JP2523541Y2 - Partial liquid cooling system for overhead valve multi-cylinder engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial liquid cooling device configured to cool a cylinder portion and a cylinder head of an overhead valve multi-cylinder engine having a sub-combustion chamber with a cooling fluid fed by pressure.

[0002]

2. Description of the Related Art As a part of a liquid cooling device for an overhead valve multi-cylinder engine, as disclosed in Japanese Patent Application Laid-Open No. 2-115516, a cooling fluid pumped by a pump is supplied to a jacket between cylinders from a pressure feeding passage. And a cooling passage between intake and exhaust valves in this order, and then sequentially pass through a sub-combustion chamber jacket and a radiator, and return to a pressure feed passage for circulation.

[0003]

In the above-mentioned conventional structure, since the coolant that has passed through the inter-valve cooling passage is merely supplied to one jacket of the sub-combustion chamber, the auxiliary combustion chamber having a relatively large diameter is used. Fluid unevenness and insufficient flow rate of the cooling liquid in the jacket are likely to occur, and the cooling performance may not be sufficiently exhibited.

An object of the present invention is to improve the cooling performance by improving the coolant supply structure to the sub-combustion chamber jacket to improve the coolant flow unevenness and insufficient flow rate in this jacket. I do.

[0005]

In order to achieve the above object, the present invention is configured as follows, for example, as shown in FIGS. That is, the jacket 19 between the cylinders communicates with the respective sub-combustion chamber jackets 27 via the respective short-circuit paths 28, and
In this embodiment, the outlet b of each short-circuit path 28 and the outlet a of the cooling path 24 between the intake and exhaust valves are opened far away from the outlet c of each sub-combustion chamber jacket 27.

[0006]

According to the structure of the present invention, the auxiliary combustion chamber jacket 2 is provided.
In addition to the coolant flowing through the intake-exhaust-valve cooling passage 24, the coolant flows from the jacket 19 between the cylinders via the short-circuit passage 28 at a position distant from the inflow position. For this reason, the flow of the coolant easily occurs over the entire area inside the sub-combustion chamber jacket 27, and the flow rate increases.

[0007]

FIG. 2 is a side view of a two-cylinder diesel engine of the overhead valve type with a part cut away, FIG. 3 is a vertical rear view of an upper part of the engine, and FIG. It is shown.

The engine 1 has a cooling system combining cooling of the crankcase 2 by air cooling and cooling of the cylinder head 3 by partial liquid cooling (oil cooling). That is, the external cool air sucked by the fan 6 of the flywheel 5 attached to the front end of the crankshaft 4 penetratingly supported by the crankcase 2 is applied to the outer periphery of the cylinder 2 a and the cylinder head 3 above the crankcase 2 via the spiral case 7. The radiator 8 of the pressure-feeding type partial liquid cooling device is cooled by a part of the cooling air drawn from the upper part of the spiral case 7 while being guided to cool them.

FIGS. 1 and 3 show the construction of a pressure-feeding type partial liquid cooling device for the cylinder head 3. That is, lubricating oil also serving as a cooling liquid is stored in an oil pan 9 formed at the bottom of the crankcase 2, and the oil is passed through a strainer 11 by a trochoid pump 10 driven by gearing with the crankshaft 4. A part of the oil which is sucked and pressurized by the pump 10 is supplied to the lubricating oil passage 13 with the pressure adjusted by the regulating valve 12, and most of the oil first passes through the regulating valve 12. It is fed into the cylinder jacket 15 from the pressure feed path 14. This cylinder jacket 15
Are the two cylinders 2a and the push rod chambers 16 outside thereof.
Is formed upright on the wall 17 between the cylinder and the push rod.

The inter-cylinder wall portion 1 between the two cylinders 2a
8, an inter-cylinder jacket 19 is formed upright, and the inter-cylinder jacket 19 and the cylinder jacket 15 are communicated from the outside of the cylinder by an oil passage 20 formed by drilling holes.

The inter-valve wall portion 2 existing between the intake and exhaust valves 21 and 22 for each cylinder 2a of the cylinder head 3 is provided.
The cooling passages 24 between the intake and exhaust valves are formed in the inside 3 in a horizontal and vertical direction, and the upper end of the cylinder jacket 15 and the start end of each cooling passage 24 between the intake and exhaust valves are communicated by a communication passage 25. The end portion of the exhaust valve cooling passage 24 is
Is connected to a sub-combustion chamber jacket 27 surrounding the sub-combustion chamber.

The end side of the inter-cylinder jacket 19 and each of the sub-combustion chamber jackets 27 are communicated with each other via short-circuit paths 28, and a cooling path between intake and exhaust valves is provided above each sub-combustion chamber jacket 27. 19 exit a and short circuit 28
The outlet c for sending out the cooling liquid is provided so as to be located away from the outlet b of each of the sub-combustion chambers, and each of the outlets c of the jackets 27 of the sub combustion chambers is led out of the cylinder head 3 through one discharge passage 29. , And is sent to the radiator 8.

That is, a part of the oil pumped by the pump 10 and sent to the cylinder jacket 15 is sent to each of the sub-combustion chamber jackets 27 via each of the communication passages 25 and each of the cooling passages 24 between the intake and exhaust valves. Another part is sent from the cylinder jacket 15 through the inter-cylinder jacket 19 and each short-circuit path 28 to each sub-combustion chamber jacket 27, during which the cylinder 2a and the cylinder head 3 are cooled and enter the radiator 8, where they are radiated. The oil cooled by the air-cooled heat radiation forms an oil (coolant) circulating system that is recovered by the oil pan 9 at the bottom of the crankcase via the return hole 30 in the cylinder head 3 and the return passage 31 in the cylinder peripheral wall. I have. The return hole 30 and the start end of one of the cooling passages 24 between the intake and exhaust valves are communicated via a relief valve 33 so that the radiator 8 is not configured to generate a higher pressure than the set pressure.

Each of the short-circuit paths 28 has a vertical hole 28a and a horizontal hole 28 at a position where the inter-cylinder jacket 19 and the auxiliary combustion chamber jacket 27 are close to each other.
b and the vertical hole 2
8a is formed upward from the bottom surface of the cylinder head 3, and the horizontal hole portion 28b extends along the drilling axis P connecting the upper portion of the vertical hole portion 28a and the casting sand removal port 34 of the sub-combustion chamber jacket 27. It is formed by drilling. Incidentally, the casting sand removal port 34 is closed by the closing tool 35 after the above-mentioned drilling.
Closed with.

[0015]

As is clear from the above description, according to the present invention, two systems of coolant flow into each sub-combustion chamber jacket, and flow through the jacket without short-circuiting to radiate heat from the outlet. Will be sent to the vessel,
The flow rate of the coolant to the sub-combustion chamber jacket is increased compared to the conventional structure in which only one system flows, and the coolant flow unevenness in the jacket is suppressed, so that the efficient sub-combustion chamber cooling becomes possible. As a result, the output, fuel efficiency and durability of the engine could be improved.

In addition, the short-circuit path for promoting the supply of the coolant to the sub-combustion chamber jacket can be easily formed by drilling, and can be short, so that the processing cost is lower than in the case where it is formed by a mold. It can be.

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view showing a configuration of a partial liquid cooling device of an overhead valve type multi-cylinder engine provided with a partial liquid cooling device according to the present invention.

FIG. 2 is a partially cutaway side view of an overhead valve type multi-cylinder engine.

FIG. 3 is a longitudinal rear view of the upper part of the engine, showing a configuration of a partial liquid cooling device.

FIG. 4 is a longitudinal rear view between cylinders.

FIG. 5 is a schematic perspective view showing a configuration of a coolant flow path.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 24 ... Cooling path between intake and exhaust valves, 2a ... Cylinder, 26
... sub combustion chamber, 3 ... cylinder head, 27 ...
Sub-combustion chamber jacket, 8 ... radiator,
28: short circuit, 10: pump,
28a: Standing hole, 14: Pressure feed path 28b: Horizontal hole, 19: Jacket between cylinders, 34: Casting sand outlet, 21: Intake valve, 35 ...
Obturator. 22 ... exhaust valve,

Claims (1)

(57) [Scope of request for utility model registration] The coolant of an overhead valve multi-cylinder engine (1) is:
By passing the pumping force of the pump (10) from the pumping path (14) to the inter-cylinder jacket (19) and the cooling path (24) between the intake and exhaust valves, each sub-combustion chamber jacket (27) and radiator ( 8), and is circulated by returning to the pressure feed path (14).
Is vertically set in the wall between cylinders between adjacent cylinders (2a), and the cooling passages (24) between the intake and exhaust valves are:
The sub-combustion chamber jacket (27) is formed longitudinally in the inter-valve wall (23) between the intake and exhaust valves (21) and (22) of the cylinder head (3). Within the sub-combustion chamber
(26) formed in a state surrounding the auxiliary combustion chamber jacket
An overhead valve multi-cylinder engine constructed by opening a casting sand removal port (34) in an outer portion of the peripheral wall of (27) and closing the casting sand removal port (34) with an obturator (35). In some liquid cooling devices, the jacket between cylinders (19) is
(28) through the respective sub-combustion chamber jackets (27), and in each sub-combustion chamber (26), the outlet (b) of each short-circuit path (28) and the cooling path (24) between the intake and exhaust valves. ) Is opened at a position far away from the outlet (c) of each sub-combustion chamber jacket (27), and each of the short-circuit paths (28) is provided with an inter-cylinder jacket (19) and an auxiliary combustion chamber jacket. (27) and a vertical hole (28a) and a horizontal hole (28b) communicating with each other at a position where they approach each other. The vertical hole (28a) extends from the bottom of the cylinder head (3). The horizontal hole (28b) is formed upward by drilling along a drilling axis (P) connecting the upper part of the vertical hole (28a) and the casting sand removal port (34). A partial liquid cooling device for an overhead valve multi-cylinder engine.