SE1051363A1 - Cooling system in a vehicle - Google Patents

Abstract

A cooling system with a circulating coolant for cooling a combustion engine in a vehicle (1) includes a first radiator (13), a first line circuit (14, 15, 16) which leads coolant from the first radiator (13) to the engine (2); a second line circuit (17, 18) which leads coolant from the engine (2) to the first radiator (13); a second radiator (20) upstream of the first radiator (13) in air flow through radiators; a third line circuit (21, 22, 24) including at least one line (21, 24) to lead coolant from a line (16) in the first line circuit to the second radiator (20), and a fourth line circuit (25, 26a-d, 27) which leads coolant from the second radiator (20) to the first line circuit (15) and which contains at least one cooler (29, 30, 31) for cooling a medium or component of the vehicle (1).

Description

10 led to the internal combustion engine. The compressed air is usually cooled in a charge air cooler located at the front of a vehicle. Thus, the compressed air can cooled to a temperature which substantially corresponds to the ambient temperature. During In cool weather conditions, the compressed air in the charge air cooler is cooled to a temperature that may be lower than the dew point temperature of the air. Thus folds water vapor in the liquid form into the charge air cooler. When the ambient air temperature is below 0 ° C there is also a risk that the precipitated water freezes to ice inside the charge air cooler. Such ice formation causes the air flow channels inside the charge air cooler is more or less clogged, resulting in a reduced fl fate of lu fi to the internal combustion engine with malfunctions or stops as a result.

Through the technology called EGR (Exhaust Gas Recirculation) it is known that recirculate some of the exhaust gases from a combustion process in a combustion engine.

The recirculating exhaust gases are mixed with the inlet air to the internal combustion engine before being led to the internal combustion engine. The addition of exhaust gases into the air gives a lower combustion temperature, which i.a. results in a reduced content of nitrogen oxides NOX in the exhaust gases. This technology is used both for otto engines and for diesel engines. The the recirculating exhaust gases are cooled in at least one EGR cooler before being mixed with inlet air. It is known to use EGR coolers in which they recirculate the exhaust gases are cooled to a temperature which substantially corresponds to the ambient temperature.

Exhaust gases contain water vapor that condenses inside the EGR cooler when the exhaust gases are cooled to a temperature lower than the dew point of the water vapor. If then the surrounding the air temperature is below 0 ° C there is also a risk of the condensed water fi freezes to ice inside the EGR cooler. Such ice formation causes the exhaust gases flow channels inside the EGR cooler are more or less clogged, resulting in the exhaust gas content of nitrogen oxides increases.

SUMMARY OF THE INVENTION The object of the present invention is to provide a cooling system in a vehicle which enables a cooling of a large number of components in the vehicle to a low temperature.

Another purpose of the cooling system is to be able to handle instantaneous peak loads. An additional purpose of the cooling system is to be able to prevent it icing in coolers containing water vapor.

The first of said objects is achieved with the cooling system of the initially mentioned type, which is characterized by the features stated in the characterizing part of claim 1 part. In the part of the cooling system referred to herein as the first line circuit has the coolant a relatively low temperature because it has been cooled in the coolant cooler. In it part of the cooling system referred to herein as the second line circuit has the coolant a relatively high temperature because it has cooled the internal combustion engine. The cooling system according to the present invention comprises an additional conduit loop. The extra the conduit loop comprises a second coolant cooler arranged in a position upstream of the ordinary coolant cooler and a third circuit with which it is possible to conduct relatively cold coolant from the first circuit to the second the coolant cooler. The first coolant cooler and the second coolant cooler are included advantage mounted in an area located at a front of the vehicle. The other one the coolant cooler is here located at least partially in front of the first the coolant cooler. A cooler och genuine and the vehicle's headwind produces a lu fi current in here a direction so that it first passes through the second coolant cooler before it passes through the first coolant cooler.

In this case, relatively cold coolant is thus taken from the first line circuit and led to a second coolant cooler where the coolant is cooled in an additional step of air having one lower temperature than the air that cools the coolant in the first coolant cooler.

The coolant thus obtains a cooling in the second coolant cooler to a low temperature which in favorable circumstances may be close to it ambient air temperature. The cold coolant that leaves the other the coolant cooler is led to a fourth line circuit where it cools at least one medium or a component of a coolant-cooled radiator. The cold coolant in the fourth the circuit is used to advantage to cool media or components such as requires cooling to a low temperature. In this case, the individual media need or the components do not have a radiator arranged at a front of the vehicle.

According to a preferred embodiment of the present invention, the fourth comprises the line circuit has at least two parallel lines, each of which includes its own cooler for cooling of a respective medium or a respective component in the vehicle. The cold the coolant in the fourth line circuit is advantageously used to cool several media or components that require cooling to a low temperature. By leading it cold coolant in fl your parallel lines, each of which is equipped with respectively cooler, all media can be cooled by coolant with the same low temperature. It is however possible to arrange one or fl your coolers in series with each other in the fourth the wiring circuit.

According to another preferred embodiment of the present invention, it comprises the third lead circuit has at least one lead with which it is possible to lead coolant from the second line circuit to the second coolant cooler. In this case thus, hot coolant is led to the other coolant cooler. This may be appropriate at times when the cooling system is heavily loaded. In this case, hot coolant is thus cooled in both the first coolant cooler and the second coolant cooler. The cooling system capacity can thus be increased to cope with instantaneous peak loads. The third the line circuit advantageously comprises a valve means which leads in a first position coolant from a line in the first line circuit to the second coolant cooler and in a second position, coolant from a line in the second line circuit leads to it the second coolant cooler. With such a valve means which can be a three-way valve can relatively cold coolant or hot coolant alternately led to the other the coolant cooler.

According to another preferred embodiment of the present invention comprises the cooling system a control unit that is adapted »to receive information from a sensor that senses a parameter that is related to the coolant temperature in the cooling system.

Said sensor advantageously senses the temperature of the coolant in the other the circuit where it has its highest temperature. The control unit can be a computer unit or the like provided with appropriate software for this task.

The control unit can set the valve means in the second position when it receives information from said sensor indicating that the coolant has a higher temperature than one reference value. Then the coolant temperature rises above a reference value that can be one maximum acceptable coolant temperature in this case automatically conducts heat coolant also to the other coolant cooler. Then the coolant temperature drops below a reference value, the Control Unit can again set the valve means in the first position then the extra cooling of the coolant is no longer needed. The cooling system may include a cooler for cooling a medium or component in the second line circuit. IN in this case, the already hot coolant used to cool the internal combustion engine is used to cool an additional medium or component in the vehicle. This component can be an oil cooler for hydraulic oil used in a hydraulic retarder. During Occasionally the vehicle is braked using a hydraulic retarder and the cooling system is exposed for a large instantaneous load. At times when the retarder is activated can so * the control unit directly set the valve means in the second position so that hot coolant is led to the second coolant cooler to increase the capacity of the cooling system.

According to another preferred embodiment, the second coolant cooler is arranged in one position upstream of a cooler for cooling a gaseous medium containing water vapor. The gaseous medium which is led to the internal combustion engine may be charge air or recirculating exhaust gases. The most diesel-powered internal combustion engines and many petrol-powered internal combustion engines are supercharged, ie. they include a turbocharger which sucks in and compresses ambient air that is led to the internal combustion engine. The the compressed air thus contains water vapor in an amount that varies with it ambient air humidity. Because the compressed lure has a higher dew point than air with ambient pressure, water can condense in the charge air cooler.

The compressed air should therefore not be cooled to a temperature below 0 ° C as condensed water vapor can then till 'freeze to ice inside the charge cooler.

The combustion engine's exhaust gases also contain water vapor in an amount that varies with the humidity of the surrounding air. Recirculating exhaust gases also have a higher pressure than ambient air. It is thus often difficult to prevent water vapor condenses inside an air-cooled EGR cooler. The recirculating exhaust gases should therefore nor is it cooled to a temperature below 0 ° C because condensed water vapor in the EGR the cooler in such cases freezes to ice.

According to another preferred embodiment, the cooling system comprises a control unit which is adapted to receive information from a sensor that senses a parameter that is related to whether icing or risk of icing is present in the radiator and to set the valve means in the second position when it receives information from said sensor which indicates that icing or the risk of icing is present in the radiator. Said sensor can be a temperature sensor that senses the temperature of the medium when it has left the cooler. Har medium at a temperature lower than 0 ° C, ice is probably formed inside the radiator. Then the control unit receives such information, it puts the valve means in the second position so that hot coolant is led to the other coolant cooler. The air that flows through it the second coolant cooler thus obtains an elevated temperature. Then this warm air when the downstream radiator melts, any ice that has formed inside the cooler. Then the control unit receives information from said sensor indicating that it there is no longer a risk of icing, it puts the valve member back in the first position.

According to another preferred embodiment of the invention, the fourth comprises the line circuit a bypass line and a valve with which the coolant can be passed the line with said cooler. Hot coolant is thus passed through the other the coolant cooler at times when the cooling system is heavily loaded and then icing is present in a radiator in the form of a charge air cooler or EGR cooler. Under such Sometimes it is also an advantage to increase the coolant flow through the other the coolant cooler. With a bypass line, the coolant can be led past the coolers in it fourth management circuit. This reduces the pressure drop in the fourth line circuit by as a result of which the coolant flow through the second coolant cooler increases as does that of the cooling system capacity.

BRIEF DESCRIPTION OF THE DRAWINGS A In the following, as an example, preferred embodiments of the invention with reference to the accompanying drawings, in which: F ig. 1 shows a cooling system according to a first embodiment of the present invention and F ig. 2 shows a cooling system according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Fig. 1 shows a vehicle 1 driven by an overcharged internal combustion engine 2. The vehicle 1 can be a heavy vehicle powered by a supercharged diesel engine. Exhaust gases from the cylinders of the internal combustion engine 2 are led, via an exhaust collector 3, to an exhaust line 4.

The exhaust gases in the exhaust line 4, which have an overpressure, are led to a turbine 5 of one turbocharger. The turbine 5 thereby provides a driving force which is transmitted via a connection, to a compressor 6. The compressor 6 thereby compresses the air which, via a lu fi filter 7, is led into an inlet line 8. A charge air cooler 9 is arranged in the inlet line 8. The charge air cooler 9 is arranged in an area A at a front portion of the vehicle 1. The function of the charge air cooler 9 is to cool the compressed air before it is supplied to the internal combustion engine 2. The compressed air is cooled in the charge cooler 9 of air forced through the charge air cooler 9 by means of a radiator fl genuine 10.

The radiator fan 10 is driven by the internal combustion engine 2 by means of a suitable connection.

The internal combustion engine 2 is cooled by coolant circulating in a cooling system. The coolant circulated in the cooling system by means of a coolant pump 11. The cooling system also comprises a thermostat 12. The coolant in the cooling system is intended to be cooled in a first coolant cooler 13, which is mounted at a front portion of the vehicle 1 in the area A. The first the coolant cooler 13 is mounted downstream of the charge cooler 9 with respect to it the flow direction of the cooling air in the area A. The cooling system comprises a first line circuit in the form of lines 14, 15, 16 which conduct the coolant from the first the coolant cooler 13 to the internal combustion engine 2. The coolant pump 11 is arranged in line 16. The cooling system comprises a second line circuit in the form of lines 17, 18 leading the coolant from the internal combustion engine 2 to the first coolant cooler 13.

The line 17 comprises a retarder cooler 19 for cooling hydraulic oil used in a retarder. At times when the coolant has too low a temperature, the thermostat conducts 12 the coolant from line 17, via lines 15, 16 to the internal combustion engine 2. I in this case, the coolant is thus not cooled in the first coolant cooler 13.

The cooling system includes an extra cable loop. The additional lead loop includes one third conduit circuit conducts coolant to a second coolant cooler 20. The third the line circuit comprises a line 21 connected to the line 16 thereof the first line circuit and a line 22 connected to the line 17 thereof second management circuit. The third line circuit includes a three-way valve 23. Then the three-way valve 23 is set in a first position, the relatively cold coolant leads from the line 21 and a line 24 to the second coolant cooler 20. When the three-way valve 23 is set in a second position, the hot coolant leads from line 22 and line 24 to it the second coolant cooler 20. The second coolant cooler 20 is arranged at the vehicle 1 front portion in a position upstream of the first coolant cooler 13 and upstream charge charger 9 with respect to the direction of the cooling lu current in area A.

The extra wire loop also includes a fourth wire circuit that conducts cold coolant from the second coolant cooler 20 to the line 15 of the first the wiring circuit. The fourth lead circuit includes an initial common lead . The common conduit 25 is split into four parallel conduits 26a-d. The four the parallel leads 26a.d merge into a common lead 27 leading the coolant to the line 15 of the first line circuit.

The first parallel line is a bypass line 26a provided with a valve 27 with which the flow through the bypass line 26a can be regulated. The other one the parallel line 26b comprises a cooler in the form of a condenser 29 of an AC system in the vehicle 1. The coolant cools a circulating refrigerant in the condenser 29 to a temperature at which it condenses. The third parallel line 26c includes a cooler 30 for cooling servo oil in the vehicle 1. The fourth parallel line 26d comprises a cooler 31 for cooling servo oil in the vehicle 1. All these media requires cooling to a low temperature. The cooling system comprises a control unit 32 for to control the three-way valve 22 and the valve 28. The control unit 32 receives information from one first temperature sensor 33 which senses the temperature of the coolant in line 17 in a position downstream of the retarder cooler 19 and a second temperature sensor 34 which senses the charge air temperature in the inlet line 8 after it has cooled in the charge air cooler 9.

During operation of the vehicle, the coolant pump 11 circulates coolant in the cooling system.

The control unit 32 receives substantially continuously information from the temperature sensor 33 regarding the temperature of the coolant in line 17 and regarding the temperature of the charging air when it leaves the charger 9. cooler 9. On occasions when the coolant has an acceptable temperature below a reference value and the charge air an acceptable temperature above one reference value, the control unit 32 ensures that the three-way valve is in the first position. When the three-way valve 32 is in the first position the coolant pump 11 directs a part of the coolant in line 16 to the internal combustion engine 2. This part of the coolant is then passed through the retarder cooler 19 and the lines 17 and 18 to the first coolant cooler 13. A the remaining part of the coolant leads the coolant pump 11 via the line 21, the three-way valve 23 and the line 24, to the second coolant cooler 20. This part of the coolant is cooled in the second coolant cooler 20 by air at ambient temperature.

The coolant leaving the second coolant cooler 20 may thus have a temperature near ambient temperature. The cold coolant is led from the other the coolant cooler 20 to the line 25. In this case, the control unit holds the valve 28 in one closed mode. Thus, the cold coolant from the line 25 will be led in parallel through the three lines 26b-d where it cools the refrigerant in the condenser 29, gearbox oil in the radiator 30 and the servo oil in the radiator 31. These media provide a very good cooling of the cold coolant. The coolant from the parallel lines 26b-d are collected in line 27 which leads the coolant to line 15 and the coolant pump 11.

If the control unit 32 receives information indicating that the coolant temperature has risen above the reference value, a higher capacity of the cooling system is required. To the coolant temperature rises above the reference value may be due to the vehicle braking using the hydraulic retarder. The cooling system is heavily loaded as the coolant also must cool the oil retarder cooler l9. The control unit 32 in this case sets the three-way valve 23 in the second position. Thus, some of the hot coolant enters the line 17 to be led, via line 22, three-way valve 23 and line 24, to the other the coolant cooler 20. In this case, hot coolant is thus cooled in both the first the coolant cooler 13 and in the second coolant cooler 20. Thus a larger one is obtained temperature difference between the coolant and the air in the second coolant cooler 20.

The cooling system's capacity to cool the coolant increases. To further increase the cooling system capacity, the control unit 32 can open the valve 28 so that the cold coolant leaves the second coolant cooler 20 is mainly passed through the bypass line 28.

This reduces the flow resistance of the cold coolant in the extra the wire loop. Coolant fl the fate through the second coolant cooler 20 increases which results in a further increased capacity of the cooling system. When the control unit 32 receives information indicating that the coolant temperature has dropped to an acceptable level below a reference value, it closes the valve 28 and sets the three-way valve 23 therein first mode.

If the controller 32 receives information from the temperature sensor 34 indicating that the charge has a lower temperature than 0 ° C, the control unit 32 states that ice is formed in the charge air cooler. The control unit 32 sets the three-way valve 23 in the second position. Thus some of the hot coolant in the line 17 will be led via the line 22, the three-way valve 23 and the line 24 to the second coolant cooler 20. Thus the lu which flows through the second coolant cooler 20 obtains a marked raising the temperature of the hot coolant before it reaches the downstream the charge air cooler 9. The air that reaches the charge air cooler 9 now has a clearly higher temperature than 0 ° C. Thus, any ice that has formed inside the charge air cooler 9 will melt.

To further increase the defrosting capacity of the cooling system, the control unit 32 can open valve 28 so that the cold coolant leaving the second coolant cooler 20 mainly led through the bypass line 28. Thus decreases the flow resistance of the cold coolant through the extra loop. F flow off hot coolant through the second coolant cooler 20 increases resulting in a further improved defrosting of the charge cooler 9. When the control unit 32 receives information indicating that the charge air temperature has risen again to an acceptable level it sets the valve 28 in the closed position and the three-way valve 23 in the first position.

Fig. 2 shows an alternative cooling system. In this case, the internal combustion engine 2 is equipped with an EGR (Exhaust Gas Recirculation) system for exhaust gas recirculation. One return line 35 for exhaust gas recirculation extends here from exhaust line 4 to the inlet line 8. The return line 35 comprises an EGR valve 36, with which the exhaust in the return line 35 can be switched off. The EGR valve 36 can also be used to steplessly control the amount of exhaust gases led from the exhaust line 4, via the return line 35, to the inlet line 8. The return line 35 comprises an EGR cooler 37 to cool the exhaust gases. Before mixing with the charge air in the inlet line 8 and is led to the internal combustion engine 2. In this case, the control unit 32 also receives information from a temperature sensor 38 which senses the temperature of the recirculating exhaust gases that they are cooled in the EGR cooler 37.

During operation of the internal combustion engine 2, the control unit 32 receives information from it the temperature sensor 38 regarding the temperature of the recirculating exhaust gases after they cooled in the second EGR cooler 37. The control unit 32 compares received temperature values with a reference temperature. To prevent icing in the second EGR cooler 37 a reference temperature can be used which is 0 ° C. As long as the control unit 32 receives information from the first temperature sensor 38 that the recirculating exhaust gases have a temperature above the reference temperature sets the control unit 32 in the valve means therein first mode. If the controller 32 receives information from the temperature sensor 38 as indicates that the recirculating exhaust gases have been cooled to a temperature below the reference temperature sets the control unit 32 in the valve means 23 in the second position. Thus some of the hot coolant in the line 17 will be led via the line 22, the three-way valve 23 and the line 24 to the second coolant cooler 20. The air as streams through the second coolant cooler 20 obtain a marked temperature increase before reaching the downstream EGR cooler 37. The air reaching the EGR cooler 37 now has a clearly higher temperature than 0 ° C. Thus comes any ice that has formed inside the EGR cooler 37 to melt. When the controller 32 receives information such as indicates that the temperature of the recirculating exhaust gases has risen again to an acceptable level level sets the three-way valve 23 in the first position.

Otherwise, this embodiment has the same properties as the embodiment in Figs. 1 except that it lacks a bypass line 28. When the three-way valve 23 is in the first position thus also here a good cooling of the coolant in the other is provided coolant cooler 20. The cold coolant from the second coolant cooler 20 is used to cool refrigerant in condenser 29, gearbox oil in radiator 30 and servo oil in the cooler 31. On occasions when the coolant has too high a temperature can the three-way valve 23 is set in the second position so that hot coolant is passed through the second 11 the coolant cooler 20 with the aim of increasing the capacity of the cooling system. On occasions like the charge air har has a too low temperature as it leaves the charge air cooler 9 is also set the three-way valve 32 in the second position. In this case, hot coolant is passed through the other the coolant cooler 20 for the purpose of defrosting the downstream charge cooler 9.

The invention is in no way limited to the described embodiments but can varies freely within the scope of the claims.

Claims (10)

10 15 20 25 30 35 12 Patent claims A cooling system with a circulating coolant for cooling an internal combustion engine in a vehicle (1), the cooling system comprising a first coolant cooler (13) where the coolant is cooled by an air stream which is led in a certain direction through the cooler, a first line circuit (14, 15 , 16) which carries coolant from the first coolant cooler (13) to the internal combustion engine (2) and a second line circuit (17, 18) which carries coolant from the internal combustion engine (2) to the first coolant cooler (13), characterized in that the cooling system comprises a second coolant cooler (20) arranged in a position upstream of the first coolant cooler (13) with respect to the direction of the cooling air stream so that at least a part of the air flowing through the second coolant cooler (20) also flows through the first coolant cooler (13) , a third conduit circuit (21, 22, 24) comprising at least one conduit (21, 24) with which it is possible to conduct coolant from a conduit (16) in the first conduit circuit. to the second coolant cooler (20) and a fourth conduit circuit (25, 26a-d, 27) which conveys coolant from the second coolant cooler (20) to the first conduit circuit (15), the fourth conductor circuit (25, 26a-d, 27) comprises at least one cooler (29, 30, 31) for cooling a medium or a component in the vehicle (1). Cooling system according to claim 1, characterized in that the fourth line circuit (25, 26a-d, 27) comprises at least two parallel lines (26b-d) each comprising a cooler (29, 30, 31) for cooling a respective medium or a respective component of the vehicle (1). Cooling system according to claim 1 or 2, characterized in that the third line circuit (21, 22, 24) comprises at least one line (22, 24). with which it is possible to conduct coolant from a line (17) in the second line circuit to the second coolant cooler (20). in Cooling system according to claim 2 or 3, characterized in that the third line circuit (21, 22, 24) comprises a valve means (23) which in a first position directs coolant from a line (16) in the first line circuit (14, 15). , 16) to the second coolant cooler (20) and in a second position coolant leads from a line (17) in the second line circuit (17, 18) to the second coolant cooler (20). 10 15 20 25 30 35 13 Cooling system according to claim 4, characterized in that the cooling system comprises a control unit (3 2) which is adapted to receive information from a sensor (3 3) which senses a parameter which is related to the coolant temperature in the cooling system. Cooling system according to any one of the preceding claims 5, characterized in that the control unit (32) is adapted to set the valve means (23) in the second position when it receives information from said sensor (33) indicating that the coolant has a higher temperature than a reference value . Cooling system according to one of the preceding claims, characterized in that the cooling system comprises a cooler (19) for cooling a medium or a component in the second line circuit (17, 18). Cooling system according to one of the preceding claims, characterized in that the second coolant cooler (20) is arranged in a position in the vehicle (1) upstream of a cooler (9, 37) for cooling a gaseous medium containing water vapor with respect to the cooling the direction of the air flow so that at least a part of the air flowing through the second coolant cooler (20) also flows through said cooler (9, 37). in Cooling system according to claims 4 and 8, characterized in that it comprises a control unit (32) which is adapted to receive information from a sensor (3 4, 38) which senses a parameter which is related to whether icing or risk of icing is present in the cooler (9, 37) and to set the valve means (32) in the second position when it receives information from said sensor (34, 38) indicating that icing or risk of icing is present in the cooler (9, 37). Cooling system according to any one of the preceding claims, characterized in that the fourth line circuit (25, 26a-d, 27) comprises a bypass line (26a) and a valve (29) with which the coolant can be led through the bypass line (26a) and thus past the line. (26b-d) with said cooler (29, 30, 31).