JPS5849688B2 - engine noreiyakkuuchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine cooling system, and more particularly to an engine cooling system equipped with a valve means for controlling the flow rate of cooling water according to the engine load and the cooling water temperature.

In conventional engine cooling systems of this type, the main focus is on engine cooling in the engine's high-load operating range.
Since the capacity of the water pump is set to ensure cooling of the engine in the high-load operating range, there is a problem in that the amount of cooling water becomes excessive in the low-load operating range, resulting in excessive cooling of the engine.

On the other hand, conventional cooling water control uses a thermostatic valve that opens only when the cooling water temperature rises above a set temperature. Since the rise in water temperature is delayed compared to the rise in wall temperature, there is a problem that there is a time delay in the activation of the thermostat valve.To prevent the engine wall from overheating, the set temperature of the thermostat valve should be set relatively low. , it is necessary to open at a low water temperature, but in this case, there is a problem that the thermostatic valve operates even under low load, causing excessive cooling of the engine.

Supercooling of the engine not only causes a deterioration of the thermal efficiency of the engine, but also causes a decrease in the combustibility of the air-fuel mixture and the engine output due to a decrease in the engine temperature (7). This has led to various problems such as deterioration of purification efficiency due to the decrease in gas re-reactivity, and in the past, in order to compensate for the decrease in engine output as described above, the mixture was enriched at low loads. Although measures have been taken to improve combustibility, there have been problems in that combustion has worsened and harmful components contained in exhaust gas have increased, polluting the atmosphere.

In view of the conventional problems, the present applicant has filed a patent application filed in 1973-
Specification No. 44755 (title of invention "Internal combustion engine cooling device"
), "A valve means is provided in the engine cooling water passage to control the area of the cooling water passage in accordance with the engine load, and when the load is low, the valve means is used to control the engine cooling chamber which constitutes a part of the cooling water passage. The present invention proposes an internal combustion engine cooling system characterized by reducing the amount of cooling water flowing through the engine, and aims to solve the problem of preventing overcooling of the engine by suppressing excessive supply of cooling water by the water pump.

Based on the above invention, the present invention provides an engine capable of controlling the amount of cooling water in accordance with the cooling water temperature, particularly at low load when the amount of cooling water is reduced, when controlling the amount of cooling water according to the engine load. The purpose is to provide a cooling device for

In order to achieve this objective, the present invention distributes an engine cooling water passage through an engine cooling chamber that controls the area of the cooling water passage according to the engine load and prevents a part of the cooling water passage during low loads. While a valve is provided that operates to reduce the amount of cooling water, the valve is also provided with a device that senses the temperature of the cooling water and suppresses the operation of the valve in the closing direction when the cooling water is at a high temperature. Also, when the cooling water temperature is high, the amount of cooling water is not reduced more than necessary.

The valve according to the present invention is operated and controlled in response to the engine load, such as the intake pipe negative pressure, the penturi negative pressure, the accelerator opening, or a combination thereof, which varies in response to the engine load.

In addition, the above-mentioned device that controls the operation of the valve according to the temperature may be a device such as a wax pellet that expands and contracts mechanically depending on the temperature of the cooling water, or an electric device that controls the operation using a temperature sensing element such as a thermistor. It may be something that is done.

The present invention will be described in detail below with reference to the accompanying drawings.

As schematically shown in FIG. 1, a cooling water passage 1 guides cooling water discharged by a water pump WP driven in synchronization with engine rotation to an engine cooling chamber E, and operates according to the cooling water temperature. This is a series of circulation paths that circulate from the radiator R to the water pump WP via the thermostatic valve TV.

In this embodiment, a load control valve LV that is controlled by the engine load and the cooling water temperature and controls the passage area of the cooling water passage 1 is provided in the cooling water passage 1 between the engine cooling chamber E and the thermostat hub TV.

In this case, the load control valve LV is controlled in accordance with the engine load such as the accelerator opening or intake pipe negative pressure and the cooling water temperature by a well-known appropriate interlocking means, a specific example of which will be shown later. During low load operation, the passage area of the cooling water passage 1 is narrowed to increase the passage resistance, thereby reducing the cooling water flow rate in the engine cooling chamber E. During high load operation of the engine, the passage area is widened to increase the passage resistance. is operated to ensure sufficient cooling water flow.

On the other hand, if the temperature of the cooling water is high, at least during low load operation of the engine, the operation of the temperature sensitive means such as wax pellets is suppressed so as not to reduce the flow rate of the cooling water more than necessary.

As is well known, the thermostatic valve TV mentioned above is
When the cooling water temperature is below a certain temperature, the cooling water is not circulated to the radiator R but bypassed to the bypass passage 2 of the radiator H.

Therefore, as shown in Fig. 2, by providing a load control valve LV in this bypass passage 2 in the same manner as described above, when the cooling water is at a low temperature and the thermostat valve TV closes the radiator R side, the engine cooling water is The entire system can be controlled according to the load and cooling water temperature.

In the embodiment shown in FIG. 3, the engine cooling chamber E is provided with a bypass passage 3 that bypasses a high temperature section cooling chamber, a semi-high temperature section cooling chamber, etc., which will be described later. A load control valve LV is provided which is operated by the load control valve LV.

In this case, the load control valve LV is operated and controlled so as to close the bypass passage 3 when the engine is under high load, and open the bypass passage 3 when the engine is under low load. By bypassing the engine, the cooling water flow rate, which substantially contributes to engine cooling, is reduced.

Further, in the embodiment shown in FIG. 4, for example, when the engine has a combustion chamber separate from the working chamber, the engine cooling chamber E
is divided into a high-temperature cooling chamber Eh that cools the area around the combustion chamber that is exposed to the highest temperature, and a semi-high-temperature cooling chamber Eq that cools the area around the working chamber that is exposed to the next highest temperature.
A load control valve LV is provided in the cooling water passage from h to the semi-high temperature cooling chamber Eq.
By narrowing down V, the flow rate of cooling water in the semi-high temperature cooling chamber Eq is regulated.

Next, the structure and operation of a specific example of the load control valve LV will be explained with reference to FIGS. 5 to 8.

In the load control valve LV shown in FIGS. 5 to 8, 10 is a flange for attachment to the cooling water passage;
11 is a cooling water passage that vertically penetrates the outer circumference of the flange 10; 12 is a bottomed cylindrical valve body that opens and closes the cooling water passage using the flange 10 as a valve seat; 13 is a passage between the bottom of the valve body 12 and the flange 10; A bellows is fixed to the inner circumference at both ends and sealed from the outside; 14 is a coil spring fitted in the bellows 13 in the axial direction; 15 is a coil spring extending from the outer circumferential surface of the flange 10 to the inside of the bellows 13; flange 10
This passage 15 is a negative pressure passage provided inside the engine, and this passage 15 communicates with an intake pipe (not shown) of the engine.

Reference numeral 16 denotes a cooling water temperature sensing member such as a thermostat or wax pellet fixed to the axial center of the bottom outer wall of the valve body 12, and 17 represents a sensing member whose tip passes through the bellows 13 and protrudes in the axial direction toward the flange 10. It is a push rod that is moved up and down by 16.

As shown in FIG. 5, when the load is low and the water temperature is low, the intake negative pressure introduced into the bellows 13 from the negative pressure passage 15 is high.
3 overcomes the spring force of the coil spring 14 and contracts,
The flange-shaped tip of the valve body 12 is crimped onto the flange 10 serving as a valve seat, and the cooling water passage 11 of the flange 10 is completely closed.

When the cooling water temperature rises and reaches a low load high water temperature, the cooling water temperature sensing element 16 pushes the push rod 17 upward in the axial direction, brings it into contact with the flange 10, and fixes itself. The reaction force from the flange 10 pushes the valve body 12 downward in the figure, and the valve element 12 is opened by an amount determined by the correlation between the intake negative pressure, the spring force of the coil spring 14, and the cooling water temperature, and the cooling water is transferred to the cooling water passage of the flange 10. Distribution to 11.

In addition, as shown in Figure 7, in the case of high load and low water temperature,
Since the intake negative pressure introduced into the bellows 13 becomes lower,
The spring force of the coil spring 14 pushes the valve body 12 downward in the figure, opening the cooling water passage 11 of the flange 10.

In this case, the push rod 17 is separated from the flange 10 by a large distance, so that the push rod 17 does not come into contact with the flange 10 even when the load is high and the water temperature is high, as shown in FIG.

Therefore, this load control valve LV controls the intake negative pressure and the spring coil 14 when the engine is under high load.
It is held at a constant opening determined by the spring force.

The operating characteristics of the load control valve LV having the above configuration will be explained with reference to the operating diagram shown in Fig. 9. As the engine load increases while the cooling water temperature is low, as shown in curve A, load control valve LV
starts to open from a certain intermediate load value a in response to a decrease in intake negative pressure.

In addition, when the load is increased when the cooling water temperature is medium, the load control valve LV, which is opened to a certain degree in advance according to the cooling water temperature, is From a certain large value b, it starts to open further and reaches the maximum load value C of the engine, where it is fully opened.

As shown in 8, when the cooling water temperature is high enough to fully open the load control valve LV, the load control valve LV is kept fully open regardless of the load, and the entire amount of cooling water is directed to the radiator R. .

In the above specific example, the load control valve LV is operated continuously according to the intake negative pressure and the cooling water temperature, but if this is done, the load control valve LV can have the function of the thermostatic valve TV. In some cases, the thermostatic valve T
V and bypass passage 2 can be omitted.

In addition, the operating mode of the load control valve LV is not limited to the above example, and especially regarding the cooling water temperature, the load control valve LV is operated by means such as a thermostat that operates in two steps above and below the set temperature. may be controlled.

As is clear from the detailed description above, the present invention provides a valve in the cooling water passage that increases or decreases the amount of cooling water to the engine cooling chamber according to an increase or decrease in engine load, and also detects the cooling water temperature and at least According to the present invention, there is provided an engine cooling device in which a valve is provided with a means for suppressing the cooling water control operation of the valve to a certain degree when the engine is under low load and the cooling water temperature is high. Cooling can be performed with high responsiveness depending on the engine load and cooling water temperature, and especially when the load is low and the water temperature is low, the cooling water flow rate can be reduced to accelerate engine warm-up and prevent engine overcooling. In the case of low load and high water temperature, by suppressing the operation of the valve in the closing direction, a sufficient amount of cooling water can be secured and the engine can be sufficiently cooled. Optimal cooling water control can be performed, thereby reducing cooling loss, improving fuel efficiency, and improving exhaust gas purification efficiency.

[Brief explanation of the drawing]

1 to 4 are cooling system diagrams of an engine cooling device according to the present invention, and FIGS. 5 to 8 are valzo analysis diagrams showing one specific example of a valve according to the present invention. The figure shows low load and low water temperature, Figure 6 shows low load and high water temperature, and Figure 7 shows high load and low water temperature.
FIG. 8 shows the case of high load and high water temperature, and FIG. 9 shows the operating characteristics of the valve, with the horizontal axis representing the load and the vertical axis representing the valve opening degree. 1...Cooling water passage, WP...Water pump, E...Engine cooling chamber, R...
・Radiator, LV...Curved valve (load control valve, 10...Flange, 12...Valve body, 13...Bellows, 14...Coil spring , 15... Negative pressure passage, 16...
...Cooling water temperature sensing element, 17...Push rod).

Claims (1)

[Claims] 1 In a water-cooled engine, in the engine cooling water passage,
The area of the cooling water passage is controlled according to the engine load, and a valve is installed that operates to reduce the amount of cooling water flowing through the engine cooling chamber, which controls part of the cooling water passage during low loads, while controlling the cooling water temperature. 1. An engine cooling device characterized in that the valve is provided with a device that detects the temperature of the cooling water and suppresses the operation of the valve in the closing direction when the temperature of the cooling water is high.