DE2852725A1 - COMPENSATING TANK FOR COOLANT - Google Patents

Description

PATENT LAWYERS ^

DIPL-ING. H. STEHMANN DIPL-PHYS. DR. K. SCHWEINZER DIPL-ING. DR. M. RAU

D-6500 Nürnberg essenweinstrasse4-6 phone 0911/203727 telex 06/23135

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Nuremberg, December 5th, 1978 17/53

Süddeutsche Kühlerfabrik Julius Fr.Behr GmbH & Co.KG., Mauserstrasse 3, D - 7000 Stuttgart 30

"Expansion tank for coolant"

The invention relates to an ^{expansion tank for coolant, the v} on its inflow side through at least two vent lines and on its outflow side through a secondary flow return line to both the coolant inlet and the coolant outlet of a cooling liquid jacket of an internal combustion engine with a heat exchanger for the heat dissipation of the cooling liquid connecting the main circuit for cooling water so is connected that one vent line as the machine operating vent line is constantly connected to the cooling water outlet, the other vent line is connected to the heat exchanger and the bypass flow return line is constantly connected to the cooling water inlet, and in which an essentially vertical inner partition forms a subdivision into an antechamber and a suction chamber , the Entltiftungsleitung in the antechamber and the bypass flow return line open into the suction chamber and the partition both one on the container rboden lying, the .. secondary stream quantity wholly or for the most part leading direct secondary stream connection between

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Antechamber and suction chamber as well as a ventilation connection between the container top wall Has antechamber and suction chamber.

In such a known expansion tank (DE-AS 2 437 502) is to improve the separation function for operating conditions in which an increased accumulation of air, vapor or gas bubbles in the Sidestream is to be expected, the sidestream connection into a connection for low-bubble coolant and into a connection connected between the antechamber and the suction chamber parallel connection for bubble-enriched cooling liquid divided and the connection for bubble-enriched Cooling liquid lies geodetically between the ventilation connection and the connection for low-bubble coolant.

This known expansion tank requires a relatively large amount of space and can often not be used in vehicles be arranged sufficiently high above the heat exchanger. This allows the heat exchanger and the internal combustion engine can only be filled incompletely with coolant because the cold water level is taken into account a sufficient expansion volume in the container below the upper edge of the water box of the associated Heat exchanger is located. From this it follows that under unfavorable operating conditions with insufficient cooling liquid volume BEZW in the internal combustion engine and in the heat exchanger. with increased air admixture in the cooling circuit must be driven.

In another expansion tank of the type mentioned (DE-AS 2 462 094) are to solve the same up-

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would be, namely to increase the separation function in the Pre-chamber additional guide means are arranged and so in terms of flow between the opening opening into the pre-chamber the one vent line and the connections of the partition switched on that the bubble-enriched Coolant of this vent line in the direction is directed to the container top wall.

This expansion tank also does not allow a limited filling at a corresponding filling speed and filling volume without air inclusion and air admixture.

In contrast, the invention is based on the in the case of an expansion tank of the type explained at the beginning, in the case of a special vehicle-related position of the heat exchanger and expansion tanks as well as spatial restrictions of the compensation container the complete Filling of the heat exchanger and the internal combustion engine in accordance with the requirements of the respective specification Fall speed and fill volume ensure and coolant losses, which in certain operating conditions as a function of the load condition, the outside air temperature, the engine oil temperature, the cooling water temperature and the overpressure protection of the cooling system can occur.

This object is achieved according to the invention by a Expansion tank in a filling chamber and in an expansion chamber dividing, tight partition and through an expansion chamber with the filling chamber on the geo-

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the highest point connecting the coolant return pipe solved.

By separating an expansion chamber according to the invention the filling chamber can be filled up to a certain water level via a filler neck will. The desired limited filling takes place through the influence of the geodetic water level change without air pockets and air admixture. By the filling limit is also guaranteed that the filling chamber will not be overfilled. The remaining volume serves as a collection volume for the coolant expansion within the operating temperature range. This means, that the expansion chamber serves as a compression volume during normal operation and approximately pipe via the coolant return pipe and a pressure relief valve connects to the atmosphere.

According to a further embodiment of the invention, it is therefore advantageous that a pressure relief valve with integrated vacuum valve and vent line in the upper area of the expansion chamber and a filler neck, the filler opening below the geodetically highest Level of the coolant return pipe is, is arranged in the filling chamber and in the closed state has no connection to the atmosphere. It is possible to vent the heat exchanger into the Include filler neck.

In a vent for two separate cooling circuits (DE-AS 2,063,298) although it is known, between a surge tank and a reserve tank ^{n is} an absolutely tight partition provided. In contrast, according to the invention, no absolutely tight partition is provided, but a coolant return pipe protrudes through the partition, so that two dependent chambers with different functions are created. The filling

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chamber takes on the main function, while the expansion chamber performs the additional functions adapted to the respective operating state and in contrast to a pure overflow vessel to accommodate a temperature-dependent Expansion volume. The otherwise required second expansion tank is used in the known Ventilation as an overflow vessel for the expansion tank to reduce water loss, d. H. the overflow vessel only the functions of the unaffected coolant supply and the reduction in size become associated with water loss.

To adapt to the tank volume of the expansion chamber when the boiling temperature is exceeded (depending on. overpressure), it is advantageous if after a Another feature of the invention, in the coolant return pipe a throttle is provided. The throttle causes a pressure increase in the circuit. This will set the boiling point increased, i.e. the evaporation of the coolant is reduced.

Further features and advantages of the invention are explained in more detail with reference to the drawing, which schematically shows an exemplary embodiment represents. It shows:

1 shows a coolant circuit with an internal combustion engine, heat exchanger and expansion tank, partially cut, and

Fig. 2 shows an expansion tank according to the invention in a section along the line A-B in FIG. 1.

The coolant circuit shown schematically in FIG. 1, for example for a vehicle, consists of an internal combustion engine 1, with a corresponding Cooling jacket, 'a heat exchanger 2 for the coolant and one driven by the internal combustion engine 1

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Fan 19, which can optionally also be switched on via a temperature-dependent coupling. The internal combustion engine is connected to the heat exchanger 2 via a coolant inlet line 5 and a coolant outlet line 6. The coolant outlet line 6 from the
Heat exchanger 2 leads to a water pump 4 and from
there to the internal combustion engine 1. In line 5 or 6 there is usually a short-circuit controlling thermostat (not shown) which switches on the heat exchanger as required depending on the coolant temperature.

A coolant expansion tank 3 is connected to the heat exchanger 2 and the internal combustion engine 1. The internal combustion engine is vented via a line 8 and the heat exchanger is vented to the expansion tank 3 via a line 9 via a filling line
(Suction line) 7, the coolant expansion tank 3 is connected to the water pump 4. This filling line 7 fulfills the task of a secondary flow return line.

From Fig. 2 it can be seen that the coolant expansion tank 3 by means of a tight, vertical partition 12 in two interdependent chambers, namely an expansion chamber 10 and a filling chamber 11 with differentiated function. The container expansion chamber 10 is equipped with a pressure relief valve provided with an integrated underpressure valve 14, a ventilation pipe 17 being provided for the overpressure valve 14 is.

The filling chamber 11 has a filler neck 16 a replenishment limit 15.

It is also possible to integrate the heat exchanger ventilation line into the filler neck 16.

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From the longitudinal section in Fig. 1, the internal structure is inside the filling chamber 11 can be seen. This structure corresponds essentially to the known expansion tank of the type described above

Partition wall 20 is provided, which divides the filling chamber 11 into an antechamber 22 and a suction chamber 23 separates. The two chambers are connected to one another by a connection 24 connected, which is arranged at a geodetically lower area of the partition wall, while in the upper area a vent connection 25 exists. The connection 24 is expediently also provided with a guide plate 21. the The operation of the expansion chamber 11 corresponds to essential to the mode of operation of the known expansion tank.

In the known containers, the heat exchanger 2 and the internal combustion engine 1 can only be filled incompletely, up to a level N4, since the cold water level is below Consideration of a sufficient expansion volume in the container 3 below the upper edge N 3 of the water tank of the heat exchanger 2 is located.

Due to the inventive division of an expansion chamber 10 can be the right half of the container, namely the Filling chamber 11 via the filler neck 16 up to one Water level limiter 15 must be filled. By the influence the geodetic water level height change N 4 to N1 is a limited replenishment without air inclusion and air admixture. The filling limit ensures that the filling chamber is not overfilled 11 takes place. The remaining volume between N 1 and N 2 serves as a collection volume within the operating temperature range, d. H. the expansion chamber 10 is used

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as compression volume and represents via the coolant return pipe 13 and the pressure relief valve 14 connect to the atmosphere.

The change in water level described ensures that that with coolant losses up to the level N 4 a stable, d. H. gas-free cooling circuit achievable is. In the case of a known container design, on the other hand, air is sucked in at an early stage via the suction line 7 to the pump 4 and thereby the functionality of the cooling circuit called into question.

The design according to the invention also reduces the loss of coolant due to water ejection, which is particularly dangerous for export vehicles for tropical countries, avoided. Water ejection is understood to be the loss of coolant, which is a function of certain operating states the load condition, the outside air temperature, the engine oil temperature, the cooling water temperature and the overpressure protection of the cooling system occurs.

Local overheating in the area of the combustion chambers of the internal combustion engine with the engine or the water pump 4 stopped, the pressure-dependent boiling temperature becomes of the coolant exceeded. The change in the Volume displaces a defined amount of coolant via the connecting lines 8, 9 to the container 3. The total volume is changed to such an extent that a remaining space is necessary.

These difficulties could indeed be caused by additional expansion volumes with correspondingly complex piping

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management and considerable costs and space requirements can be solved. However, there is a risk of leaks in the pipe system, since many more pipes are necessary, with the leaks then leading to failure of the circulatory system.

It is also possible to use the valve overpressure to protect the circuit to increase. With this measure, however, an additional expansion volume cannot in principle can be saved. Due to the additional dynamic pressure increase in the water-air heat exchanger and in the case of other components, however, this requires considerable costs (reinforced heat exchanger, stronger seals, modified hose connections).

When dividing the expansion tank according to the invention 3 into an expansion chamber 10 and a filling chamber 11, the mentioned coolant losses are avoided or reduced even under unfavorable operating conditions.

If, for example, under unfavorable operating conditions, an expanding amount of steam occurs that exceeds the Vent lines 8 and 9 a quantity of coolant from the colder zones of the cooling circuit in the filling chamber 11 of the container 3 presses, then the coolant level in this chamber 11 first rises to the N level and then passes through the coolant return pipe into the expansion chamber 10. Depending on the operating status, d. H. Depending on the volume requirement, the expansion chamber 10 fills more or less. The maximum filling level is reached at N 5. The escape of the chamber air or as the coolant evaporation progresses the amount of steam takes place via the vent pipe 17 and the pressure relief valve 14. The overflowing

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The liquid or the amount of steam can be controlled via a throttle 18 in the coolant return pipe 13 for adaptation to the container volume 10. There will be a targeted degassing taking into account the expansion volume offered, so that no major water values
loss occurs.

In the event of a subsequent change in the operating status in the post-heating area the internal combustion engine, for example starting the engine or coolant circulation or delayed cooling, the gas bubble condenses in the endangered area. The resulting lack of coolant must be compensated for in the short term be, d. H. the accumulation of the displaced amount of coolant in the expansion chamber 10 must be possible are quickly available as a functional volume in the cooling circuit or in the filling chamber 11.

s.

The pressure difference created by the condensation of the volume of steam Between the cooling circuit and the atmospheric overpressure, the underpressure valve integrated in the overpressure valve 14 opens and thereby enables the coolant to flow back out of the expansion chamber 10 via the coolant return pipe 13 into the filling chamber 11. The forwarding of the coolant from the chamber 11 to the internal combustion engine takes place in a known manner Via the suction line 7 to the water pump 4.

Compensating tanks according to the invention can be used in an advantageous manner Manufacture from plastic in large series.

The invention is not limited to the illustrated and described exemplary embodiment. It also includes all professional modifications and further training as well as partial and sub-combinations of the described and / or features and measures shown.

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Claims (3)

PATENTANWÄLTE DiPL-ING. H. STEHMANN DIPL-PHYS. DR. K. SCHWEINZER DIPL-ING. DR. M. RAU D-8500 NORNBERG ESSENWEINSTRASSE 4-6 TELEPHONE 0911/20 37 27 TELEX Oi / 23135 Nuremberg, December 5, 1978 17/53 Süddeutsche Kühlerfabrik Julius Fr.Behr GmbH & Co.KG., Mauserstrasse 3, D - 7000 Stuttgart 30 Expectations \ J Compensating tank for coolant, which is connected on its inflow side by at least two vent lines and on its outflow side by a secondary flow return line to a main circuit for cooling water that connects both the coolant inlet and the coolant outlet of a coolant jacket of an internal combustion engine with a heat exchanger for the heat dissipation of the coolant, that one vent line as the machine _{operating vent line is constantly connected to the cooling water outlet r,} the other vent line is connected to the heat exchanger and the bypass flow return line is constantly connected to the cooling water inlet, and in which an essentially vertical inner partition forms a subdivision into an antechamber and a suction chamber, the vent lines open into the antechamber and the secondary flow return line into the suction chamber and the partition wall both one at the bottom of the container 030Q2A / Ö421 has a direct bypass flow connection between antechamber and suction chamber lying on the top wall of the container between the antechamber and suction chamber, characterized by a compensating tank (3) in a filling chamber (11) and a direct bypass flow connection between the antechamber and suction chamber, which leads the bypass flow quantity in whole or for the most part Dense partition (12) dividing the expansion chamber (10) and through a coolant return pipe (13) connecting the expansion chamber (10) to the filling chamber (11) at the geodetically highest point. 2. Compensating tank according to claim 1, characterized in that a pressure relief valve (14) with integrated vacuum valve and vent line (17) in the upper region of the expansion chamber (10) and a filler neck (16), the filler opening below the geodetically highest level of the coolant return pipe (13 ) is located in the filling chamber (11) and has no connection to the atmosphere in the closed state. 3. Expansion tank according to claim 1 or 2, characterized in that a throttle (18) is provided in the coolant return pipe (13). 030024/0421