Expansion tank for the coolant of fluid-cooled internal combustion engines

Abstract

An expansion tank for the coolant of a fluid-cooled machine, in particular a machine-operated water-borne vehicle or a truck includes at least one inlet connection arranged in the lower region of the expansion tank, and an outlet connection for connection of the expansion tank to a cooling circuit of an internal combustion engine. A filler nozzle is arranged in the upper region of the expansion tank and has a lower edge spaced from an expansion tank cover to limit the fill level. At least one valve seals the filler nozzle for filling the expansion tank and protects the cooling system from over-pressure. Furthermore, an air volume in the expansion tank, which remains on maximum filling of the expansion tank with coolant, can be adjusted.

Claims

1. An expansion tank for coolant of a fluid-cooled machine, comprising: an outer wall and an expansion tank cover; at least one inlet connection arranged in a lower region of the expansion tank, and an outlet connection for connection of the expansion tank to a cooling circuit of the fluid-cooled machine; a filler nozzle for filling the expansion tank arranged in the upper region of the expansion tank, the filler nozzle having a lower edge spaced from the expansion tank cover to limit the fill level to a maximum fill level; at least one valve sealing the filler nozzle and protecting the cooling system from over-pressure; and at least one air chamber with an air inlet opening and a closing device, wherein the air inlet opening can be opened and closed by the closing device to adjust an air volume in an interior of the expansion tank that remains when the tank is filled to the maximum level and that is usable for producing a pre-pressure, wherein the air inlet opening fluidically connects the at least one air chamber to only an interior of the expansion tank when the air inlet opening is opened, whereby the at least one air chamber is not directly connected to an exterior of the expansion tank when the air inlet opening is opened.

2. The expansion tank according to claim 1, wherein the fluid-cooled machine is a fluid-cooled internal combustion engine of a vehicle.

3. The expansion tank according to claim 1, wherein the air inlet opening is disposed above the lower edge of the filler nozzle.

4. The expansion tank according to claim 1, wherein the at least one air chamber is arranged at least one of: on an inside of the expansion tank in the upper region of the expansion tank; and outside the expansion tank and connected to the upper region of the expansion tank via a fluid line.

5. The expansion tank according to claim 1, wherein the at least one air chamber includes two air chambers.

6. The expansion tank according to claim 5, wherein inner volumes of the two air chambers are the same size.

7. The expansion tank according to claim 5, wherein inner volumes of the two air chambers are different sizes.

8. The expansion tank according to claim 1, wherein the closing device is one of a screw plug, a closing lid, and a flap.

9. The expansion tank according to claim 1, wherein the closing device is one of a non-return valve, a spring-loaded valve, and a pneumatically or electrically controlled valve.

10. The expansion tank according to claim 1, wherein the air inlet opening of the at least one air chamber is arranged such that in operation of the expansion tank, coolant is prevented from entering the at least one air chamber when the air inlet opening is opened.

11. A truck or ship with a fluid-cooled machine and an expansion tank according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The preferred embodiments and features of the invention described above may be combined arbitrarily. Further details and advantages of the invention are described below with reference to the enclosed drawings. In the drawings:

(2) FIG. 1 is a diagrammatic view of an expansion tank known from the prior art,

(3) FIG. 2 is a diagrammatic view of an expansion tank according to an embodiment of the invention, and

(4) FIG. 3 is a diagrammatic view of an expansion tank according to a further embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) The same or functionally equivalent elements carry the same reference numerals in all figures. To avoid repetition, with reference to the function of elements 1 to 5 and 9 of FIGS. 2 and 3, reference is made to the relevant description of FIG. 1.

(6) The special feature of the expansion tanks 20 and 30 shown in FIGS. 2 and 3 lies in the two air pockets 6, 6 provided additionally, each of which has an assigned closing element 7, 7 with which each air pocket 6, 6 can either be opened or closed. In an open state, the air pocket 6, 6 is in fluidic connection with the basic gas volume of the expansion tank 20 or 30. Each of the air pockets 6, 6 has an air inlet opening 8, 8 which lies above the lower edge 9 of the filler nozzle 4 in the upper inner region of the expansion tank and can be closed with the closing element 7, 7. When the air inlet opening 8, 8 is in the open state, the respective air pocket is fluidically connected to the upper interior of the expansion tank, so that air can flow into the opened air pocket 6, 6 from the basic volume. In a structurally simple embodiment, the closing element 7, 7 is configured as a screw plug.

(7) The embodiment shown in FIG. 3 shows the supply connection 11 (not shown in FIGS. 1 and 2) arranged in the lower region of the expansion tank 10 and protruding into this, and the outlet connection 12 for connection of the expansion tank 10 to the cooling circuit of the internal combustion engine. The expansion tank 30 furthermore comprisesas already explained abovea filler nozzle 4 which is arranged in the upper region of the expansion tank 30 and has a lower edge 9 spaced from the cover of the expansion tank 14 to limit the fill level, and a valve 5 sealing the filler nozzle 4, which serves to protect the cooling system against over-pressure and via which the expansion tank 30 can be filled with the coolant 1. An overflow pipe 16 is arranged below the valve 5, via which fluid can flow out when the valve 5 is opened. Furthermore, in the expansion tank 30, a connection 15 is provided for a level sensor for fill level measurement and a connection 17 for pre-pressure measurement.

(8) To improve the dissipation of air bubbles, a baffle element is provided in the lower inner region of the expansion tank 30, which is preferably formed as a partition 13. Such a partition has the function of changing the flow direction of the fluid and extending the flow path of the coolant in the expansion tank in order to dissipate as much air as possible.

(9) As already explained above, two air chambers 6, 6 are provided below the expansion tank cover 14 in the upper region of the expansion tank 30 on the side opposite the valve 4, and the air inlet opening 8, 8 of these chambers 6, 6 can be closed or opened with a screw plug 7, 7. The screw head here protrudes from the top of the expansion tank 30 and can be actuated from the outside. By adjusting the screw plugs 7, 7, the air chambers 6, 6 can be opened in order to vary the volume available inside the expansion tank for the air in the expansion tank and adapt this optimally to the respective coolant circuit.

(10) As an example, a procedure is described below for adapting the expansion tank to a cooling circuit by adjusting the air volume available, e.g., during installation of the expansion tank 6, 6 in the vehicle. Here first the air volume required is determined depending on the coolant expansion, the pre-pressure required and the opening pressure of the valve 5. The air volume required is set in the expansion tank by the base volume, i.e., all air pockets 6, 6 are closed, or where applicable by the base volume and the specified number of required air pockets 6, 6 if a larger air volume has been determined.

(11) The required number of air pockets 6, 6 is then opened, i.e., fluidically connected to the base volume, by means of the screw plug 7, 7. The cooling circuit is then filled with coolant to the lower edge 9 of the filler nozzle 4 for the first fill. The engine is then operated until the cooling circuit is fully purged in order to remove any remaining air bubbles from the cooling circuit. Then when the engine is cold, coolant is added again up to the lower edge 9 of the filler nozzle 4. Then the pre-pressure is measured via the connection 17 while the engine is in real operation, in order to test the function of the expansion tank 30. If too high a pre-pressure is set or if the valve 5 blows off too early, a further air pocket 6, 6 can be opened. If the pre-pressure is too low, an air pocket 6, 6 may be closed. This offers the advantage that the expansion tank 30 can be adapted to the particular cooling circuit merely by changing the volume available for the air in the expansion tank.

(12) Although the invention has been described with reference to specific exemplary embodiments, it is evident to the person skilled in the art that various changes may be made and equivalents used as replacement, without leaving the scope of the invention. In addition, many modifications can be made without leaving the associated area. Consequently, the invention is not limited to the exemplary embodiments disclosed, but comprises all exemplary embodiments which fall in the region of the attached claims. In particular, the invention also claims protection for the subject and features of the subclaims, irrespective of the claims to which reference is made.

LIST OF REFERENCE NUMERALS

(13) 1 Coolant 2 Air volume 3 Outer wall 4 Filler nozzle 5 Valve 6 Air chamber 7 Closing device 8 Air inlet opening 9 Lower edge 10 Expansion tank 11 Inlet connection 12 Outlet connection 13 Separating wall 14 Expansion tank cover 15 Connection for level sensor 16 Overflow pipe 17 Connection for pre-pressure measurement 20 Expansion tank 30 Expansion tank