WO2011099899A1

WO2011099899A1 - Method for filling a coolant system for an internal combustion engine

Info

Publication number: WO2011099899A1
Application number: PCT/SE2010/000031
Authority: WO
Inventors: Gunnar Theorell
Original assignee: Volvo Lastvagnar AB
Current assignee: Volvo Truck Corp
Priority date: 2010-02-11
Filing date: 2010-02-11
Publication date: 2011-08-18
Anticipated expiration: 2012-08-11

Abstract

The invention relates to a method for filling a coolant system 100 of an internal combustion engine 1 with liquid coolant, said coolant system comprising said internal combustion engine, a radiator 2, an expansion tank 3 and a heat exchanger 5, said method comprising the steps of filling the coolant system with liquid coolant, removing air pockets by creating an underpressure in said coolant system by pumping out liquid coolant from the expansion tank to a reservoir tank, compensating the removed air pockets and the pumped out liquid coolant from the expansion tank with liquid coolant.

Description

D E S C R I P T I O N

Method for filling a coolant system for an internal combustion engine

TECHNICAL FIELD

The invention relates to a method for filling a coolant system for an internal combustion engine according to the preamble of the independent claim.

BACKGROUND OF THE INVENTION

Ever since the fist motor vehicle was produced the means for cooling the motor has been a radiator filled with water and interconnected by means of rubbeF hoses. The heater for the passenger compartment is coupled to this cooling system with additional rubber hoses.

Most automobile cooling systems are simple to refill, however they require the technician's full attention until the cooling system is completely full and the air is bled out. EGR-coolers, retarder-coolers, gearbox-coolers may impair adequate venting during filling/refilling. Compartment elements in busses and

cooling/heating devices on trailers, semi-trailers or containers connectable to a truck may also be problematic to vent. Depending on the make and model of the automobile this procedure can take more or less time since the engine has to be warm for the thermostat to open up and thereby allowing trapped air in the coolers to escape through the bled off valve.

In some vehicles the procedure described above may still not be sufficient since some air may still be trapped in the cooling system.

The problem with leaving air in the vehicle cooling system is that a dangerous condition may arise if too much air remains. Air in the system can due to formation of steam expand when heated and blow the hoses or otherwise weaken the hoses thereby shortening the lifespan of the cooling system of the vehicle. Air in the cooling system may also cause the water to be trapped in the water channels of the engine, which may in the end may result in an overheated engine and total engine damage. Trapped air in the cooling system may be drawn with the flow of coolant and mixed with said coolant. Small air bubbles may be created which may take a substantial time to vent out from the cooling system. Refilling may most often be necessary, which in some cases have to be done after a vehicle has left the repairshop which is a problem.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved method and apparatus for filling/refilling a cooling system of an internal combustion engine with liquid coolant which reduces or eliminates the problems described above.

The objects are achieved by the features of the independent claims. The other claims and the description disclose advantageous embodiments of the invention. In a first aspect of the invention it is provided a method for filling a coolant system 100 of an internal combustion engine 1 with liquid coolant, said coolant system comprising said internal combustion engine, a radiator 2, an expansion tank 3 and a heat exchanger 5. Said method comprising the steps of: filling the coolant system with liquid coolant, removing air pockets by creating an underpressure in said coolant system by pumping out liquid coolant from the expansion tank to a reservoir tank, and compensating the removed air pockets and the pumped out liquid coolant from the expansion tank with liquid coolant.

An advantage with the present invention is that the method can easily be performed on any vehicle with small or no modifications to the existing cooling system for the internal combustion engine provided in said vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention together with the above-mentioned and other objects and advantages may best be understood from the following detailed description of the embodiment(s), but not restricted to the embodiments, wherein is shown schematically:

Fig. 1 depicts a cooling system for an internal combustion engine

connected to a first example embodiment of an apparatus for filling

/refilling said cooling system.

Fig 2 depicts a cooling system for an internal combustion engine

connected to a second example embodiment of an apparatus for filling /refilling said cooling system.

Fig. 3 depicts a cooling system for an internal combustion engine

connected to a third example embodiment of an apparatus for filling /refilling said cooling system.

Fig. 4 depicts a cooling system for an internal combustion engine

connected to a fourth example embodiment of an apparatus for filling

/refilling said cooling system.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In the drawings, equal or similar elements are referred to by equal reference numerals. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. Moreover, the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention.

Fig. 1 depicts schematically a cooling system 100 for an internal combustion engine 1 connectable to a first example embodiment of an apparatus 50 for filling/refilling said cooling system. Said cooling system 100 comprises said internal combustion engine 1 , a radiator 2, an expansion tank 3, a compartment heat exchanger 5, a filling pipe 6, bleeding pipes 7. The radiator 2 is connected to the internal combustion engine 1 via pressure hose 9 and a suction hose 8.

When a thermostat 27 is open said liquid coolant is circulated from the thermostat 27 to the radiator 2 via the pressure hose 9. From said radiator 2 said liquid coolant is then circulated to the pump 26 and further to the internal combustion engine 1 via the suction hose 8. From the internal combustion engine 1 said liquid coolant is returned to the thermostat 27. When a thermostat 27 is closed said liquid coolant is circulated from the

thermostat 27 to a bypass pipe 37. From said bypass pipe 37 said liquid coolant is then circulated to the pump 26 and further to the internal combustion engine 1. From the internal combustion engine 1 said liquid coolant is returned to the thermostat 27.

The thermostat 27 may also be in any position between fully closed and fully opened.

The compartment heat exchanger 5 is connected to the top of the internal combustion engine 1 via a first pipe 31 and to the suction hose via a second pipe 33. Liquid coolant is in this configuration passing the compartment heat exchanger 5 only when the thermostat 27 is open.

At the bottom of the radiator 2 it may be provided a drain plug for draining the radiator and internal combustion engine from liquid coolant.

Bleeding pipes 7 are arranged on top of the internal combustion engine 1 and on top of the radiator 2 connected to the expansion tank. The expansion tank 3 may further be connected to the bottom of the radiator 2 or the inlet (suction side) of the liquid coolant pump via a filling pipe 6. Said expansion tank is provided with a tight-fitting cap 22.

Said apparatus 50 for filling/refilling said cooling system 100 comprises a pump 4, a first pump pipe 21 , a second pump pipe 20 and a liquid vessel 10. The pump is connectable to the expansion tank 3 via said first pump pipe 21. The first pump pipe 21 may be inserted through the tight sealed cap 22 into said expansion tank 3. The second pump pipe 20 may be connectable to the liquid vessel 10.

The cooling system 100 may be filled with liquid coolant by providing said liquid coolant into the expansion tank 3. Liquid coolant is transported from the expansion tank 3 out into the cooling system 100 via filling pipe 6. Wile filling up the cooling system 100 with water said tight-fitting cap 22 may be removed. Enclosed air in the cooling system may be pressed out by the liquid coolant and may be led to the expansion tank 3 via the bleeding pipes 7 from the internal combustion engine 1 and the radiator 2. When the cooling system is filled with liquid coolant, some air pockets may still be left in the internal combustion engine 1 , the radiator 2, the compartment heat exchanger 5, EGR-coolers, retarder-cooler, gearbox-cooler, final drive-cooler etc. Underpressure (below atmospheric pressure) may be created by pumping our liquid coolant from the expansion tank 3 when the tight sealing cap 22 is attached to said expansion tank 3. The liquid coolant may be pumped out from the expansion tank 3 by the pump 4 delivering said pumped out liquid coolant to the liquid vessel 10 via the second pump pipe 20. When liquid coolant is pumped out from the expansion tank 3, air pockets may be removed from the internal combustion engine 1 , the radiator 2 and the compartment heat exchanger 5. The removed air from said regions is replaced with liquid coolant which is provided into the cooling system through the expansion tank. The provision of liquid coolant at this stage may be performed by reversing the pump 4 and pumping liquid coolant from the liquid vessel 0 via the second pump pipe 20 to the pump 4 and then further to the expansion tank via the first pump pipe 21. Liquid coolant may also at this stage be provided to the expansion tank 3 by removing the tight sealing cap 22 and pouring water into the expansion tank 3 in a traditional manner.

Figure 2 illustrates an alternative example embodiment of an apparatus 50 for filling/refilling said cooling system 100. Said apparatus 50 comprises in addition to the apparatus illustrated in figure 1 a bypass pump pipe 39 connected between the bottom of the liquid vessel 10 and the first pump pipe 21 at a position above the tight seal cap 22. Said bypass pump pipe 39 comprises a valve 29. When starting to pump out liquid coolant from the expansion tank said valve 29 is open. While said pump 4 pumps out liquid coolant from the expansion tank said valve is successively closed, i.e., the operation of valve 29 may start from an open position when said pump 4 starts to pump and the closing event takes a predetermined time. With this procedure one can accomplish a slow venting with normal speed of the pump 4. Air is transported in the liquid coolant system to the expansion tank before the liquid coolant hoses are squeezed together because of the

underpressure in the liquid coolant system. Another reason for using this procedure is to prohibit an overheated pump 4. Opening of valve 29 and slow closing may be repeated until there is no air in the liquid coolant system.

Figure 3 illustrates yet an alternative example embodiment of an apparatus 50 for filling/refilling said cooling system 100. Said apparatus 50 comprises in addition to the apparatus illustrated in figure 1 an expansion tank bleed pipe 41 , a second pump 12, a pressure pipe 24, a suction pipe 23, a first valve 16, a second valve 15, a third valve 14, drain pipe 43.

The expansion tank bleed pipe 41 is connectable between the expansion tank 3 through its tight seal cap 22 and the second pump pipe 20. Said tank bleed pipe 41 comprises a valve 16. As can be seen from figure 3 the first pump pipe 21 is extending all the way the bottom of the expansion tank 3 while the expansion tank bleed pipe 41 is only extending a short distance into the expansion tank 3. The reason for this difference is because the first pump pipe 21 is supposed to remove liquid from the expansion tank 3, while the expansion tank bleed pipe 41 is supposed to bleed air from the expansion tank 3.

The second pump pipe 20 is connectable to the liquid vessel 10. The second pump 12 is connectable to the bottom of the radiator 2 to a radiator drain valve 13 via the pressure pipe 24. Said pressure pipe comprises a second valve 15. The suction pipe 23 is connectable between the pump 2 and the liquid in the vessel 10. The drain pipe 43 is connected to the pressure pipe 24 and an open end of said drain pipe 43 is directed to the vessel 10. Said drain pipe 43 comprises a third valve 14. When draining the cooling system 100 of liquid coolant, pump 4 and the second pump 12 is shut off with the drain valve 13, third valve 14 and the valve 16 in an open position. Instead of opening valve 16 the tight seal cap 22 may be removed. When filling the cooling system 100 the second pump 12 is on and pump 4 is off The valve 16 and the second valve 5 are open and the third valve 14 is closed.

When starting to pump out liquid coolant from the expansion tank 3, pump 4 is running and the second pump 12 is off. The third valve 14 and the valve 16 are closed. The second valve 15 may initially be open and is successively closed. In an alternative embodiment said valve 15 is closed when the pump 4 is starting to pump out liquid coolant from the expansion tank 3. The pump 4 and 12 may comprise a non-return valve. Figure 4 illustrates still another example embodiment of an apparatus 50 for filling/refilling said cooling system 100. Said apparatus 50 comprises in addition to the apparatus illustrated in figure 1 a non return valve 19, an expansion tank suction pipe 21 , a first three way valve 18, a second three way valve 25, a pressure pipe 24, a suction pipe 23, a third valve 14, and a drain pipe 43.

Said non return valve 19 is provided in the second pump pipe 20. The expansion tank suction pipe 21 is provided between the expansion tank 3 and the second three way valve 25. The second pump pipe 20 is connectable to the expansion tank 3 through the tight seal cap 22 and directed to the vessel 10. Said second pump pipe 20 is also connected to the first three way valve 8 via a three way valve pipe 55. The pump 4 is connectable to the drain valve 13 in the bottom of the radiator 2 via the pressure pipe 24 comprising the first three way valve 18. Said pump 4 is also connectable to the vessel 0 via the suction pipe 23 which comprises the second three way valve 25. The drain pipe 43 is connected between the drain valve 13 and the first three way valve 8 to said pressure pipe 24. The other free end of said drain pipe 43 is directed to the vessel 10. Said drain pipe 43 comprises a third valve 14. When draining the cooling system 100 said tight sealed cap 22 may be loose or alternatively there may be a bleeding screw provided on for example said cap for allowing air to be sucked into the cooling system when the third valve 14 and the drain valve 13 are opened up. While draining the system said pump 4 is off.

When filling the cooling system 100 the pump 4 is on and the third valve 14 is closed. The second three way valve 25 is in an open position between suction pipe 21 and the pump 4, and closed between the pump 4 and expansion tank suction pipe 21. The first three way valve 18 is in an open position between the pressure pipe 24 and the drain valve 13, and closed between the pressure pipe 24 and the pump pipe 20. The drain valve 13 is in an open position when filling the cooling system 100. .

When starting to pump out liquid coolant from the expansion tank 3 said pump 4 is on and the second three way valve 25 is open between the pump 4 and the suction pipe 23, and closed between the pump 4 and the suction pipe 23. The first three way valve 18 is open between the pressure pipe 24 and the pump pipe 20, and closed between the pressure pipe 24 and the drain valve 13. The drain valve 13 may be open to valve 17 during this phase since the first three way valve 18is closed between the pump 4 and said drain valve 13. The third valve 14 is initially opened and is successively closed while the liquid is started to be pumped out from the expansion tank 3.

Said pump 4 may be an air pressure driven or electrical membrane pump, an impeller pump or similar pumps available on the market for pumping liquid.

Claims

C L A I M S

A method for filling a coolant system 100 of an internal combustion engine 1 with liquid coolant, said coolant system comprising said internal combustion engine, a radiator 2, an expansion tank 3 and a heat exchanger 5, said method comprising the steps of:

a. filling the coolant system with liquid coolant, characterized in that said method further comprising the steps of:

b. removing air pockets by creating an underpressure in said coolant system by pumping out liquid coolant from the expansion tank to a reservoir tank,

c. compensating the removed air pockets and the pumped out liquid coolant from the expansion tank with liquid coolant.

The method according to claim 1 , wherein said heat exchanger is located at a higher position than said expansion tank.

The method according to claim , wherein said filling is made by providing liquid coolant from the bottom of the liquid coolant system.

The method according to claim 1 , wherein the same pump is used for filling liquid coolant into the coolant system and removing liquid coolant from the expansion tank.

The method according to claim 4, wherein liquid coolant is provided from the reservoir tank to the expansion tank when filling the system.