SE1650651A1

SE1650651A1 - A multi-valve device for a cooling system

Info

Publication number: SE1650651A1
Application number: SE1650651A
Authority: SE
Inventors: Kardos Zoltan; Hall Ola
Original assignee: Scania Cv Ab
Priority date: 2016-05-16
Filing date: 2016-05-16
Publication date: 2017-11-17
Also published as: DE102017004458A1; DE102017004458B4; SE541819C2

Abstract

17 Abstract The present invention relates to a multi-valve device for a cooling system configuredto cool a combustion engine (2) and at least one further object (18). The multi- Valvedevice comprises a ho11oW Valve body (26) rotatably arranged to different angularpositions in a housing (25). The Valve body (26) comprises a number of openings (31-34) coinciding With ports (5a°-5g°) in the housing (25) such that coo1ant of a heatedtemperature (TH), coo1ant coo1ed to a first temperature (T1), coo1ant coo1ed to a secondtemperature (Tz) or a specific miXture of coolants of said temperatures (TH, T1, Tz) isdirected, Via ports (5a°, 5e°-5h°) of the housing (25) to the combustion engine (2) andthe further object (18) in dependence of the angular position of the Valve body (26) inthe housing (25). (Pig. 2)

Description

A multi-valve device for a cooling system BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates to a multi-valve device for a cooling system according to the preamble of claim l.

A cooling system in a vehicle is many times used to cool a combustion engine and atleast one further object. The further object may be a component or ﬂuid. In certaincase, such a further object may require a lower operating temperature than thecombustion engine. In this case, the cooling system can create two coolanttemperatures using two radiators cooled by air of different temperatures. The coolant atthe higher temperature may be directed to the combustion engine and the coolant at thelower temperature may be directed to said further object. Certain object requires awell-controlled cooling for optimal efficiency. In this case, the design of the coolingsystem is complicated with a plurality of valves and control devices for the valves arranged in different positions of the cooling system.

A WHR system (Waste Heat Recovery System) can be used in vehicles for recoveringwaste thermal energy and convert it to mechanical energy or electric energy. TheWHR system may absorb waste thermal energy from the eXhaust gases of acombustion engine. In order to achieve a high thermal efficiency in a WHR-system,the working medium is to be cooled in a condenser to a condensation temperature aslow as possible and substantially without subcooling. In order to achieve such acondensation temperature, the working medium is to be cooled with coolant of asuitable temperature and ﬂow rate. However, the required cooling effect of theworking medium in the condenser may vary rapidly with the temperature and ﬂow rateof the eXhaust gases. Thus, it is necessary to continuously provide a quick and reliablecontrol of the temperature and the ﬂow rate of the coolant directed to the condenser in order to maintain a high thermal efficiency of the WHR-system.

SUMMARY OF THE INVENTION The object of the present invention is to provide a multi-valve device in a coolingsystem Which is able to eXclusively control the coolant ﬂoW in the cooling system andprovide an optimal cooling of a combustion engine as Well as a further object in a quick and reliable manner.

The above mentioned object is achieved by the multi-valve device according to thecharacterized part of claim l. The multi-valve comprises an inlet port receiving heatedcoolant from the combustion engine. The multi-valve comprises outlet ports directinguncooled coolant and /or coolant from the first radiator to the combustion engine.Consequently, the multi-valve device performs the same Work as a conventionalthermostat in a cooling system. Furthermore, the multi-valve comprises outlet portsable to direct heated coolant and/or coolant at the second temperature to the furtherobject. Thus, the multi-valve is able to direct coolant of an adjustable temperature tothe further object Within a temperature range defined by the heated temperature and thesecond temperature. The design of the multi-valve device With a rotatable valve bodyin a housing, makes it also possible to adjust the ﬂoW areas for the coolant in a steplessmanner and thus the coolant ﬂoW rate to the combustion engine and the further object.The above mentioned properties of the multi-valve make it possible provide an optimalcooling of the combustion engine as Well as the further object during substantially alloperating conditions. No further valves need to be used for the distribution of the coolant in the cooling system.

According to an embodiment of the invention, the multi-valve device comprises anactuator moving the valve body to a substantially arbitrary angular position in thehousing and a control unit Which initiates the movement of the valve body to a desiredangular positions in the housing. The actuator may be an electric motor and the controlunit may be a computer unit having access to information about suitable angular positions of the valve body in the housing at different operating conditions.

According to an embodiment of the invention, the multi-valve comprises an eighthport directing coolant at the first temperature to the further object. In this case, it is alsopossible to solely direct coolant at the first coolant temperature to the further object orcoolant at the first temperature in combination With coolant at the heated temperature and coolant at the second temperature.

According to an embodiment of the invention, the Valve body comprises three holloWvalve parts rigidly connected to each other and arranged along a longitudinal aXis ofthe valve body. Such a design of the valve body makes it possible to rotate all valveparts as a unit to different angular positions in the housing. Said three valve parts mayhave a spherical-shape. It is relatively easy to provide a tight sealing between therespective spherical valve parts and the housing. Alternatively, the holloW valve parts may have a cylindrical- shape.

According to an embodiment of the invention, the first valve part comprises at leastone opening to be connectable to the first port, the second port and the third port of thehousing. Thus, the first valve part receives heated coolant from the engine outlet linevia the first port. The first valve part may direct the heated coolant back to thecombustion engine Without cooling and/or to the first radiator. The valve body maycomprise an open ﬂoW passage between the first valve part and the second valve part.Consequently, a part of the heated coolant entering the first valve part is directed to thesecond valve part via said ﬂoW passage. The second valve part may comprise at leastone opening connectable to the siXth port and the seventh port. The second valve partmay direct the heated coolant to the further object Without cooling and/or, via thesecond radiator, to the further object. Thus, the second valve part makes it possible todirect coolant to the further object Within a temperature range defined by the secondcoolant temperature and the heated coolant temperature. A third valve part maycomprise at least one opening connectable to the fourth port, the fifth port and theeighth port. The third valve part receives coolant from the first radiator of the firstcoolant temperature. The third valve part may direct the coolant at the first temperature to the combustion engine and/or the further object.

According to an embodiment of the invention, the ports directing coolant to the furtherobject has a smaller cross sectional area than the ports directing coolant to thecombustion engine. The cross sectional areas of the ports define the ﬂoW area for thecoolant and the coolant ﬂoW rate through the ports. During most operating condition,the combustion engine needs to be cooled With a larger cooling effect than the furtherobject. The cooling effect is related to the coolant temperature and the coolant ﬂoWrate. One Way to direct a smaller coolant ﬂoW rate to the further object than to thecombustion engine is to give the ports directing coolant to the further object smaller dimensions than the ports directing coolant to the combustion engine.

According to an embodiment of the invention, the control unit is configured to receiveinformation about a parameter related to the temperature of the combustion engine, toestimate the temperature of the coolant to be supplied to the combustion engine, todetermine an angular position of the valve body in the housing at Which said estimatedcoolant temperature is directed to the combustion engine, and to activate the activatorsuch that it moves the valve body to the determined angular position in the housing.The coolant in the engine outlet line has a temperature related to the temperature of thecombustion engine. Thus, the control unit may receive information from a temperaturesensor sensing the temperature of the coolant in the engine outlet line. ln case thetemperature of the combustion engine is lower than an optimal operating temperature,the control unit initiates a movement of the valve body to an angular position inrelation to the housing in Which it directs uncooled coolant to the combustion engine.ln case the temperature of the combustion engine is higher than the optimal operatingtemperature, the control unit initiates a movement of the valve body to an angularposition in relation to the housing in Which it directs coolant at the first temperature tothe combustion engine. According to a third altemative, the control unit directs asuitable miXture of uncooled coolant and coolant at the first temperature to the combustion engine.

According to an embodiment of the invention, the control unit is configured to receiveinformation about a parameter related to the temperature of the further object, toestimate the temperature of the coolant to be supplied to the further object, todetermine an angular position of the valve body in the housing at Which coolant of saidestimated coolant temperature is directed to the further object, and to activate theactuator such that it moves the valve body to the detern1ined angular position in thehousing. ln case the temperature of the further object is lower than an optimaloperating temperature, the control unit initiates a movement of the valve body to anangular position in relation to the housing in Which it mainly directs uncooled coolantto the further object. In case the temperature of the further object is higher than theoptimal operating temperature, the control unit initiates a movement of the valve bodyto an angular position in relation to the housing in Which it mainly directs coolant atthe second temperature to the further object. According to a third altemative, thecontrol unit directs a suitable miXture of uncooled coolant, coolant at the first temperature and coolant at the second temperature to the further object.

According to an embodiment of the invention, the control unit is configured toestimate the temperature of the coolant to be supplied to the further object by means ofinformation about the heated coolant temperature, the first coolant temperature, thesecond temperature. The above mentioned coolant temperatures varies during differentoperating conditions. Thus, it is necessary for the control unit to substantiallycontinuously receive information about actual values of said temperatures.Temperature sensors, Which are arranged in suitable positions in the cooling system, may provide the control unit With this information.

According to an embodiment of the invention, the control unit is also configured todetermine the cooling demand of the further object by means of information about thecoolant ﬂoW rate in the cooling system. The cooling effect of the further objectdepends on the temperature difference between the coolant and the further object andthe coolant ﬂoW rate to the further component. The coolant ﬂoW rate in the coolingsystem is defined by the coolant pump. The pump may be driven by the combustionengine. ln this case, the coolant ﬂoW rate is related to the speed of the combustionengine. The control unit may by information about the actual coolant ﬂoW rate in thecooling system estimate the temperature of the coolant to be directed to the further object With a high accuracy.

According to an embodiment of the invention, the further object is a Working mediumcooled in a condenser of a WHR system. Preferably, the coolant directed to thecondenser has a temperature and a ﬂoW rate Which results in a cooling of the Workingmedium in the condenser to a condensation pressure just above l bar. lt is nearlyalways possible to provide a coolant ﬂoW rate through the condenser Which results in acooling of the Working medium in the condenser to a desired condensationtemperature/pressure at different operating condition. HoWever, by practical reasons,it is many times suitable to avoid negative pressures in a WHR-system. ln this case, itis suitable to obtain a condensation pressure just above l bar. The desired pressurerange may, for example, be in the range l, l - l, 5 bar. It is to be noted that acondensation pressure for a Working medium has a corresponding condensationtemperature. The Working medium in the WHR- system may be ethanol. Ethanol has anevaporation temperature of about 78°C at l bar. It is relatively easy to accomplish acoolant temperature at a suitable level beloW the evaporation temperature of ethanoland cool the ethanol in a condenser to a condensation temperature just above 78°C.

HoWever, it is possible to use other Working mediums such as for example R245fa.

Alternatively, the further object may be another object which requires a well-controlled cooling for optimal efficiency. Such objects may be charge air, hybrid power electronics etc..

BRIEF DESCRIPTION OF THE DRAVVINGS In the following a preferred embodiment of the invention is described, as an example, with reference to the attached drawings, in which: Fig. l shows a cooling system comprising a multi-valve device according to theinvention, Fig. 2 shows a the multi-valve more in detail and Fig. 3 shows graphs defining the coolant ﬂow rate, via different ports of the multiple-valve, to the combustion engine and the condenser as a function of the angular position of a valve body.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THEINVENTION Fig. l shows a schematically disclosed vehicle l powered by a combustion engine 2.The vehicle l may be a heavy vehicle and the combustion engine 2 may be a dieselengine. The vehicle l comprises a cooling system comprising an engine inlet line 3directing coolant to the combustion engine 2. The engine inlet line 3 is provided with acoolant pump 4 circulating a coolant in the cooling system. Initially, the pump 4circulates the coolant to the combustion engine 2. The coolant cools the combustionengine 2. The coolant leaving the combustion engine 2 is received in an engine outletline Sa. The coolant leaving the combustion engine 2 has a heated temperature TH. Thecooling system comprises a multi-valve device. The multi-valve device comprises amulti-valve 5, an actuator 6 and a control unit 7. The multi-valve 5 receives coolant atthe heated temperature TH via the engine outlet line Sa. The cooling system comprisesa first radiator 8 in which the coolant is cooled to a first temperature T1 and a secondradiator 9 in which the coolant is cooled to a second temperature Tz. In this case, acharge air cooler l0 is arranged between the first radiator 8 and the second radiator 9.A radiator fan ll and the ram air provide a cooling air stream through the secondradiator 9, the charge air cooler l0 and the first radiator 8 during operation of the vehicle l. The second radiator 9 is arranged in an upstream position of the first radiator 8 in view of the ﬂow direction of the cooling air stream. Consequently, during mostoperating conditions, the coolant in the second radiator 9 is cooled to a lowertemperature than the coolant in the first radiator 8. Thus, the second coolant temperature Tz is generally lower than the first coolant temperature T1.

As indicated above, the multi-valve 5 is connected to the engine outlet line 5a.Furthermore, the multi-valve 5 is connected to a primary bypass line 5b directingcoolant at the heated temperature TH back to the combustion engine 2 without cooling,a first radiator inlet line 5c directing coolant at the heated temperature TH to the firstradiator 8, a first radiator outlet line 5d directing coolant at the first temperature T1from the first radiator 8a back to the multi-valve 5, a first engine line 5e directingcoolant at the first temperature T1 to the combustion engine 2, a secondary bypass line5f directing coolant at the heated temperature TH, via a condenser inlet line 18a, to acondenser 18 in a WHR system, a second condenser line 5g directing coolant at thesecond temperature Tz , via a condenser inlet line 18a, to a condenser 18 and a firstcondenser line 5h directing coolant at the first temperature T1, via the condenser inletline 18a, to the condenser 18. A condenser outlet line 18b directs the coolant from thecondenser 18 to the engine inlet line 3. Alternatively, the condenser outlet line 18b directs the coolant from the condenser 18 to the engine outlet line 5a.

A first temperature sensor 22 senses the temperature T1 of the coolant leaving the firstradiator 8, a second temperature sensor 23 senses the temperature Tz of the coolantleaving the second radiator 9, and a third temperature sensor 24 senses the heatedcoolant temperature TH in the engine outlet line 5a. The control unit 7 receivesinformation from the temperature sensors 22-24 about the actual temperatures TH, T1,Tz. The control unit 7 also receives information 4a about the coolant ﬂow rate in thecooling circuit. The coolant ﬂow rate is defined by the speed of the pump 4. In case,the pump 4 is driven by the combustion engine 2, the coolant ﬂow rate in the cooling system is related to the speed of the combustion engine 2.

The vehicle is provided with a WHR- system (Waste Heat Recovery system). TheWHR- system comprises a pump 12 which pressurizes and circulates a workingmedium in a closed circuit 13. In this case, the working medium is ethanol. However,it is possible to use other kinds of working mediums such as for example R245fa. Thepump 12 pressurizes and circulates the working medium to an evaporator 14. The working medium is heated in the evaporator 14, for example, by eXhaust gases from the combustion engine. The Working medium is heated in the evaporator 14 to atemperature at Which it evaporates. The Working medium is circulated from theevaporator 14 to an eXpander 15. The pressurised and heated Working medium eXpandsin the eXpander 15. The eXpander 15 generates a rotary motion Which may betransmitted, via a suitable mechanical transmission 16, to a shaft 17 of the power trainof the vehicle 1. Alternatively, the eXpander 15 may be connected to a generatortransforn1ing mechanical energy into electrical energy. The electrical energy may bestored in a battery. The stored electrical energy can be supplied to an electrical engine for driving of the vehicle or a component on the vehicle in a later state.

After the Working medium has passed through the eXpander 15, it is directed to thecondenser 18. The Working medium is cooled in the condenser 18 by coolant from thecooling system to a temperature at Which it condenses. The Working medium isdirected from the condenser 18 to a receiver 19. The pressure in the receiver 19 can bevaried by means of a pressure regulator 19a. The pump 12 sucks Working mediumfrom the bottom of the receiver 19 ensuring that only Working medium in a liquid stateis supplied to the pump 12. A second control unit 20 controls the operation of theWHR-system. The second control unit 20 controls the operation of the pump 12 andthe eXpander 15. The WHR- system makes it possible to transform therrnal energy fromthe eXhaust gases to mechanical energy or electrical energy. A temperature sensor 21or a pressure sensor senses the condensation temperature or the condensation pressure in the condenser 18.

The temperature of eXhaust gases and thus the heating effect of the Working medium inthe evaporator 14 varies during different operating conditions. ln order to maintain asubstantially continuously high therrnal efficiency in the WHR- system, the Workingmedium in the condenser 18 is to be cooled With an adjustable cooling effect. It isfavourable to establish a condensation pressure as loW as possible at the differentoperating conditions. HoWever, it is suitable to avoid negative pressure in the WHR-system by practical reasons. ln vieW of these facts, it is suitable to provide a cooling ofthe Working medium in the condenser 18 to a condensation pressure just above 1bar.Consequently, in order to maintain a high thermal efficiency it is necessary to adjustthe cooling effect of the Working medium in the condenser 18 in vieW of the suppliedheat energy from the eXhaust gases such that the condensation pressure Will be just above 1 bar. The Working medium ethanol has a condensation temperature of 78°C at 1 bar. ln this case, it is suitable to accomplish a condensation temperature of just above78°C in the condenser 18.

Fig. 2 shows the multi-valve 5 more in detail. The multi-valve comprises a cylinder-shaped housing 25 and a Valve body 26 rotatably arranged in the housing 25 around arotation aXis 27. The housing 25 and the Valve body 26 has a longitudinal extension inthe direction of the rotation aXis 27. The Valve body 26 comprises three hollowspherical Valve parts 26a, 26b, 26c arranged in different transverse planes A, B, C ofthe housing 25. A first hollow part 26a and a second hollow part 26b are designed as aunit. Said unit comprises an inner ﬂow passage 26d allows ﬂow communicationbetween the first Valve part 26a and the second Valve part 26b. A third Valve part 26c isconnected to the first Valve part 26a Via a first shaft 26e. The second Valve part 26b isconnected to the actuator 6 Via a second shaft 26f. The Valve parts 26a-26c and theshafts 26e, 26f define the Valve body 26 which is rotatably arranged as a unit by the actuator 6.

The Valve body26 is rotatably arranged around the rotation aXis 27 by means ofbearings 29. The bearings 29 are arranged between the housing 25 and the shafts 26e,26f. A plurality of seals in the form of O-rings 30 are arranged between the shafts 26e,26f and the housing 25. The actuator 6, which may be an electric motor, is configuredto rotate the Valve body 26 to different angular positions in the housing 25. Thehousing 25 comprises a plurality of ports 5a°-5h° arranged in different transverseplanes A, B, C of the housing 25. The housing 25 comprises, in the first transverseplane A, a first port 5a'to be connected to the engine outlet line 5a, a second port 5b° tobe connected to the primary bypass line 5b, and a third port 5c° to be connected to thefirst radiator inlet line 5c. The housing 25 comprises, in the second transverse plane B,a siXth port 5f° to be connected to the secondary bypass line 5e and a seventh port 5g°to be connected to the second radiator inlet line 5g. The housing 25 comprises, in thethird transverse plane C a fourth port 5d° to be connected to the first radiator outlet line5d, a fifth port 5e° to be connected to the first engine line 5e, and an eight port 5h° tobe connected to the first condenser line 5h. The first port 5a°, the second port 5b° andthe third port 5c° of the housing 25 are in communication with the first Valve part 26aof the Valve body 26. The siXth port 5f°, and the seventh port 5g° are in communicationwith the second Valve part 26b of the Valve body 26. The fourth port 5d°, the fifth port5e° and the eighth port 5h° are in communication with third Valve part 26c of the Valvebody 26.

The first Valve part 26a comprises at least one periphery opening 31. The opening 31may extend around a relatively large part of the circumference of the first valve part26a of the valve body. The opening 31 is configured to more or less coincide with thefirst port Sa', the second port Sb' and the third port Sc' in different angular positions.The second valve part 26b comprises at least two periphery openings 32, 33 extendingaround different circumference parts of the second valve part 26b. The openings 32, 33are configured to more or less coincide with the sixth port Sf' and the seventh portSg'in different angular positions. The third valve part 26c comprises at least oneperiphery opening 34 extending around a part of the circumference of the third valvepart 26c. The opening 34 is configured to more or less coincide with the fourth portSd', the fifth port Se' and the eighth port Sh' in different angular positions. A sealing36 is arranged between each valve part 26a, 26b, 26c of the valve body 26 and thehousing 2S. The relative position between the openings 31-34 of the valve body 26and the ports Sa'-Sh' of the housing 2S defines an adjustable ﬂow area for the coolant.In case, an opening 31-34 completely coincides with one of the ports Sa'-Sh', the ﬂowarea and the coolant ﬂow rate are at a maximum. In case the openings 31-34 partlycoincides with the ports Sa'-Sh' the ﬂow area and the coolant ﬂow rate will be lowerthan the maximum. The ports Sf'-Sh' directing coolant to condenser 18 have smallercross sectional areas than the remaining ports Sa'-Se'. As a consequence, the multi-valve 26 directs a lower coolant ﬂow rate to the condenser 18 than to the combustion engine 2.

Fig. 3 shows an example of the coolant ﬂow rate at different temperatures directed tothe combustion engine 2 and the condenser 18. A first graph I, which is shown with abold solid line, indicates the coolant ﬂow rate at the heated temperature TH directed tothe combustion engine via the second port Sb' and the primary bypass line Sb. Asecond graph II, which is shown with a thin solid line, indicates the coolant ﬂow rate atthe first temperature directed to the combustion engine 2 via the fifth port Se' and thefirst engine line Se. Consequently, the graphs I and II define the coolant ﬂow rate tothe combustion engine 2. The sum of the coolant ﬂow rates in graph I and graph II isdefined as 100% when the valve body 26 is within an angular range of 20°-360° in thehousing 2S. A third graph III, which is shown with a dashed and dotted line, indicatesthe coolant ﬂow rate at the heated temperature TH to the condenser 18 via the sixthport Sf' and secondary bypass line Sf. A fourth graph IV, which is shown with a dashed line, indicates the coolant ﬂow rate at the second coolant temperature Tz 11 directed to the condenser 18 via the Seventh port 5g and the second condenser line 5g.A fifth graph V, which is shown with a dotted line, indicates the coolant ﬂow rate atthe first coolant temperature T1 directed to the condenser 18 via the eighth port 5h° andthe first condenser line 5h. Thus, the graphs III, IV, V indicate the coolant ﬂow rate atthree different temperatures TH, T1 and Tz to be directed to the condenser 18 atdifferent angular positions of the valve body 26 in the housing 25. The sum of thecoolant ﬂow rates defined in the graphs III, IV, V is 50% of the coolant ﬂow rates tothe combustion engine 2 when the valve body 26 is within an angular range of 30°-350° in relation to the housing 25. Consequently, the multi-valve 5 is designed suchthat it directs a lower coolant ﬂow rate to the condenser l8 than to the combustion engine 2 within a main part of the angular range.

During operation, the control unit 7 receives substantially continuously informationfrom said temperature sensors 22, 23, 24 about the actual coolant temperatures TH, T1,Tz and information 4a about the actual coolant ﬂow rate in the cooling system. Duringoperating conditions when the combustion engine 2 has a lower temperature than alowest temperature within an optimal operating temperature range, the combustionengine 2 does not need to be cooled at all. The control unit 7 initiates an activation ofthe actuator 6 such that it moves the valve body 26 to an angular position within theangular range of 280°-350° in which 100% of uncooled coolant at the heatedtemperature TH is directed to the combustion engine 2. Thus, no coolant is directed tothe first radiator. In the above mentioned angular range, it is possible to vary thecoolant ﬂow temperature directed to the condenser l8. It is, for example, possible todirect uncooled coolant at the heated temperature TH according to graph III to thecondenser, cooled coolant at the condenser temperature Tz according to graph IV to thecondenser l8 or an arbitrary n1ix of coolant of said coolant temperatures TH, Tz to thecondenser l8. The control unit 7 also receives information from the second control unit20 about the operating condition of the WHR system. The control unit 7 may, forexample, receive information from the sensor 2l about the actual condensationtemperature in the condenser l8. The control unit 7 estimates a desired condensationtemperature of the working medium in the condenser l8. When ethanol is used asworking medium, a condensation temperature of about 80°C is desirable during mostoperating conditions. The control unit 7 is able to vary the temperature of the coolantdirected to the condenser l8. The control unit 7 estimates a required temperature of thecoolant to be directed to the condenser l8 at the constant coolant ﬂow rate in order to cool the working medium to the desired condensation temperature in the condenser l8. 12 The control unit 7 deterrnines one angular position of the valve member 26 Within theangular range 280°-350° at Which the coolant has the required temperature for cooling the Working medium to the desired condensation temperature in the condenser 18. Thecontrol unit 7 activates the actuator 6 Which rotates the valve member 26 to the determined angular position.

During operating conditions When the combustion engine 2 has a temperature Withinthe optimal operating temperature range, some cooling of the combustion engine isusually required in order to maintain the temperature of the combustion engine 2. lnthis case, the control unit 7 may initiate a movement of the valve body 26 to an angularposition Within the angular range 120°-280° in Which a miXture of coolant at the heatedtemperature TH and the first temperature T1 is directed to the combustion engine 2. Inthe above mentioned angular position range, it is possible to direct coolant at the firstcoolant temperature T1 according to graph V to the condenser 18, coolant at the secondcoolant temperature Tz according to graph IV to the condenser 18 or an arbitrary mixof coolants at said temperatures T1, Tz to the condenser 18. The control unit 10receives information from the second control unit 20 about the operating condition ofthe WHR system. The control unit 7 estimates a required temperature of the coolant tobe directed to the condenser 18 at the actual coolant ﬂoW rate in the cooling system inorder to cool the Working medium to the desired condensation temperature in thecondenser 18. The control unit 7 determines an angular position of the valve member26 Within the angular range 120°-280° at Which the coolant cools the combustionengine 2 and the Working medium in the condenser 18 in an optimal manner. Thecontrol unit 7 activates the actuator 6 Which rotates the valve member 26 to the determined angular position.

During operating conditions When the combustion engine 2 has a higher temperaturethan a highest temperature in an optimal operating temperature range, the combustionengine 2 does need to be cooled in an optimal manner. The control unit 7 initiates andactivation of the actuator to an angular position Within the angular range of 10°-120° inWhich 100% coolant at the first temperature T1 is directed to the combustion engine 2.ln the above mentioned angular range, it is possible to direct uncooled coolant at theheated temperature TH, according to graph III, to the condenser 18, coolant at thesecond temperature Tz, according to graph V, to the condenser 18 or an arbitrary mixof coolant at the heated temperature TH and the second temperature Tz to the condenser 18. The control unit 7 receives information from the second control unit 20 13 about the operating condition of the WHR system. The control unit 7 estimates arequired temperature of the coolant to be directed to the condenser 18 at the actualcoolant ﬂoW rate in the cooling system order to cool the Working medium to thedesired condensation temperature in the condenser 18. The control unit 7 detern1inesan angular position of the Valve member 26 Within the angular range 10°-120° atWhich the coolant cools the Working medium to the desired condensation temperaturein the condenser 18. The control unit 7 activates the actuator 6 Which rotates the Valve member 26 to the determined angular position.

The invention is not restricted to the described embodiment but may be Varied freely Within the scope of the claims.

Claims

14 Claims

1. l. A multi-valve device for a Cooling system configured to cool a combustion engine(2) and at least one further object (18), Wherein the cooling system comprises a pump(4) circulating a coolant in the cooling system, an engine outlet line (5a) receivingcoolant at a heated temperature (TH), a first radiator (8) cooling the coolant to a firsttemperature (T1), and a second radiator (9) cooling the coolant to a secondtemperature (Tz) Which is lower than the first temperature (T1) during most operatingconditions of the cooling system, characterized in that the multi- valve devicecomprises - a housing (25) comprising a first port (5a°) receiving coolant at the heatedtemperature (TH) from the engine outlet line (5a), a second port (5b°) directing coolantat the heated temperature (TH) to the combustion engine (2), a third port (5c°) directingcoolant at the heated temperature (TH) to the first radiator (8), a fourth port (5d°)receiving coolant at the first temperature (T1) from the first radiator (8), a fifth port(5e°) directing coolant at the first temperature (T1) to the combustion engine (2), asiXth port (5f°) directing coolant at the heated temperature (TH) to the further object(l8), a seventh port (5g°) directing coolant at the second temperature (Tz), via thesecond radiator (9), to the further object (l8), and - a holloW valve body (26) rotatably arranged to different angular positions in thehousing (25) and Which comprises a number of openings (31-34) coinciding With theports (5a°-5g°) in the housing (25) such that coolant at the heated temperature (TH),coolant at the first temperature (T1) or a specific miXture of these coolants is directedto the combustion engine (2) and that coolant at the heated temperature (TH), coolant atthe second temperature (Tz) or a miXture of coolants of said temperatures (TH, Tz) aredirected to the further object (l8) in dependence of the angular position of the valvebody (26) in the housing (25).

2. A multi-valve device for a cooling system, characterized in that it comprises anactuator (6) configured to rotate the valve body (26) to different angular positions inthe housing (25), and a control unit (7) configured to initiate activation of the actuator(6) such that it rotates the valve body (26) to a deterrr1ined angular position in thehousing (25).

3. A multi-valve device for a cooling system, characterized in that the multi-valvecomprises an eighth port (5h°) directing coolant at the first temperature (T1) to thefurther object (l8).

4. A multi-valve device according to any one of the preceding claims, characterized inthat the valve body (26) comprises three holloW valve parts (26a-26c) rigidly connected to each other and rotatably arranged around a rotation aXis (27).

5. A multi-valve device according to claim 4, characterized in that said three holloW valve parts (26a, 26c) has a spherical shape.

6. A multi-valve device according to claim 4 or 5, characterized in that the first valvepart (26a) comprises at least one opening (31) to be connectable to the first port (5a°),the second port (5b°) and the third port (5c°) of the housing (25).

7. A multi-valve device according to any one of the claims 4 to 6, characterized in thata second valve part (26b) comprises at least one opening (32, 33) to be connectable tothe siXth port (5a°) and the seventh port (5g°).

8. A multi-valve device according to claim 6 and 7, characterized in that the valvebody comprises a ﬂoW passage (26d) between the first valve part (26a) and the secondvalve part (26b).

9. A multi-valve device according to any one of the claims 4 to 8, characterized in thata third valve part (26c) comprises at least one opening (34) is connectable to the fourthport (5d°), the fifth port (5e°) and the eighth port (5g°).

10. l0. A multi-valve device according to any one of the preceding claims, characterizedi_n that the ports ( 5f°-5h°) directing coolant to the further object (18) has a smaller cross sectional area than the ports (5b°- 5c°) directing coolant to the combustion engine (2)-

11. ll. A multi-valve device according to any one of the preceding claims, characterizedi_n that the control unit (7) is configured to receive information about a parameterrelated to the temperature of the combustion engine (2), to estimate the temperature ofthe coolant to be supplied to the combustion engine (2), to determine an angularposition of the valve body (26) in the housing (25) at Which coolant of said estimated coolant temperature is directed to the combustion engine (2), and to activate the 16 actuator (6) such that it moves the Valve body (26) to the determined angular positionin the housing (25).

12. A multi-valve device according to any one of the preceding claims, characterizedi_n that the control unit (7) is configured to receive information about a parameterrelated to the temperature of the further object (18), to estimate the temperature of thecoolant to be supplied to the further object (18), to determine an angular position of thevalve body (26) in the housing (25) at Which coolant of said estimated coolanttemperature is directed to the further object (18), and to activate the actuator (6) suchthat it moves the valve body (26) to the deterrnined angular position in the housing(25).

13. A multi-valve device according to any one of the proceeding claims, characterizedi_n that the control unit (7) is configured to estimate temperature of the coolant to besupplied to the further object (18) by means of information about the heated coolant temperature (TH), the first coolant temperature (Ti), the second temperature (Tz).

14. A multi-valve device according to claim 13, characterized in that the control unit(7) is configured to determine the cooling demand of the further object (18) by means of information (4a) about the coolant ﬂoW rate in the cooling system.

15. A multi-valve device according to any one of the preceding claims, characterizedi_n that the further object is a Working medium cooled in a condenser (18) of a WHR system.