JPH08218864A - Liquid cooling device for engine - Google Patents

Abstract

PURPOSE: To effectively cool a cylinder head by a method wherein a head cooling jacket is formed in the shape of a passage starting from an input formed on one side of a cylinder head and winding, in order, an exhaust port and a combustion chamber, and extending to an outlet communicated with a cylinder cooling jacket. CONSTITUTION: A head cooling jacket 41 winding, in order, an exhaust port 37 and a combustion chamber, is formed as a single passage at a cylinder head 33 without forming a loop. Further, a connection pipe 41a being an inlet is protruded from the outer surface of the cylinder head 33, and the downstream end of a third oil pipe P3 is connected thereto. The outlet 41b of the head cooling jacket 41 is communicated with the one side part of a cylinder jacket formed at a cylinder block in such a manner to surround a cylinder sleeve. Thus, oil flowing from the third oil pipe P3 to the cooling jacket 41 flows through, in order, the exhaust port 37 and the periphery of the combustion chamber, and during the flow of the oil, short-circuit and stagnation are prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine liquid cooling device using water or oil as a cooling liquid, and more particularly to a head cooling jacket formed on a cylinder head having an exhaust port and a combustion chamber, and a cylinder block having a cylinder. The present invention relates to an improved cylinder cooling jacket formed in the above, and a cooling liquid flowing from the head cooling jacket to the cylinder cooling jacket.

[0002]

2. Description of the Related Art In such a conventional cooling device, as disclosed in, for example, Japanese Patent Publication No. 62-33405, a head cooling jacket, a cylindrical jacket portion surrounding an exhaust port, and a circle surrounding a combustion chamber are disclosed. The annular jacket portion is configured to communicate with each other, and the annular jacket portion is communicated with the cylinder cooling jacket through a large number of through holes.

[0003]

In the head cooling jacket in the conventional liquid cooling device as described above, a short circuit or stagnation is likely to occur in the flow of the cooling liquid, and a large amount of the cooling liquid is required to cause the flow over the entire jacket. However, doing so is not preferable because it increases the load on the pump.

The present invention has been made in view of the above circumstances, and even a cooling liquid having a relatively small flow rate can be circulated throughout the head cooling jacket to effectively cool the cylinder head. The purpose is to provide a device.

[0005]

In order to achieve the above object, in the present invention, a head cooling jacket starts from an inlet formed on one side of a cylinder head and sequentially surrounds an exhaust port and a combustion chamber to cool the cylinder. It is characterized in that it is formed in the shape of a single passage leading to an outlet communicating with the jacket.

[0006]

According to the above feature, when the cooling liquid flows into the inlet of the block cooling jacket, it sequentially goes around each of the exhaust port and the combustion chamber and moves from one outlet to the cylinder cooling jacket, during which the cooling liquid flows. Since no short circuit or stagnation occurs in the cylinder head, it is possible to effectively cool the cylinder head even with a coolant having a relatively small flow rate.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of an engine equipped with a working machine according to the present invention, FIG. 2 is a right side view thereof, FIG. 3 is a left side view thereof, and FIG. 4 is a bottom view thereof. In these drawings, an engine 1 with a working machine includes a vertical engine 2 and a gas mixture generator 4 such as a carburetor attached to the upper surface of the engine 2.
An air cleaner 5 connected to the intake port of the air-fuel mixture generator 4, a starter motor 6 and a working machine 7 mounted on the upper surface of the engine 2, and an exhaust gas arranged below the engine 2 in parallel with its cylinder axis. The heat exchanger 8 and a cross section L arranged along one side surface and the lower surface of the exhaust heat exchanger 8.
It is composed of a V-shaped oil tank 9 and a frame 11 which accommodates the oil tank 9, the exhaust heat exchanger 8 and the lower portion of the engine 2, and supports the engine 2 via a plurality of anti-vibration rubbers 10. The oil tank 9 is a frame 11
Fixed to. An oil supply port 12 is provided on the upper wall of the oil tank 9, and is normally closed by a cap 13.

As shown in the above figures and FIG. 5, the engine 2 is provided with a first oil pump 15 for cooling and a second oil pump 16 for lubrication. The first oil pump 15 is of a large capacity and low pressure type, and the first oil pipe P ₁
Through the second oil pipe P ₂ , the oil pumped from the oil tank 9 is pumped to the exhaust heat exchanger 8. As shown in FIG. 5, the exhaust heat exchanger 8 has an oil passage 18 disposed in an exhaust muffler chamber 17 for introducing the exhaust gas of the engine 2. By exchanging heat with the oil flowing through the engine, the exhaust gas is cooled and the temperature of the oil is raised to accelerate warming up of the engine 2.

The oil that has passed through the exhaust heat exchanger 8 flows through the third oil pipe P ₃ to cooling jackets 41 and 42 of the engine 2 which will be described later. The path of the oil that has passed through the jacket is controlled by the thermostat 19 (see FIGS. 5 and 9). That is, at low temperature, the fourth oil pipe P
₄ , the path is controlled to the fifth oil pipe P ₅ at high temperature, the oil directed to the fourth oil pipe P ₄ immediately returns to the oil tank 9, and the oil directed to the fifth oil pipe P ₅ is After passing through the radiator 20, it is returned to the thermostat 19 by the sixth oil pipe P ₆ and guided to the fourth oil pipe P ₄ and is returned to the oil tank 9.

On the other hand, the second oil pump 16 is of a small capacity and high pressure type, and the oil pumped from the oil tank 9 through the seventh oil pipe P _{7 is} passed through the oil passage 21 in the wall of the engine 2 to the oil filter 22. Pump to. The oil filtered by the oil filter 22 is supplied through the oil gallery 24 in the engine 2 to the lubrication parts such as the crankshaft, the piston and the valve mechanism, and the lubricated oil flows down to the bottom of the crank chamber of the engine 2. The oil is returned to the oil tank 9 through the eighth oil pipe P ₈ .

As shown in FIG. 5, the crank chamber of the engine 2 communicates with the upper space in the oil tank 9 via a breather passage 23.

6 to 11 show the construction of the vertical engine 2 and the mounting structure of the starter motor 6 and the working machine 7 for the vertical engine 2. FIG. 6 is a longitudinal sectional front view of the engine 2, and FIG. 7 is a sectional view taken along line 7-7, and FIG.
8 sectional view, FIG. 9 is a sectional view taken along line 9-9 of FIG. 1, FIG. 10 is a sectional view taken along line 10-10 of FIG. 6, and FIG.
It is a line sectional view.

As shown in FIGS. 6 and 7, the crankcase 25 of the engine 2 is a case half 25 that is divided into upper and lower halves.
a, 25b, and these case halves 25a,
The upper and lower ends of a crank shaft 26 and a cam shaft 27, which are respectively arranged in the vertical direction, are supported by 25b, and the crank shaft 26 decelerates and drives the cam shaft 27 via a timing belt 28.

A cylinder block 29 is integrally connected to the upper case half body 25a, and a piston 32, which is connected to the crankshaft 26 via a connecting rod 31, is slidably fitted to a cylinder sleeve 30 that is cast and wrapped therein. It A cylinder head 33 is bolted to the outer end surface of the cylinder block 29, and a head cover 34 is bolted to the outer end surface of the cylinder head 33.

The cylinder head 33 has a combustion chamber 3
5, an intake port 36 for introducing the air-fuel mixture generated by the air-fuel mixture generator 4, and an exhaust port 37 for guiding the exhaust gas from the combustion chamber 35 to the exhaust silencer 17 are provided. The intake and exhaust valves 38 and 39 for opening and closing the valves 36 and 37 are driven by a known valve operating device 40 (see FIG. 8) including the cam shaft 27.

As shown in FIGS. 6, 10 and 11, in the cylinder head 33, a head cooling jacket 41, in which the exhaust port 37 sequentially surrounds the combustion chamber 35 without forming a loop, is formed as one passage. At the same time, a connection pipe 41a serving as an inlet thereof is provided so as to project from the outer surface of the cylinder head 33, and the downstream end of the third oil pipe P ₃ is connected to this.

The outlet 41 of the head cooling jacket 41
b communicates with one side of a cylindrical cylinder cooling jacket 42 formed in the cylinder block 29 so as to surround the cylinder sleeve 30, and the other side of the jacket 42 communicates with an inlet 19a of the thermostat 19. To do.

Therefore, the oil flowing into the head cooling jacket 41 from the third oil pipe P ₃ is exhausted from the exhaust port 36.
Further, the cylinder head 33 can be effectively cooled because the cylinder head 33 passes through each circumference of the combustion chamber 35 sequentially and during that time there is no short circuit or stagnation of the flow. The oil that has passed through the head cooling jacket 41 moves to the cylinder cooling jacket 42 and cools around the cylinder sleeve 30.
Head to thermostat 19.

Referring again to FIGS. 6 and 7, the crankshaft 2
The flywheel 43 is fitted to the upper end of the bolt 6, and the bolt 44
It is fixed in. The flywheel 43 has a joint plate 46 having a power output hole 45 coaxial with the crankshaft 26.
Are fixed by bolts 47, and the input shaft 7a of the working machine 7 is splined or keyed to the power take-out hole 45 thereof.

A ring gear 48 is fixed to the outer periphery of the flywheel 43. The starter motor 6 having a pinion 49 for driving the flywheel 43 is arranged in parallel on one side of the working machine 7 when the engine is started. The starter motor 6 and the working machine 7 are fixed to the upper end of a mount case 51 joined to the upper surfaces of the crankcase 25 and the cylinder block 29 with bolts 50 so as to surround the flywheel 43 with bolts 52 and 53.

By mounting the starter motor 6 and the working machine 7 in parallel to the mount case 51 surrounding the flywheel 43 at the upper end of the crankshaft 26 thus arranged in the vertical direction, the starter is projected in the vertical projection plane of the engine 2. The motor 6 and the working machine 7 can be housed, and the overall height can be lowered, so that the working machine-equipped engine 1 can be made compact.

Moreover, a sub-assembly is formed by the mount case 51, the starter motor 6 and the working machine 7,
If this is attached to the engine 2, the assembly can be carried out efficiently, and the mount case 51 is attached to the flywheel 4
Since it also serves as the cover of 3, it can contribute to simplification of the structure.

Further, since the input shaft 7a of the working machine 7 is splined or key-connected to the power take-out hole 45 of the joint plate 46 fixedly mounted on the flywheel 43, the amount of upward projection of the working machine 7 from the engine 2 is reduced. It can be kept as low as possible to further reduce the overall height.

FIG. 12 shows a modified example of the present invention, in which the second oil pipe P ₂ connected to the discharge side of the first pump 15 is branched to the seventh oil pipe P ₇ , which is connected to the second oil pump 16. The configuration is the same as that of the previous embodiment except that it is connected to the suction side, and in the figure, the same reference numerals are given to the corresponding portions with the previous embodiment.

According to this modification, the second oil pump 1
Since 6 further pressurizes the oil pressurized by the first pump 15, high-pressure lubricating oil can be obtained and each part of the engine 2 can be effectively lubricated.

In the above embodiment, various design changes can be made without departing from the gist of the present invention. For example, water can also be used as the cooling liquid that flows through the cooling jackets 41 and 42 of the engine 2.

[0028]

As described above, according to the present invention, the head cooling jacket starts from the inlet formed on one side of the cylinder head and sequentially surrounds the exhaust port and the combustion chamber to the outlet communicating with the cylinder cooling jacket. Since the cooling liquid is formed in the shape of a single passage, no short circuit or stagnation of the flow occurs during the sequential circulation of the cooling liquid around each of the exhaust port and the combustion chamber. Therefore, the cylinder head can be effectively cooled with the cooling liquid having a relatively small flow rate, and the load on the pump can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of an engine with a working machine according to the present invention.

FIG. 2 is a view on arrow 2 of FIG.

FIG. 3 is a view taken in the direction of arrow 3 in FIG. 2;

FIG. 4 is a view on arrow 4 of FIG.

FIG. 5: Schematic diagram of engine cooling and lubrication system

FIG. 6 is a vertical plan view of the engine.

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;

8 is a sectional view taken along line 8-8 in FIG. 6;

9 is a sectional view taken along line 9-9 of FIG.

10 is a sectional view taken along line 10-10 of FIG.

11 is a cross-sectional view taken along line 11-11 of FIG.

FIG. 12 is a schematic diagram corresponding to FIG. 5, showing a modified example of the present invention.

[Explanation of symbols]

 29 Cylinder Block 30 Cylinder Sleeve 33 Cylinder Head 35 Combustion Chamber 37 Exhaust Port 41 Head Cooling Jacket 41a Inlet 41b Outlet 42 Cylinder Cooling Jacket

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Satake 1-4-1 Chuo, Wako-shi, Saitama Stock Research Institute Honda Technical Research Institute

Claims (1)

[Claims] 1. An exhaust port (37) and a combustion chamber (35)
A head cooling jacket (41) formed on a cylinder head (33) having a cylinder and a cylinder cooling jacket (42) formed on a cylinder block (29) having a cylinder (30). In a liquid cooling device for an engine, in which a cooling liquid is made to flow to the cooling jacket (42), the head cooling jacket (41) is connected to the cylinder head (3
3) An outlet (41b) which starts from an inlet (41a) formed on one side and sequentially surrounds an exhaust port (37) and a combustion chamber (35) and communicates with a cylinder cooling jacket (42).
A liquid cooling device for an engine, characterized in that it is formed in the shape of a single passage leading to.