JP5522874B2 - Vehicle cooling system - Google Patents

Description

  The present invention relates to a vehicle cooling system described in the preamble of claim 1.

  There are numerous coolers and components in vehicles that require cooling to temperatures below that achievable by the coolant of the combustion engine cooling system. One such cooler is an AC system condenser. This condenser is usually located in front of the radiator at the front of the vehicle, where it is cooled by air at the same temperature as the surroundings. However, it is impossible for all coolers and components that require cooling to some low temperature to be placed in front of the vehicle radiator and to be in contact with air at the same temperature as the surroundings. Other examples of coolers and components that are desired to be cooled in a cooler medium than the coolant of the combustion engine cooling system include gearbox oil oil coolers, servo oil oil coolers, brake compressors, Turbine and electrical control unit.

  In many cases, coolants in engine cooling systems are also used to cool media and components other than combustion engines. Certain media or components that the engine cooling system cools may require a very high instantaneous cooling effect. An example of such a component is a hydraulic retarder. When using an engine cooling system to cool hydraulic retarder hydraulic fluid, the cooling system must provide a very large cooling effect when the retarder is operating. If a retarder is used to brake the vehicle on a long downhill, the engine cooling system can be continuously loaded for a long time, resulting in overheating of the coolant in the engine cooling system. There is a fear.

  The amount of air that can be supplied to a supercharged combustion engine not only depends on the pressure of the air, but also on the temperature of the air. In order to supply as much air as possible to the engine, it is inevitably necessary to cool the compressed air with a charge air cooler and then guide it to the engine. This compressed air is usually cooled by a charge air cooler located at the front of the vehicle. In this way, the compressed air can be cooled to a temperature that substantially matches the ambient temperature. In cold weather conditions, this compressed air may be cooled by the charge air cooler to a temperature lower than the dew point temperature of the compressed air. As a result, water vapor condenses in the charge air cooler and becomes liquid. May be. When the temperature of the surrounding air is lower than 0 ° C., the condensed water may be frozen into ice in the air supply cooler. Such ice formation will more or less block the conduit through which the charge air in the charge air cooler flows, resulting in a reduced flow rate of air flowing to the engine, resulting in malfunctions or malfunctions. Will stop or.

A technique known as EGR (exhaust gas recirculation) is a known method of recirculating a portion of the exhaust gas produced by a combustion process in a combustion engine. This recirculated exhaust gas is mixed with the intake air that is sent to the engine, after which the mixture is directed to the engine. When exhaust gas is added to the intake air to the engine, the combustion temperature is lowered, and as a result, the content of nitrogen oxides NO _{x in} the exhaust gas is reduced. This technique is used for both Otto engines and diesel engines. The recirculated exhaust gas is cooled with at least one EGR cooler and then mixed with the intake air. In fact, it is known to use an EGR cooler in which the recirculated exhaust gas is cooled to a temperature that substantially matches the ambient temperature. The exhaust gas contains water vapor which condenses when cooled in the EGR cooler to a temperature below the dew point of the water vapor. When the temperature of the surrounding air is lower than 0 ° C., the condensed water may freeze into ice in the EGR cooler. Such ice formation will more or less block the conduit through which the exhaust gas flows in the EGR cooler, thereby increasing the nitrogen oxide content of the exhaust gas.

  The object of the present invention is to propose a cooling system for a vehicle which makes it possible to cool a number of components of the vehicle to a certain low temperature. Another purpose of the cooling system is to enable the cooling system to handle instantaneous peak loads. Another purpose of the cooling system is to allow the cooling system to prevent ice formation in a cooler containing water vapor.

  Among these objects, the first object is achieved by a cooling system of the kind mentioned in the introduction part, which has the characteristics described in the characterizing part of claim 1. In the portion of this cooling system referred to herein as the first tube circuit, the temperature of the coolant after being cooled by the radiator is relatively low. In the portion of this cooling system, referred to herein as the second tube circuit, the coolant temperature after cooling the engine is relatively high. The cooling system according to the invention comprises an additional line loop. This additional line loop allows a second radiator located upstream of this normal radiator and a relatively cool coolant from the first pipe circuit to be routed to the second radiator. A third tube circuit. Advantageously, the first radiator and the second radiator are mounted in a region located at the front of the vehicle. In this case, the second radiator is located at least partially in front of the first radiator. In this case, the cooler fan and the ventilation generated by the vehicle moving forward provide an air flow in a direction that passes through the second radiator and then through the first radiator.

  Therefore, in this case, the relatively cool coolant from the first tube circuit is directed to the second radiator, where the air is cooler than the air that cools the coolant in the first radiator. Undergo an additional cooling step cooled by. Therefore, the coolant is cooled to a certain low temperature by the second radiator. In an advantageous situation, this temperature is close to the ambient temperature. The cooled coolant leaving the second radiator is directed to a fourth tube circuit where it cools at least one medium or component in the coolant cooled cooler. Advantageously, the chilled coolant in this fourth tube circuit is used to cool media or components that require cooling to some low temperature. In this case, the various media or component coolers need not be located in the front of the vehicle.

  According to a preferred embodiment of the present invention, the fourth tube circuit includes at least two parallel lines each including a corresponding respective cooler for cooling a corresponding medium or component of the vehicle. . Advantageously, a chilled coolant in the fourth tube circuit is used to cool two or more media or components that require cooling to some low temperature. By passing a chilled coolant through several parallel lines each containing a corresponding respective cooler, all of those media can be cooled by the same low temperature coolant. However, it is also possible for one or more coolers to be arranged in series with each other in the fourth tube circuit.

  According to another preferred embodiment of the present invention, the third tube circuit includes at least one conduit that allows the coolant from the second tube circuit to be directed to the second radiator. Therefore, in this case, the warm coolant is led to the second radiator. This may be appropriate when the cooling system is heavily loaded. Therefore, in this case, the warm coolant is cooled by both the first radiator and the second radiator. Thus, the capacity of the cooling system can be increased to handle instantaneous peak loads. Advantageously, the third tube circuit directs the coolant from the conduit of the first tube circuit to the second radiator in the first position, and in the second position the second tube circuit Valve means for directing coolant from the conduit to the second radiator. By using such valve means, which can be a three-way valve, a relatively cool coolant or a relatively warm coolant can be directed alternately to the second radiator.

  According to another preferred embodiment of the invention, the cooling system comprises a control unit adapted to receive information from sensors monitoring parameters related to the temperature of the coolant of the cooling system. Advantageously, this sensor monitors the temperature of the coolant in the second tube circuit having the highest temperature. This control unit can be a computer unit or other similar unit in which software suitable for this purpose is stored. The control unit can place the valve means in the second position when it receives information from the sensor that the coolant temperature is above a reference value. If the coolant temperature rises above the reference value, the control unit in this case automatically also guides the warm coolant to the second radiator. This reference value can be the highest allowable coolant temperature. When the coolant temperature falls below the reference value, i.e. when no further cooling of the coolant is needed anymore, the control unit can place the valve means in the first position again. The cooling system may include a cooler in the second tube circuit that cools the medium or component. Thus, in this case, the already warmed coolant after cooling the engine is used for the purpose of cooling another vehicle or component of the vehicle. This component can be an oil cooler for hydraulic oil used in hydraulic retarders. When the vehicle is being braked by a hydraulic retarder, this cooling system is momentarily loaded. When the retarder is activated, the control unit can immediately place the valve means in the second position to allow warm coolant to flow to the second radiator to increase the capacity of the cooling system.

  According to another preferred embodiment, the second radiator is located upstream of a cooler that cools the gaseous medium containing water vapor. This gaseous medium directed to the engine can be charge air or recirculated exhaust gas. Most diesel engines and many gasoline engines are supercharged. That is, these engines have a turbo unit that draws in ambient air and compresses it, and the compressed air is directed to the engine. This compressed air therefore contains water vapor. The amount of water vapor varies depending on the amount of water in the surrounding air. Since the dew point of this compressed air is higher than that of ambient pressure air, water may condense in the charge air cooler. Therefore, this compressed air should not be cooled to a temperature below 0 ° C. This is because if the compressed air is cooled to a temperature lower than 0 ° C., the condensed water vapor may freeze and become ice in the charge air cooler. Engine exhaust gas also contains water vapor. The amount of water vapor varies depending on the amount of water in the surrounding air. The pressure of the recirculated exhaust gas is also higher than the pressure of the surrounding air. Therefore, in many cases, it is difficult to prevent condensation of water vapor in the air-cooled EGR cooler. Therefore, it should be ensured that the recirculated exhaust gas is not cooled to a temperature below 0 ° C. This is because if the recirculated exhaust gas is cooled to a temperature lower than 0 ° C., the condensed water vapor may freeze and become ice in the EGR cooler.

  According to another preferred embodiment, the cooling system receives information from sensors that monitor parameters relating to whether ice has formed in the cooler or whether there is a risk of ice forming in the cooler. The valve means is placed in the second position when information is received from the sensor that the ice has formed in the cooler or that there is a risk of ice forming in the cooler. A control unit adapted to This sensor can be a temperature sensor that monitors the temperature of the medium as it exits the cooler. When the temperature of the medium is lower than 0 ° C., there is a high possibility that ice is formed in the cooler. Upon receiving such information, the control unit places the valve means in the second position so that warm coolant is directed to the second radiator. Therefore, the air that has passed through the second radiator has a high temperature. When reaching the downstream cooler, this warm air melts the ice formed in the cooler. Upon receiving information from this sensor that there is no longer any risk of ice formation, the control unit again places the valve means in the first position.

  According to another embodiment of the invention, the fourth pipe circuit comprises a bypass line and a valve that allows the coolant to be guided without passing through a line including a cooler. Thus, when the cooling system is heavily loaded and when ice is formed in a cooler in the form of a charge air cooler or EGR cooler, warm coolant is directed into the second radiator. In such circumstances, it is also advantageous to increase the coolant flow rate through the second radiator. The bypass line makes it possible to direct the coolant without going through the cooler in the fourth pipe circuit. Thus, the pressure drop in the fourth tube circuit is reduced, thereby increasing the coolant flow rate through the second radiator and the capacity of the cooling system.

  The preferred embodiments of the present invention will now be described by way of example with reference to the accompanying drawings.

The figure which shows the cooling system based on 1st Example of this invention. The figure which shows the cooling system based on the 2nd Example of this invention.

  FIG. 1 shows a vehicle 1 that is powered by a supercharged combustion engine 2. The vehicle 1 can be a heavy vehicle powered by a supercharged diesel engine. Exhaust gas from the cylinder of the engine 2 is guided to the exhaust pipe line 4 through the exhaust manifold 3. The exhaust gas in the exhaust line 4 having a pressure higher than the atmospheric pressure is led to the turbine 5 of the turbo unit. Accordingly, a driving force is supplied to the turbine 5, and this driving force is transmitted to the compressor 6 through the connection. The compressor 6 compresses the air guided to the intake pipe line 8 through the air filter 7. A supply air cooler 9 is disposed in the intake pipe line 8. The air supply cooler 9 is located in the area A in the front portion of the vehicle 1. The purpose of the charge air cooler 9 is to cool this compressed air before directing it to the engine 2. In the air supply cooler 9, the compressed air is cooled by the air forcedly passed through the air supply cooler 9 by the cooler fan 10 and the ventilation generated by the vehicle moving forward. The cooler fan 10 is driven by the engine 2 via a suitable connection.

  The engine 2 is cooled by a coolant circulating in the cooling system. This coolant is circulated in the cooling system by the coolant pump 11. The cooling system further comprises a thermostat 12. The coolant of the cooling system is intended to be cooled by the first radiator 13 attached to the area A in the front part of the vehicle 1. The first radiator 13 is located downstream of the supply air cooler 9 with respect to the direction of the cooling air flow in the region A. The cooling system comprises a first pipe circuit in the form of ducts 14, 15, 16 that lead the coolant from the first radiator 13 to the engine 2. The coolant pump 11 is located in the pipeline 16. The cooling system comprises a second tube circuit in the form of conduits 17, 18 that lead the coolant from the engine 2 to the first radiator 13. The pipe line 17 includes a retarder cooler 19 that cools hydraulic oil used in the retarder. When the temperature of the coolant is too low, the thermostat 12 guides the coolant from the pipe line 17 to the engine 2 through the pipe lines 15 and 16. Therefore, in that situation, the coolant is not cooled by the first radiator 13.

  The cooling system includes an additional line loop. This additional line loop includes a third tube circuit that directs the coolant to the second radiator 20. The third pipe circuit includes a pipe line 21 connected to the pipe line 16 of the first pipe circuit and a pipe line 22 connected to the pipe line 17 of the second pipe circuit. This third tube circuit includes a three-way valve 23. When in the first position, the three-way valve 23 guides relatively cool coolant from the conduit 21 and the conduit 24 to the second radiator 20. When in the second position, the three-way valve 23 guides the warm coolant from the conduit 22 and the conduit 24 to the second radiator 20. The second radiator 20 is located on the upstream side of the first radiator 13 and the supply air cooler 9 in the front part of the vehicle 1 with respect to the direction of the cooling air flow in the region A. This additional line loop further includes a fourth line circuit that directs the chilled coolant from the second radiator 20 to the line 15 of the first line circuit. This fourth tube circuit initially includes a common line 25. The common pipe 25 is divided into four parallel pipes 26a to 26d. These four parallel pipes 26a-d are gathered together to form a common pipe 27 that guides the coolant to the pipe 15 of the first pipe circuit.

  The first parallel line takes the form of a bypass line 26a with a valve 28, thereby allowing the valve 28 to regulate the flow through the bypass line 26a. The second parallel line 26 b comprises a cooler in the form of a condenser 29 of the AC system of the vehicle 1. The coolant cools the circulating refrigerant in the condenser 29 to a temperature at which the circulating refrigerant condenses. The third parallel pipe 26 c includes a cooler 30 that cools the servo oil of the vehicle 1. The fourth parallel pipe 26 d includes a cooler 31 that cools the servo oil of the vehicle 1. All of these media are media that need to be cooled to some low temperature. The cooling system includes a control unit 32 that controls the three-way valve 23 and the valve 28. The control unit 32 includes a first temperature sensor 33 that monitors the temperature of the coolant in the pipe line 17 at a position downstream of the retarder cooler 19, and an intake pipe line that has been cooled by the charge air cooler 9. Information is received from a second temperature sensor 34 that monitors the temperature of the supply air in the engine 8.

  During operation of the vehicle, the coolant pump 11 circulates the coolant of the cooling system. The control unit 32 substantially continuously receives information from the temperature sensor 33 regarding the temperature of the coolant in the conduit 17 and information from the temperature sensor 34 regarding the temperature of the supply air as it leaves the supply air cooler 9. To receive. When the coolant temperature is an allowable temperature lower than the reference value and the supply air temperature is an allowable temperature higher than the reference value, the control unit 32 maintains the three-way valve in the first position. When the three-way valve 23 is in the first position, the coolant pump 11 guides a part of the coolant in the pipe line 16 to the engine 2. This part of the coolant is then led to the first radiator 13 via the retarder cooler 19 and the ducts 17 and 18. The remaining portion of the coolant is guided to the second radiator 20 by the coolant pump 11 through the conduit 21, the three-way valve 23 and the conduit 24. This part of the coolant is cooled by the second radiator 20 with air at the same temperature as the surroundings. Therefore, the temperature of the coolant leaving the second radiator 20 may be close to the ambient temperature. The cooled coolant is guided from the second radiator 20 to the conduit 25. In this situation, the control unit maintains the valve 28 in the closed position. Therefore, the cooled coolant from the pipe 25 is guided in parallel into the three pipes 26b to 26d, where the refrigerant in the condenser 29, the gear box oil in the cooler 30, and the cooler 31 Cool the servo oil. These media are very well cooled by this cold coolant. The coolant from the parallel conduits 26 b-d merges into the conduit 27, which guides this coolant to the conduit 15 and the coolant pump 11.

  If the control unit 32 receives information that the coolant temperature has risen above the reference value, the capacity of the cooling system needs to be increased. This event, where the coolant temperature rises above the reference value, can occur when the hydraulic retarder brakes the vehicle. When the coolant must also cool the air in the retarder cooler 19, it places a heavy load on the cooling system. In this situation, the control unit 32 places the three-way valve 23 in the second position. Thereby, a part of the warm coolant in the pipe line 17 is guided to the second radiator 20 via the pipe line 22, the three-way valve 23 and the pipe line 24. Therefore, in this situation, the warm coolant is cooled by the first radiator 13 and the second radiator 20. As a result, the temperature difference between the coolant in the second radiator 20 and air becomes larger. The ability of the cooling system to cool the coolant is increased. In order to further increase the capacity of the cooling system, the control unit 32 may open the valve 28 so that the chilled coolant exiting the second radiator 20 is directed primarily into the bypass line 26a. it can. This reduces the flow resistance to the chilled coolant flowing through this additional line loop. The coolant flow rate through the second tube circuit 20 is increased, resulting in a further increase in the capacity of the cooling system. Upon receiving information that the coolant temperature has dropped to an acceptable level below the reference value, the control unit 32 closes the valve 28 and places the three-way valve 23 in the first position.

  When the information that the temperature of the supply air is lower than 0 ° C. is received from the temperature sensor 34, the control unit 32 knows that ice is formed in the supply air cooler. In that case, the control unit 32 places the three-way valve 23 in the second position. Thereby, a part of the warm coolant in the pipe line 17 is guided to the second radiator 20 via the pipe line 22, the three-way valve 23 and the pipe line 24. Therefore, the temperature of the air passing through the second radiator 20 is significantly increased by the warm coolant before the air reaches the downstream air supply cooler 9. Therefore, the temperature of the air reaching the charge air cooler 9 is clearly higher than 0 ° C. Therefore, any ice formed in the charge air cooler 9 will melt. In order to further increase the deicing capacity of the cooling system, the control unit 32 opens the valve 28 so that the cooled coolant exiting the second radiator 20 is mainly led into the bypass line 26a. be able to. This reduces the flow resistance to the chilled coolant flowing through this additional line loop. The flow rate of the warm coolant passing through the second radiator 20 is increased, and as a result, the deicing capability of the charge air cooler 9 is further improved. Upon receiving information that the supply air temperature has risen again to an acceptable level, control unit 32 places valve 28 in the closed position and three-way valve 23 in the first position.

  FIG. 2 shows an alternative cooling system. In this case, the combustion engine 2 includes an EGR (exhaust gas recirculation) system that recirculates the exhaust gas. In this example, a return line 35 for recirculating exhaust gas extends from the exhaust line 4 to the intake line 8. The return line 35 includes an EGR valve 36 that allows the flow of exhaust gas in the return line 35 to be blocked. Using the EGR valve 36, the amount of exhaust gas led from the exhaust pipe 4 to the intake pipe 8 via the return pipe 35 can be controlled steplessly. The return line 35 includes an EGR cooler 37 that cools the exhaust gas before the exhaust gas is mixed with the intake air in the intake pipe 8 and led to the engine 2. In this case, the control unit 32 also receives information from a temperature sensor 38 that monitors the temperature of the recirculated exhaust gas after being cooled by the EGR cooler 37.

  During operation of the engine 2, the control unit 32 receives information from the temperature sensor 38 regarding the temperature of the recirculated exhaust gas after being cooled by the second EGR cooler 37. The control unit 32 compares the received temperature value with a reference temperature. In order to prevent the formation of ice in the second EGR cooler 37, the reference temperature used can be set to 0 ° C. As soon as the information that the temperature of the recirculated exhaust gas is higher than the reference temperature is received from the first temperature sensor 38, the control unit 32 places the valve means in the first position. When receiving information from the temperature sensor 38 that the temperature of the recirculated exhaust gas has been cooled to a temperature lower than the reference temperature, the control unit 32 places the valve means 23 in the second position. Thereby, a part of the warm coolant in the pipe line 17 is guided to the second radiator 20 via the pipe line 22, the three-way valve 23 and the pipe line 24. The temperature of the air passing through the second radiator 20 rises significantly before the air reaches the downstream EGR cooler 37. Therefore, the temperature of the air reaching the EGR cooler 37 is clearly higher than 0 ° C. Therefore, all the ice formed in the EGR cooler 37 melts. Upon receiving information that the temperature of the recirculated exhaust gas has risen again to an acceptable level, the control unit 32 places the three-way valve 23 in the first position.

  In other respects, this embodiment has the same features as the embodiment of FIG. 1 except that it does not have a bypass line 26a. Therefore, also in this embodiment, when the three-way valve 23 is in the first position, the coolant is well cooled by the second radiator 20. The cooled coolant from the second radiator is used to cool the refrigerant in the condenser 29, the gear box oil in the cooler 30, and the servo oil in the cooler 31. When the coolant temperature is too high, the three-way valve 23 may be placed in the second position so that warm coolant is directed into the second radiator 20 to increase the capacity of the cooling system. it can. Similarly, when the temperature of the supply air leaving the supply air cooler 9 is too low, the three-way valve 23 is placed in the second position. In this situation, a warm coolant is introduced into the second radiator 20 in order to melt the ice in the downstream air supply cooler 9.

  The invention is in no way limited to the examples described, but it can be freely varied within the scope of the claims.

Claims (8)

A cooling system comprising a circulating coolant for cooling the combustion engine of the vehicle (1), the cooling system comprising:
A first heat radiator (13), wherein the coolant is cooled by an air flow guided to pass through a cooler in a specific direction. A first radiator (13),
A first pipe circuit (14, 15, 16) for guiding the coolant from the first radiator (13) to the combustion engine (2);
A second pipe circuit (17, 18) for guiding coolant from the combustion engine (2) to the first radiator (13);
A second radiator (20) disposed upstream of the first radiator (13) with respect to the direction of the cooling air flow, wherein at least air passing through the second radiator (20) A second radiator (20) arranged such that a part thereof also passes through the first radiator (13);
A third tube comprising at least one conduit (21, 24) allowing the coolant from the conduit (16) of the first conduit circuit to be directed to the second radiator (20); Circuit (21, 22, 24);
A fourth pipe circuit (25, 26a-d, 27) for guiding the coolant from the second radiator (20) to the first pipe circuit (15), the medium of the vehicle (1); Or a fourth tube circuit (25, 26a-d, 27) comprising at least one cooler (29, 30, 31) for cooling the component,
At least one enabling said third tube circuit (21, 22, 24) to direct coolant from said second tube circuit line (17) to said second radiator (20); Including the pipelines (22, 24),
When the third pipe circuit (21, 22, 24) is in the first position, the coolant from the pipe (16) of the first pipe circuit (14, 15, 16) is transferred to the second heat release. Valve means (23) leading to the radiator (20) and in the second position, the coolant from the conduit (17) of the second pipe circuit (17, 18) to the second radiator (20). A cooling system.   The fourth tube circuit (25, 26a-d, 27) includes at least two parallel devices each including a cooler (29, 30, 31) that cools each medium or component of the vehicle (1). The cooling system according to claim 1, characterized in that it comprises lines (26b-d).   3. A control unit (32) adapted to receive information from a sensor (33) that monitors a parameter related to the temperature of the coolant of the cooling system. The cooling system described.   The control unit (32) is adapted to place the valve means (23) in the second position when receiving information from the sensor (33) that the coolant temperature is higher than a reference value. The cooling system according to claim 3, wherein:   5. A cooling device (19) for cooling a medium or a component is provided in the second tube circuit (17, 18) according to any one of the preceding claims. Cooling system.   The second radiator (20) is arranged on the upstream side of the cooler (9, 37) for cooling the gaseous medium containing water vapor with respect to the direction of the cooling air flow. 6. The vehicle according to claim 1, wherein at least part of the air that has passed through is disposed in the vehicle (1) so as to pass through the cooler (9, 37). The cooling system described in the section.   Sensors (34, 38) that monitor parameters related to whether ice has formed in the cooler (9, 37) or whether ice may form in the cooler (9, 37). Information adapted to receive information from the said cooler (9, 37) or information that ice may be formed in said cooler (9, 37) The control unit (32) according to claim 6, characterized in that it comprises a control unit (32) adapted to place the valve means (32) in the second position when received from a sensor (34, 38). Cooling system.   The fourth pipe circuit (25, 26a-d, 27) passes a bypass line (26a) and the coolant through the bypass line (26a) and thus the cooler (29, 30, 31). 8. Cooling according to any one of claims 1 to 7, characterized in that it comprises a valve (28) that allows the conduit (26b-d) to be guided without passing through it. system.

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