JPS63138117A - Device for preventing overheat during forward inclination in vertical water-cooled engine - Google Patents

Abstract

PURPOSE:To enable fetching out of steam staying in an air reservoir in a head jacket and to prevent the occurrence of deficiency in cooling, by a method wherein a temperature-sensitive actuating valve performing an opening work at temperature higher than the evaporating temperature of cooling water is connected to the steam outlet port of a cylinder head. CONSTITUTION:Cooling water for an engine is circulated from a cylinder jacket 7 through a head jacket 8, a hot water return pipe 26, a radiator 5, a cooling water feed pipe 29, and a water pump 13, and a pressure regulating valve 24 is disposed in the cooling water circulating system. In this device, a temperature- sensitive actuating valve 35 opened at a temperature higher than the evaporative temperature of cooling water is connected to a steam outlet formed in the rear part of a cylinder head 2. When the engine is used in, for example, inclination orientation and steam begins to gather in an air reservoir in a head jacket 8, the temperature-sensitive actuating valve 35 is opened, steam is fetched out from the interior of the head jacket 8, and the deficiency in cooling of the cylinder head 2 is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for preventing overheating of a head portion of a water-cooled engine caused by use in an inclined position.

(Prior art) In the case of a vertical engine in which a radiator is placed on the front side of the engine body and the engine body and radiator are connected by a hot water return pipe led out from the front side of the head jacket, the engine is used in a forward tilted position. This causes a steam pocket to form at the rear of the head jacket, causing local overheating of the cylinder head.

For this reason, in the past, a pressure regulating valve such as a radiator cab was installed in the cooling water circulation system between the engine and the radiator, and a steam outlet was installed in the rear part of the cylinder head, which communicated the front part with the radiator. A pressure regulating valve was installed at the steam outlet.

(Problem to be solved) However, when a pressure regulating valve is installed at the steam outlet, the set pressure of the pressure regulating valve in the cooling water circulation system and the set pressure of the pressure regulating valve located at the steam outlet are set to the same pressure. It turns out. For this reason, when operating in a tilted position, steam accumulates in the head jacket or cooling water circulation system, causing an increase in internal pressure.
Both valves were opened, and steam was blown out from one valve and cooling water was blown out from the other valve, resulting in a shortage of cooling water.

(Means for Solving the Problems) The present invention solves the above-mentioned problems and enables smooth cooling over a long period of time.To this end, the cooling circulation system is established between the engine and the radiator. In a vertical engine that has a steam outlet in the cylinder head, a temperature-sensitive valve whose operating temperature is set to open at a temperature higher than the boiling temperature of the cooling water is connected to the steam outlet. It is characterized by the fact that

(Function) In the present invention, is there a cooling water circulation system between the engine and the radiator? +4, and in vertical engines with a steam outlet in the shilling head, the steam outlet is equipped with a temperature-sensitive valve whose operating temperature is set to open at a temperature higher than the boiling temperature of the cooling water. Since the engine is operated with the engine tilted forward, if an air pocket is created in the head jacket, steam at a temperature higher than the boiling temperature of the cooling water will be generated at the same time as steam is generated. will act on the temperature-sensitive valve, so the temperature-sensitive valve will open and take out the steam. At this time, the pressure in the cooling water circulation system has not risen to the set pressure of the pressure regulating valve, and water does not blow out from the pressure regulating valve.On the contrary, the engine is operated with the engine tilted backwards. In this case, a steam pocket will be formed in the upper part of the radiator, and the temperature-sensitive valve will be exposed to the cooling water in the head jacket. Since the temperature of the cooling water itself never exceeds its boiling point, in this case the temperature-sensitive valve will be closed, the cooling water will not blow out, and the steam pressure will not exceed the set pressure of the pressure regulating valve. This causes the pressure regulating valve to operate and extract steam.

(Example) The drawings show an example of the present invention, and FIG. 1 is an exploded view of the main part.
FIG. 2 is a schematic diagram of the vertical water-cooled engine.

In the figure, a vertical water-cooled engine (E) has a cylinder head (2) and a spatula cover (3) fixed above a cylinder block (1), and a cooling fan (4) and a radiator (5) in front of it. It is arranged.

The above-mentioned cylinder block (1) has a cylinder jacket (7) formed in the gap between four cylinders (6) arranged in parallel across the front and back, and a head jacket (8) formed in the cylinder spatula r (2'). , the above cylinder jacket (7
) is communicated with the outlet (9) at the rear side of the engine (E).

In addition, a water pump chamber (10) is provided behind the cooling fan (4), and a rotor (10) is mounted on the fan shaft (11).
12) is accommodated in the water pump chamber (10) to form a water pump (13), and a crankshaft (14) is interlocked with the fan shaft (11) via a belt (15).

A thermostatic valve chamber (16) is formed above the water pump chamber (10), and a thermostatic valve (1) and a solenoid (19) are connected to the partition plate (17) as a boundary.
A superheat prevention valve (20) that operates in conjunction with the engine is provided in parallel connection, and the thermostatic valve chamber (16) of the head jacket (8) is located on the engine rear side of the head jacket (8).
) on the side opposite to the end (21) that communicates with f! HIS
Connect the water temperature sensor (not shown) attached to (22) to the above solenoid (19), and
The valve opening command temperature T of the water temperature sensor is set to approximately 82° C., and the valve opening command temperature T0 of the water temperature sensor is set to approximately 100° C. (ie, a temperature of T″C0 or higher and lower than or equal to the boiling point of the coolant).

A radiator cap (24) having a pressure regulating valve function is disposed in the upper tank (23) of the radiator (5), and the upper tank (23) is connected to the outlet (25) of the thermostatic valve chamber (16). Hot water return pipe (2
G) and lower tank (27) of the radiator (5).
By connecting the inlet (28) of the water pump chamber (10) and the inlet (28) of the water pump chamber (10) with a cold water supply pipe (29), and communicating the outlet (30) of the water pump chamber (10) with the inlet of the cylinder jacket (7), It constitutes the cooling water circulation system. The inlet (28) of the water pump chamber (10) is communicated with the jacket side chamber (31) of the thermostat valve chamber (16) through a bypass (32).

In addition, a steam outlet (34) is provided in the rear upper wall (33) of the cylinder head (2).
4) is fixed with a temperature-sensitive operating valve (35). The operating temperature of this temperature-sensitive operating valve (35) is set so that it is closed when the temperature is lower than the boiling temperature of the coolant, and opens when the temperature is higher than the boiling temperature.

A steam extraction pipe (38) is led out from the housing (37) on the downstream side of the valve seat (36) of the temperature-sensitive valve (35), and the tip of this steam extraction pipe (38) is connected to the condensed water tank. (
39).

In the engine cooling system configured as described above, when the engine is used in a forward tilted position, the water level of the cooling water becomes the state shown by the dashed line in Fig. 2, and air flows into the rear part of the head jacket (8). A buildup occurs.

Since the temperature of the steam is higher than the boiling temperature of the cooling water, when steam accumulates in the air pocket, the steam temperature acts on the temperature-sensitive valve (35), causing the temperature-sensitive valve (35) to open. The valve will operate to extract steam from inside the head jacket (8). This prevents the cylinder head (2) from becoming insufficiently cooled.

Conversely, if the engine is used in a backward tilted position, the water level of the cooling water will be as shown by the two-dot chain line in Figure 2, and an air pocket will be formed in the radiator (5), causing the temperature sensor to rise. The actuation valve (35) will be exposed to the cooling liquid. Since the temperature of the coolant never rises above the boiling temperature, in this case the temperature-sensitive valve will not open, the coolant will not leak, and the cylinder head will not be sufficiently cooled. Nor.

In the above embodiment, a thermostatic throat valve is used as the temperature-sensitive operating valve (35), but the valve element may be made of a shape memory alloy to open the valve.

(Effects) In the present invention, in a vertical engine in which the engine and the radiator constitute a cooling water circulation system and a steam outlet is provided in the cylinder head, the steam outlet is heated at a temperature higher than the boiling temperature of the cooling water. A temperature-sensitive valve whose operating temperature is set to open the valve is connected, so even when operating the engine in a forward-leaning position that causes air pockets inside the head jacket, the boiling temperature of the cooling water is maintained at the same time as steam is generated. Since the steam at a higher temperature than the temperature-sensitive valve will act on the temperature-sensitive valve, the temperature-sensitive valve will open and take out the steam.

This reliably prevents the cylinder head from becoming overheated due to insufficient cooling locally, and since only steam is extracted, there is no possibility of a shortage of cooling water due to cooling water blowing out. , it is possible to perform stable engine cooling over a long period of time.

Furthermore, since the cylinder head is simply equipped with a temperature-sensitive operating valve, the structure is simple, and the overall height of the engine does not increase, making it possible to obtain a compact engine.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is an exploded view of the main parts.
FIG. 2 is a schematic diagram of the vertical water-cooled engine. 2... Cylinder head, 5... Radiator, 7...
・Schilling jacket, 8...Head jacket, 1
3...Water pump, 24...Pressure regulating valve, 26
...Hot water return pipe, 29...Cold water supply pipe, 34...
Steam outlet, 35...temperature-sensitive valve, E...engine.

Claims (1)

[Claims] 1. A radiator (5) is arranged on the front side of the engine body (E), and the engine cooling water is routed from the cylinder jacket (7) to the head jacket (8), the hot water return pipe (26), and the radiator ( 5) A cooling water circulation system is constructed by circulating the cold water through the cold water supply pipe (29) and the water pump (13) to the cylinder jacket (7), and a pressure regulating valve (24) is installed in this cooling water circulation system. In a forward tilting overheating prevention device for a vertical engine, which is provided with a steam outlet (34) at the rear of the cylinder head (2), the steam outlet (34) is provided with a steam outlet (34) at a temperature higher than the boiling temperature of the cooling water. An overheat prevention device for a vertical water-cooled engine when tilting forward, characterized by connecting a temperature-sensitive valve (35) that opens and opens depending on the temperature.