JP3243549B2 - Boiling-cooled engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a boiling-cooled engine.

[0002]

2. Description of the Related Art As a conventional technology of a boiling cooling type engine,
There is one disclosed in Japanese Patent Publication No. 3-4727. As shown in FIG. 5, similarly to the present invention, this is provided with a refrigerant circulation path 103 in which a liquid cooling jacket 101 and a condenser 102 communicate with each other.
The vapor of the cooling liquid 105 generated by boiling in the liquid cooling jacket 101 is introduced into the condenser 102 and condensed, and the condensed cooling liquid 105 is condensed into the liquid cooling jacket 1.
01.

In this prior art, a reservoir tank 122 having a ventilation cap 121 is connected to a refrigerant circulation path 103 through an air discharge path 123 so that the air discharge path
3, a normally closed solenoid valve 124 is provided, and the refrigerant circulation path 1
A pump 125 and a three-way solenoid valve 126 are provided in the middle of 03,
A reservoir tank 122 is connected to the three-way solenoid valve 126 via a refrigerant reciprocating passage 127, and the liquid cooling jacket 101 is connected.
Temperature detecting means 11 for detecting the temperature of the cooling liquid and the liquid level in the inside
0 and a liquid level detecting means 128. Based on the detection of the detected temperature and the liquid level, a normally closed solenoid valve 124 and a pump 1 are provided.
25 and the three-way solenoid valve 126 can be controlled, and the condenser 102 is provided with a second liquid level detecting means 129 so that the electric fan 104 can be started based on the detection of the liquid level.

That is, after the engine is started, the normally closed solenoid valve 1
With the three-way solenoid valve 126 set to the flow path A, the pump 125 is driven in the reverse direction, and the reservoir tank 12 is opened.
2, the coolant 105 is filled in the refrigerant circulation path 103,
The pump 125 is stopped, and the normally closed solenoid valve 124 is closed to stand by. When the detected temperature exceeds the target temperature, the pump 1
25, the cooling liquid 105 is discharged from the condenser 102 to the reservoir tank 122, and the liquid cooling jacket 1 is discharged.
01 and a gas-phase refrigerant region are formed on the upper part of the condenser 102,
When the cooling liquid 105 promotes boiling and the liquid level in the liquid cooling jacket 101 decreases to a predetermined level, the condenser 10
2 is supplied to the liquid cooling jacket 101 by driving the pump 125 in the forward direction.

[0005] After the warm-up operation, once the detected temperature has once risen to the target temperature, the refrigerant circulation path 103 is closed while the three-way solenoid valve 126 is in the flow path B. And
When the detected temperature becomes higher than the target temperature, the three-way solenoid valve 126 is switched to the flow path A and the pump 12
5 is driven in the forward direction, the coolant 105 is discharged from the condenser 102 to the reservoir tank 122, and the condenser 1 is discharged.
The height of the liquid level in the refrigerant circulation path 103 is reduced, the heat radiation capacity of the condenser 102 is increased, and the temperature in the refrigerant circulation path 103 is rapidly reduced. When the liquid level in the condenser 102 decreases to a predetermined level, the electric fan 104 is started, and the condensation in the condenser 102 is promoted by the forced cooling air.

On the other hand, when the detected temperature becomes lower than the target temperature, the three-way solenoid valve 126 is switched to the flow path A, and the pump 125 is driven in the reverse direction so that the coolant 105 in the reservoir tank 122 is condensed. 102, the liquid level in the condenser 102 is increased, the heat radiation capability of the condenser 102 is reduced, and the refrigerant circulation path 10
The temperature in 3 is quickly raised.

[0007]

The above prior art has the following problems. In order to control the heat radiation, the temperature and the liquid level of the coolant 105 in the liquid cooling jacket 101 and the liquid level of the coolant 105 in the condenser 102 are detected.
4, the opening and closing of the three-way solenoid valve 126, the start / stop of the pump 125, the forward / reverse drive of the pump 125, and the activation of the electric fan 104 need to be controlled.

[0008] The coolant 10 in the reservoir tank 122
Since 5 becomes vapor and escapes from the ventilation cap 121, it is necessary to periodically perform the operation of replenishing the cooling liquid 105.

An air discharge passage 123 and a refrigerant reciprocating passage 127 are required as auxiliary passages, a normally closed solenoid valve 124 and a three-way solenoid valve 126 are required as control valves, and a pump 125
And a temperature detecting means 110 in the liquid cooling jacket 101, a liquid level detecting means 128, and a second liquid level detecting means 129 of the condenser 102 are required as detecting means. Therefore, the number of parts is large,
The structure is also complicated.

The object of the first invention is as follows. Simplify control of heat dissipation. Eliminate the need for periodic coolant replenishment. To reduce the number of parts and simplify the structure. The object of the second invention is, in addition to the object of the first invention,
In the following points. To reduce the size of the accumulator. The object of the third invention is as follows in addition to the object of the first invention or the second invention. Improve cooling efficiency. To control combustion noise.

A fourth object of the present invention is as follows, in addition to the objects of the first to third aspects of the present invention. To reduce the size of a capacitor. Suppress the noise caused by the vibration of the radiation fins. The object of the fifth invention is as follows in addition to the object of any of the first to fourth inventions. To promote cooling of the surrounding part of the exhaust valve. The object of the sixth invention is as follows in addition to the object of any of the first to fifth inventions. (10) To promote cooling of the exhaust port wall.

[0012]

[Means for Solving the Problems]

(First invention) A first invention comprises a refrigerant circulation path 3 having a liquid cooling jacket 1 and a condenser 2 as shown in FIG. 1 or FIG.
The vapor of the cooling liquid 5 generated by boiling in the liquid cooling jacket 1 is introduced into the condenser 2 to be condensed, and the condensed cooling liquid 5 is returned to the liquid cooling jacket 1.
A boiling-cooled engine is characterized as follows.

[0013] That is, the refrigerant circulation path 3 having no control valve, via a refrigerant reciprocating passage 6 by constantly communicated refrigerant reservoir chamber 8 of the accumulator 7 to form a hermetic circuit, increases or decreases in response to the calorific value of the engine Temperature detecting means 10 for detecting the temperature of the refrigerant, and pressure detecting means in the refrigerant circulation passage 3 are provided.
Instead, the rotation speed of the electric fan 4 can be controlled by the control means 11 based only on the temperature detected by the temperature detection means 10.

(Second Invention) A second invention is shown in FIG.
As shown in (1), the first invention is characterized in that the refrigerant storage chamber 8 of the accumulator 7 communicates with the liquid phase portion of the refrigerant circulation path 3.

(Third invention) A third invention is shown in FIG.
As shown in (1), in the first invention or the second invention, the initial internal pressure of the refrigerant circulation path 3 is set so that the internal pressure of the refrigerant circulation path 3 is always kept lower than the atmospheric pressure even during engine operation. And

(Fourth Invention) In a fourth invention, as shown in FIG. 1 to FIG. 4, a heat radiation fin 13 is formed on the outer peripheral wall 12 of the liquid cooling jacket 1 in any one of the first invention to the third invention. The cooling air is passed around the outer peripheral wall 12 of the liquid cooling jacket 1.

(Fifth Invention) In a fifth invention, as shown in FIG. 3, in any one of the first invention to the fourth invention, an intake port port wall 15 around the intake valve port 14 and an exhaust valve port 16 around the intake valve port 14. Between the cooling valve passage gap 18 and the exhaust valve port wall 17.
Is formed.

(Sixth Invention) As shown in FIG. 3A, the sixth invention is based on any one of the first invention to the fifth invention.
The cooling liquid inlet 19 of the liquid cooling jacket 1 is connected to the exhaust port wall 2
It is characterized by aiming at zero.

[0019]

Actions and effects of the present invention

(First Invention) The first invention has the following operational effects (see FIG. 1 or FIG. 4). Since the internal pressure of the refrigerant circulation path 3 is maintained substantially constant by the accumulator 7, the boiling point of the cooling liquid 5 is substantially constant, and the evaporation rate of the cooling liquid 5 is proportional to the calorific value of the engine. For this reason, the amount of heat radiation can be optimized simply by detecting the temperature that increases or decreases in accordance with the amount of heat generated by the engine, and by controlling the rotation speed of the electric fan 4 based on the detected value. Be transformed into

Since the refrigerant circulation path 3, the refrigerant reciprocating path 6, and the refrigerant storage chamber 8 of the accumulator 7 are communicated with each other to form an airtight circuit, there is no possibility that the vapor of the cooling liquid 5 leaks into the atmosphere. There is no need to periodically perform the replenishment work of No. 5.

No air discharge passage is required as an auxiliary passage, no control valve is required, and only the temperature detection means 10 is required as the detection means. Therefore, the number of parts is small and the structure is simple.

(Second Invention) The second invention has the following functions and effects in addition to the functions and effects of the first invention (see FIG. 1 or FIG. 4). Since the coolant 5 is reciprocated between the accumulator 7 and the refrigerant circulation path 3, the accumulator 7 can be downsized as compared with a case in which gas such as vapor of the coolant 5 is reciprocated.

(Third Invention) The third invention has the following functions and effects in addition to the functions and effects of the first invention or the second invention (see FIG. 1 or FIG. 4). Since the internal pressure of the refrigerant circulation path 3 is always kept lower than the atmospheric pressure even during the operation of the engine, the boiling point of the coolant 5 is always kept low, the evaporation speed of the coolant 5 increases, and the cooling efficiency increases.

Since the internal pressure of the refrigerant circulation path 3 is always kept lower than the atmospheric pressure, the density of the gas phase in the refrigerant circulation path 3 is kept low. For this reason, the combustion noise does not easily propagate in the liquid cooling jacket 1, and the noise is suppressed.

(Fourth Invention) The fourth invention has the following functions and effects in addition to the functions and effects of any of the first to third inventions (see FIGS. 1 to 4). Since the cooling fins 13 are formed on the outer peripheral wall 12 of the liquid cooling jacket 1 and the cooling air is allowed to pass therethrough, the liquid cooling jacket 1 also radiates heat and the capacitor 2 can be downsized.

Since the air cooling by the radiation fins 13 is only for assisting the liquid cooling, it is not necessary to lengthen the projecting dimension of the radiation fins 13 as in the case of the air-cooled engine. For this reason, the protrusion size of the radiation fin 13 can be shortened, and its vibration can be suppressed, and the noise due to the vibration of the radiation fin 13 can be suppressed.

(Fifth Invention) The fifth invention has the following function and effect in addition to the functions and effects of any of the first to fourth inventions (see FIG. 3). The vapor of the cooling liquid 5 generated in the liquid cooling jacket 1 quickly passes through the cooling liquid passage gap 18 together with the cooling liquid 5, and it is difficult for the vapor to collect around the exhaust valve port wall 17, and the cooling liquid 5 is narrow. By passing through the coolant passage gap 18,
The flow velocity is accelerated, and the coolant 5
Heat dissipation to the body is promoted. For this reason, the thermal distortion of the peripheral portion of the exhaust valve port 16 is suppressed, and the sealing performance when closing the exhaust valve (not shown) can be maintained high, and the peripheral portion of the exhaust valve port 16 is prevented from cracking. can do.

(Sixth invention) The sixth invention is the first to fifth inventions.
The following operation and effect are obtained in addition to the operation and effect of any of the inventions (see FIG. 3A). (10) Since the low-temperature coolant 5 introduced from the coolant inlet 19 flows toward the exhaust port wall 20, the exhaust port wall 2
The vapor of the cooling liquid 5 generated on the surface of the cooling liquid
Is quickly washed away by the coolant 5 introduced from the
Since the contact between the exhaust port wall 20 and the low-temperature coolant 5 is promoted, the cooling of the exhaust port wall 20, which has the highest temperature, is promoted, and the entire cylinder head 30 is cooled in a well-balanced manner. Less likely.

[0029]

Embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 3 are views for explaining a boiling-cooling engine according to a first embodiment of the present invention. This engine is a general single-cylinder, spark ignition type engine having the following configuration. As shown in FIG. 1, a cylinder block 33 in which a crankcase 31 and a cylinder 32 are integrated is provided.
0 is assembled, and a rocker arm case 34 is assembled above the cylinder head 30. A lubricating oil 35 is stored in the inner bottom of the crankcase 31.

In this embodiment, since boiling cooling is performed,
As shown in FIG. 1, a refrigerant circulation path 3 having a liquid cooling jacket 1 and a condenser 2 is provided, an electric fan 4 is provided in the condenser 2, and a vapor of a cooling liquid 5 generated by boiling in the liquid cooling jacket 1 is removed. The cooling liquid 5 introduced into the condenser 2 is condensed, and the condensed cooling liquid 5 is returned to the liquid cooling jacket 1.

The liquid cooling jacket 1 includes a cylinder head 30
, But not provided on the cylinder 32. The condenser 2 has an upper tank 38 and a lower tank 39 above and below a core 37 having a vertical tube 36. The liquid cooling jacket 1 and the upper tank 38 communicate with each other through a vapor passage 40. The lower tank 39 and the liquid cooling jacket 1 communicate with each other through a cooling liquid passage 41. As a result, the refrigerant circulation path 3 is configured such that the liquid cooling jacket 1, the vapor passage 40, the condenser 2, and the cooling liquid passage 41 communicate with each other in order. A pump 25 is provided in the middle of the coolant passage 41, and the coolant 5 condensed by the condenser 2 is returned to the liquid cooling jacket 1 by the pump 25.

[0032] In this embodiment, to simplify the control of the heat radiation, the refrigerant circulation path 3 having no control valve, is communicated constantly <br/> communicating refrigerant reservoir chamber 8 of the accumulator 7 via the refrigerant reciprocating passage 6 Forming an airtight circuit, and providing a temperature detecting means 10 for detecting a temperature that increases or decreases in accordance with the calorific value of the engine,
No pressure detecting means in the refrigerant circulation passage 3 is provided, and the rotational speed of the electric fan 4 can be controlled by the control means 11 based only on the temperature detected by the temperature detecting means 10.

The accumulator 7 is constituted by dividing the refrigerant reservoir chamber 8 and the pressure regulating chamber 42 by a metal diaphragm 43, absorbs fluctuations in the internal pressure of the refrigerant circulation path 3, and maintains the internal pressure of the refrigerant circulation path 3 almost constant. The boiling point of the cooling liquid 5 is made substantially constant. The temperature detecting means 10 includes the capacitor 2
The coolant temperature at the outlet 9 of the system. The control of the rotation speed of the electric fan 4 is performed as follows.

That is, the temperature detecting means 10 is controlled by the control means 1
1, the control means 11 is connected to the electric fan 4, the reference temperature is set to a temperature slightly lower than the boiling point of the cooling liquid 5, and when the detected temperature at the outlet 9 of the condenser 2 becomes the boiling point, Is determined to be insufficient, the control means 11 increases the rotation speed of the electric fan 4, and conversely, if the detected temperature is too low below the reference temperature,
When it is determined that the cooling is excessive, the control unit 11 reduces the rotation speed of the electric fan 4. The temperature detected by the temperature detecting means 10 may be a lubricating oil temperature, an engine machine wall temperature, an ambient temperature of the engine (cooling exhaust air temperature, hood temperature, etc.).

In this embodiment, in order to reduce the size of the accumulator 7, the refrigerant storage chamber 8 of the accumulator 7 is communicated with the liquid phase portion of the refrigerant circulation path 3. That is, the refrigerant storage chamber 8 is connected in the middle of the coolant passage 41.

In this embodiment, in order to increase the cooling efficiency, the initial internal pressure of the refrigerant circulation path 3 is set so that the internal pressure of the refrigerant circulation path 3 is always kept lower than the atmospheric pressure even during engine operation. That is, the internal pressure of the refrigerant circulation path 3 is maintained lower than the atmospheric pressure (negative pressure) even during the full load operation in which the heat generation amount of the engine is maximized and the evaporation speed of the coolant is maximized. Specifically, the set pressure of the pressure adjustment chamber 42 of the accumulator 7 is set lower than the atmospheric pressure. If the set pressure of the pressure regulating chamber 42 of the accumulator 7 is set higher than the atmospheric pressure, the internal pressure of the refrigerant circulation path 3 is maintained at a positive pressure.

In this embodiment, in order to reduce the size of the condenser 2, a radiation fin 13 is formed on the outer peripheral wall 12 of the liquid cooling jacket 1 so that cooling air can pass around the outer peripheral wall 12 of the liquid cooling jacket 1. It is. As shown in FIG. 2, the peripheral wall of the cylinder 32 is air-cooled by the cooling air from the flywheel fan 44, and a part of the cooling air passes through the periphery of the outer peripheral wall 12 of the liquid cooling jacket 1 so that the cooling liquid is cooled. 5 is used for heat radiation.

In this embodiment, as shown in FIG. 3, in order to promote cooling of the peripheral portion of the exhaust valve port 16, the intake valve port 1
A coolant passage gap 18 is formed between the intake port port wall 15 around the exhaust port 4 and the exhaust port port wall 17 around the exhaust valve port 16.

In this embodiment, as shown in FIG. 3A, the cooling liquid inlet 19 of the liquid cooling jacket 1 is directed to the exhaust port wall 20 in order to promote cooling of the exhaust port wall 20.

In the boiling cooling engine according to the second embodiment shown in FIG. 4, the refrigerant circulation path 3 is formed only by the liquid cooling jacket 1 and the condenser 2, and the cooling liquid 5 evaporated in the liquid cooling jacket 1 is cooled by the condenser. The cooling liquid 5 penetrates into the liquid cooling jacket 1 and is condensed. The coolant storage chamber 8 of the accumulator 7 is connected to the liquid cooling jacket 1. The condenser 2 is mounted on the cylinder head 30 and is inclined to reduce the overall height. The temperature detecting means 10 detects the temperature of the lubricating oil 35. Other configurations are the same as those of the first embodiment. In FIG. 4, the same elements as those of the first embodiment are denoted by the same reference numerals.

[Brief description of the drawings]

FIG. 1 is a vertical sectional rear view of a boiling cooling engine according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional front view of the engine of FIG. 1;

3A and 3B are views for explaining a cylinder head of the engine of FIG. 1, wherein FIG. 3A is a cross-sectional plan view, and FIG. 3B is FIG. 3A.
FIG. 7 is a sectional view taken along line BB of FIG.

FIG. 4 is a vertical sectional rear view of an essential part of a boiling cooling engine according to a second embodiment of the present invention.

FIG. 5 is a diagram corresponding to FIG. 1 of the prior art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid cooling jacket, 2 ... Condenser, 3 ... Refrigerant circulation path, 4 ... Electric fan, 5 ... Coolant, 6 ... Refrigerant reciprocating path,
7: accumulator, 8: refrigerant chamber, 9: outlet, 10
... temperature detecting means, 11 ... control means, 12 ... outer peripheral wall, 13
... radiation fins, 14 ... intake valve port, 15 ... intake valve port port wall, 16 ... exhaust valve port, 17 ... exhaust valve port port wall, 18 ...
Coolant passage gap, 19: coolant inlet, 20: exhaust port wall.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI F01P 3/02 F01P 3/02 P 7/04 7/04 A // F01P 11/18 11/18 A (56) References Features Kaihei 4-22708 (JP, A) JP-A 61-65259 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01P 3/22 F01P 1/02 F01P 3/02

Claims (6)

(57) [Claims] 1. A refrigerant circulation path (3) having a liquid cooling jacket (1) and a condenser (2), an electric fan (4) provided in the condenser (2), and A boiling-cooled engine in which steam of a cooling liquid (5) generated by boiling is introduced into a condenser (2) to be condensed, and the condensed cooling liquid (5) is returned to a liquid cooling jacket (1). , A refrigerant reciprocating passage is provided in the refrigerant circulation path (3) having no control valve.
(6) via a refrigerant reservoir chamber of the accumulator (7) and (8) normal
When we communicate to form a hermetic circuit, the temperature detection means (10) for detecting the temperature increase or decrease in response to the calorific value of the engine provided, pressure detecting means of the refrigerant circulation passage (3) in the not provided, the < A boiling-cooled engine wherein the rotation speed of the electric fan (4) can be controlled by the control means (11) based only on the temperature detected by the temperature detection means (10). 2. The boiling-cooled engine according to claim 1, wherein a refrigerant storage chamber (8) of the accumulator (7) communicates with a liquid phase portion of the refrigerant circulation path (3). Cooled engine. 3. The boiling cooling type engine according to claim 1, wherein the internal pressure of the refrigerant circulation path (3) is always kept lower than the atmospheric pressure even during operation of the engine. 3) An ebullient cooling engine, wherein the initial internal pressure is set. 4. The boiling-cooled engine according to claim 1, wherein the cooling jacket is a liquid-cooled jacket.
A heat-radiating fin (13) is formed on the outer peripheral wall (12) of the liquid cooling jacket (1), and cooling air is passed around the outer peripheral wall (12) of the liquid cooling jacket (1). 5. An evaporative cooling engine according to claim 1, wherein an intake port port wall (15) around the intake valve port (14) and an exhaust gas around the exhaust valve port (16). A boiling-cooling engine, wherein a cooling liquid passage gap (18) is formed between the cooling liquid passage gap (18) and the valve port wall (17). 6. The boiling-cooled engine according to claim 1, wherein the cooling jacket is a liquid-cooled jacket.
Of the cooling liquid inlet (19) toward the exhaust port wall (20).
A boiling-cooled engine characterized by the following.