JPS6183423A - Pump-anomaly diagnosing apparatus in evaporative cooling apparatus for internal-combustion engine - Google Patents

Abstract

PURPOSE:To detect the driving state of a pump and permit anomaly indication by detecting the electric current or the revolution speed of a motor for driving the cooling-water circulation pump of an evaporative cooling apparatus. CONSTITUTION:The cooling water in an internal-combustion engine 1 is evaporated in a cylinder head 4, and liquefied in a condenser 10, passing through a pipe 7, and the liquefied cooling water in a lower tank 13 is allowed to circulate into a water jacket 2 through a pipe 15 by a pump 16. The electric-current value or the revolution speed of a driving motor for the pump 16 is always detected, and compared with a prescribed aimed value in a controller 40. When the pump generates cavitation, the revolution speed abnormally increases, and when the pump is clogged with dusts, the electric current supplied for the motor abnormally increases or the revolution speed abnormally reduces because of stick, and the alarm indication for anomaly is immediately generated.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention efficiently cools the engine by storing liquid phase refrigerant up to a predetermined level in the water jacket of an engine and boiling and vaporizing it, and converts the generated vapor into a condenser. The present invention relates to a pump abnormality diagnostic device for diagnosing the presence or absence of abnormality in a pump in a boiling cooling system for an internal combustion engine in which the condensed liquid is circulated and supplied to a water jacket by a pump.

<Prior art> In the well-known water-cooled cooling system used in internal combustion engines for automobiles, a considerable temperature difference occurs between the water inlet and the water outlet of the water jacket, making it difficult to achieve uniform cooling. It is difficult to achieve this, and there is a natural limit to the heat exchange efficiency of the radiator, so the radiator and cooling fan have to be large.

From this point of view, cooling devices that utilize the latent heat of boiling and vaporization of cooling water have been attracting attention in recent years (for example, the
(See Publication No. 7608, Japanese Unexamined Patent Publication No. 57-62912)
. Basically, this system boils and vaporizes the liquid phase refrigerant (cooling water) inside the water jacket, leads the generated vapor to an external condenser, condenses it, and liquefies it, and then circulates it back into the water jacket. Compared to a water-cooled type that uses a simple temperature change of the cooling water, a cooling system that uses this phase change of the refrigerant can satisfy the required amount of heat dissipation by circulating a much smaller amount of cooling water. It has been pointed out that the capacitor can be made much smaller than a conventional radiator, and it also has the advantage of making the temperature distribution uniform in each part of the engine.

However, such boiling cooling devices, which are considered to have various advantages, have not yet been put into practical use.

Namely, the above-mentioned Japanese Patent Publication No. 57-57608 and Japanese Patent Application Laid-open No. 57-57
The refrigerant circulation system described in Publication No. 7-62912, etc. has an unsealed structure in which part of the refrigerant circulation system is open to the atmosphere, and the loss of vaporized refrigerant is so large that it cannot be ignored in practical terms. This is because it is difficult to completely remove air, which is a non-condensable gas, from the system, resulting in problems such as a significant decrease in cooling performance due to residual air.

In view of the above-mentioned circumstances, the present applicant has previously proposed a boiling cooling device in which a predetermined amount of refrigerant is sealed in a closed refrigerant circulation system to perform a boiling and condensing cycle (
Patent Application No. 1983-100157, Patent Application No. 59-14037
No. 8, etc.). In these devices, for example, at startup, the system is first filled with liquid phase refrigerant, and then excess refrigerant is discharged into a reservoir tank while preventing air from entering, thereby sealing a predetermined amount of refrigerant in the closed system. Yes, while the engine is running, the refrigerant supply pump circulates and supplies liquid refrigerant equivalent to the generated steam to the water jacket, keeping the liquid level of the refrigerant above a predetermined level at all times to ensure cooling of the combustion chamber walls, etc. We aim to do so.

<Problems to be Solved by the Invention> By the way, in such a boiling cooling device, the liquid level in the water jacket is monitored and the refrigerant supply pump is controlled on and off so that the liquid level is always around a predetermined level. However, it is difficult to use an engine-driven mechanical pump as the refrigerant supply pump, and it is necessary to use an electric pump.

However, compared to mechanical pumps, electric pumps
Stains are often caused by biting of dirt, etc.

Furthermore, since high-temperature refrigerant flows in a boiling cooling device, there is a risk of cavitation occurring at the pump inlet.

If such a pump malfunctions, it becomes impossible to maintain the liquid level in the water jacket at a specified level, and the liquid level gradually drops, exposing the combustion chamber walls, which can cause engine seizure, etc. become.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a pump abnormality diagnostic device for an evaporative cooling system in order to reliably detect failure of a pump or the occurrence of cavitation and to promptly deal with the problem.

Means for Solving the Problems> In order to achieve the above object, the present invention provides a water jacket A for an engine that stores a liquid phase refrigerant and has a vapor outlet at the top, as shown in FIG. a condenser B connected to the vapor outlet to condense and liquefy the vapor phase refrigerant and having a refrigerant tank at the bottom; an electric refrigerant supply pump C provided between the refrigerant tank and the water jacket; A boiling cooling system for an internal combustion engine comprising a control device for controlling on/off of a supply pump, a detection means E for detecting a motor current value or rotational speed of the refrigerant supply pump C, and a pump-on command by the control device. A determining means F determines that the pump is abnormal when the detected value of the detecting means E is outside a predetermined range, and an alarm means G issues an alarm when determining that the pump is abnormal.

In other words, the motor current value or rotational speed of the refrigerant supply pump C is detected by the detection means, and if the detected value by the detection means is outside a predetermined range even though the control device is issuing a pump-on command. In this case, the determining means F determines that the pump is abnormal. In this case, if the current value is too small or the rotation speed is too high, it is due to an abnormality such as idling due to pump cavitation, and conversely, if the current value is too large or the rotation speed is too small, It is thought that this is an abnormality such as staining caused by clogging with dust or the like. When it is determined that the pump is abnormal, the alarm means G issues a warning such as an abnormality display.

<Embodiment> FIG. 2 shows an embodiment of the evaporative cooling device according to the present invention.

In FIG. 2, ■ indicates an internal combustion engine, and 2 indicates a water jacket. Water jacket 2 is internal combustion engine 1
It is formed across both the cylinder block 3 and the cylinder head 4 so as to surround the outer periphery of the cylinder and combustion chamber, and a plurality of steam outlets 5 are provided at appropriate positions in the upper part, which is normally a gas phase space. ing. These steam outlets 5
communicates with a steam passage 7 via a steam manifold 6, and this steam passage 7 communicates with an upper tank 11 of a condenser 10, which will be described later. In addition, the steam manifold 6 includes
An air discharge section 8 serving as the top of the refrigerant circulation system is formed in an upwardly erected shape, and a camp 9 seals the opening at its upper end.

The condenser 10 includes an upper tank 11 to which the steam passage 7 is connected, a core section 12 mainly consisting of fine vertical tubes, and a lower tank 13 (not necessarily the condenser IO) that temporarily stores the liquefied refrigerant condensed in the core section 12. ) is composed of
For example, it is installed at a position such as the front of the vehicle that receives the wind from when the vehicle is running, and is further provided with an electric cooling fan 14 on the front or rear side for forced cooling. And lower tank 1
3 has one end of a refrigerant circulation passage 15 connected to its lower part.

An electric refrigerant supply pump 1 is installed in the middle of the refrigerant circulation passage 15.
6 and a second electromagnetic valve 24 to be described later are interposed, and the other end of the refrigerant circulation passage 15 is connected to a refrigerant port 17 of the water jacket 2 on the cylinder head 4 side.

A refrigerant circulation system is constituted by the water jacket 2 - steam passage 7 - condenser 1 - refrigerant circulation passage 15 (refrigerant supply pump 16° second solenoid valve 24) - water jacket 2.

Next, reference numeral 18 denotes a reservoir tank, which is provided outside the refrigerant circulation system to store a preliminary liquid phase refrigerant, and is installed at a position approximately the same height as the water jacket 2, Cap with ventilation function 1
9 to the atmosphere.

Then, an air exhaust passage 21 is connected to the air exhaust part 8 of the steam manifold 6, which is the top part of the refrigerant circulation system, via a normally closed first solenoid valve 20, in order to exhaust the air in the system. Further, in order to recover the liquid phase refrigerant that overflows at the same time as air is discharged, the tip of this air discharge passage 21 is opened into the reservoir tank 18.

Additionally, an auxiliary refrigerant passage 22 is provided at the bottom of the reservoir tank 18.
．． 23 are connected. One auxiliary refrigerant passage 22 is connected to the refrigerant circulation passage 15 via a second electromagnetic valve 24 which is a three-way valve. In the demagnetized state, the second solenoid valve 24 shuts off the refrigerant circulation passage 15 and connects the lower tank 13 and the reservoir tank 18 to the refrigerant supply pump 16 through the auxiliary refrigerant passage 22.
In the excited state, the auxiliary refrigerant passage 22 is shut off and the refrigerant circulation passage 15 is brought into communication (flow path B).

Here, as the refrigerant supply pump 16, one that can pump the liquid phase refrigerant in both forward and reverse directions is used. , the liquid phase refrigerant can be forcibly discharged from the lower tank 13 to the reservoir tank 18, and by driving in the opposite direction, the liquid phase refrigerant can be forcibly introduced from the reservoir tank 18 to the lower tank 13. If the refrigerant supply pump 16 is driven in the forward direction in the state of path B, the lower tank 13
Liquid phase refrigerant can be circulated and supplied from the water jacket 2 to the water jacket 2.

Further, the other auxiliary refrigerant passage 23 is connected to a relatively upper part of the lower tank 13, and a third solenoid valve 25 is connected to the upper part of the lower tank 13.
is interposed.

The electromagnetic valves 20, 24, 25, the refrigerant supply pump 16, and the cooling fan 14 are driven and controlled by a control device 40 with a built-in micro combinator. liquid level sensor 41,
Control, which will be described later, is performed based on detection signals from a second liquid level sensor 42 provided on the lower tank 13, a temperature sensor 43 provided on the water jacket 2, a negative pressure switch 44 provided on the air discharge section 8, and the like.

The first and second liquid level sensors 41 and 42 detect whether the refrigerant liquid level has reached a set level in an on/off manner using, for example, a float type sensor using a reed switch. The first liquid level sensor 41 has its detection level set at a height approximately in the middle of the cylinder head 4, and the second liquid level sensor 42 has its detection level set at a position slightly above the opening of the auxiliary refrigerant passage 23. It is set in the height position. Further, the temperature sensor 43 is provided at a position slightly below the first liquid level sensor 41, that is, at a position where it is normally immersed in the liquid phase refrigerant, so as to detect the refrigerant temperature within the water jacket 2. In addition, the negative pressure switch 44 uses a diaphragm that responds to the differential pressure between atmospheric pressure and system pressure, and detects whether or not there is negative pressure in the system with respect to the atmospheric pressure in the operating environment. It is supposed to be done.

An overview of the control will be explained with reference to the flowchart in FIG. 3. When the engine is started, air exhaust control (R1) is first performed (only at the time of cold start). This is achieved by opening the first solenoid valve 20, setting the second solenoid valve 24 to flow path A, and closing the third solenoid valve 25, and driving the refrigerant supply pump 16 in the reverse direction for a predetermined period of time. A liquid phase refrigerant is introduced into the system through a refrigerant passage 22 to completely fill the system with water, and air remaining in the system is collected in the upper part of the system and discharged to a reservoir tank 18 through an air discharge passage 21.

Next, perform warm-up side 1 (R2) -0 This is the first solenoid valve 2
0 is closed, the second solenoid valve 24 is opened in the flow path B, and the third solenoid valve 25 is opened, and the lower tank 3 and the reservoir tank 18 are kept in communication, that is, the system is left open to the atmosphere, and the system is on standby. Then, as boiling starts within the water jacket 2, surplus refrigerant in the system is discharged from the lower tank 13 through the auxiliary refrigerant passage 23 to the reservoir tank 18. Then, when the refrigerant temperature in the water jacket 2 reaches the target temperature or the liquid level in either the water jacket 2 or the lower tank 13 falls below the set level, the third solenoid valve 25 is closed and the system keep it in a sealed state.

After that, control loops such as temperature side m (fan control), liquid level control (pump control), etc. are repeated until the engine stops.

Temperature control (R3) turns the cooling fan 14 on and off so that the refrigerant temperature in the water jacket 2 reaches the target temperature.
The liquid level control (R4) controls the refrigerant supply pump 16 to O depending on the liquid level in the water jacket 2.
N-OFF (forward rotation/stop) and maintains the liquid level in the water jacket 2 above a set level by circulating and supplying liquid phase refrigerant.

In this case, as long as the temperature inside the system is within a predetermined range and the liquid level in the lower tank 13 is below the set level, the above control is repeated while keeping the inside of the system in a sealed state.

In addition, when the refrigerant temperature in the water jacket 2 significantly exceeds the target temperature and the liquid level in the lower tank 13 exceeds the set level, the heat dissipation area of the condenser 10 is substantially expanded. Surface reduction control (R
Do 5). This changes the refrigerant supply pump 16 from the closed state.
is driven in normal rotation and switches the second solenoid valve 24 according to the level of the liquid level in the water jacket 2, thereby transferring the liquid phase refrigerant in the lower tank 13 to the reservoir tank 18 while ensuring the liquid level in the water jacket 2. The heat dissipation area of the capacitor 10 is expanded by discharging the heat.

In addition, when the refrigerant temperature in the water jacket 2 is significantly lower than the target temperature, in order to substantially reduce the heat dissipation area of the condenser 10, the condenser liquid level rise control (
Perform R6). This means that when the system has a negative pressure, the third solenoid valve 25 is opened to introduce liquid phase refrigerant from the reservoir tank 18 to the lower tank 13, and when the system has a positive pressure,
The second electromagnetic valve 24 is set to flow path A, and the refrigerant supply pump 16 is driven in reverse to introduce liquid refrigerant into the system from the reservoir tank 18.

The details of each control are described in Japanese Patent Application No. 140378/1982.

Meanwhile, during such control, an interrupt routine for diagnosing pump abnormality is executed at predetermined time intervals according to the flowchart shown in FIG.

To explain this pump abnormality diagnosis routine, in step 1 (SL in the figure) it is determined whether or not an ON command has been issued to the pump 16;

If , this routine ends.

If YES in step 1, proceed to step 2 and read the motor current value I of the pump 16. Specifically, pump 1
A current detection resistor 50 may be interposed on the ground terminal side of the motor No. 6, and the terminal voltage V=IR may be detected. Next, in step 3, the detected current value ■ is set to a predetermined upper limit value 1 ma
x and the lower limit value 1m1n.

If it is determined in step 3 that 1m1n≦I≦■max, it is considered normal and this routine ends.

However, if ■ < lm1n, it is considered that the pump 16 is idling due to cavitation in addition to a disconnection, etc., and is abnormal, so proceed to step 4 and display the abnormality on the warning lamp 51 etc. By this,
Issue a warning to the driver.

In addition, if i>Imax, it is considered that the pump 16 is in a stain state due to dirt or the like getting caught in it, and is abnormal. issue a warning.

By detecting an abnormality in the pump 16 and promptly alerting the operator in this way, if the pump 16 continues to malfunction, the liquid level in the water jacket 2 will drop significantly and the combustion chamber walls will be exposed. It is possible to prevent burn-in and the like from occurring.

In this embodiment, an abnormality in the pump 16 is detected from the motor current value, but the rotational speed of the pump 16 is detected using a photoelectric pickup or the like, and the pump 16 is detected from the rotational speed.
The presence or absence of the abnormality in step 6 may be diagnosed. In this case, if the rotation speed is below the lower limit even when the pump is commanded to turn on, there may be a disconnection or a stuck condition, and if it is above the upper limit, it may be idle due to pump cavitation. .

Further, in this embodiment, only an alarm is issued when a pump abnormality is determined, but various fail-safe measures may be automatically performed at the same time. For example, if the pump is stuck due to dirt or other particles getting stuck in it, the jam will often be released by rotating the pump in the opposite direction to the current direction of rotation.In such cases, temporarily turn off the pump. For example, it is driven in the opposite direction.

<Effects of the Invention> As explained above, according to the present invention, it is possible to simply diagnose whether or not there is an abnormality in the pump in the boiling cooling system, and promptly notify the operator of the abnormality in the event of an abnormality. The effect is that the safety of the boiling cooling device capable of cooling the engine can be improved and its value can be further increased.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a block diagram showing an embodiment of the boiling cooling device according to the present invention, Fig. 3 is a flow chart showing an overview of control, and Fig. 4 is a pump abnormality. 3 is a flowchart of a diagnostic routine. 1... Internal combustion engine 2... Water jacket 5.
... Steam outlet 7... Steam passage 10... Condenser 13... Lower tank 15... Refrigerant circulation passage 16... Refrigerant supply pump 17... Refrigerant population 18... Reservoir tank 20... First solenoid valve 24... Second solenoid valve 25... Third solenoid valve 40... Control device 41... First liquid level sensor
42...Second liquid level sensor 43...Temperature sensor
50... Current detection resistor 51... Warning lamp

Claims (1)

[Claims] A water jacket for an engine that stores a liquid phase refrigerant and has a vapor outlet at the top; a condenser connected to the vapor outlet for condensing and liquefying the vapor phase refrigerant and having a refrigerant tank at the bottom; the refrigerant tank and the water jacket. Detecting the motor current value or rotational speed of the refrigerant supply pump in a boiling cooling system for an internal combustion engine comprising an electric refrigerant supply pump provided between the refrigerant supply pump and a control device that controls on/off the refrigerant supply pump. a determining means for determining that the pump is abnormal when a detected value of the detecting means is outside a predetermined range when the control device issues a pump-on command; and an alarm means for issuing an alarm when determining that the pump is abnormal. Pump abnormality diagnosis device.