JPS61247817A - Cooling system of car engine - Google Patents

Abstract

PURPOSE:To improve the thermal efficiency of an engine by allowing the cooling water to circulate from the lower part to the upper part in a radiator, thus eliminating the thermal over-shoot and surge pressure which are generated in a water passage on the initial valve opening of a thermostat. CONSTITUTION:The discharge port 3 of a water pump 2 is opened into the lower inflow port 4 of a water jacket 1. The upper effluence port 5 of the water jacket 1 and the lower opened port 7 of a radiator 6 are directly connected through a water passage 8, and a bottom bypass type thermostat 13 is set into a thermostat housing 12 formed between a water passage 11 connected to the upper opened port 9 of the radiator 6 and the suction port 10 of the water pump 2, and fixed by a cap 14. Further, a thick bypass water passage 15 is installed between the thermostat housing 12 and the intermediate junction joint J of the water passage 8 which communicates from the effluence port 5 of the water jacket 1 and the lower opened port 7 of the radiator 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling system for an automobile engine, and particularly relates to a cooling system in which cooling water is recirculated from the lower part of a radiator to the upper part of the radiator, which is the opposite of the conventional cooling system. This is a cooling system that eliminates the effects of outside temperature and increases the thermal efficiency of automobile engines.

As shown in Figures 1 and 2, the conventional automobile engine cooling system uses an outlet temperature control system in which a thermostat housing B is installed at the outlet of a water jacket A. As shown in the figure, since the thermostat in thermostat housing B is closed, water is supplied from water pump D.
Cooling water sent to jacket A passes through thermostat housing B, narrow bypass channel C, and returns to water.
Since the coolant is sucked into pump D and short-circuited, the temperature of the coolant increases quickly.

When the temperature at the outlet of water jacket A exceeds the valve opening temperature of the thermostat, part of the cooling water flows from thermostat housing B to radiator E from top to bottom and joins bypass flow C on the way, as shown in Figure 2. The water is then sucked into water pump D, where it is transformed into reflux that reaches the inlet of water jacket A.

However, in reality, the response speed of the thermostat is much slower than the rate of increase in water temperature, so the temperature at the outlet of water jacket A may exceed the thermostat's valve opening temperature by about 20 to 25 degrees Celsius, and in this case, the thermostat will suddenly open. do. If the valve is opened in this condition, the lower part of the radiator E
The cold flow suddenly flows into the bulk water jacket (A), and the water jacket inlet is rapidly cooled. This rapid temperature change causes a large thermal overshoot and associated large surge pressure to occur in the waterway, and if this is repeated repeatedly, cracks may occur in the cylinder and cylinder head.

Various malfunctions occurred, including damage to the thermostat.

- Occasionally causes serious engine trouble.

This overshoot and surge pressure phenomenon becomes more intense as the outside temperature is lower, that is, as the thermal gradient above and below the radiator becomes larger.

In recent years, an inlet temperature control system with a thermostat installed at the inlet of the water jacket has been adopted.
Rapid temperature changes have been alleviated, but this is because the thermostat is located close to the inlet of the water jacket and is installed with the bottom pulp facing upwards, making maintenance and inspection completely impossible for users. It becomes.

The purpose of the present invention is to eliminate the thermal overshoot and surge pressure that occur in the cooling water channel of an automobile engine, eliminate the influence of outside temperature, and furthermore, set the thermostat in the normal position where the bottom pulp is located below. It is to obtain an automobile engine cooling system that is easy to inspect.

The automotive engine cooling system of the present invention
This belongs to the inlet temperature control method in which a thermostat is installed at the inlet of the jacket, but the thermostat is installed in the normal position with the bottom pulp facing downward, making maintenance and inspection easier, and also helps eliminate thermal overshoot and surge pressure that occur in the water channel. In order to further ensure the elimination of the influence of outside temperature, the cooling water is recirculated from the bottom to the top of the radiator in the opposite direction.

That is, as shown in Fig. 4, a thermostat is installed in the thermostat housing B at the branch point of the water channel that leads to the upper opening of the radiator E and the inlet of the water pump D, and the thermostat is installed in the thermostat housing B at the branch point of the water channel that leads to the upper opening of the radiator E and the inlet of the water pump D. A thick bypass waterway C is provided between the branch point of the waterway leading to the lower opening and the thermostat housing 8, so that cooling water flows back from the bottom to the top of the radiator E when the thermostat is opened.

Examples of the present invention will be described below.

In FIG. 6, l is the water jacket of the engine, 2 is a water pump, and its discharge port 3 opens into the inlet port 4 of the water jacket l. A thermostat housing 12 at a branch point of a waterway 11 that connects the outlet 5 of the water jacket 1 and the lower part of the radiator 6 with a waterway 8 and communicates with the upper opening 9 of the radiator 6 and the inlet 10 of the water pump 2. As shown in the figure, the bottom bypass type thermostat 13 is fixed in the normal position with a cap 14.

Further, a thick bypass waterway 15 is provided between the housing 12 and a branching point J of the waterway 8 leading to the lower part between the outlet 5 of the water jacket 1 and the lower part of the radiator 6.

FIG. 7 shows the bottom bypass type thermostat in its closed state, FIG. 8 shows its fully open state, and FIG. 9 shows its side view.

Flange 1 opening pulp sheet 16 in FIG.
A bridge 19 opening a cooling water passage 18 is formed on the upper side of the bridge 7, and a frame 20 is fixed to the lower side of the bridge 19. pulp·
The H/L/F 21 that engages the seat 16 is press-fitted into the guide 23 of the thermoelement 22.

It is fixed in place by a ring 24. A compression spring 25 engages between the pulp 21 and the frame 20. The known thermo-element 22 includes a heat-sensitive tube 26 (FIG. 7) and a guide 231.
Elastic seal cylinder 27. Bush Wand 28.
It is composed of Wax 29. 30 is a seal backing. A shaft 31 is fixed to the bottom surface of the heat-sensitive cylinder 26, and a bottom pulp 32 is slidably inserted therein. 33 is a compression spring;
34 is a retaining ring that prevents the bottom pulp 32 from falling off.

The thermo element 22 of the thermostat is the pulp 21
The structure must be such that it is not affected by external cold currents through it. For example, if the thermo-element 22 is affected by the low-temperature flow of the water channel 11 through the pulp 21 when the valve is closed, the thermostat will not open the valve unless the temperature reaches a temperature higher than the specified valve-opening temperature, which will prevent thermal overshading and surge pressure. , provoke.

Therefore, the pulp 21 is inserted into the guide n of the thermo element 22.
Press it into place and fix it in place with the retaining ring 24.

The pulp 21 and thermoelement 22 are separated. Further, the pulp 21 and the guide field are made of a material insensitive to heat, and if necessary, the pulp 21 is coated with elastic rubber to prevent water leakage when the valve is closed.

Now, when the cooling water temperature rises above the valve opening temperature of the thermostat 13, the increased volume of the melted wax 29 is transferred to the bush rond 28 (
Squeeze this upward against the spring 25 that warps the two swords.

However, since the tip of the bushing rod is spherically engaged with the bridge 19 and does not move, the pulp 21 is relatively opened downward (FIG. 8). 35 is a known jiggle pulp (Figure 9)
.

Now, at the beginning of the engine startup (Fig. 6), the thermostat 13 closes the pulp 21, so the water
The cooling water sent from the pump 2 to the water jacket 1 enters the thermostat housing 12 from the bypass waterway 15 through the bypass hole 36, and is sucked into the water pump 2 again for short-circuit reflux, so the water temperature rises quickly.

(Figures 3 and 6) However, since the thermostat 13 is closed during this period, there is no cooling water flowing back to the radiator 6, but the water
Since the outlet 5 of the jacket 1 is directly connected to the lower part of the radiator 6, heat conduction and convection continue from the bottom to the top of the radiator, which makes sense for heat transfer. Also, since the upper part of the radiator 6 is kept warm by the bonnet in the engine room, heat is accumulated and the radiator 6
And the temperature of the waterway of the pre-evil will gradually rise. By the time the thermostat reaches the valve opening temperature, there is almost no thermal gradient above and below the radiator, and the influence of outside temperature is eliminated.

In this way, the heat of the short-circuited cooling water is taken away by the radiator 6 and the cooling water that precedes it, so the rate of increase in water temperature during warm-up is slow.

And that speed approaches the response speed of the thermostat.

When the temperature of the cooling water circulating in the short circuit reaches the valve opening temperature, the cooling water in the water channel 11, which has already risen to a considerable temperature, passes through the pulp 21 and initially enters the housing 12 in a small amount, forming a high temperature and large amount of bypass flow. Mix. Therefore, the housing 12
The temperature of the cooling water inside will drop temporarily, but thermostat 13
does not respond immediately, so as the valve remains open, the water temperature rises and the valve opening lift of the thermostat 13 increases.At the same time, the bypass hole 36 is narrowed and the amount of water passing through the radiator 6 from bottom to top increases. Afterwards, as the load on the engine increases, the valve opening lift of the thermostat 13 increases, and when the bottom pulp 32 finally blocks the bypass hole 36, the entire amount of cooling water from the water jacket outlet 5 flows down the radiator 6. The water flows upward, passes through the water pump 2, and returns to the water jacket l (Figs. 5 and 10).Then, a thermo sensor (not shown) turns on the radiator cooling fan 37. Driven.

If the valve opening lift increases further, the bottom pulp 32
moves back against the spring 33, so the thermostat 13
can be fully opened (Figure 8).

As explained above, in the automobile engine cooling system of the present invention, there is no risk of overshoot exceeding the valve opening temperature of the thermostat, so the valve opening temperature of the thermostat is raised to atomize the fuel in the cylinder. It can promote vaporization and increase the thermal efficiency of the engine.

Furthermore, since the thermostat can be installed in the normal position, maintenance and inspection are easy, and since the thermostat housing is independent, there is an advantage that it can be installed anywhere.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of an automobile engine cooling system using an outlet temperature control method, FIG. 3, FIG. 4, and FIG. 5 are illustrations of an automobile engine cooling system using an inlet temperature control method. The seventh example shows when the thermostat is closed.
The figure shows the bottom bypass type thermostat in its closed state, Fig. 8 shows its fully open state, Fig. 9 shows its side view, and Fig. 10 shows the cooling water when the bottom pulp blocks the bypass hole. Show the flow. 1...Water jacket, 2...
・Water pump, 3...Water pump
Pump discharge port, 4...Water jacket inflow 0.5...Water jacket outlet. 6...Radiator, 7...Lower opening of radiator, 9...Upper opening of radiator, 10...Water pump inlet, 12...
...Thermostat housing, 13...
・Bottom bypass type thermostat, 15...
・Bypass conduit, 21...Pulp, 32...
...bottom pulp, 36...bypass hole.

Claims (1)

[Claims] 1. Insert the bottom of the radiator into the housing at the junction of the water channel leading to the top opening of the radiator and the water pump inlet.
A thermostat is installed in the normal position where the pulp is located below, and a bypass waterway is provided between the water jacket outlet and the water jacket branching point that leads to the bottom opening of the radiator and the housing, so that the cooling water returns from the bottom to the top of the radiator. A cooling system for an automobile engine configured to.