switching the valve means in accordance with the temperature state of the engine. Cooling device for internal combustion engine. 2. The internal combustion engine according to claim 1, wherein the control means switches the valve means so that air is introduced into the oil jacket during warm-up and lubricating oil is introduced into the oil jacket after warm-up. Cooling system.