SE1451485A1

SE1451485A1 - An expansion tank of a motor vehicle engine cooling system

Info

Publication number: SE1451485A1
Application number: SE1451485A
Authority: SE
Inventors: Kardos Zoltan; Strömberg Andreas
Original assignee: Scania Cv Ab
Priority date: 2014-12-05
Filing date: 2014-12-05
Publication date: 2016-06-06
Also published as: WO2016089278A1; SE541173C2; DE112015004898T5

Abstract

An expansion tank of a motor vehicle engine cooling system has a first opening 24 into an upper inner space (11) of the tank intended to be above a maximum level of coolant inside the tank and configured to be connected to a source (12) of compressed gas. A closing cap (16) is configured to close an opening (14) for filling the tank with coolant. A valve means has a member (23) configured to spring-loadly urge a valve body (22) to close said first opening (24) upon removal of the closing cap (16) from the filling opening (14). The closing cap (16) has a striking member (26) configured to hit and mechanically move the valve body (22) against the action of said spring load to open said first opening (24) to connect the inner space (11) to the source (12) of compressed gas upon movement of the closing cap (16) to a position closing the filling opening (14).(Fig 2).

Description

1 AN EXPANSION TANK OF A MOTOR VEHICLE ENGINE COOLING SYSTEM TECHINCAL FIELD OF THE INVENTION The present invention relates to an expansion tank of a motor vehicle engine cooling system comprising a first opening into an upper inner space of the tank intended to be above a maximum level of coolant inside the tank and configured to be connected to a source of compressed gas, valve means transferrable between positions of closing and opening a connectionof said source to said inner space through said first opening, • a closing cap configured to close a filling opening into said inner space of the tank and removable from that opening for filling the tank with coolant, and control means configured to control said valve means to open or close said connection.

The invention is not restricted to such expansion tanks of engine cooling systems of any particular type of motor vehicle, although the invention is particularly applicable to utility vehicles, especially wheeled utility vehicles, such as trucks or lorries and bus- es.

Actively pressurizing a motor vehicle engine cooling system by connecting said inner space of the expansion tank to a source of compressed gas, normally compressed air, is made for being able to respond to sudden quick fluctuations of pressure levels of 2 the cooling system, for example when a water retarder is used for braking the motor vehicle. It is for an expansion tank with such active pressurizing important that the supply of pressurized gas to said inner space of the expansion tank is interrupted when said closing cap is removed from the filling opening for filling or refilling the tank with coolant, since there is otherwise a risk that the gas flow out through said filling opening draws hot coolant out of this opening and spray it onto a person filling the expansion tank with more coolant.

BACKGROUND ART Known expansion tanks of the type defined in the introduction have a valve means in the form of a solenoid valve which is con- trolled to close either by a voltage applied thereto by sensing if a removal of said closing cap is started or by making the solenoid valve dead and automatically disconnect the pressurized gas when the ignition of the motor vehicle is switched off.

US 2011/0308484 Al discloses an expansion tank of a motor vehicle engine cooling system functioning in a similar way by having the tank pressurized by turbo charged air, so that the supply of compressed air to said inner space of the tank automatically disappears when the engine is switched off.

Problems are adhered to known expansion tanks in motor vehicle engine cooling systems having a pressurized inner space above the coolant. To use a solenoid valve for switch off an active pressure is both expensive and complicated, and the proper function of the solenoid valve has to be diagnosed. Furthermore 3 would it be desired to refill the expansion tank with coolant when the motor vehicle engine is idling and the expansion tank is pressurized air flowing out of the filling opening will bring coolant to also be sprayed out of this opening.

SUMMARY OF THE INVENTION The object of the present invention is to provide an expansion tank of the type defined in the introduction being improved in at 10 least some aspect with respect to such expansion tanks already known.

This object is according to the invention obtained by providing such an expansion tank with the features listed in the character- izing part of appended patent claim 1.

By providing a valve means in the form of a mechanical valve and including said control means in said closing cap for mechanically move the valve body of the valve means leakage or spray- ing of coolant out through the filling opening may be completely avoided irrespectively of the operation of the engine of the motor vehicle or the function of the electric system of the vehicle or any sensors or voltage controlling a solenoid valve. It is advantageous to have the entire control of the supply of compressed gas to said inner space of the expansion tank integrated in the ex- pansion tank without any remote activation of valve means making a proper control of the pressurizing of the expansion tank simple and obtainable at a low cost. 4 According to an embodiment of the invention said closing cap is provided with a sealing member configured to bear against portions of the tank so as to sealingly close the tank with respect to the exterior when the closing cap in said position closing said fill- ing opening. Such a sealing member ensures that compressed gas from said source of compressed gas entering said inner space through said first opening will stay inside the expansion tank when the closing cap is closing the filling opening of the expansion tank.

According to another embodiment of the invention said sealing member is configured to enter into a state of sealingly closing the tank with respect to the exterior upon movement of said closing cap with respect to a body of the tank towards said position clos- ing said filling opening before said striking member reaches and hits said valve body and to remain in said state of sealingly closing upon removal of said closing cap from said closing position past a position of the closing cap in which said striking member has left said valve body and allowed it to close said first opening by said spring load. Such an arrangement of the sealing member ensures that under no circumstances compressed gas from the source of compressed gas may escape from the expansion tank through the filling opening when the source of compressed gas is connected to said inner space of the expansion tank. When the closing cap is removed from the closing position for filling the expansion tank with coolant said sealing member will seal the expansion tank with respect to the exterior at least until the valve means has reliably closed the connection of said source to the expansion tank, and when the closing cap is applied to the ex- pansion tank again and moved towards the closing position the sealing member will start to seal the expansion tank with respect to the exterior before said valve means open said connection again.

According to another embodiment of the invention said filling opening is formed by a short tube-like member of the tank connecting to said inner space, and said closing cap has a male part configured to be introduced into said tube-like member for reaching said position closing said filling opening by the closing cap.

This design of the filling opening and the closing cap facilitates achievement of the behaviour desired of said control means and valve means when operating the closing cap for refilling the expansion tank with coolant.

According to another embodiment of the invention said sealing member is arranged around said male part to seal by bearing against an internal wall of said tube-like member. A reliable sealing may easily be obtained in this way. It is then advantageous to have a sealing member in the form of an 0-ring, which will then be sealed by being slightly deformed by having a larger cross- section than the distance separating the male part and said internal wall.

According to another embodiment of the invention said male part of the closing cap has an end portion configured to push said valve body to open said first opening and hold it open against the action of said spring load in said closing position of said closing cap. Reliable control of said valve means with said closing cap close to said closing position may be obtained in this way. 6 According to another embodiment of the invention said first opening opens into said tube-like member of the tank, said valve body has a projecting portion configured to project through said first opening into said tube-like member in the closing position of the valve body, said end portion of said male part of the closing cap is configured to hit said projecting portion and push this in a direction out of said tube-like member against the action of said spring load to open said first opening for connecting said inner space to said source of compressed gas in said closing position of the closing cap. Said end portion of said male member of the closing cap is then advantageously formed by an outer inclined shoulder on said male part of the closing cap for smooth control of said valve means without any real risk of malfunction.

According to another embodiment of the invention said valve body has regions facing away from said first opening and configured to be acted upon by compressed gas from said source to assist said spring load member to urge the valve body towards a position of closing said first opening. Thus, even if compressed gas from said source arrives to said valve means when this has to close the connection of said source to the expansion tank this compressed air will act to close the valve means.

According to another embodiment of the invention said closing cap is provided with a thread configured to enter into engage- ment with a complementary thread of said tube-like member for attaching the closing cap to a body of the expansion tank for closing said filling opening. The closing cap is then preferably provided with an inner thread to enter into engagement with an outer thread of the tube-like member. 7 According to another embodiment of the invention said inner space of the tank is through the first opening configured to be connected to a source of compressed air. A source of corn- pressed air is present in most motor vehicles for providing other parts of the motor vehicle, such as wheel suspension and brakes, with compressed air.

The invention also relates to a motor vehicle engine cooling sys- tern provided with an expansion tank according to the invention and a motor vehicle provided with an engine cooling system with an expansion tank according to the invention.

Other advantageous features as well as advantages of the pre- sent invention appear from the description following below.

BREIF DESCRIPTION OF THE DRAWINGS With reference to the appended drawings, below follows a specif- ic description of embodiments of the invention cited as examples.

In the drawings: Fig 1is a very schematic view showing the general con- struction of a motor vehicle cooling system provided with an expansion tank according to the invention, Fig 2is an enlarged view showing a section of the part of an expansion tank according to the invention where filling 8 of coolant into the tank is intended to take place with the expansion tank closed by a closing cap, Fig 3is a view similar to that of Fig 2 showing how a re- moval of said closing cap has started for filling the ex- pansion tank with coolant, and Fig 4is a view similar to Fig 2 of an expansion tank accord- ing to a second embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION The general construction of an engine cooling system 1 of a mo- tor vehicle 2 which may be provided with an expansion tank according to the present invention is by way of example illustrated in Fig 1. A radiator 3, a radiator cooling fan 4, a water pump 5, a thermostat 6 and a coolant expansion tank 7 of the motor vehicle engine cooling system are shown. Coolant are circulated in the hoses 8 shown for cooling an engine of the motor vehicle. The expansion tank 7 is provided for allowing the coolant to expand within the system when the temperature thereof raises.

Reference is now also made to Fig 2. The expansion tank is filled with coolant 9 not more than to a maximum level 10 for having an upper inner space 11 filled with air above the coolant level. The expansion tank is pressurized by having said inner space 11 connected to a source 12 of compressed air through a first opening 24, so that an overpressure of for example 1 bar will prevail in said inner space 11. 9 The expansion tank has a tube-like member 13 providing a filling opening 14 into the inner space 11 and connected to a body 15 of the expansion tank 7. A closing cap 16 is configured to close said filling opening 14 in a closing position as shown in Fig 2.

The tube-like member 13 is provided with an outer thread 17 and the closing cap 16 with an inner thread 18 for allowing the closing cap 16 to be held in the closing position shown in Fig 2 and removed therefrom by rotation thereof.

The closing cap 16 is provided with a male part 19 to be introduced into the tube-like member 13. A sealing member in the form of an 0-ring 20 is arranged around the male part 19 to seal said inner space 11 of the expansion tank with respect to the ex- tenor by bearing against an internal wall 21 of the tube-like member 13.

The expansion tank also comprises a valve means having a valve body 22 and a member in the form of a spring 23 configured to spring-badly urge the valve body to close said first opening 24 as shown in Fig 3. The first opening 24 opens into the tube-like member 13 of the tank, and the valve body has a projecting portion 25 configured to project into the tube-like member 13. An end portion of the male part 19 of the closing cap 16 is formed by an outer inclined annular shoulder 26. This annular shoulder 26 will press said projecting portion 25 of the valve body 22 in the direction out of the tube-like member through the first opening 24 against the action of the spring 23 and also the action of compressed air from said source 12 acting upon regions 27 of the valve body facing away from the first opening 24 for keeping the inner space 11 of the expansion tank connected to the source 12 of compressed air and by that pressurize it when the closing cap 16 is in the closing position shown in Fig 2.

Filling of the expansion tank 7 with coolant is made in the follow- ing way. When the closing cap 16 is removed from the closing position shown in Fig 2 by turning it the annular shoulder 26 of the male part 19 leaves the contact with the valve body 22, which is then pressed by the action of said spring 23 assisted by the compressed air from the source 12 to close the first opening 24 as shown in Fig 3. The 0-ring 20 is still sealing the inner space 11 of the expansion tank with respect to the exterior. The closing cap 16 may then securely be totally removed from the expansion tank with the source of compressed air disconnected from the expansion tank by the valve means in the first opening 24. Cool- ant may then be filled into the expansion tank and the male part 19 of the closing cap 16 introduced into the tube-like member 13 and the closing cap turned for moving it towards the position shown in Fig 2. The 0-ring 20 will during this movement enter into sealing contact with the internal wall 21 of the tube-like member 13 before the annular shoulder 26 reaches the portion 25 of the valve body projecting into the tube-like member, whereupon this will happen and the shoulder 26 will push the projecting portion 25 against the action of the spring 23 in the direction out of the tube-like member for opening the connection of the source 12 of compressed air to the inner space 11 of the expansion tank through the first opening 24.

An expansion tank according to a second embodiment of the in- vention is schematically illustrated in Fig 4, and this differs from 11 the embodiment shown in Fig 2 and 3 mainly by the fact that said first opening 30 into the inner space 11 of the expansion tank is located in a wall 31 of the tank body 15 close to the tube-like member 13 providing the filling opening 14. The body 32 of a valve for closing said first opening 30 is spring-loaded by a spring 33 towards the closing position, and end portions 34 of a male part 35 of the closing cap 36 will hit the valve body 32 and move it against the action of the spring 33 to open said first opening 30 in the closing position of the closing cap 36 as seen in Fig 4. When the male part 35 of the closing cap 36 is moved in the direction out of the tube-like member 13 the spring 33 will automatically press the valve body 32 in a position closing the first opening 30 and by that disconnecting the source of compressed air from the expansion tank.

The invention is of course in no way restricted to the embodiments described above, since many possibilities to modifications thereof are likely to be obvious to one skilled in the art without having to deviate from the scope of invention defined in the appended claims.

The closing cap may of course be connected to the expansion vessel by other means than a screw connection, such as by a bayonet coupling as indicated in Fig 4. 12

Claims

Claims 1. An expansion tank (7) of a motor vehicle engine cooling system comprising • a first opening (24, 30) into an upper inner space (11) of the tank intended to be above a maximum level (10) of coolant inside the tank and configured to be connected to a source (12) of compressed gas,

1. valve means transferrable between positions of closing and opening a connection of said source (12) to said inner space (11) through said first opening, 2. a closing cap (16, 36) configured to close a filling opening (14) into said inner space (11) of the tank and removable from that opening for filling the tank with coolant, and 3. control means configured to control said valve means to open or close said connection, characterized in that said valve means comprises a mechanical valve with a valve body (22, 32) arranged in the region of said first opening (24, 30), that said control means is included in said closing cap (16, 36), that said valve means has a member (23, 33) configured to spring-badly urge said valve body to close said first opening upon removal of the closing cap (16, 36) from said filling opening (14), and that said control means comprises a striking member (26, 34) of said closing cap configured to hit and mechanically move said valve body (22, 32) against the action of said spring-load to open said first opening (24, 30) to connect said inner space (11) to said source (12) of com- 13 pressed gas upon movement of said closing cap to a position closing said filling opening (14).

2. An expansion tank according to claim 1, characterized in that said closing cap (16, 36) is provided with a sealing member (20) configured to bear against portions of the tank so as to sealingly close the tank with respect to the exterior when the closing cap (16, 36) is in said position closing said filling opening.

3. An expansion tank according to claim 2, characterized in that said sealing member (20) is configured to enter into a state of sealingly closing the tank with respect to the exterior upon movement of said closing cap (16, 36) with respect to a body (15) of the tank towards said position closing said filling opening before said striking member (26, 34) reaches and hits said valve body (22, 32) and to remain in said state of sealingly closing upon removal of said closing cap from said closing position past a position of the closing cap (16, 36) in which said striking member (26, 34) has left said valve body (22, 32) and allowed it to close said first opening (24, 30) by said spring-load.

4. An expansion tank according to any of the preceding claims, characterized in that said filling opening (14) is formed by a short tube-like member (13) of the tank connecting to said inner space (11), and that said closing cap (16, 36) has a male part (19, 35) configured to be introduced into said tubelike member for reaching said position closing said filling opening by the closing cap. 14

5. An expansion tank according to claim 4, characterized in that said sealing member (20) is arranged around said male part (19, 35) to seal by bearing against an internal wall (21) of said tube-like member (13).

6. An expansion tank according to claim 5, characterized in that said sealing member is an 0-ring (20).

7. An expansion tank according to claim 4, characterized in that said male part (19, 35) of the closing cap has an end portion (26, 34) configured to push said valve body to open said first opening (24, 30) and hold it open against the action of said spring load in said closing position of said closing cap (16, 36).

8. An expansion tank according to claim 7, characterized in that said first opening (24) opens into said tube-like member (13) of the tank, that said valve body (22) has a projecting portion configured to project through said first opening into said tube-like member in the closing position of the valve body, and that said end portion (26) of said male part (19) of the closing cap is configured to hit said projecting portion (25) and push this in a direction out of said tube-like member (13) against the action of said spring load to open said first opening (24) for connecting said inner space (11) to said source (12) of compressed gas in said closing position of the closing cap (16).

9. An expansion tank according to claim 8, characterized in that said end portion of said male part (19) of the closing cap (16) is formed by an outer inclined shoulder (26) on said male part (19) of the closing cap.

10. An expansion tank according to claim 8 or 9, characterized in that said valve body (22) has regions (27) facing away from said first opening (24) and configured to be acted upon by compressed gas from said source (12) to assist said spring load member (23) to urge the valve body (22) towards a position of closing said first opening (24).

11. An expansion tank according to any of claims 4-10, characterized in that said closing cap (16) is provided with a thread (18) configured to enter into engagement with a complementary thread (17) of said tube-like member (13) for attaching the closing cap (16) to a body of the expansion tank for closing said filling opening (14).

12. An expansion tank according to claim 11, characterized in that the closing cap (16) is provided with an inner thread (18) to enter into engagement with an outer thread (17) on the tube-like member (13).

13. An expansion tank according to any of the preceding claims, characterized in that said inner space (11) of the tank is through the first opening (24, 30) configured to be connected to a source (12) of compressed air. 16 L A motor vehicle engine cooling system, characterized in it has an expansion tank (7) according to any of claims 1- . A motor vehicle, especially a wheeled motor vehicle, cha terized in that it has an engine cooling system with an pansion tank (7) according to any of claims 1-13.