EP0657633B1 - Partially filled boiling liquid cooling system - Google Patents

Description

The invention relates to a partially flooded vapor cooling system according to the preamble of the first claim.

Such a system is known for example from DE-A 40 01 208. Here the reservoir is located below the condenser. This stipulates a minimum height that cannot always be ensured with today's vehicles.

The object of the present invention is to remedy this and to propose an arrangement and configuration for a storage container for liquid condensate in a generic cooling system which is simple in construction and has the least possible outlay for filling and checking the fill level.

This object is achieved by the characterizing features of claim 1. In terms of structure, this creates a cooling system in the area of the condenser, which is identical to the conventional cooling cooling systems and can therefore be filled. This also reduces the overall height to today's usual dimensions, so that installation problems are minimized. The length of the ventilation line determines the filling level when the internal combustion engine is cold. As a result, the system can be very easily adapted to different cooling system sizes by simply shortening or lengthening the ventilation line. Another advantage of the solution according to the invention can be seen in the fact that the lateral arrangement of the storage container and its connection to the condensate collector of the condenser provide the best possible functional reliability even in extreme driving and vehicle conditions, since it is always ensured that the condensate pump has sufficient liquid condensate is available on their suction side.

The subclaims describe advantageous developments of the invention.

Claim 2 prevents in particular that excessive steam entry into the expansion tank occurs when the condenser is fully charged with steam.

Figur 1

einen schematisierten Querschnitt durch ein teilgeflutetes Verdampfungskühlsystem nach der Erfindung;

Figur 2

das System nach Figur 1 bei der Erstbefüllung;

Figur 3 bis 6

das System gemäß Figur 1 bei verschiedenen Belastungszuständen.

The invention is explained in more detail below with the aid of a selected example. They represent:

Figure 1

a schematic cross section through a partially flooded evaporative cooling system according to the invention;

Figure 2

the system of Figure 1 at the initial filling;

Figure 3 to 6

the system of Figure 1 with different load conditions.

FIG. 1 shows an internal combustion engine 1 with an evaporative cooling system. It consists of the cold rooms 2 in the crankcase 3 and the cold rooms 4 in the Lindenkopf 5.

A flow line 6 leads from the cylinder head 5 to a steam separator 7.

The steam separator 7 is connected to the inlet connection 8 of a cross-flow condenser 9. Accordingly, the condenser 9 has a lateral inlet collecting box 10 and an outlet collecting box 11.

A connecting line 12 connects the two header boxes 10 and 11 at their lower end and leads via a return line 13 to a condensate feed pump 14. Before the condensate feed pump 14, the condensate line 15, which branches off from the steam separator 7, opens into the return line 13.

The condensate feed pump 14 conveys the liquid condensate via the line 16 into the lower part of the cold rooms 2 in the crankcase 3.

Laterally next to the condensate collection box 11, the reservoir 17 is arranged in one piece with it. At its lower end there is a passage opening 18 which connects the storage container 17 to the condensate collection box 11.

From its upper end 19, a ventilation line 21 branches off from the storage container 17 via a throttle point 20 and runs in the condensate collection box 11 to level I. The beginning of the ventilation line 21 in area 19 lies at a level II, which below the lower edge of the inlet connector 8 runs into the condenser 9.

The storage container 17 has a closure lid 22, which serves to fill the liquid condensate into the storage container. Furthermore, a connecting line 23 branches off from the storage container 17 to the surroundings. So that no dirt from the environment enters this connecting line 23, it has an appropriately designed opening and / or a molecular sieve at its free end. Furthermore, the free end of the connecting line 23 is arranged so that it can be cooled by the wind. This ensures that almost no coolant can escape even in the vapor state.

In Figure 2, the system of Figure 1 is shown after an initial filling with the coolant pump stopped. For the first filling, the closure cover 22 is opened and condensate is filled in until the condensate in the storage container 17 is above level II. The ventilation line 21 is then completely filled and the condenser 9 with its collecting boxes 10 and 11 is partially filled with condensate. Furthermore, the collecting line 12 and the condensate return line 13 are completely filled with condensate.

The condensate in lines 15 and 16 is at the same filling level as the condenser 9. The filling level in line 16 results from the fact that the condensate feed pump 14 does not completely block in the rest position, but rather only represents an increased flow resistance.

The arrangement according to FIG. 3 arises when the one filled according to FIG. 2 and through the closure cover 22 closed system, the coolant delivery pump 14 is switched on.

As a result, the condensate is pumped into the cold rooms 2 and 4 and into the flow line 6 to the steam separator 7. From the steam separator 7, it runs through the line 15 to the condensate return line 13 and thus to the suction side of the condensate feed pump 14. This process displaces the air in the previously unfilled spaces and can escape via the ventilation line 21 and the connecting line 23. As a result, the condensate level in the storage container 17 simultaneously drops to level I, which corresponds to the cold filling level when the internal combustion engine is stopped.

If the level falls below this level while the internal combustion engine is at a standstill, the operator must refill liquid condensate, i.e. coolant.

The state in FIG. 4 arises in the cooling system according to FIG. 2 when the internal combustion engine has been started and is operating in the part-load range, that is to say releases heat to the liquid condensate, so that first vapor bubbles can form in the cooling rooms 2 and 4. The running condensate feed pump ensures that the cooling chambers of the internal combustion engine are constantly supplied with liquid condensate. Excess condensate and steam which forms are mixed with liquid condensate are conveyed via the feed line 6 to the steam separator 7, where the steam separates from the liquid coolant. The steam then passes into the inlet port 8 of the condenser 9, where it can condense. As a result of the vapor formation, the condensate level in the condenser and its collecting tanks drops, so that the ventilation line 21 at its lower end no longer immersed in the condensate. As a result, the air displaced by the steam can escape from the condenser into the storage container 17 and from there via the connecting line 23 to the outside. Due to the increasing pressure in the system, the condensate level in the storage container 17 increases slightly above the filling level I.

At full load, the state shown in Figure 5 results. It differs in the load state according to FIG. 4 in that practically the entire condenser 9 is now filled with steam. As a result, the condensate level in the condenser 9 drops further, while it increases further in the reservoir 17. Because of the throttling point 20, little or no steam escapes through the ventilation line 21 into the storage container 17 and further into the connecting line 23. Because of the position of its end in the wind, it condenses there and can be sucked back into the storage container 17 when the engine load decreases .

The state of the decreasing load is shown in Figure 6. Decreasing engine load also means decreasing vapor bubble formation and increase in the liquid condensate. This also lowers the pressure in the cooling system, so that ambient air can be supplied via the connecting line 23, the reservoir 17, the throttle 20 and the ventilation line 21. This prevents negative pressure in the system. With this load condition, the condensate level in the storage tank drops below fill level I.

Claims (7)

1. A partially filled evaporation cooling system for internal combustion engines with a condenser and a reservoir for liquid condensate which is connected to the ambient environment via a connecting line,
   characterised in that the reservoir (17) is arranged on the side of the condenser (9) and forms an integral part of the condenser (9), that the reservoir (17) extends to the base of the neighbouring condensate collecting box (11), that a flow connection (18) is provided in this region between the reservoir (17) and the condensate collecting box (11) and that a ventilation line (21) extends from the upper region of the reservoir (17) into the neighbouring condensate collection box (11) up to the fill level I when the internal combustion engine (1) is cold.
2. A partially filled evaporation cooling system according to claim 1,
   characterised in that a restrictor (20) is arranged in the reservoir (17) at the start of the ventilation line (21).
3. A partially filled evaporation cooling system according to claim 1 or claim 2,
   characterised in that the reservoir (17) is sealed by a cover (22) with a pressure relief valve.
4. A partially filled evaporation cooling system according to any one of the preceding claims,
   characterised in that the condenser (9) is a crossflow condenser.
5. A partially filled evaporation cooling system according to one of the preceding claims,
   characterised in that the reservoir (17) has at least partially transparent outer walls.
6. A partially filled evaporation cooling system according to one of the preceding claims,
   characterised in that the start of the ventilation line (21) lies below the inlet (8) for vapour in the condenser (9).
7. A partially filled evaporation cooling system according to one of the preceding claims,
   characterised in that a level switch is built into the base of the reservoir.

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