SE541222C2

SE541222C2 - A multi-valve and a multi-valve device for a cooling system

Info

Publication number: SE541222C2
Application number: SE1650652A
Authority: SE
Inventors: Ola Hall; Zoltan Kardos
Original assignee: Scania Cv Ab
Priority date: 2016-05-16
Filing date: 2016-05-16
Publication date: 2019-05-07
Also published as: DE102017004438B4; SE1650652A1; DE102017004438A1

Abstract

The present invention relates to a multi-valve for a cooling system configured to cool a combustion engine (2) and at least one further object (18). The multi- valve comprises a hollow valve body (26) rotatably arranged to different angular positions in a housing (25). The valve body (26) comprises a first valve part (26a) arranged in a first transverse plane (A) through the housing (25). The first valve part (26a) comprises at least one opening (31) coinciding with ports (5a’, 5b’, 5c’) in the housing (25). This ports (5a’, 5b’, 5c’) receives heated coolant and they direct the received coolant to the combustion engine or/and to the first radiator. The valve body (26) comprises a second valve part (26b) arranged in a second transverse plane (B) through the housing (25). The second valve part (26b) comprises at least one opening (32, 33) coinciding with ports (5f , 5g’) in the housing (25). This ports (5f, 5g’) direct coolant to the further object (18) or/and the second radiator (9). The multi-valve comprises a temperature controlled valve member (28) arranged in a flow passage (26d) between the first valve part (26a) and the second valve part (26b). The valve member (28) is configured to block the flow passage (26d) when the coolant has a lower temperature than a regulating temperature of the valve member (28).

Description

A multi-valve and a multi-valve device for a cooling system BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates to a multi-valve for a cooling system according to the preamble of claim 1.

A cooling system in a vehicle is many times used to cool a combustion engine and at least one further object. The further object may be a component or fluid. In certain case, such a further object may require a lower operating temperature than the combustion engine. In this case, the cooling system can create two coolant temperatures using two radiators cooled by air of different temperatures. The coolant at the higher temperature may be directed to the combustion engine and the coolant at the lower temperature may be directed to said further object. Certain object requires a well-controlled cooling for optimal efficiency. In this case, the design of the cooling system 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 recovering waste thermal energy and convert it to mechanical energy or electric energy. The WHR system may absorb waste thermal energy from the exhaust gases of a combustion 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 as low as possible and substantially without subcooling. In order to achieve such a condensation temperature, the working medium is to be cooled with coolant of a suitable temperature and flow rate. However, the required cooling effect of the working medium in the condenser may vary rapidly with the temperature and flow rate of the exhaust gases. Thus, it is necessary to continuously provide a quick and reliable control 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 in a cooling system which is able to exclusively control the coolant flow in the cooling system and provide 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 according to the characterized part of claim 1. The multiple valve comprises a valve body including a first valve part and a second valve part. The first valve part receives heated coolant which it directs to the combustion engine and /or to the first radiator. The second valve part has a port directing coolant to the second radiator. A flow passage is arranged between the first valve part and the second valve part. The flow passage comprises a valve member. The valve member is configured to close the flow passage when the received heated coolant in the multi-vale has a lower temperature than a regulating temperature and to open the flow passage when the heated coolant has a higher temperature than a regulating temperature. The temperature of the heated coolant is related to the temperature of the combustion engine. During operating conditions when the combustion engine has a low temperature, it is desired to heat the combustion engine to its optimal operating temperature as quick as possible. In this case, the valve member closes the flow passage between the first valve part and the second valve part. As a consequence, no coolant flow is directed to the second valve part and the second radiator. In order to further increase the heating process of the combustion engine, the valve body is moved to an angular position in the housing in which no coolant flow is directed to the first radiator. Thus, the entire heated coolant flow rate is directed to the combustion engine without cooling. The existence of the valve member in the flow passage between the first valve part and the second valve part simplifies the control of the coolant flow during operating conditions when the combustion engine has a low temperature. As soon as the combustion engine receives an optimal operating temperature, the valve member is to be moved to the open position such that it is possible to direct coolant to the second valve part and the second radiator.

According to an embodiment of the invention, the valve member comprises a blocking member movably arranged between a closed position in which it blocks said flow passage and an open position in which it allows a coolant flow through the flow passage and a power unit configured to move the blocking member to the open position against the action of a spring member when the coolant has a higher temperature than said regulating temperature. Such a valve member may have a relatively simple design. Alternatively, the spring moves the blocking member to the closed position and the power unit moves the blocking member to the open position against the action of the spring. The power unit may comprise a casing enclosing a material configured to change volume at the regulating temperature. The material may be a suitable wax material changing phase between a solid phase and a liquid phase at the regulating temperature. Such a power unit is inexpensive and it has a very reliable function. In this case, the valve member may be designed as a wax thermostat.

Alternatively, the power member may be an electrical switch which moves the blocking member between the open position and the closed position in view of the temperature of the heated coolant. A temperature sensor may sense the temperature of the coolant leaving the combustion engine, a control unit may receive information about the coolant temperature and control the electric switch such that it moves the blocking member to the closed position when the heated coolant has a lower temperature than the regulating temperature and to the open position when the heated coolant has a higher temperature than the regulating temperature.

According to an embodiment of the invention, the housing comprises, in the second transverse plane, a port directing heated coolant to the further object. Thus, the housing comprises, a port directing coolant, via the second radiator, to the further object and a port directing heated coolant to the further object. Consequently, it is possible to direct coolant at the second temperature, coolant at the heated temperature or and mixture of coolant having an arbitrary temperature in a temperature range defined by the heated temperature and the second temperature to the further object.

According to an embodiment of the invention, the housing comprises further ports in a third transverse plane, wherein the valve body comprises a third valve part comprising at least one opening configured to coincide with the at least one port in the third transverse plane of the housing. The housing may, in the third transverse plane, comprise a port receiving coolant from the first radiator, a port directing the received coolant from the first radiator to the combustion engine and a port directing the received coolant from the first radiator to the further object. Thus, the third valve part receives coolant at the first temperature and directs it to the combustion engine and/or the further object.

According to an embodiment of the invention, the third valve part is rigidly connected to the first valve part and the second valve part such they are rotatably arranged in the housing as a unit. Thus, all parts of the valve body are rotated simultaneously by the actuator to a common angular position in the housing. The valve parts may have a spherical- shape. Such a design makes it relatively easy to provide a tight sealing between the respective spherical valve parts and the housing. Alternatively, the hollow parts may have a cylindrical-shape.

According to an embodiment of the invention, the ports directing coolant to the further object has a smaller cross sectional area than the ports directing coolant to the combustion engine. The cross section area of the ports define the flow area for the coolant and the coolant flow rate. During most operating conditions, the combustion engine needs to be cooled with a larger cooling effect than the further object. The cooling effect is related to the temperature difference and the coolant flow rate. One way to direct a smaller coolant flow rate to the further object than to the combustion engine is to give the ports directing coolant to the further object smaller dimensions than the ports directing coolant at the combustion engine.

According to an embodiment of the invention, the multi-valve is a part of multi-valve device which except the multi-valve comprises an actuator configured to rotate the valve body to different angular positions in the housing, and a control unit configured to initiate activation of the actuator such that it rotates the valve body to a determined angular position in the housing. The actuator may be an electric motor and the control unit may be a computer unit having access to information about suitable angular positions of the valve body in the housing at different operating conditions.

BRIEF DESCRIPTION OF THE DRAWINGS In the following a preferred embodiment of the invention is described, as an example, with reference to the attached drawings, in which: Fig. 1 shows a cooling system comprising a multi-valve according to the invention, 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 THE INVENTION Fig. 1 shows a schematically disclosed vehicle 1 powered by a combustion engine 2. The vehicle 1 may be a heavy vehicle and the combustion engine 2 may be a diesel engine. The vehicle 1 comprises a cooling system comprising an engine inlet line 3 directing coolant to the combustion engine 2. The engine inlet line 3 is provided with a coolant pump 4 circulating a coolant in the cooling system. Initially, the pump 4 circulates the coolant to the combustion engine 2. The coolant cools the combustion engine 2. The coolant leaving the combustion engine 2 is received in an engine outlet line 5a. The coolant leaving the combustion engine 2 has a heated temperature TH. The cooling system comprises a multi-valve device. The multi-valve device comprises a multi-valve 5, an actuator 6 and a control unit 7. The multi-valve 5 receives coolant at a heated temperature THvia the engine outlet line 5 a. The cooling system comprises a first radiator 8 in which the coolant is cooled to a first temperature T1and a second radiator 9 in which the coolant is cooled to a second temperature T2. In this case, a charge air cooler 10 is arranged between the first radiator 8 and the second radiator 9. A radiator fan 11 and the ram air provide a cooling air stream through the second radiator 9, the charge air cooler 10 and the first radiator 8 during operation of the vehicle 1. 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 most operating conditions, the coolant in the second radiator 9 is cooled to a lower temperature than the coolant in the first radiator 8. Thus, the second coolant temperature T2is generally lower than the first coolant temperature T1.

As indicated above, the multi-valve 5 is connected to the engine outlet line 5 a.

Furthermore, the multi-valve 5 is connected to a primary bypass line 5b directing coolant at the heated temperature THback to the combustion engine 2 without cooling, a first radiator inlet line 5 c directing the coolant at the heated temperature THto the first radiator 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 directing coolant at the first temperature T1to the combustion engine 2, a secondary bypass line 5f directing coolant at the heated temperature TH, via a condenser inlet line 18a, to a condenser 18 in a WHR system, a second condenser line 5g directing coolant at the second temperature T2, via the condenser inlet line 18a, to the condenser 18 and a first condenser line 5h directing coolant at the first temperature T1, via the condenser inlet line 18a, to a condenser 18. A condenser outlet line 18b directs the coolant from the condenser 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 5 a.

A first temperature sensor 22 senses the temperature T1of the coolant leaving the first radiator 8, a second temperature sensor 23 senses the temperature T2of the coolant leaving the second radiator 9, and a third temperature sensor 24 senses the heated coolant temperature THin the engine outlet line 5 a. The control unit 7 receives information from the temperature sensors 22-24 about the actual temperatures TH, T1, T2. The control unit 7 also receives information 4a about the coolant flow rate in the cooling 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). The WHR-system comprises a pump 12 which pressurizes and circulates a working medium 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. The pump 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 a temperature at which it evaporates. The working medium is circulated from the evaporator 14 to an expander 15. The pressurised and heated working medium expands in the expander 15. The expander 15 generates a rotary motion which may be transmitted, via a suitable mechanical transmission 16, to a shaft 17 of the power train of the vehicle 1. Alternatively, the expander 15 may be connected to a generator transforming mechanical energy into electrical energy. The electrical energy may be stored 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 the condenser 18. The working medium is cooled in the condenser 18 by coolant from the cooling system to a temperature at which it condenses. The working medium is directed from the condenser 18 to a receiver 19. The pressure in the receiver 19 can be varied by means of a pressure regulator 19a. The pump 12 sucks working medium from the bottom of the receiver 19 ensuring that only working medium in a liquid state is supplied to the pump 12. A second control unit 20 controls the operation of the WHR-system. The second control unit 20 controls the operation of the pump 12 and the expander 15. The WHR-system makes it possible to transform thermal energy from the exhaust gases to mechanical energy or electrical energy. A temperature sensor 21 or 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 in the evaporator 14 varies during different operating conditions. In order to maintain a substantially continuously high thermal efficiency in the WHR-system, the working medium in the condenser 18 is to be cooled with an adjustable cooling effect. It is favourable to establish a condensation pressure as low as possible at the different operating conditions. However, it is suitable to avoid negative pressure in the WHR-system by practical reasons. In view of these facts, it is suitable to provide a cooling of the working medium in the condenser 18 to a condensation pressure just above 1 bar. Consequently, in order to maintain a high thermal efficiency it is necessary to adjust the cooling effect of the working medium in the condenser 18 in view of the supplied heat 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. In this case, it is suitable to accomplish a condensation temperature of just above 78°C in the condenser 18.

Fig. 2 shows the multi-valve 5 more in detail. The multi-valve comprises a cylindershaped housing 25 and a valve body 26 rotatably arranged in the housing 25 around a rotation axis 27. The housing 25 and the valve body 26 has a longitudinal extension in the direction of the rotation axis 27. The valve body 26 comprises three hollow spherical valve parts 26a, 26b, 26c arranged in different transverse planes A, B, C of the housing 25. A first hollow part 26a and a second hollow part 26b are designed as a unit. Said unit comprises an inner flow passage 26d allows flow communication between the first valve part 26a and the second valve part 26b. A valve member 28 is arranged in the flow passage 26d. The valve member 28 comprises a blocking member 28a movably arranged between a closed position in which it blocks said flow passage 26d and an open position in which it allows coolant flow through the flow passage 26d. A power unit 28b is configured to move the blocking member 28a to the open position against the action of a spring member 28c when the coolant has a higher temperature than said regulating temperature. In this case, the power unit is exemplified as a casing 28b enclosing a material configured to change phase and volume at the regulating temperature. The material may be a wax material changing phase between a solid phase and a liquid phase at the regulating temperature. A third valve part 26c is connected to the first valve part 26a via a first shaft 26e. The second valve part 26b is connected to the actuator 6 via a second shaft 26f. The valve parts 26a-26c and the shafts 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 of bearings 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 configured to rotate the valve body 26 to different angular positions in the housing 25. The housing 25 comprises a plurality of ports 5a’-5h’ arranged in different transverse planes A, B, C of the housing 25. The housing 25 comprises, in the first transverse plane A, a first port 5 a 'to be connected to the engine outlet line 5 a, a second port 5b’ to be connected to the primary bypass line 5b, and a third port 5c’ to be connected to the first radiator inlet line 5c. The housing 25 comprises, in the second transverse plane B, a sixth port 5 f 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 the third transverse plane C a fourth port 5d’ to be connected to the first radiator outlet line 5d, a fifth port 5e’ to be connected to the first engine line 5e, and an eight port 5h’ to be connected to the first condenser line 5h. The first port 5a’, the second port 5b’ and the third port 5c’ of the housing 25 are in communication with the first valve part 26a of the valve body 26. The sixth port 5f , and the seventh port 5g’ are in communication with the second valve part 26b of the valve body 26. The fourth port 5d’, the fifth port 5e’ and the eighth port 5h’ are in communication with third valve part 26c of the valve body 26.

The first valve part 26a comprises at least one periphery opening 31. The opening 31 may extend around a relatively large part of the circumference of the first valve part first port 5a', the second port 5b’ and the third port 5c’ in different angular positions. The second valve part 26b comprises at least two periphery openings 32, 33 extending around a part of the circumference of the second valve part 26b. The openings 32, 33 are configured to more or less coincide with the sixth port 5f and the seventh port 5g’in different angular positions. The third valve part 26c comprises at least one periphery opening 34 extending around a part of the circumference of the third valve part 26c. The opening 34 is configured to more or less coincide with the fourth port 5d’, the fifth port 5e’ and the eighth port 5h’ in different angular positions. A sealing 36 is arranged between each valve part 26a, 26b, 26c of the valve body 26 and the housing 25. The relative position between the openings 31 -34 of the valve body 26 and the ports 5a’-5h’ of the housing 25 defines an adjustable flow area for the coolant. In case, an opening 31-34 completely coincides with one of the ports 5a’-5h’, the flow area and the coolant flow rate are at a maximum. In case the openings 31-34 partly coincides with the ports 5a’-5h’ the flow area and the coolant flow rate will be lower than the maximum. The ports 5f -5h’ directing coolant to condenser 18 have smaller cross sectional areas than the remaining ports 5a’-5e’. As a consequence, the multivalve 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 to the combustion engine 2 and the condenser 18. A first graph I, which is shown with a bold solid line, indicates the coolant flow rate at the heated temperature THdirected to the combustion engine via the second port 5b’ and the primary bypass line 5b. A second graph II, which is shown with a thin solid line, indicates the coolant flow rate at the first temperature T1directed to the combustion engine 2 via the fifth port 5e’ and the first engine line 5e. Consequently, the graphs I and II define the coolant flow rate to the combustion engine 2. The sum of the coolant flow rates in graph I and graph II is defined as 100% when the valve body 26 is within an angular range of 20°-360° in the housing 25. A third graph III, which is shown with a dashed and dotted line, indicates the coolant flow rate at the heated temperature THto the condenser 18 via the sixth port 5f and secondary bypass line 5f. A fourth graph IV, which is shown with a dashed line, indicates the coolant flow rate at the second coolant temperature T2directed 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 at the first coolant temperature T1directed to the condenser 18 via the eighth port 5h’ and the first condenser line 5h. Thus, the graphs III, IV, V indicate the coolant flow rate at three different temperatures TH, T1and T2to be directed to the condenser 18 at different angular positions of the valve body 26 in the housing 25. The sum of the coolant flow rates defined in the graphs III, IV, V is 50% of the coolant flow rates to the 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 such that it directs a lower coolant flow rate to the condenser 18 than to the combustion engine 2 within a main part of the angular range.

During operation, the control unit 7 receives substantially continuously information from said temperature sensors 22, 23, 24 about the actual coolant temperatures TH,T1, T2and information 4a about the actual coolant flow rate in the cooling system. During operating conditions when the combustion engine 2 has a lower temperature than a lowest temperature within an optimal operating temperature range, the combustion engine 2 does not need to be cooled at all. The control unit 7 initiates an activation of the actuator 6 such that it moves the valve body 26 to an angular position within the angular range of 280°-350° in which 100% of uncooled coolant at the heated temperature THis directed to the combustion engine 2. Thus, no coolant is directed to the first radiator. Furthermore, the low temperature of the coolant results in that the wax material in the casing 28b is in solid state and the blocking member 28a is in a closed position. Thus the entire coolant flow is directed to the combustion engine without cooling. As a consequence, the combustion engine will be heated quickly to its operating temperature in which it works with an optimal efficiency.

During operating conditions when the combustion engine 2 has a temperature within the optimal operating temperature range, some cooling of the combustion engine is usually required in order to maintain the temperature of the combustion engine 2. The temperature of the coolant reaches the regulating temperature of the wax material in the casing 28b which melts. As a consequence, the blocking member 28a is moved from the closed position to an open position. In this case, the control unit 7 may initiate a movement of the valve body 26 to an angular position within the angular range 120°-280° in which a mixture of coolant at the heated temperature THand the first temperature T1is directed to the combustion engine 2. In the above mentioned angular position range, it is possible to direct coolant at the first coolant temperature T1according to graph V to the condenser 18, coolant at the second coolant temperature T2according to graph IV to the condenser 18 or an arbitrary mix of coolants at said temperatures T1, T2to the condenser 18. The control unit 10 receives information from the second control unit 20 about the operating condition of the WHR system. The control unit 7 estimates a required temperature of the coolant to be directed to the condenser 18 at the actual coolant flow rate in the cooling system in order to cool the working medium to the desired condensation temperature in the condenser 18. The control unit 7 determines an angular position of the valve member 26 within the angular range 120°-280° at which the coolant cools the combustion engine 2 and the working medium in the condenser 18 in an optimal manner. The control 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 temperature than a highest temperature in an optimal operating temperature range, the combustion engine 2 does need to be cooled in an optimal manner. The blocking member 28a is in the open position. The control unit 7 initiates and activation of the actuator to an angular position within the angular range of 10°-120° in which 100% coolant at the first temperature T1is directed to the combustion engine 2. In the above mentioned angular range, it is possible to direct uncooled coolant at the heated temperature TH, according to graph III, to the condenser 18, coolant at the second temperature T2, according to graph V, to the condenser 18 or an arbitrary mix of coolant at the heated temperature THand the second temperature T2to the condenser 18. The control unit 7 receives information from the second control unit 20 about the operating condition of the WHR system. The control unit 7 estimates a required temperature of the coolant to be directed to the condenser 18 at the actual coolant flow rate in the cooling system order to cool the working medium to the desired condensation temperature in the condenser 18. The control unit 7 determines an angular position of the valve member 26 within the angular range 10°-120° at which the coolant cools the working medium to the desired condensation temperature in 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

1. A multi-valve 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 (5 a) receiving coolant at a heated temperature (TH), a first radiator (8) cooling the coolant to a first temperature (T1), a second radiator (9) cooling the coolant to a second temperature (T2) which is lower than the first temperature (T1) during most operating conditions, wherein the multi- valve comprises a housing (25) which in a first transverse plane (A) comprises a port (5a’) receiving coolant at the heated temperature (TH), a port (5b’) directing the received coolant to the combustion engine (2) and a port (5c’) directing the received coolant to the first radiator (8) and which in a second transverse plane (B), comprises a port (5’g) directing coolant to the second radiator (9), and a hollow valve body (26) rotatably arranged to different angular positions in the housing (25), wherein the hollow valve body (26) comprises a first valve part (26a) comprising at least one opening (31) configured to coincide with the ports (5a’, 5b’, 5c’) in the first transverse plane (A) of the housing (25), a second valve part (26b) comprising at least one opening (32, 33) configured to coincide with the port (5g’) in the second transverse plane (B) of the housing (25), and a flow passage (26d) extending between the first valve part (26a) and the second valve part (26b), characterized in that the multi-valve comprises a temperature controlled valve member (28) arranged in said flow passage (26d), which is configured to prevent a coolant flow from the first valve part (26a) to the second valve part (26b) when the coolant has a lower temperature than a regulating temperature of the valve member (28) and to allow a coolant flow from the first valve part (26a) to the second valve part (26b) when the coolant has a higher temperature than the regulating temperature of the valve member (28).

2. A multi-valve according to claim 1, characterized in that the valve member (28) comprises a blocking member (28a) movably arranged between a closed position in which it blocks said flow passage (26d) and an open position in which it allows coolant flow through the flow passage (26d) and a switch mechanism (28b) configured to move the blocking member (28a) to the open position against the action of a spring member (28c) when the coolant has a higher temperature than said regulating temperature.

3. A multi-valve according to claim 2, characterized in that the switch mechanism comprises a casing (28b) enclosing a material configured to change volume at the regulating temperature.

4. A multi-valve according to claim 1 or 2, characterized in that valve member (28) is controlled by a control unit (7).

5. A multi-valve according to any one of the preceding claims, characterized in that the housing (25) comprises, in the second transverse plane (B), a port (5f ) directing coolant to the further object (18).

6. A multi-valve according to any one of the preceding claims, characterized in that the housing (25) comprises further ports (5d’, 5e’, 5h’) in a third transverse plane (C), wherein the hollow valve body (25) comprises a third valve part (26c) comprising at least one opening (34) configured to coincide with the at least one port (5d’, 5e’, 5h’) in the third transverse plane (C) of the housing (25).

7. A multi-valve according to claim 6, characterized in that the housing (25) comprises, in the third transverse plane (C), a port (5d’) receiving coolant from the first radiator (8), a port (5e’) directing the received coolant from the first radiator (8) to the combustion engine (2) and a port (5h’) directing the received coolant from the first radiator (8) to the further object (18).

8. A multi-valve according to claim 6 or 7, characterized in that the third valve part (26c) is rigidly connected to the first valve part (26a) and the second valve part (26b) such they are rotatably arranged in the housing (25) as a unit.

9. A multi-valve according to any one of the preceding claims, characterized in that the valve parts (26a-26c) have a spherical-shape.

10. Multi-valve according to any one of the preceding claims, characterized in 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. A multi-valve device comprises a multi-valve according to any one of the preceding claims, characterized in that it comprises an actuator (6) configured to rotate the valve body (26) to different angular positions in the 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 determined angular position in the housing (25).