JPS60108525A - Evaporative cooling device for engine - Google Patents

Abstract

PURPOSE:To simplify a temperature control circuit and to improve durability of a feed pump, by a method wherein, in an evaporative cooling type engine, a cooling fan is controlled so that the more an output is increased, the more the temperature of a refrigerant is decreased, and a surplus refrigerant solution flows around and is guided into the downstream of a condenser. CONSTITUTION:A refrigerant evaporated by a water jacket 22 is cooled and condensed by a condenser 23 to which cool air is fed by a cooling fan 26, and is returned again to the water jacket 22 with the aid of a feed pump 25. The cooling fan 26 is energized and controlled through the working of a temperature change-over switch 65 and a temperature switch 61 on the low temperature side or a switch 62 on the high temperature side, and the temperature change-over switch is adapted to be closed during high output in linkage with a throttle valve. A bypass passage 67 is open in a position slightly below the refrigerant steam passage of a steam manifold 29, and a surplus refrigerant solution flows around and is guided to a tank 24 of the condenser 23.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an improvement in a boiling cooling device that cools an engine temperature based on boiling air of a liquid phase refrigerant.

(Technical Background) The water-cooled cooling system that circulates cooling water between the engine water jacket and the radiator has heat dissipation t'
In order to satisfy the requirements, it is necessary to circulate the cooling water of the dog, which causes a large drive loss in the water pump, and it is necessary to variably control the cooling water to the appropriate temperature depending on the engine operating condition. On the other hand, Japanese Patent Publication No. 57-57608 and U.S. Patent No. 43676
No. 99 proposes a cooling system that uses the latent heat of vaporization of water to cool the engine through cooling water circulation fJtlt1. Cooling is performed through a cycle in which the steam is boiled with heat, all of the generated steam is heated in a radiator, and then returned to the water jacket. Because the structure is designed to avoid this, there are maintenance problems such as easy cooling water consumption, and the engine temperature is fixed at the boiling point of the cooling water under atmospheric pressure, so the heat exchanger and heat exchanger are subject to fluctuations. There was a problem in that it was difficult to apply it to automobile engines etc. that had a large capacity.

On the other hand, the present applicant, in Japanese Patent Application No. 58-145467, etc., sealed a liquid-phase refrigerant in a closed-loop cooling circuit, and by varying its pressure, the boiling point was completely controlled and the engine operating state was improved. We are proposing a boiling cooling system that can perform efficient cooling according to the conditions.

To explain this with reference to Fig. 1, in Fig. 1 21 is the engine (main body), 22 is a water jacket filled mostly with liquid phase refrigerant such as water, and 23 is water jacket 2.
24 is a tank that stores the liquefied refrigerant from condenser 23; 25 is a storage refrigerant sound in tank 24; a supply pot that returns to the water jacket 22; 26 is a forced cooling air to condenser 23; It is a cooling fan that supplies

The water jacket 22 is formed over the cylinder block 2]a and the cylinder head 21b so as to completely surround the cylinders and combustion chambers of the engine 21, and a predetermined liquid phase refrigerant is sealed inside the water jacket 22. The upper part of the water jacket 22 is a gas phase space 22a filled with refrigerant vapor.

In addition, in a multi-cylinder engine, the gas phase air 822a is communicated between each cylinder section.

The water jacket 22 is connected to the condenser inlet section 30 via a refrigerant injection pipe (steam manifold) 29 and a steam passage 27 connected to the water jacket 22 facing the gas phase space 22a. An injection port 29a located at the top of the circulation path and rising upward is sealed with a cap 2'9b).

The lower tank 24 of the condenser 23 communicates with the water jacket 22 through a refrigerant passage 28 .

A closed circuit in which refrigerant circulates is formed between the water jacket 22 and the condenser 23.

In the case of an automobile, the condenser 23 is installed at a position where the wind flows through the vehicle, and the cooling fan 26 is positioned on the front or rear side of the vehicle to supply forced cooling air to the condenser 23. Also,
The supply pump 25 is located in the middle of the refrigerant passage 28 and pumps the liquid phase refrigerant stored in the tank 24 to the water jacket 22 based on a command from a control system to be described later. In addition,
The cooling fan 26 and the supply pump 25 are both electric or mechanical driven by the engine 21 via an electromagnetic clutch or the like.

50 is a control circuit that controls the operation of the supply pump 25 and the cooling fan 26, and includes a temperature sensor 32 and other means (not shown) for detecting the engine operating state, similar to the liquid level sensor 31 provided in the cylinder head 21b. ) forms a control system.

The liquid level sensor 31 is a type of switch whose output changes on and off depending on the position of the refrigerant liquid level with respect to the detection section. Based on this change in output, the 1tilJH circuit 50 drives the supply bono knob 25 until the refrigerant level reaches the predetermined level again when the refrigerant level falls below a predetermined value depending on the position of the liquid level sensor 31. The refrigerant stored in the tank 24 is replenished into the water jacket 22. Therefore, the water jacket 22 always has one or more predetermined refrigerant liquids.

The standard amount of liquid refrigerant sealed in this cooling system is:
It is set to such an extent that the inside of the condenser 23 is in a gaseous state while the refrigerant is secured to a predetermined liquid level in the water jacket 22 as described above.

The temperature sensor 32 detects the engine temperature from the temperature or pressure of the refrigerant and provides it to the control circuit 50 as an output total actual temperature signal corresponding to the engine temperature.

The control circuit 50 uses the detected value of the actual temperature from the temperature sensor 32 as well as the edge/rotation, throttle opening, and fuel supply 1.
etc. are detected through well-known sensors to determine the engine operating status a.
Based on the comparison with the actual temperature, the operation or stop sound of the cooling fan 726 is controlled so that the engine temperature reaches a predetermined temperature corresponding to the driving situation at that time.

It goes without saying that the relationship between the engine operating state and the control temperature value can be set freely depending on the engine specifications, purpose, and application, but in general, in automobile engines, the load or rotational speed is Maintains a relatively high temperature in the operating range where the temperature is low.

The temperature should be lowered in the high-speed, high-load range.

To explain the basic function of the cooling system based on the above configuration, when the liquid phase refrigerant in the water jack 22 is heated by the engine combustion heat, it reaches a boiling point according to the pressure in the system at that time. Start boiling a when the temperature is reached,
It removes the latent heat of vaporization and converts it into evaporation.

At this time, the refrigerant boils vigorously in the high-temperature parts of the engine 21 and cools the part corresponding to the latent heat of vaporization, so that the combustion chamber and the cylinder wall are kept at a substantially uniform temperature. From this, it becomes possible to raise the temperature of the entire combustion chamber to near the limit temperature that does not cause problems such as abnormal combustion.

The refrigerant vapor generated as a result of the boiling cooling action is transferred to the steam passage 2.
7, flows from the gas phase space 22a of the water jacket 22 to the condenser 23, is cooled by heat exchange with outside air in the condenser 23, is condensed and liquefied, and is successively transferred to the tank 24.
is stored in

In this case, as described above, the inside of the condenser 23 is in a gas phase, and the high-temperature refrigerant vapor is transferred to the outside air with a large temperature difference under a good heat transfer state with the metal surface that constitutes the condenser 23. Since it is cooled, the heat dissipation efficiency is significantly increased compared to when heat is dissipated in the liquid phase. Incidentally, for this reason, the condenser 23 and the cooling fan 26 can be significantly smaller than those in the past.

The refrigerant that is liquefied in the condenser 23 and stored in the tank 24 is returned to the water jacket 22 again by the operation of the supply pump f25 as the refrigerant liquid level in the water jacket 22 decreases, and by repeating the above, boiling cooling is achieved. can continue.

On the other hand, in such a closed-circuit boiling cooling device, the pressure inside the system always becomes negative when the engine is stopped. Therefore, as a countermeasure against this negative pressure, the gas phase space 22a is replaced with a liquid phase refrigerant from an auxiliary tank 41 provided outside.

In the auxiliary tack 41 VC, a liquid phase refrigerant having a capacity at least as strong as that of the gas phase space 22a is stored, and atmospheric pressure is introduced into the interior thereof through a camp 41a'i having a ventilation function.

This auxiliary tank 41 communicates with the water jacket 22 via an auxiliary passage 37 having a solenoid valve 34 interposed therebetween.

When the solenoid valve 34 is opened after the engine is stopped, the refrigerant stored in the auxiliary tank 41 is introduced into the system based on the decrease in pressure due to the drop in hot water temperature, and soon the air space in the system is mostly filled with liquid phase refrigerant. It will be replaced.

This makes it possible to reliably prevent harmful air from entering the cooling system when the engine is stopped.

Note that when the engine is started in the above state, the liquid phase refrigerant in the system is pushed back into the auxiliary passage 37 and the auxiliary tank 41 by the pressure of the refrigerant vapor that has been boiled and vaporized by the combustion heat. Since the refrigerant liquid # in the water jacket 22 is maintained at a predetermined value by the replenishment operation of the supply bonder 25, apparently only the liquid # in the condenser 23 decreases and its liquid level rises.

Eventually, when the inside of the capacitor 23 becomes a gas phase, the tank 2
The electromagnetic valve 34 closes based on a signal from the liquid level sensor 39 that detects this from the liquid level of 4.

Thereafter, the boiling cooling described above is performed.

Furthermore, in this device, in order to eliminate air if it enters the system, the auxiliary tank 41 and the refrigerant liquid passage 28 can be communicated via the second auxiliary passage 36,
Three-way solenoid valve 33 when air enters? The suction side of the supply pump 25 is switched from the entire lower tack 24 side to the auxiliary passage 36 through the supply pump 25, and the supply pump 25 is driven to force-feed the refrigerant in the auxiliary tank 41 to the water jacket 22. At this time, the solenoid valve 35 of the passage 38 that communicates the top of the cooling system circuit with the inside of the auxiliary tank 41 (atmospheric pressure) is opened to discharge the intruding air.

This air bleeding operation is performed by installing a liquid level sensor 401 in the refrigerant injection pipe 29 at the top of the cooling system circuit to detect the refrigerant liquid level when the machine is cold. In other words, when the machine is cold, the system is filled with liquid-phase refrigerant as described above, but if air has entered the system, the amount of refrigerant introduced 1 will be reduced by that amount, and the space will be freed. The rest, in other words, the liquid level sensor 4o
The introduction of refrigerant ends before reaching the level of . Therefore 1
For example, air intrusion can be detected via the liquid level sensor 4o immediately after starting a cold engine.

When the refrigerant liquid level reaches the position of the liquid level sensor 40 by the operation of the supply bonder 25, the passage 36
．． 38 to finish air bleeding.

This boiling cooling system encloses liquid phase refrigerant in a closed circuit that is isolated from the outside as described above, and cools the engine based on the boiling vaporization of the liquid, so the refrigerant does not escape to the outside. However, the internal pressure of the circuit changes rapidly as cooling air is supplied to the condenser, which maintains the interior of the condenser in a gas phase, making it possible to easily control the engine temperature according to the operating conditions.

However, on the other hand, according to this boiling cooling system, the cooling fan 26 and the supply pump 25 are electronically controlled via the temperature sensor 32 and the liquid level sensor 31.The control system tends to be complicated and expensive. In addition, the supply pop 25 in particular operates intermittently depending on the liquid level, which tends to reduce its durability, and there is also the problem that the intermittent operating noise is easily heard as noise. Ta.

(Object of the invention) The present invention has been made by focusing on such problems.
It is an object of the present invention to provide a boiling cooling device that can exhibit excellent cooling performance peculiar to boiling cooling with a simple control system, and also to solve problems of durability and noise of a supply pump.

(Disclosure of the Invention) In order to achieve the above d1 objective, the present invention provides a plurality of temperature switches that close at mutually different refrigerant liquid temperatures, and also includes an intake throttle valve, an accelerator pedal, a control lever for a fuel injection bonder, etc. A temperature selector switch is provided that is linked to the engine's output adjustment device and selects the lower temperature switch when the output is high.The control current for the cooling fan is controlled via the high temperature switch when the output is low and when the output is high. Is it possible to obtain the desired temperature control characteristics by forming a control circuit that supplies all the low-temperature switches to each valve? f-I paid the actual tax.

Further, in the present invention, a bypass passage is provided to introduce the refrigerant liquid in the water jacket directly to the downstream side of the condenser, that is, without passing through the condenser.

When the liquid needle in the water jacket increases beyond a certain level, the excess liquid is released into the total bypass passage to maintain the maximum liquid t' in the jacket constant. This allows the supply pop to remain in operation at all times.

Embodiments of the present invention will be described below based on the drawings. Note that parts that are substantially the same as those in FIG. 1 are designated with the same reference numerals.

(Embodiment) In the present invention, as shown in FIG. 2, for example, two temperature switches 61 and 62 are provided in the cylinder head 21b, and the operation of the cooling fan 26 is controlled based on the opening and closing of the switches.

The temperature switches 61 and 62 operate at different refrigerant liquid temperatures, and as illustrated in FIG.
is 100°C or higher, and the high temperature side switch 62 is 110°C.
Each is closed with the above steps.

FIG. 4 shows an example of a control circuit that drives the cooling fan 26 (in this case, an electric fan) in response to opening and closing of the two temperature switches 61 and 62.

In the figure, 63 is a financial resource, 64 is a key switch, and the supply pump 25 (electric pop) is energized by closing the key switch 64 and starts full operation. On the other hand, the cooling fan 26 operates via a circuit in which the two temperature switches 6] and 62' are connected in parallel, only when the key switch 64 is in the closed state and either temperature switch is closed. Power is applied.

However, a temperature change-over switch 65 is connected in series to the low-temperature side temperature switch 1, and the cooling fan 26 operates depending only on the high-temperature side temperature switch 62 for songs in which this change-over switch 65 is open.

The temperature changeover switch 65 is linked to the engine's output adjustment device and is opened during the discharge operation.

In this case, in conjunction with the intake throttle valve 66 of the Ganlin engine, the switch 65 opens when the opening degree of the throttle p valve 66 is below a certain level.

That is, when the opening degree of the throttle valve 66 is small.

The cooling fan/26 operates only when the high-temperature side temperature switch 2 is closed, that is, only when the temperature of the refrigerant #i reaches 110'C or higher. As a result, e, the temperature is 110T
, the switch 2 opens and the cooling fan 26 stops. By repeating this process, the liquid temperature at the time of discharge will be approximately 110'.
CK kept.

On the other hand, when the opening degree of the throttle valve 66 increases and the temperature switching intero 5 closes, the cooling fan 26 starts operating when the low temperature side temperature switch 61 closes, that is, when the liquid temperature reaches 100°C. , ioo'c, the operation is stopped and the liquid temperature is controlled by about 100'CK.

In this way, the desired control operation of high temperature under discharge power conditions and low temperature under high power conditions is obtained.

lOh, this example uses a 2 ftM temperature switch 61.6
2, the entire temperature is controlled in two stages: high and low.

It goes without saying that three or more temperature switches may be provided to control the temperature in multiple stages.

Further, the selector switch 5 for selecting the plurality of switches is linked to a fuel injection pop control lever in the case of a diesel engine.

It is also possible to switch using other output adjustment devices.

By the way, the supply pump 251- is constantly operated when the engine is running to continue supplying the refrigerant liquid to the water jacket 22, but at this time, the excess refrigerant liquid is sent to the suction side of the co-feeding pop 25 via the bypass passage 67. will be returned to.

In this case, the bypass passage 67 opens slightly below the refrigerant vapor passage portion of the vapor manifold 29.

The cold fM liquid is introduced into the tank 24vc by bypassing the condenser 23 so that the refrigerant liquid level does not rise above this opening.

This overflow of the refrigerant liquid maintains the refrigerant liquid inside the jacket 22 at a predetermined value. This makes its control significantly easier. Further, by continuously operating the supply pump 25, fluctuations in pop load due to intermittent operation are eliminated, thereby increasing its durability and reducing noise.

Incidentally, since the liquid needle of the jacket 22 does not bulge and decrease, it is sufficient to use a small supply pump 25 and drive it at low speed.

Furthermore, in the present invention, in order to prevent outside air from entering the cooling system when the engine is stopped, all of the refrigerant liquid in the auxiliary tank 41 is introduced through a valve means.In this embodiment, the float valve 7o is used as the valve means. A check valve 71 is provided in parallel (FIGS. 2 and 5).

The passages 37 from the auxiliary tank 41 are connected to the lower tank 2, respectively.
The first passage part 37a is opened and closed by a float valve 70, and the second passage part 37b is opened and closed by a check valve 7].

As shown in FIG. 5, the float valve 70 includes a float 74 that is swingably supported in the nozzle 24 with a shaft 73 as a fulcrum.
fLv from the valve body 76 provided at the tip of the arm 75 that swings together with the float 74, and the refrigerant Iv in the tuck 24.
When Lt is less than a predetermined value, the first passage section 3
7ak closed. In addition, 77 is a balano weight provided so that the float valve 70 can be reliably opened and closed with a predetermined liquid 1.

On the other hand, the check valve 71 normally closes the valve body 79 against the hydraulic pressure from the auxiliary tack 41 by the elastic force of the coil spring 78, and the internal pressure of the tank 24 falls below a predetermined value, for example, atmospheric pressure. Then, the valve is opened and refrigerant liquid is introduced into the tuck 24.

In a cold engine shutdown condition, the inside of the cooling system closed circuit is filled with liquid-phase refrigerant, so the float valve 70 is open to the first passage portion 37a'. Therefore, when the engine is started and the system internal pressure increases, the refrigerant is pushed out to the auxiliary tack 41 via the first passage portion 37a and the passage 37'. In this way, the refrigerant liquid in the closed circuit gradually decreases, and eventually reaches tank 2.
When the refrigerant liquid -° at step 4 decreases to a certain level, the float valve 70 closes and extrusion of the refrigerant ends, and thereafter the cooling system circuit is cut off from the outside and the desired boiling cooling state is achieved.

When the edge/ is stopped in this state, the refrigerant vapor is absorbed into the cooling liquid and the system internal pressure drops below atmospheric pressure. Based on this pressure drop, the check valve 71 opens, and the passage 37 and The stored refrigerant of the auxiliary tank 41 is introduced into the circuit via the second passage portion 37b. However, since the float valve 70 opens after some refrigerant liquid has been introduced into the filter 24, the refrigerant liquid will be introduced mainly through the first passage portion 37a from then on. When the refrigerant liquid thus introduced is discharged from the circuit, the internal pressure of the system becomes approximately atmospheric pressure, and the introduction of the refrigerant liquid ends. Note that if the condenser 23 actively dissipates heat even though the edge/load is relatively low, such as when the vehicle is continuously dismounted, the refrigerant will condense excessively and the internal pressure and temperature will rise above the necessary level. Even in such a supercooled state, the check valve 71 opens based on the decrease in the internal pressure, so it is unlikely that a supercooled state will actually occur. That is, when the check valve 71 opens, the refrigerant from the auxiliary valve 71 is introduced into the condenser 23 to offset the decreased internal pressure, reducing its effective heat radiation area and avoiding wasteful heat radiation.

In this embodiment, as in FIG. 1, electromagnetic valves 33, 35 and passages 36, 38 are provided as second valve means for venting air that has entered the circuit.

The functions of the two solenoid valves 33 and 35 are exactly the same as those shown in FIG. communicates the passage 36 from the auxiliary tank 41 with the refrigerant passage 28, and the second solenoid valve 35 opens the passage 38 to communicate the top of the gas phase space 22a with the space of the auxiliary tank 41.
Based on the operation of the supply pop 25, the refrigerant liquid introduced into the circuit from the auxiliary tank 41 is brought into a state in which the intruding air can be pushed out.

In the control circuit shown in FIG. 4, the opening/closing control of the electromagnetic valves 33 and 35 is controlled by a switch 80 that is linked to the engine's cold start device.
By doing so, the circuit configuration for air exhaust control can be simplified.

In this case, the choke valve 81 is used as the cold start device that drives the switch 80, and when the opening degree of the choke valve 81 is small, the switch 80 is closed and the solenoid valves 33, 35 are energized. For this reason, when starting a cold machine, be sure to close the auxiliary tank 41.
Since the refrigerant liquid is introduced into the cooling system circuit, the intruded air can be reliably discharged.

This control is performed regardless of the presence or absence of invading air at the time of cold start, but excess refrigerant liquid introduced into the circuit when no air is invading is passed through the passage 38 to the auxiliary tack. Sent back to 41.

As the warm-up progresses and the opening degree of the choke valve 81 increases, the switch 80 opens and the energization to the solenoid valves 33 and 35 ends, and the cooling system becomes a closed circuit again. Air exhaust control can also be achieved with an extremely simple control circuit.

Note that some diesel engines are equipped with a glow circuit for heating the combustion chamber as a cold starting device, but if the solenoid valves 33 and 35 are energized together with the glow plug through this glow circuit, the same result as above can be achieved. 1 (Effects of the Invention) As mentioned above, according to the present invention, the desired temperature control according to the operating state of the engine can be realized with an extremely simple electric circuit. In addition, since the refrigerant gauze in the quarter jacket is suppressed to a certain extent by overflowing into the bypass passage, the supply pump only needs to be relatively small and operate constantly, and therefore the boiling cooling system The control system can be greatly simplified, and the durability and quietness of the supply pump can also be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a prior art example of an evaporative cooling device. Fig. 2 is an outline diagram of an embodiment of the present invention, Fig. 3 is a diagram of the operating characteristics of the temperature switch, Fig. 4 is a circuit configuration diagram of the control system, and Fig. 5 is an enlarged view of section v in Fig. 2. It is. 21 river engineering body), 22 river water jacket, 2
3... Condenser, 24... Tank, 25... Supply pump, 26... Cooling fan/, 27... Steam vent 1
passage, 28...refrigerant passage, 33.35... solenoid valve,
41...Auxiliary valve, 61.62...Temperature switch, 65...Temperature selection switch, 66...Intake throttle valve, 67...Bypass passage, 7o...F'-1 Masu, 7
1...Tenku valve, 8o...Switch (for air exhaust), 81...Choke valve. Patent applicant Nissan Motor Co., Ltd. Figure 1 Figure 2 Figure 5 Figure 3 Warm layer, ゛C

Claims (1)

[Scope of Claims] 1. An engine water jacket filled mostly with liquid-phase refrigerant and a condenser whose interior is kept in a vapor phase are connected by an upper vapor passage through which refrigerant vapor flows and a lower refrigerant passage through which liquid refrigerant flows. A closed circuit is formed in which the refrigerant circulates, and an auxiliary tank in which all of the liquid refrigerant is stored is connected to the closed circuit via a valve means, and the liquefied refrigerant from the condenser is supplied to the entire water jacket. It is equipped with a cooling fan that supplies forced cooling air to the pump and condenser, and has multiple temperature switches that close at different refrigerant liquid temperatures, as well as an output adjustment device that adjusts the temperature on the low temperature side during high output. One side forms a control circuit that controls the drive of the cooling fan via a temperature selector switch that selects the switch. A boiling cooling system for an engine, which is characterized by providing a bypass passage for introducing excess refrigerant liquid from a water jacket into the downstream of a condenser. 2. The valve means includes a float valve that opens based on buoyancy in the refrigerant liquid when the liquefied refrigerant η from the condenser is above a predetermined value, and a float valve that opens when the pressure in the closed circuit of the cooling system is below a predetermined value. The boiling cooling system for an engine according to claim 1, further comprising a check valve that opens based on the decrease in the pressure in the circuit and is connected in parallel. 3. As a valve means, a three-way solenoid valve that selectively introduces refrigerant from the condenser or auxiliary tank to the supply pump, and a solenoid valve that connects or closes the top of the closed circuit of the cooling system to the auxiliary tank are provided. A circuit is formed in the control circuit that energizes the two solenoid valves via a switch that is linked to the cold engine starting device, so that the gas phase space in the closed circuit of the cooling system is filled with the refrigerant liquid introduced from the auxiliary tank when starting the cold engine. The evaporative cooling device for an engine according to claim 1, characterized in that: