JPH0723694B2 - Cooling system for partially liquid-cooled in-line multi-cylinder air-cooled diesel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a partial liquid cooling series in which a high temperature portion in a head block is cooled by a cooling liquid and other portions are cooled by cooling air. It relates to a multi-cylinder engine.

<< Prior Art >> As a conventional cooling method for a cylinder head of a multi-cylinder engine, either an all-water cooling type or an all-air cooling type is adopted.
In the all-water cooling type, a cooling water jacket is formed over the entire area of the head block, and water cooling is uniformly performed without distinguishing between the heat storage part such as the fuel injection nozzle mounting part and the valve opening part and the parts other than the heat storage part. Has been done. In the all-air-cooled type, the air is uniformly cooled without distinguishing the heat storage part and the part other than the heat storage part. Further, in both the case of the all-water cooling type and the case of the all-air cooling type, the portion between the valve openings is cooled only by the refrigerant passing through the gap between the opposed valve opening port walls.

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

(I) In the all-water-cooled type, since the heat storage portion such as the fuel injection nozzle mounting portion of the head block and the valve opening portion and the portion other than the heat storage portion are uniformly water-cooled, a large amount of heat is radiated to the cooling water,
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, since the heat storage portion that is relatively easily overheated is cooled only by air cooling, it is necessary to suppress thermal damage due to overheating of the heat storage portion, and therefore the combustion temperature cannot be set too high. 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.

(Iii) In both cases of the all-water cooling type and the all-air cooling type, the cooling between the valve ports is performed only by the refrigerant passing through the gap between the facing valve port ports. For this reason, when this gap becomes narrow and the flow rate of the refrigerant passing therethrough decreases, only the portion between the valve openings of both valve orifice peripheral portions becomes significantly hotter than other portions, and a large heat drop causes Thermal distortion occurs in the peripheries of both valve openings, and combustion gas leaks from both valve openings. Therefore, since it is necessary to secure a wide gap, the diameters of both valve openings cannot be increased, and the intake / exhaust efficiency cannot be improved.

An object of the present invention is to provide a cooling device for a partially liquid-cooled in-line multi-cylinder air-cooled diesel engine that can solve the above problems.

<< Means for Solving the Problems >> The present invention has the following features. That is, a plurality of cylinders (8) are arranged side by side in front and back, and the intake ports (9) and exhaust ports (10) of the respective cylinders are arranged in front and back on the head block (3). The fuel injection nozzle mounting portion (15) is formed on one lateral side of the intervalve portion (27) of each cylinder.

The cooling liquid chamber (16) is formed so as to surround the fuel injection nozzle mounting portion (15), and the cooling liquid supply path (18) passing through the inside of the meat portion of the intervalve portion (27) is connected to the cooling liquid chamber (16). 16) to cool the fuel injection nozzle mounting part (15) of the head block (3) partially with the cooling liquid passing through the chamber (16) after cooling,
The valve opening portion (27) is partially liquid-cooled with the cooling liquid passing through the cooling liquid supply passage (18). And the head block (3)
Cooling air is supplied from the cooling fan (6) to the cooling air passage (17) therein, and the head block (3) can be air-cooled by the cooling air passing through the cooling air passage (17).

<< Operation >> According to the present invention, the fuel injection nozzle mounting portion (15), which is a heat storage portion of the head block (3), and the intervalve portion (27) are partially liquid-cooled, and the heat storage portion of the head block (3). Other parts are air-cooled. In particular, the inter-valve opening portion (27) is strongly cooled from the inside of the meat portion by the cooling liquid passing through the cooling liquid supply passage (18).

<< Practical Examples >> The drawings show the embodiments of the present invention. FIG. 1 is a cross-sectional plan view of a cylinder head of a two-cylinder diesel engine, and FIG.
It is a vertical side view of a cylinder diesel engine.

In this engine, a crankcase (1) and a cylinder block (2) are integrally formed to form a cylinder block (2).
A head block (3) is fixed to the upper side of the engine to form an engine body (E), and a cooling fan (6) is attached to a front end of a crank shaft (5) protruding from a front wall (4) of a crank case (1). Fix and install the cooling fan (6) in the wind guide case (7)
The engine is cooled by being surrounded by and being supplied to the cylinder block (2) and the head block (3) by the cooling air generated by the cooling fan (6).

As shown in FIG. 1, the head block (3) is provided with an intake port (9) and an exhaust port (10) corresponding to each cylinder (8), and the valve of this intake port (9) is formed. The port (11) and the valve port (12) of the exhaust port (10) are arranged in parallel with the crankshaft (5). The end portion (13) of the intake port (9) on the manifold side is on one side surface of the head block (3), and the end portion (14) of the exhaust port (10) on the manifold side is the other side surface of the head block (3). Each has a cross flow type valve arrangement. A spherical auxiliary combustion chamber (15) is provided on the outlet side of the intake port (9) between the valve ports (11) and (12) of both ports (9) and (10). By disposing the fuel injection nozzle facing the sub combustion chamber (15), the sub combustion chamber (15) serves as a mounting portion for the fuel injection nozzle, and the fuel injection nozzle mounting portion (sub combustion chamber) (15) A cooling liquid chamber (16) through which the cooling liquid flows is formed in the periphery. Further, a cooling air passage (17) is formed in the head block (3) in a state of penetrating forward and backward so that cooling air can flow along the axis of the crankshaft. And
In the cooling liquid chamber (16), a part of the lubricating oil pumped by a lubricating oil pump (not shown) serves as the cooling liquid and is formed around the cylinder (8) and the head block (3) as a cooling liquid supply passage (cooling). The cooling oil passage (18) is provided with a portion formed in the inner head block (3) between the valve openings (2).
It is formed so as to pass through the meat wall in 7). The cooling fan (6) side end (front end) of the cooling air passage (17) is used as the cooling air inlet (19), and the rear end of the cooling air passage (17) is used as the cooling air outlet (20). Each is formed.

The cooling oil from the cooling liquid chamber (cooling oil chamber) (16) is fed to the oil cooler (21) arranged on the upper wall of the wind guide case (7) at the upper part of the cooling fan (6), and this oil is supplied. While passing through the cooler (21), it is cooled by exchanging heat with the cooling air generated by the cooling fan (6), and then from the cooling oil return port to the oil pan (22) in the crankcase (1). It is supposed to be returned.

In the figure, reference numeral (23) is a push rod insertion hole, (24) is an intake valve, (25) is an exhaust valve, and (26) is a crankcase (1).
It is a gear case arranged at the rear end of the.

3 and 4 respectively show another embodiment of the head block (3), and the one shown in FIG. 3 is formed so as to correspond to each cylinder (8) by an intake port (9) and an exhaust port. By positioning the arrangement of (10) symmetrically with the adjacent cylinders (8), the exhaust port (1
The valve mouth (12) of (0) is located close to each other, and the auxiliary combustion chamber (15) of the adjacent cylinder (8) is surrounded by one cooling liquid chamber (16). . This arrangement can be applied to even-cylinder engines such as 4-cylinder engines as well as 2-cylinder engines. Further, in the structure shown in FIG. 4, the intake valve openings (11) in the adjacent cylinders are arranged close to each other, and the intake ports (9) are joined to each other and opened on the upper surface of the head block (3). It is a thing.

Incidentally, in the one shown in FIG. 3, the merged port may be the intake port, and in the one shown in FIG. 4, the merged port may be the exhaust port. Further, the present invention may be applied to a direct injection diesel engine. In that case, the cooling liquid chamber (16) is formed around the nozzle holder portion.

Further, although the engine lubricating oil is used as the cooling liquid supplied to the periphery of the combustion chamber in each of the above-described embodiments, a dedicated cooling liquid (for example, cooling water) may be used.

<< Effect >> The present invention has the following effects.

The fuel injection nozzle mounting portion, which is the heat storage portion of the head block, and the portion between the valve openings are partially liquid-cooled, and the portions other than the heat storage portion of the head block are air-cooled. For this reason, compared to an all-water cooling type in which the heat storage part of the head block and parts other than the heat storage part are all uniformly cooled without distinction, the amount of heat radiated to the cooling liquid is small and the amount of cooling liquid used is small. , The engine can be lightened accordingly. Further, a radiator such as an oil cooler or a radiator that radiates the heat of the cooling liquid 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, the heat storage part, which is relatively easily overheated, is strongly cooled by liquid cooling. For this reason, the combustion temperature can be set higher without fear of thermal damage to the heat storage unit, as compared with the all air cooling type in which the heat storage unit is cooled only slowly. 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 portion between the valve openings is strongly cooled from the inside of the meat portion by the cooling liquid that passes through the cooling liquid supply passage. Therefore, even if the gap between the facing valve inner port walls becomes narrower and the cooling air passing therethrough decreases or disappears, only the portion between the valve openings in the volume valve orifice peripheral portion is compared with other portions. Does not rise to high temperature, and thermal distortion does not easily occur in the peripheral wall of the metering valve. For this reason,
Unlike the all-water cooling type or all-air cooling type, in which the cooling between the valve ports is performed only by the refrigerant that passes through the gap between the facing valve port walls, both valves can be used without consideration of securing this gap. It is possible to increase the intake and exhaust efficiency by increasing the diameter of the mouth.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a cross-sectional plan view of a head block of an in-line two-cylinder diesel engine, FIG. 2 is a partially cutaway side view of the same engine, and FIGS. It is a cross-sectional top view of the head block which shows an Example. 3 ... Head block, 6 ... Cooling fan, 7 ... Wind guide case, 8 ... Cylinder, 9 ... Intake port, 10 ... Exhaust port, 11 ... Intake valve port, 12 ... Exhaust valve port, 15 …… Fuel injection nozzle mounting part, 16 …… Coolant chamber, 17 ……
Cooling air passage, 18 ... Cooling liquid supply passage, 19 ... Cooling air inlet,
20 …… Cooling air outlet, E …… Engine body.

Claims (1)

[Claims] 1. A plurality of cylinders (8) are arranged side by side in front and rear, and an intake port (9) and an exhaust port (10) in each cylinder.
The valve openings (11) and (12) of the cylinder are arranged side by side in the head block (3), and the combustion injection nozzle mounting portion (15) is formed on one lateral side of the intervalve portion (27) of each cylinder. The cooling liquid chamber (16) is formed so as to surround the fuel injection nozzle mounting portion (15), and the cooling liquid supply passage (18) passing through the meat portion of the intervalve opening portion (27) is connected to the cooling liquid chamber (18). 16) to partially cool the fuel injection nozzle mounting portion (15) of the head block (3) with the cooling liquid passing through the cooling liquid chamber (16), and the intervalve portion (27). Is partially liquid-cooled by the cooling liquid passing through the cooling liquid supply passage (18), and the cooling air is supplied from the cooling fan (6) to the cooling air passage (17) in the head block (3) to cool the cooling air passage. The head block (3) can be air-cooled by cooling air passing through (17). Cooling device separation-cooled series multi-cylinder diesel engine.