JPH0726529B2 - Partially oil-cooled air-cooled engine cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Field of Use >> The present invention is a partial oil in which a peripheral portion of a combustion chamber in a head block is liquid-cooled by using engine lubricating oil and other portions are air-cooled. The present invention relates to a cooling device for a cold engine.

<< Prior Art >> As a conventional cooling method for a cylinder head of an engine, either an all-water cooling type or an all-air cooling type is usually adopted.
In the all-water cooling type, a cooling water jacket is formed over the entire area of the head block, and water is uniformly cooled without distinguishing between the heat storage part such as the auxiliary combustion chamber and the parts other than this heat storage part. In the all air cooling type, air is uniformly cooled without distinguishing between the heat storage part such as the auxiliary combustion chamber and the parts other than this heat storage part.

<Problems to be solved> For all water-cooled type and all air-cooled type, the following problem (i)
・ There is (ii).

(I) In the all-water cooling type, the heat storage portion of the head block and the portion other than the heat storage portion are uniformly water cooled. Therefore, a large amount of heat is radiated to the cooling water, and it is necessary to use a large amount of cooling water, which increases the weight of the engine. In addition, a radiator such as a radiator that radiates the cooling water also becomes large, and the engine becomes large accordingly.

(Ii) In the case of the all-water cooling type, the parts other than the heat storage part, which are relatively hard to be overheated, are supercooled by water cooling. Therefore, a large amount of unnecessary heat is radiated from the main combustion chamber to this supercooled portion, resulting in a large heat loss. On the other hand, in the case of the all air cooling type, the heat storage portion which is relatively overheated is cooled only by air cooling. Therefore, the combustion temperature cannot be set too high because it is necessary to suppress thermal damage due to overheating of the heat storage unit. As described above, high power cannot be obtained in the all-water cooling type due to heat loss and in the all-air cooling type due to limitation of combustion temperature.

On the other hand, there is also a partially oil-cooled type disclosed in Mikai Film of Japanese Utility Model Publication No. 63-40524. Like the present invention, it has the following structure. That is, a cooling fan is arranged on the front side of the crankcase, the outer circumference of the cooling fan is surrounded by a wind guide case, a cooling air passage in the front-back direction is formed in the head block, and the air passage inlet on the front side of the cooling air passage is introduced. The sub-combustion chamber formed on the head block is surrounded by a cooling oil chamber from the surroundings, a part of the lubricating oil is supplied to the cooling oil chamber, and the cooling air passing backward in the cooling air passage is used to cool the head block. And the sub-combustion chamber of the head block is partially cooled with the cooling oil in the cooling oil chamber.

According to this partial oil cooling method, the sub-combustion chamber is partially oil-cooled and the other parts are air-cooled, so that the problem (i)
Can solve (ii).

However, in this conventional technique, an air guide is opened above the air guide case, and an oil cooler facing the air guide is provided above the air guide case, and the cooling air generated in the air guide case is transferred to the head block and the oil cooler. It is designed to be divided into two.
In addition, the cooling oil return port of the oil cooler is connected to the cooling oil return passage inside the head block and the wall of the cylinder barrel, and the cooling oil from the cooling oil return port is passed from the cooling oil return passage to the crankcase oil pan. I am going to return it to.

Therefore, the following new problems (iii) to (v) occur.

(Iii) Part of the cooling air generated in the air guide case is diverted to the oil cooler. Therefore, the amount of cooling air supplied to the head block is correspondingly reduced, and the air cooling efficiency of the head block is reduced.

(Iv) Part of the cooling air generated in the air guide case is diverted to the head block. Therefore, the amount of cooling air supplied to the oil cooler is correspondingly reduced, and the heat dissipation efficiency of the oil cooler is reduced.

(V) Cooling oil radiated by the oil cooler passes through the flesh wall of the head block or cylinder barrel, which radiates a large amount of heat, and is reheated to return to the oil pan. Therefore, the oil temperature in the oil pan rises, the cooling oil having a relatively high temperature is sent to the cooling oil chamber, and the oil cooling efficiency of the auxiliary combustion chamber becomes low.

An object of the present invention is to provide a cylinder head cooling device for a column-type multi-cylinder diesel engine that can solve the above problems.

<< Means for Solving the Problems >> According to the present invention, a cooling fan (6) is arranged on the front side of a crankcase (2), and the outer periphery of the cooling fan (6) is surrounded by a wind guide case (7) to provide a head block ( 3) A cooling air passage (18) in the front-rear direction is formed in the air passage, and the air passage inlet (29) on the front side of the cooling air passage (18) faces the air guide case (7), and is attached to the head block (3). The formed sub combustion chamber (16) is surrounded by a cooling oil chamber (17) from the surroundings, and a part of the lubricating oil is supplied to the cooling oil chamber (17), and the cooling air passage (18) is directed backward. The head block (3) is air-cooled by the passing cooling air, and the sub combustion chamber (16) of the head block (3) is partially cooled by the cooling oil passing through the cooling oil chamber (17). A cooling system for a partially oil-cooled air-cooled engine that is configured as a head block 3) Behind the cooling air passage (18), an oil cooler (19) facing the air passage outlet (30) is provided behind the cooling air passage (18), and the cooling oil outlet of the cooling oil chamber (17) is connected to the oil cooler (19). The cooling oil return port (20) of the oil cooler (19) is connected to the inside of the gear case (9) provided at the outer rear part of the crankcase (2) so that the cooling oil from the cooling oil return port (20) is connected. Is returned from the inside of the gear case (9) to the oil pan (21) of the crank case (2).

<< Operation >> According to the present invention, the sub-combustion chamber (16), which is the heat storage portion of the head block (3), is partially oil-cooled, and the portion of the head block (3) other than the heat storage portion is air-cooled. The cooling air generated in the air guide case (7) is supplied to the cooling air passage (18) in the head block (3) without being divided into the oil cooler (19). Then, most of the cooling air supplied to the cooling air passage (18) of the head block (3) is supplied to the oil cooler (19) as it is. Further, the cooling oil radiated by the oil cooler (19) passes through the gear case (9) with a small amount of heat radiation and returns to the oil pan (21) at a low temperature.

<Examples> The drawings show examples of the present invention. Fig. 1 is a partially cutaway side view of an in-line two-cylinder diesel engine, Fig. 2 is a cross-sectional plan view of a head block, and Fig. 3 is a rear view of the engine. It is a figure.

This engine (E) forms a crankcase (2) by integrally forming a cylinder barrel portion, in which two cylinders (1) are arranged at the front and rear, with a crank chamber portion. Fix the head block (3) on the upper side,
A cooling fan (6) which also functions as a flywheel is arranged at the tip of a crankshaft (5) protruding forward from a front side wall (4) of the crankcase (2), and the cooling fan (6) is surrounded by a wind guide case. By arranging (7), the cooling air generated by the cooling fan (6) is sent to the crankcase (2) part and the head block (3) part to cool the engine. The gear case (9) accommodating the timing gear (8) is formed on the rear side of (2).

As shown in FIG. 2, the head block (3) is provided with an intake port (10) and an exhaust port (11) corresponding to each cylinder (1), and the valve of this intake port (10) is formed. The port (12) and the valve port (13) of the exhaust port (11) are arranged in parallel with the crankshaft (5). The manifold side end (14) of the intake port (10) is on one side surface of the head block (3), and the manifold side end (15) of the exhaust port (11) is on the other side surface of the head block (3). Each has a cross flow type valve arrangement. A spherical auxiliary combustion chamber (16) is provided in the inlet side of the intake ports (10) between the valve openings (12) (13) of both ports (10) (11). A combustion injection nozzle is placed facing this sub-combustion chamber (16) and
A cooling oil chamber (17) through which a cooling liquid flows is formed around the auxiliary combustion chamber (16). A cooling air passage (18) is formed inside the head block (3) so that the cooling air can flow along the axis of the crankshaft, and the front side of the cooling air passage (18) is formed. The air duct entrance (29) is exposed to the wind guide case (7). Then, in the cooling oil chamber (17), a part of the lubricating oil pumped by a lubricating oil pump (not shown) is used as a cooling liquid to form a cooling oil passage around the cylinder (1) and the head block (3). It is designed to be supplied via. As a result, the head block (3) is air-cooled by the cooling air passing backward through the cooling air passage (18), and the sub combustion chamber (16) of the head block (3) passes through the cooling chamber (17). Partial oil cooling with cooling oil.

The cooling oil from the cooling liquid chamber (cooling oil chamber) (17) is sent to the oil cooler (19) arranged corresponding to the cylinder barrel portion and the head block (3) in the upper part of the gear case (9), While passing through the oil cooler (19), the cylinder barrel portion and the head block (3) are cooled by exchanging heat with the cooling air that has been cooled, and then cooled from the cooling oil return port (20) to the gear case (9). ) And is returned to the oil pan (21) in the crankcase (2). That is, an oil cooler (19) facing the air passage outlet (30) on the rear side of the cooling air passage (18) is provided behind the head block (3), and the cooling oil outlet of the cooling oil chamber (17) is connected to the oil. The cooling oil return port (20) of the oil cooler (19) is connected to the inside of the gear case (9) provided at the outer rear part of the crankcase (2), and the cooling oil return port (20) is connected. ) From the gear case (9) is returned to the oil pan (21) of the crankcase (2).

In this embodiment, the opening (22) of the gear case (9)
The side cover plate (23) that closes the cylinder is fastened to the opening of the crankcase (2) by a large number of bolts, but as shown in FIG. Positioning portions for the side cover plate (23) are formed vertically at corresponding positions, and at least the upper positioning portion (24) is formed.
Is composed of a reamer bolt (25). By using the reamer bolts (25) in this way, relative sliding between the side cover plate (23) and the crankcase (2) is prevented, and the side cover plate (23) is prevented.
Can be firmly fixed to the crankcase (2). Further, the tightening is surely performed on the center of the cylinder where stress is concentrated and on the upper surface.

In the figure, reference numeral (26) is a push rod insertion hole, (27) is an intake valve, and (28) is an exhaust valve.

In the above embodiment, the in-line multi-cylinder engine is described,
The present invention can also be applied to a single cylinder engine.

The present invention has the following effects.

The sub-combustion chamber, which is the heat storage portion of the head block, is partially oil-cooled, and the portion of the head block other than the heat storage portion is air-cooled. Therefore, compared to an all-water cooling type that uniformly cools water without distinguishing between the heat storage part of the head block and the part other than the heat storage part, the amount of heat radiated to the cooling liquid is small, and a small amount of cooling oil is used. The engine can be made lighter by that amount.
In addition, the oil cooler that dissipates the heat of the cooling oil is also small, and the engine can be downsized accordingly.

The parts other than the heat storage part, which are relatively hard to be overheated, are gently cooled by air cooling, and the supercooling of this part is suppressed. Therefore, unnecessary heat radiation from the main combustion chamber can be suppressed, and heat loss can be reduced, as compared with an all-water cooling type in which parts other than the heat storage part are supercooled by water cooling. On the other hand, since the oil storage of the heat storage section that is relatively easily overheated is strongly cooled, the combustion temperature is set higher without fear of thermal damage to the heat storage section compared to the all-air cooling type where the heat storage section is cooled only slowly. can do. In this way, since the combustion temperature can be set high at the same time as the reduction of heat loss, higher output can be obtained as compared with the all-water cooling type or all-air cooling type.

The cooling air generated in the air guide case is supplied to the cooling air passage in the head block without being divided into the oil cooler. Therefore, as compared with the case where a part of the cooling air in the air guide case is divided into the oil cooler, the cooling air supply amount to the cooling air passage in the head block is increased and the air cooling efficiency of the head block is increased.

A large amount of cooling air supplied to the cooling air passage in the head block is supplied to the oil cooler as it is. Therefore, as compared with the case where a part of the cooling air in the air guide case is diverted to the cooling air passage in the head block, the amount of cooling air supplied to the oil cooler increases and the heat dissipation efficiency of the oil cooler increases.

Cooling oil radiated by the oil cooler passes through the gear case with a small amount of heat radiation and returns to the oil pan at low temperature. For this reason, the cooling oil after heat dissipation passes through the meat wall such as a head block with a large amount of heat dissipation and returns to the oil pan, so that the oil temperature in the oil pan does not rise and the cooling temperature is relatively low. Oil can be supplied to the cooling oil chamber, and the oil cooling efficiency of the auxiliary combustion chamber is increased.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a partially cutaway side view of an in-line two-cylinder diesel engine, FIG. 2 is a cross-sectional plan view of a head block, FIG. 3 is a rear view of the same engine, and FIG.
The drawing is a sectional view taken along the line IV-IV in FIG. 2 ... Crank case, 3 ... Head block, 6 ...
Cooling fan, 7 ... Wind guide case, 9 ... Gear case, 16
…… Sub-combustion chamber, 17 …… Cooling oil chamber, 18 …… Cooling air passage, 19 …… Oil cooler, 20 …… (19) Cooling oil return port, 21 …… Oil pan, 29 …… Air passage inlet , 30 …… Airway exit.

Claims (1)

[Claims] 1. A cooling fan (6) is arranged on the front side of a crankcase (2), the outer periphery of the cooling fan (6) is surrounded by an air guide case (7), and cooling is performed in the head block (3) in the longitudinal direction. The sub-combustion chamber (16) formed in the head block (3) by forming the air passage (18) so that the air passage inlet (29) on the front side of the cooling air passage (18) faces the air guide case (7). Is surrounded by a cooling oil chamber (17) so that a part of the lubricating oil is supplied to the cooling oil chamber (17), and the head block (is supplied by cooling air passing backward through the cooling air passage (18) ( 3) is air-cooled, and the sub-combustion chamber (16) of the head block (3) is partially oil-cooled by the cooling oil passing through the cooling oil chamber (17). Which is a cooling device of the cooling air passage (18) behind the head block (3). The oil cooler (19) facing the air passage outlet (30) on the rear side is provided, and the cooling oil outlet of the cooling oil chamber (17) is connected to the oil cooler (19) so that the cooling oil of the oil cooler (19) is connected. The return port (20) is communicatively connected to the inside of the gear case (9) provided at the outer rear part of the crankcase (2), and the cooling oil from the cooling oil return port (20) is fed from the inside of the gear case (9) to the crankcase (2). A cooling device for a partially oil-cooled air-cooled engine, which is configured to be returned to the oil pan (21).