JPH01170708A - Cooling structure of engine - Google Patents

Abstract

PURPOSE:To improve radiation efficiency of a condenser by cooling the head and cylinder portions of a combustion chamber respectively with the utilization of heat of vaporization of refrigerant and oil while introducing vaporized refrigerant into the condenser after heating it with high temperature oil. CONSTITUTION:After refrigerant liquid in a tank 16 is forcibly sent by a pump 17, a boiling and cooling means 19 boils and vaporizes the refrigerant liquid by injecting the refrigerant liquid into a head cooling chamber 13 from a nozzle 14 to cool the cylinder head 3 side portion of a combustion chamber 7. On the other hand, an oil cooling means 23, after supplying oil in an oil pan 4 to a cylinder cooling chamber 12 by a pump 20, cools the cylinder block 2 side portion of combustion chamber 7 by injecting oil from a nozzle 22 to a piston 6. The heat of oil is transmitted to the vaporized refrigerant in a heat exchanger 26. The vaporized refrigerant receiving heat is cooled by the atmosphere in a condenser 28 to be condensed and liquefied.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cooling structure for an engine, and in particular to an improved technique for evaporating a refrigerant and cooling it by the heat of evaporation.

(Prior art) Conventionally, as an engine cooling method, the engine is cooled by cooling water flowing through the engine cylinder or water jacket, and the cooling water whose temperature rises due to heat exchange is cooled by heat radiation by a radiator. Water-cooled systems are generally widely used, but
In recent years, for the purpose of improving cooling performance, for example,
As disclosed in Japanese Patent No. 77726 and the like, a so-called boiling cooling method is attracting attention. In other words, this system boils the refrigerant liquid stored in the cooling chamber inside the engine using the heat generated by the engine, evaporates it, and uses the heat of vaporization to cool the engine, and the refrigerant that has been vaporized by the cooling is transferred to the engine. It has a circulation system in which the refrigerant is cooled by heat radiation through heat exchange with the atmosphere in an external condenser, condenses to the original refrigerant liquid, and then supplies the refrigerant liquid again to the cooling chamber of the engine. Since the boiling point of the refrigerant can be changed depending on the refrigerant pressure, it has the advantage of being able to cope with various operating conditions of the engine.

(Problem to be Solved by the Invention) By the way, in such a boiling cooling system, the larger the temperature difference between the refrigerant vapor in the condenser and the atmosphere, the higher the heat dissipation efficiency in the condenser, and the larger the capacitance. It is possible to achieve miniaturization by reducing the size.

However, when the refrigerant vapor generated in the cooling chamber of the cylinder head is directly supplied to the condenser as in the conventional system described above, the temperature of the refrigerant vapor remains at the boiling point temperature of the refrigerant itself, and no further increase in temperature can be expected. , there is a limit to reducing the capacitance of the capacitor.

The present invention has been made in view of the above, and its purpose is to heat the refrigerant by a predetermined means, instead of directly guiding the refrigerant vaporized in the cylinder head of the engine to the condenser as described above. The purpose of the present invention is to raise the temperature of the refrigerant vapor significantly relative to the atmospheric temperature before introducing the vapor, thereby increasing the heat dissipation efficiency in the condenser and reducing the capacity and size of the condenser.

(Means for solving the problem) In order to achieve this object, the solution of the present invention boils and vaporizes the refrigerant in the cylinder head part of the engine and cools it by the heat of vaporization, while the cylinder block part is cooled by oil. The vaporized refrigerant vapor is heated and heated by exchanging heat with the high-temperature oil used to cool the cylinder block, and then supplied to the condenser.

Specifically, the configuration of the present invention includes: a boiling cooling means that evaporates a liquefied refrigerant and cools a combustion chamber head portion with the heat of vaporization; an oil cooling means that cools a combustion chamber cylinder portion with oil; a heat exchange means for transmitting the heat of the oil in the oil cooling means to the refrigerant vapor vaporized by the boiling cooling means; and a heat exchange means for cooling the refrigerant vapor heat transferred from the oil by the heat exchange means to condense and liquefy it by heat exchange with the atmosphere. It is characterized by being equipped with a capacitor.

(Function) With the above configuration, in the present invention, the refrigerant liquid is evaporated and vaporized by the boiling cooling means in the cylinder head portion of the engine, and the combustion chamber head portion is cooled by the heat of vaporization.

On the other hand, oil is supplied to the cylinder block of the engine by an oil cooling means, and the cylinder portion of the combustion chamber is cooled by the oil, and at the same time, the oil is conversely heated to a high temperature as a result of this cooling. The refrigerant vapor vaporized in the boiling cooling means is supplied to the heat exchange means, where it exchanges heat with the high-temperature oil, and is then supplied to the condenser, where it is cooled by heat exchange with the atmosphere and returned to its original state. It is condensed into a refrigerant liquid and then supplied to the combustion chamber head cooling means.

In that case, in the heat exchange means, the refrigerant vapor is heated by heat exchange with the high-temperature oil, and is heated to a temperature higher than the refrigerant boiling point temperature. This heated refrigerant vapor is then supplied to the condenser, ensuring a large temperature difference between the refrigerant vapor and the atmosphere, thereby increasing the heat dissipation efficiency of the condenser and reducing its capacity.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the overall configuration of a first embodiment of the present invention, and 1 is:
The engine 1 mainly includes a cylinder block 2, a cylinder head 3 hermetically sealed to the upper surface of the cylinder block 2, and an oil pan 4 joined to the lower end of the cylinder head. The engine has a combustion chamber 7 which is sealed by a cylinder 5 formed in the cylinder 5, the top surface of a piston 6 that reciprocates within the cylinder 5, and the lower surface of the cylinder head 3.

Inside the cylinder head 3, an intake valve 8 is provided in the combustion chamber 7.
An intake port 9 that supplies intake air through the combustion chamber 7, and an exhaust port 11 that discharges exhaust gas in the combustion chamber 7 through the exhaust valve 10.
is formed.

Further, in the cylinder block 2, a cylinder cooling chamber 12 formed of a sealed cavity is formed at a position around the cylinder 5 including the lower part of the combustion chamber 7. On the other hand, in the cylinder head 3, a head cooling chamber 13 consisting of a sealed cavity is formed at a position corresponding to the upper part of the combustion chamber 7. As shown in enlarged detail in FIG. 2, on the clay wall of the head cooling chamber 13 of this cylinder head 3, a refrigerant liquid injection nozzle 14 is installed at a position approximately on the center line of the cylinder 5, and its lower end is connected to the head cooling chamber 13. It is installed facing inside 13. As shown in enlarged detail in FIG. 3, this refrigerant liquid injection nozzle 14 is located at its lower end facing the head cooling chamber 13, and is directed toward the valve bridge 3a (see FIG. 2) corresponding to the position directly above the combustion chamber 7. It has a first jet nozzle 14a that opens, and a pair of second jet nozzles 14b, 14b that open toward the outer wall surfaces of the walls of the intake and exhaust ports 9, 11, respectively. A normally closed pressure valve 15 is attached to the outlet 14b and opens only when the discharge pressure of the refrigerant liquid (discharge pressure of the pump 17 described later) rises to a predetermined pressure or higher.

The refrigerant liquid injection nozzle 14 is connected to a refrigerant tank 16 that stores a refrigerant liquid such as a fluorocarbon compound through a refrigerant liquid supply passage 18 in which a pump 17 is interposed, and the refrigerant liquid in the refrigerant tank 16 is pumped. 17 and injected into the head cooling chamber 13 from the injection nozzle 14, the refrigerant liquid is boiled and vaporized by the heat generated in the combustion chamber 7, and the vaporization heat is used to cool the head portion of the combustion chamber, that is, the combustion chamber 7. A boiling cooling means 19 is configured to cool the side portion (upper part) of the cylinder head 3.

On the other hand, 20 is an oil pump that sucks and discharges oil in the oil pan 4, and the oil pump 20 is connected to the cylinder cooling chamber 12 in the cylinder block 2 via an oil passage 21. Further, a branch oil passage 21a is connected to the downstream end of the oil passage 21, and the branch oil passage 21a is connected to an oil injection nozzle 22 that opens toward the lower surface of the piston 6.
The oil in the oil pan 4 is supplied to the cylinder cooling chamber 12 by the operation of the oil pump 20, and the oil is injected from the oil injection nozzle 22 as an oil jet toward the lower surface of the piston 6. An oil cooling means 23 is configured to cool the cylinder block 2 side portion with oil.

The upper end of the head cooling chamber 13 of the cylinder head 3 is opened to the outside, and the upstream end of a steam passage 25 in which a blower 24 is interposed is connected to the opening. The steam passage 25 and the oil passage 21 are overlapped with each other in the middle, and the overlapping portion allows the heat exchanger 2
6 is formed, and in this heat exchanger 26, the heat of the oil in the oil cooling means 23 is transferred to the boiling cooling means 1.
9 to transmit the vaporized refrigerant vapor. That is, as shown in enlarged detail in FIGS. 4 and 5, the heat exchanger 26 consists of an inner tube 26a and an outer tube 26b disposed concentrically outside the inner tube 26a. A steam passage 25 and an oil passage 21 are formed between an inner tube 26a and an outer tube 26b, respectively. In addition, the inner pipe 26
The inner peripheral wall of the tube a has inner fins 26c, 26c, . , . Conversely, the refrigerant vapor is heated, and the oil in the oil passage 21 is cooled by exchanging heat with the atmosphere.

Further, the downstream end of the steam passage 25 is connected to a condenser 28 that is forcibly cooled by a cooling fan 27, and this condenser 28 is connected to the refrigerant tank 16 via a refrigerant liquid return passage 29. The refrigerant vapor transferred from the oil by the heat exchanger 26 is cooled by heat exchange with the atmosphere, and is condensed and liquefied.

The pump 17 is a control unit 3 with a built-in CPU.
The operation is controlled by 0. This control unit 3
0 includes three parts of the cylinder head 3 that substantially correspond to the injection direction of the refrigerant liquid injected from the three injection ports 14a, 14b, and 14b of the refrigerant liquid injection nozzle 14, that is, the valve bridge 3a and the intake/exhaust boat. The output signals of the first to third temperature sensors 31 to 33, which respectively detect the temperature of the wall of 9.11, are input, and the control unit 30 operates the pump 17 according to the temperature in the head cooling chamber 13. It is designed to be controlled. That is, to explain the control signal processing procedure in the control unit 30 with reference to FIG. 6, first, in step S1, the 0N10F of the ignition key switch
It is determined whether the engine 1 is in operation by detecting the F state, and when this determination is NO indicating that the engine 1 is in a stopped state, the control is terminated. When the determination is YES, the process proceeds to steps 82 to S4, where it is determined in order whether the detected values of the first to third temperature sensors 31 to 33 are higher than, for example, 3oo'c, and all detected values are If the determination is No, the engine 1 is warmed up or in a low load range, and the process proceeds to step S5, where the pump 17 is placed in a low pressure operating state so that the refrigerant discharge pressure is low. After that, the process returns to the first step S1.

On the other hand, if at least one of the determinations in steps 82 to S4 is YES,
When this happens, it is assumed that the engine 1 is in a high load range, and the process proceeds to step S8, where the pump 17 is put into a high pressure operating state so that the refrigerant liquid discharge pressure becomes high, and then the process proceeds to step S.
Return to 1.

The upstream end of a drain passage 35 with an on-off valve 34 interposed therein is opened at the bottom of the head cooling chamber 13 of the cylinder head 3, and the downstream end of the drain passage 35 is connected to the refrigerant tank 1.
It is connected to 6.

Next, to explain the operation of the above embodiment, when the engine 1 is operated, the pump 17, the blower 24, and the cooling fan 27 are operated, and the operation of the pump 17 causes the refrigerant liquid in the refrigerant tank 16 to be supplied to the refrigerant liquid. It is supplied to the head cooling chamber 13 in the cylinder head 3 of the engine 1 through the passage 18, and is ejected from the injection nozzle 14 toward the inner bottom of the head cooling chamber 13. This refrigerant liquid is in the head cooling chamber 1.
The cylinder head 3 receives heat generated from the combustion chamber 7 and accumulates in a boiling state at the bottom of the combustion chamber 7 and gradually evaporates, and the cylinder head 3 portion of the combustion chamber 7 is cooled by the heat of vaporization during the evaporation.

At that time, the valve bridge 3a in the cylinder head 3
The temperatures at three locations on the walls of the intake/exhaust boats 9 and 11 are detected by temperature sensors 31 to 33, respectively, and the control unit 30 that receives the output signals from the temperature sensors 31 to 33 determines that the detected temperatures are all 300. When the temperature is lower than 'C, it is determined that the engine 1 is in a warm-up state or a low load region, and the pump 17 operates at a low pressure to maintain the refrigerant discharge pressure low. In this state, the two second injection ports 14b in the refrigerant liquid injection nozzle 14,
The pressure valves 15, 15 attached to the head 14b do not open, and the refrigerant liquid is injected into the head cooling chamber 13 only through the first injection port 14a, which is always open. Therefore, a small amount of refrigerant liquid is supplied only toward the valve bridge 3a portion of the head cooling chamber 13 where the temperature tends to rise. On the other hand, if even one of the three detected temperatures exceeds 300"C, it is determined that this is due to the engine 1 shifting to a high load range, and the pump 17 operates at high pressure to reduce the refrigerant liquid discharge pressure. In this state, the two pressure valves 15.15 of the refrigerant liquid injection nozzle open to the well, and the refrigerant liquid flows not only to the first injection port 14a but also to the two second injection ports 14b, 1.
4b and is injected into the head cooling chamber 13. Therefore, approximately three times as much refrigerant liquid is supplied to the head cooling chamber 13 as compared to the above-mentioned low load region. As a result, the combustion chamber head portion of the engine 1 can be cooled in response to changes in the amount of heat generated by the engine, and the engine 1 can be stably cooled over a wide range of operating ranges.

Further, since the refrigerant liquid is injected into the head cooling chamber 13 by the injection nozzle 14, the refrigerant liquid stored in the head cooling chamber 13 is sufficiently stirred, and thermal boundaries are formed within the head cooling chamber 13. Since no surface is formed, the heat exchange efficiency between the wall surface of the head cooling chamber 13 and the refrigerant can be increased, and the evaporation of the refrigerant can be promoted.

On the other hand, due to the operation of the oil pump 20, the oil in the oil pan 4 is sucked up and supplied to the cylinder cooling chamber 12 in the cylinder block 2 via the oil passage 21. The cylinder portion of the combustion chamber 7 is cooled by this oil. After such cooling, the oil returns to the oil pan 4.

The refrigerant vapor generated in the head cooling chamber 1°3 is sucked by the blower 24 and supplied to the heat exchanger 2δ via the steam passage 25. Heat is exchanged with.

At this time, the temperature of the refrigerant vapor vaporized in the head cooling chamber 13 is the boiling point of the refrigerant, whereas the oil stored in the oil pan 4 cools the cylinder part of the combustion chamber. rises to a temperature higher than the boiling point of the refrigerant. Therefore, in the heat exchanger 26,
From the high temperature oil flowing through the oil passage 21 to the steam passage 25
Heat is transferred to the refrigerant vapor inside, and the temperature of the refrigerant vapor rises above its boiling point to become heated vapor.

On the other hand, oil is cooled by refrigerant vapor, and its temperature decreases.

Moreover, since the oil passage 21 in the heat exchanger 26 is disposed on the outside so as to be able to exchange heat with the atmosphere by the outer fins 26d, 26d, . Since this cooled oil is supplied to the cylinder cooling chamber 12 and the like, the cylinder portion of the combustion chamber can be effectively cooled.

Furthermore, the heat exchanger 26 was passed through. The refrigerant vapor whose temperature has increased flows into the condenser 28 and is cooled and condensed through heat exchange with the atmosphere to return to its original liquid state, and the refrigerant liquid is returned to the refrigerant tank 16 via the refrigerant liquid return passage 29. Ru.

At this time, since the temperature of the refrigerant vapor before flowing into the condenser 28 has risen to a high temperature, the temperature difference between the refrigerant vapor and the atmosphere increases, and heat transfer occurs rapidly to that extent. Heat dissipation efficiency increases. As a result, the capacitance of the capacitor 28 can be reduced, making it more compact.

In addition, in this case, since the refrigerant is forcibly circulated by the pump 17 and the blower 24 through a closed cycle composed of the refrigerant liquid supply passage 18, the steam passage 25, and the refrigerant liquid return passage 29, the refrigerant is is not released into the atmosphere, which is advantageous in preventing air pollution.

(Other Embodiments) FIG. 7 shows the overall configuration of a second embodiment, which is designed to promote warm-up of the engine. Note that the same parts as in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted. Also, the schematic structure of the engine is shown.

That is, in this embodiment, the refrigerant liquid supply passage 18 with the pump 17 interposed therein is opened at the bottom of the head cooling chamber 13 in the cylinder head 3 .

Further, the upstream end of the refrigerant liquid supply passage 18 and the recirculation passage 2
A refrigerant tank 1 that stores refrigerant liquid is directly connected to the downstream end of the refrigerant liquid supply passage 18 (downstream end of the refrigerant liquid return passage 29') and the vapor passage 25.
6' are connected via a refrigerant passage 37. Further, a refrigerant passage 37 connecting the refrigerant tank 16' and the upstream end of the refrigerant liquid supply passage 18 is provided with an on-off valve 38, and a refrigerant is supplied from the refrigerant liquid supply passage 18 to the refrigerant tank 16' side as shown by the arrow in the figure. An auxiliary pump 39 for pumping liquid is provided. Further, an on-off valve 40 is provided in the steam passage 25 downstream of the branch connection with the refrigerant passage 37. The above two on-off valves 38.40 and the two pumps 17.39 are configured to be operated and controlled by a control unit 30', and this control unit 30' is configured to control the temperature of the cylinder head 3 of the engine 1. Output signals from a temperature sensor 31' for detecting the temperature and a liquid level sensor 41 for detecting the level of the refrigerant liquid in the head cooling chamber 13 are inputted.

The control procedure of the control unit 30' for the on-off valves 38, 40 and the pumps 17, 39 will be schematically explained with reference to FIG. In step Sho, the output signal of the temperature sensor 31' is read, and in the next step So, it is determined whether the engine 1 is being warmed up based on the detected temperature. If it is determined as YES during warming up, step S+
2, the on-off valve 40 of the steam passage 25 is closed and the on-off valve 38 of the refrigerant passage 37 is opened, and the auxiliary pump 39 is kept stopped and the pump 17 is operated. As a result, the refrigerant liquid in the refrigerant tank 16' is supplied to the head cooling chamber 13 via the refrigerant passage 37 and the refrigerant liquid supply passage 18 to fill the head cooling chamber 13.
The refrigerant liquid then flows back into the refrigerant tank 16' through the refrigerant passage 37, forming a closed cycle, and the refrigerant liquid itself cools the head portion of the combustion chamber.

On the other hand, when the detected temperature rises close to the boiling point of the refrigerant and it is determined in step So that warming up of the engine 1 is completed, the process proceeds to step SI3, and the pump 17
The operation of the head cooling chamber 13 is stopped and the auxiliary pump 39 is operated to drain the refrigerant liquid filling the head cooling chamber 13 into the refrigerant tank 1.
6' to lower the liquid level. After that, in step S, it is determined whether the liquid level of the refrigerant liquid detected by the liquid level sensor 41 has decreased to a set value, and after waiting for the liquid level to drop to the set value, in step S+5, The on-off valve 38 is closed and the auxiliary pump 39 is stopped. Thereafter, the process proceeds to step S+6, where the on-off valve 40 is opened and the pump 17 is operated again to perform boiling cooling similar to that in the first embodiment.

Therefore, in this embodiment, the temperature sensor 31'
When the detected temperature of the cylinder head 3 is low and the engine 1 is warmed up, the on-off valve 40 is closed, the on-off valve 38 is opened, and the pump 17 is operated.

For this reason, after the refrigerant liquid in the refrigerant tank 16' is supplied to the head cooling chamber 13 and the chamber is filled, the vapor passage 25 is
Then, the refrigerant flows back into the refrigerant tank 16' via the refrigerant passage 37. In this state, the head cooling chamber 13
The refrigerant does not evaporate, and the head of the combustion chamber is cooled not by the heat of vaporization of the refrigerant, but by exchanging heat with the refrigerant liquid itself, which reduces the cooling capacity and promotes warm-up of the engine 1. can do.

At that time, from the head cooling chamber 13 to the refrigerant tank 16'
Since the refrigerant liquid that returns to the engine 1 does not pass through the condenser 28, a temperature drop due to heat exchange between the refrigerant liquid and the atmosphere is suppressed, and warm-up of the engine 1 can be promoted more effectively.

On the other hand, when the detected temperature rises to near the boiling point of the refrigerant and warm-up of the engine 1 is completed, the operation of the pump 17 is first stopped and the auxiliary pump 39 is operated instead. Therefore, the refrigerant liquid filling the head cooling chamber 13 is returned to the refrigerant tank 16', and its liquid level is lowered. When the liquid level falls to a set value, the on-off valve 38 is closed, the operation of the auxiliary pump 39 is stopped, and the refrigerant is stored and held in the refrigerant tank 16'. After this, the on-off valve 40 of the steam passage 25
is opened, the pump 17 is operated, and the refrigerant liquid is evaporated in the head cooling chamber 13, and the refrigerant vapor is condensed and liquefied in the condenser 28, thereby performing normal boiling cooling.

Therefore, in the case of the present embodiment, there is an advantage that, while employing the boiling cooling method with excellent cooling performance, warm-up of the engine 1 can be promoted and the engine 1 can be quickly shifted to a warm-up completion state.

FIG. 9 shows a third embodiment of the present invention, in which in the boiling cooling system as in the above embodiment, when the vapor of a low boiling point refrigerant is used as a heat source for a vehicle heater, the refrigerant vapor temperature in extremely cold conditions is There is a concern that the heat capacity of the heater may be insufficient due to the low temperature, but this problem is solved.

In the case of this embodiment, both ends of a heater refrigerant passage 42 are opened in the head cooling chamber 13 of the cylinder head 3 of the engine 1, and a heat exchanger communicating with the passenger compartment is located in the middle of the heater refrigerant passage 42. A heater core 43, a heater valve 44, and a blower 45 are arranged in series. 4
6 is a fan that blows air to the heater core 43.

Further, an on-off valve 47 is provided in the steam passage 25 that sends refrigerant vapor in the head cooling chamber 13 to the condenser 28 . The on-off valves 34, 47, the heater valve 44, and the blower 45 are operated and controlled by a control unit 30'l that receives an output signal from a temperature sensor 31' that detects the temperature of the cylinder head 3. The control procedure is the 10th
To explain along the flowchart shown in the figure, first, step S? At step a, the temperature detected by the temperature sensor 31' is read, and at step S2+, the temperature is compared with a predetermined value. Then, the detected temperature is lower than the predetermined value YE
When S (extremely cold), the process proceeds to step S22, where both the on-off valves 34 and 47 are closed, the heater valve 44 is opened, and the blower 45 is operated.

On the other hand, when the detected temperature is higher than a predetermined value (NO), in step S23, both the on-off valves 34 and 47 are opened, and the pump 17 is operated to shift to a normal boiling cooling state.

Therefore, in this embodiment, when the temperature detected by the 31 temperature sensors is lower than a predetermined value, it is assumed that it is extremely cold, and the on-off valves 34 and 47 are closed, and the heater valve 44 is also opened. The blower 45 becomes operational. In this state, the refrigerant vapor is hermetically sealed within the head cooling chamber 13, its vapor pressure increases, and the boiling point of the refrigerant increases. Since this refrigerant vapor whose temperature has increased circulates between the head cooling chamber 13 and the heater core 43, the heat radiation temperature of the heater core 43 can be increased, and a suitable heat source for the heater can therefore be secured.

On the other hand, when the temperature detected by the temperature sensor 31' is not extremely cold and is higher than a predetermined value, both the on-off valves 34 and 47 are opened and the pump 17 is also operated, resulting in a normal boiling cooling state.

(Effects of the Invention) As explained above, according to the present invention, the engine is cooled by the heat of vaporization of the evaporative refrigerant, and the vaporized refrigerant vapor is cooled by a condenser outside the engine to condense and liquefy it. In contrast to this cooling structure, the engine's combustion chamber head section is cooled by the heat of vaporization of the refrigerant, while the combustion chamber cylinder section is cooled by oil, and the vaporized refrigerant vapor is used to cool the combustion chamber cylinder section. By exchanging heat with oil to raise the temperature and then leading it to the condenser, the temperature of the refrigerant vapor flowing into the condenser can be raised to above the refrigerant boiling point temperature, and a large temperature difference between it and the atmosphere is ensured. The heat dissipation efficiency of the capacitor can be increased, and therefore the capacitance of the capacitor can be reduced to make it more compact.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is an overall configuration diagram, FIG. 2 is an enlarged sectional view of the cylinder head portion of the engine, and FIG. 3 is an essential part of a refrigerant liquid injection nozzle. Figure 4 is a vertical cross-sectional view showing the main parts of the heat exchanger, Figure 5 is a cross-sectional view taken along the ■-V line in Figure 4, and Figure 6 is a schematic diagram of the signal processing procedure performed in the control unit. FIG. 7 and 8 show a second embodiment, FIG. 7 is a diagram corresponding to FIG. 1, and FIG. 8 is a flowchart of the control procedure. 9 and 10 show the third embodiment, FIG. 9 is a diagram corresponding to FIG. 1, and FIG. 10 is a flowchart of the control procedure. 1...Engine, 2...Cylinder block, 3...
- Cylinder head, 7... Combustion chamber, 12... Cylinder cooling chamber, 13... Head cooling chamber, 19... Boiling cooling means, 21... Oil passage, 23... Oil cooling means, 25... Steam passage, 26... Heat exchanger (heat exchange means), 28... Condenser, 30.30', 30
'···control unit. Patent applicant Mazda Motor Corporation ・÷−゛−・2
'(°-・-1△ Agent Patent Attorney 1) Hiroji: r5- Figure 1 Figure 3] 4 Figure 4 Figure 5 Figure 8 Figure 7

Claims (1)

[Claims] (1) A boiling cooling means that evaporates the liquefied refrigerant and cools the head portion of the combustion chamber with the heat of vaporization, and an oil cooling means that cools the cylinder portion of the combustion chamber with oil.
a heat exchange means for transmitting the heat of the oil in the oil cooling means to the refrigerant vapor vaporized by the boiling cooling means; and a heat exchange means for transmitting the heat of the oil in the oil cooling means to the refrigerant vapor vaporized by the boiling cooling means, and cooling the refrigerant vapor heat transferred from the oil by the heat exchange means to condensation and liquefaction by heat exchange with the atmosphere. An engine cooling structure characterized by being equipped with a condenser.