DE102021121407A1 - Coolant circuit, hydrodynamic retarder arrangement and vehicle - Google Patents

Abstract

A vehicle coolant circuit (20) is described, which is set up to dissipate heat generated by a vehicle component (1, 11). The coolant circuit (20) has a heat exchanger (3), which is set up for adjusting the temperature of coolant in the coolant circuit (20), an expansion tank (5), a static line (7), the expansion tank (5) with a first Section (2 ') of the coolant circuit (20) connects, and an impeller pump (9) which is arranged in the static line (7). The present description also relates to a hydrodynamic retarder arrangement (10) and a vehicle (30) with a coolant circuit (20).

Description

TECHNICAL AREA

The present description relates to a vehicle coolant circuit configured to dissipate heat generated by a vehicle component. The present description further relates to a hydrodynamic retarder arrangement and a vehicle with a coolant circuit.

BACKGROUND

Contemporary vehicles have various components that require cooling. Examples are internal combustion engines, electric machines, batteries for propulsion, power circuits, fuel cells, retarders and others. Coolant circuits typically have coolant channels and one or more heat exchangers configured to adjust the temperature of coolant in the coolant circuit, and a coolant pump configured to circulate coolant through the coolant circuit.

Some refrigerant circuits use an expansion tank, also known as an expansion tank, to protect the refrigerant circuit from excessive pressures. An expansion tank allows air and coolant to expand in the coolant circuit when the temperature and pressure rise, with the coolant being able to flow back into the coolant circuit when the temperature and pressure drop. An expansion tank is typically connected to a portion of the refrigerant circuit by a static line. Such a line is referred to as a static line because during normal operation of the coolant circuit there is generally essentially no flow of coolant or at least only a small flow of coolant through the static line, which is why the pressure in the static line is essentially static, ie essentially no fluctuations occur during normal operation of the coolant circuit.

Coolant circuits of different types each have common problems. One problem is that the pressure fluctuations in the coolant loop can cause pressures below the instantaneous ambient pressure, which can stress the coolant loop and cause hoses to collapse and be sucked flat. If one or more hoses are sucked flat, then the flow through the hose or hoses is impeded, which limits the flow as a whole. Repeated compression/collapse of hoses can damage the hose and eventually lead to rupture.

Another problem is cavitation in pumps and other systems or components. Cavitation is a phenomenon in which pressure changes in a liquid result in the formation of gas-filled cavities in places where the pressure is relatively low. Cavitation can cause significant wear of components such as pumps, valves and other systems and components of the coolant cycle.

Attempts have been made to prevent the problem associated with low pressures in coolant circuits by pressurizing the expansion tank with compressed air from a vehicle's pneumatic system, such as a pneumatic brake system. However, when using pressure generation with external means, various problems can arise, especially with sensitive components and systems. The introduction of air into the system can cause problems in that refrigerant can damage valves and even backflow into compressed air tanks of the pneumatic system.

Another way to prevent the low pressure problem in a refrigerant circuit with an expansion tank is to raise the temperature in the cooling system. The static pressure increases with the expansion of refrigerant and the volume of air in the expansion tank decreases. However, elevated temperatures can only be used to generate higher static pressures if the system maintains the temperature at a certain level. In electric vehicles this can be difficult due to the low heat generated in the system.

Some types of components, such as hydrodynamic retarders, are particularly susceptible to generating high pressure fluctuations in the coolant circuit. Hydrodynamic retarders are devices used on vehicles to supplement or replace some of the functions of primary braking assemblies, such as friction-based braking assemblies. Such retarders use viscous frictional forces of coolant in a space between a rotor and a stator. The rotor is usually connected to a shaft of the vehicle, such as a shaft of the vehicle's gearbox, via a retarder transmission. Retarders have several advantages. For example, compared to friction-based braking arrangements, they are less prone to overheating, for example when the vehicle is braked while driving downhill. Furthermore, retarders reduce Use the wear of primary, friction-based brake assemblies.

When braking, the working space of the retarder is filled with a certain volume of coolant and when the braking process is completed, the working space is normally emptied of coolant. As discussed above, there is a problem with hydrodynamic retarders in that they create significant pressure fluctuations in the associated coolant circuit, particularly when braking is initiated and terminated. The pressure fluctuations can cause pressures below ambient pressure, causing stress on the coolant circuit and can cause hoses to flatten out. If one or more hoses are sucked flat then flow through the hose(s) will be restricted, restricting overall flow and consequently the supply of coolant to the retarder. As stated above, repeated squeezing/collapsing of hoses can damage them and eventually lead to rupture.

Furthermore, for today's consumer market, it is desired that the products have various features and functions, with the products having properties and/or features conducive to inexpensive manufacture and assembly.

BRIEF DESCRIPTION

It is an object of the present invention to overcome or at least mitigate at least some of the problems and disadvantages set forth above.

According to a first variant of the invention, the objective is achieved by a vehicle coolant circuit that is set up to dissipate heat generated by a vehicle component. The coolant circuit has a heat exchanger configured to adjust (regulate) the temperature of coolant in the coolant circuit, an expansion tank, a static line connecting the expansion tank to a first portion of the coolant circuit, and an impeller pump disposed in the static line is.

Since the coolant circuit has an impeller pump in the static line, a coolant circuit capable of increasing the pressure in the coolant circuit without the need for pneumatic pressurization and without depending on the coolant temperature in the coolant circuit is provided. Accordingly, this results in a coolant circuit in which the pressure in the coolant circuit can be easily adjusted by adjusting the impeller pump, even when a coolant temperature in the coolant circuit is low, such as when the coolant circuit is set up to cool a or multiple components of an electric drive system.

Since the coolant circuit avoids the need for pneumatic pressure generation, the result is a reliable and long-lasting coolant circuit. Since the coolant circuit has an impeller pump, i.e. a standardized low-cost component, a coolant circuit is provided in which the pressure in the coolant circuit can be increased, the coolant circuit having requirements and properties which are conducive to low-cost manufacture and assembly.

Since the coolant circuit has an impeller pump, more stable pressure levels can be achieved in the coolant circuit compared to using a piston pump, because the impeller pump generates a relatively even coolant flow.

There is thus provided a coolant circuit with requirements for raising the pressure in the coolant circuit in a simple, efficient and reliable manner. Another result is a coolant circuit in which cavitation and buckling/collapse of hoses in the coolant circuit can be avoided in a simple, effective and reliable manner.

Furthermore, a coolant circuit is provided in which the pressure is easily controllable by simply controlling the pumping rate of the pump, for example according to determined pressure requirements of the coolant circuit.

A coolant circuit is thus provided which overcomes at least some of the problems and disadvantages mentioned above or at least reduces their effect. The above objective is thus achieved.

Optionally, an inlet of the impeller pump is in fluid communication with the expansion tank and an outlet of the impeller pump is in fluid communication with the first portion of the coolant circuit. In these exemplary embodiments, the impeller pump is thus set up to pump coolant in the direction from the expansion tank to the first section of the coolant circuit when the pump is activated. A coolant circuit is thus provided which is able to withstand the pressure in the coolant circuit easily increased by activating the impeller pump.

Optionally, the impeller pump is a centrifugal pump. There is thus provided a coolant circuit capable of raising the pressure in the coolant circuit in a simple, efficient and reliable manner, the coolant circuit being designed for low cost manufacture and assembly. Since the coolant circuit has a centrifugal pump, a free flow path is set up via the pump, which causes more stable pressure conditions in the coolant circuit in comparison to using a positive displacement pump, such as a piston pump.

Optionally, the coolant loop further includes a circulation pump configured to circulate coolant through the coolant loop. This provides a coolant circuit with the ability to cool one or more components in an efficient and controlled manner.

Optionally, the coolant circuit has a control arrangement, the control arrangement being set up to control the operation of the impeller pump for setting (regulating) a fluid pressure in the coolant circuit. This provides a refrigerant circuit that has stable pressures in a simple, effective, and reliable manner.

The control arrangement is optionally set up to control the pumping rate of the impeller pump in order to set a fluid pressure in the coolant circuit. This provides a refrigerant circuit capable of generating even more stable pressures under various conditions in a simple, effective and reliable manner.

Optionally, the expansion tank has a pressure relief valve configured to open to atmosphere when a pressure in the expansion tank rises above a threshold. A coolant circuit is thus provided which is set up to operate at a static pressure above the current ambient pressures even when the impeller pump is inactive.

Optionally, the coolant circuit has a vent line connecting the expansion tank to a second section of the coolant circuit. With this, the coolant circuit can be vented in an effective manner. Furthermore, a coolant circuit is thus provided, in which the ventilation line can be used as a return line for coolant, which is supplied to the coolant circuit by the impeller pump. This also achieves more stable pressure values in the coolant circuit.

Optionally, the second section of the coolant circuit is a section of the heat exchanger. A coolant circuit is thus provided with the possibility of venting the heat exchanger in an efficient manner, with the vent line also being able to be used as a return line for coolant, which is fed to the retarder circuit by the impeller pump. The possibility is opened up of effectively venting the heat exchanger by activating the impeller pump.

Optionally, the vent line has a flow resistance. This achieves even more stable pressure levels in the coolant circuit.

Optionally, the vent line has a valve. A coolant circuit is thus provided in which the fluid pressure in the coolant circuit can be adjusted even better simply by adjusting an opening state of the valve.

Optionally, the coolant circuit has a control arrangement, the control arrangement being set up to control the opening state of the valve for adjusting the fluid pressure in the coolant circuit. A coolant circuit is thus provided with which even more stable pressure levels in the coolant circuit are achieved under various conditions.

Optionally, the second section is positioned upstream of the first section with respect to a desired direction of flow through a circuit section of the coolant circuit between the first and second sections of the coolant circuit, the coolant circuit having a one-way valve located in the circuit section. The one-way valve may be configured to prevent flow of coolant through the loop portion in a direction from the first portion to the second portion of the coolant loop. This provides a coolant loop in which the impeller pump can be used to circulate coolant through the coolant loop, ie, to cause coolant to flow through the static line to the coolant loop and components therein, and through the vent line and expansion tank back to the static line . In this way, the impeller pump can be used in cooling mode, with the coolant circuit cooling a component in the coolant circuit, such as the cooling of a retarder.

Optionally, the coolant circuit is a retarder circuit configured to dissipate heat generated by the retarder. A retarder circuit is thus provided which is able to avoid the problems of pressures below ambient pressure or at least reduce their effect. This is because the impeller pump can be used to raise the fluid pressure in the retarder circuit.

As a further result, a retarder circuit is provided which is capable of alleviating stresses on the retarder circuit and avoiding component buckling/collapse in a simple, robust and effective manner. Furthermore, a retarder circuit is provided with which the supply of coolant to the hydrodynamic retarder can be ensured in a simple, robust and effective manner.

Optionally, the retarder is a hydrodynamic retarder, with the first section of the coolant circuit being arranged upstream of a coolant inlet of the hydrodynamic retarder with respect to a desired flow direction towards the coolant inlet. A retarder circuit is thus provided with which the problems of pressures below the ambient pressure of the retarder circuit can be avoided or at least their effect can be reduced. This is because the fluid pressure in an inlet line connected to the coolant inlet of the retarder can be raised in a simple manner by actuating the impeller pump, for example in connection with initiating or ending braking using the hydrodynamic retarder.

It also provides a retarder circuit that reduces stresses on the retarder circuit and prevents component buckling/collapse in a simple, robust, and effective manner. Also a retarder circuit is provided with characteristics to ensure a supply of coolant to the hydrodynamic retarder in a simple, robust and efficient manner.

According to a second variant of the invention, the object is achieved by a hydrodynamic retarder arrangement with a hydrodynamic retarder which is set up to brake the rotation of a shaft of a vehicle, and with a coolant circuit according to some exemplary embodiments of the present description, the coolant circuit being set up for discharging heat generated by the hydrodynamic retarder.

Since the hydrodynamic retarder arrangement has a coolant circuit according to some of the exemplary embodiments shown here, it is able to avoid or at least mitigate the problem of subambient pressures in the coolant circuit, simply by operating the impeller pump, for example in connection with a start or termination of a braking process of the hydrodynamic retarder.

A further result is a hydrodynamic retarder arrangement that is designed to reduce loads on the coolant circuit and to avoid buckling/collapse of components in a simple, robust and effective manner. Furthermore, a hydrodynamic retarder arrangement is provided with properties that ensure a supply of coolant to the hydrodynamic retarder in a simple, robust and efficient manner.

Accordingly, a hydrodynamic retarder assembly is provided that overcomes or at least mitigates the effects of at least some of the problems and disadvantages identified above. Thus, the above objective is achieved.

Optionally, the hydrodynamic retarder assembly has a control arrangement configured to operate the impeller pump in a retarder cooling mode in which the impeller pump circulates coolant through a working space in the hydrodynamic retarder. In this way, the hydrodynamic retarder arrangement is able to cool the working space of the retarder and also other sections of the retarder arrangement and coolant in the coolant circuit, in an energetically efficient manner. In some prior art solutions, a rotor in the hydrodynamic retarder is actuated, i.e. rotated, so as to cool the retarder after operation. However, by circulating coolant through the working space with the impeller pump, the retarder and working space are cooled in a considerably more energetically efficient manner compared to such prior art.

According to a third variant of the invention, the aim is achieved by a vehicle with a coolant circuit according to some of the exemplary embodiments described here, or by a hydrodynamic retarder according to some of the exemplary embodiments described here.

Since the vehicle has a coolant circuit according to some of the exemplary embodiments described here or a hydrodynamic retarder according to some of the exemplary embodiments described here, a vehicle is provided with which at least some of the above Problems and disadvantages are overcome or at least their effects are reduced. As a result, the above objective is achieved.

Further features and advantages of the present invention will become more apparent from the appended patent claims and the following detailed description.

character list

• 1 erläutert einen Fahrzeug-Kühlmittelkreislauf gemäß einigen Ausführungsbeispielen,
• 2 erläutert eine hydrodynamische Retarderanordnung gemäß einigen Ausführungsbeispielen und
• 3 zeigt ein Fahrzeug gemäß einigen Ausführungsbeispielen.

Various variants of the invention, including the respective features and advantages, become clear from the exemplary embodiments, as described in more detail below and illustrated in the drawings:

• 1 explains a vehicle coolant circuit according to some embodiments,
• 2 explains a hydrodynamic retarder assembly according to some embodiments and
• 3 12 shows a vehicle according to some embodiments.

DESCRIPTION OF DETAILS

Variants of the present invention will now be described in more detail. The same reference numbers refer to the same elements. Well-known functions or devices are not described in detail for the sake of conciseness and/or clarity.

1 1 shows a vehicle coolant loop 20 according to some embodiments. The vehicle coolant circuit 20 is sometimes also referred to here as “coolant circuit 20”. The coolant circuit 20 can also be referred to as a vehicle cooling system 20 , as a vehicle cooling circuit 20 or as a vehicle cooling system 20 . The coolant circuit 20 is set up to dissipate heat generated by a vehicle component 11 . According to the illustrated exemplary embodiments, vehicle component 11 is a component of an electric drive system of the vehicle, such as an electric machine, a battery for the drive, a fuel cell, elements of power electronics or the like. On the other hand or in addition, the coolant circuit 20 can be configured to dissipate heat generated by other types of components, such as an internal combustion engine, a retarder or the like. The coolant circuit 20 has a heat exchanger 3 which is set up for adjusting the temperature of coolant in the coolant circuit 20. The heat exchanger 3 can be a radiator which is set up for distributing heat of the coolant in the coolant circuit 20 into the environment.

The coolant circuit 20 further includes a circulation pump 15 configured to circulate coolant through the coolant circuit 20. The coolant may comprise an aqueous solution, such as a glycol-based aqueous solution. Furthermore, the coolant circuit 20 has a secondary line 22 which bypasses the heat exchanger 3 and a valve 24 which is set up to conduct coolant through the secondary line 22 and/or the heat exchanger 3 . The valve 24 can be a thermostatic valve which is set up to direct coolant through the bypass line 22 and/or the heat exchanger 3 according to the temperature of the coolant reaching the valve 24 . On the other hand or in addition, the valve 24 can be electronically controlled, for example by a control arrangement 21, according to the temperature of coolant in the coolant circuit 20 and/or a cooling requirement with regard to the vehicle component 11.

Furthermore, the coolant circuit 20 has an expansion tank 5 and a static line 4 which connects the expansion tank 5 to a first section 2 ′ of the coolant circuit 20 . According to exemplary embodiments, the coolant circuit 20 has an impeller pump 9 which is arranged in the static line 9 . The impeller pump 9 is set up to pump coolant in the direction from the expansion tank 5 to the first section 2' of the coolant circuit 20 during operation. That is, the impeller pump 9 has an inlet 9' in fluid communication with the expansion tank 5 and an outlet 9'' in fluid communication with the first portion 2' of the coolant circuit 20. Due to these features, a coolant circuit 20 is provided which can raise the pressure in the coolant circuit 20 without having to rely on pneumatic pressure generation and without being dependent on the temperature in the coolant circuit 20. This results in a coolant circuit 20 in which the pressure in the coolant circuit 20 can be adjusted in a simple manner of the impeller pump 9 can be set, even if a coolant temperature in the coolant circuit 20 is low, which is usually the case with a coolant circuit 20 that is set up for cooling a component 11 of an electric drive system, such as the coolant circuit 20 according to in 1 illustrated embodiment.

Furthermore, a coolant circuit 20 is provided with features for raising the pressure in the coolant circuit 20 in a simple, efficient and reliable manner, simply by controlling the impeller pump 9, as will be explained in more detail herein. Furthermore, due to the impeller pump 9, a coolant circuit 20 is provided in which cavitation and compression/collapse tion of hoses of the coolant circuit 20 can be avoided in a simple, efficient and reliable manner. As used herein, the term "pressurizing coolant circuit 20" includes an increase in fluid pressure in at least a portion of coolant circuit 20.

According to some embodiments, the impeller pump 9 is not a positive displacement impeller pump, such as a centrifugal pump. This provides a free flow path across the impeller pump 9, allowing for more stable pressures in the coolant circuit 20 compared to using a positive displacement pump such as a piston pump. Also, more stable pressure levels can be achieved in the coolant circuit 20 compared to using a positive displacement pump because an impeller pump without a positive displacement, such as a centrifugal pump, is able to produce a continuous flow of coolant compared to a pump with positive combustion, like a piston pump.

According to the illustrated embodiments, the coolant circuit 20 has a control arrangement 21. The control arrangement 21 is set up to control the operation of the impeller pump 9 to set a fluid pressure in the coolant circuit 20. The control arrangement 21 can be set up to control the pumping rate of the impeller pump 9, ie the rotational speed of the Impeller pump 9 for setting a fluid pressure in the coolant circuit 20. This achieves a coolant circuit 20 which is able to achieve stable pressure levels in different operating states of the coolant circuit 20 in a simple, efficient and reliable manner. The impeller pump 9 can be an electrically driven impeller pump 9 .

According to the illustrated exemplary embodiments, the expansion tank 5 has a pressure relief valve 25 which is set up to open to the atmosphere when a pressure within the expansion tank 5 rises above a threshold value. Accordingly, according to the exemplary embodiments illustrated, the coolant circuit 20 is pressure-controlled and set up for operation at pressure levels above a current ambient pressure, even when the impeller pump 9 is not active. Furthermore, according to the exemplary embodiments illustrated, the pressure relief valve 25 is set up to open to the atmosphere when a pressure within the expansion tank 5 falls below a second threshold value.

According to the illustrated embodiments, the coolant circuit 20 has a vent line 17. The vent line 17 connects the expansion tank 5 to a second section 23 of the coolant circuit 20. According to the illustrated embodiments, the second section 23 of the coolant circuit 20 is a section of the heat exchanger 3. According to the illustrated embodiments the second section 23 of the coolant circuit is a section at the outlet tank of the heat exchanger 3, ie a section downstream of cooling channels of the heat exchanger 3. The vent line 27 can be used as a return line for coolant, which is transferred by the impeller pump 9 into the coolant circuit 20. In this way, the pressure in the coolant circuit 20 can be adjusted in an improved manner and the heat exchanger 3 can be vented efficiently. The connection between the static line 7 and the coolant circuit 20 is thus referred to as a first section 2 'of the coolant circuit 20 and the connection between the vent line 17 and the coolant circuit 20 is thus referred to as a second section 23 of the coolant circuit 20. According to a further embodiment For example, the vent line 17 may connect the expansion tank 5 to a portion of the refrigerant circuit 20 other than the heat exchanger 3 . For example, vent line 17 may connect expansion tank 5 to an upper point of a line or component such as component 11 . According to some embodiments, the vent line 17 is connected to the static line 7 at a point between the outlet 9" of the impeller pump 9 and the first section 2' of the coolant circuit 20, i.e. at a point between the outlet 9" of the impeller pump 9 and the connection between the static line 7 and the coolant circuit 20.

Furthermore, according to the exemplary embodiments shown, the ventilation line 17 has a flow resistance 27. Correspondingly 1 the flow resistance 27 can have a valve 27 . The control arrangement 21 can be set up to control the opening state of the valve 27 in order in this way to set, in particular to regulate, the fluid pressure in the coolant circuit 20 . In such embodiments, the control assembly 21 may control the valve 27 to a more closed condition so as to increase the fluid pressure in the coolant circuit 20 and control the valve 27 to a more open condition so as to decrease the fluid pressure in the coolant circuit 20 . In other embodiments, flow restrictor 27 may be of a different type or structure, such as a structure having a reduced effective area flow path.

According to some embodiments of the present description, the control arrangement 21 can be equipped with a bleed mode, in which the control arrangement 21 operates the pump 9 so that a flow of coolant through the heat exchanger 3 and the vent line 17, even if it is determined that the coolant circuit 20 should not be pressurized. In such an embodiment, the control arrangement 21 can control the valve 27 to an open state in the vent mode.

The second section 23 of the coolant circuit 20 can be arranged upstream of the first section 2 ′ of the coolant circuit 20 in relation to the intended direction of flow through the coolant circuit 20 . In other words: according to some embodiments, the second section 23 is arranged upstream of the first section 2' between the first and second sections 2', 23 of the coolant circuit 20 with respect to the direction of flow through the circular section 22'' of the coolant circuit 20. How 1 shows, according to some embodiments of the present description, the coolant circuit 20 has a one-way valve 28, which is arranged in the circuit section 20" of the coolant circuit 20 between the first and second sections 2', 23. According to the illustrated embodiments, this is one-way valve 28 is set up to prevent a flow of coolant from the first section 2' towards the second section 23 through the coolant circuit 20. In other words: according to the illustrated embodiments, the one-way valve 28 is set up to prevent a flow of coolant through the Circuit section 20" in a direction from the first section 2' to the second section 23. This provides a coolant circuit 20 in which the impeller pump 9 can be used to circulate coolant through the coolant circuit 20, i.e. to cause a coolant flow through the static line 7 to the coolant circuit 20 and components 11 arranged therein and through the heat exchanger 3 and through the vent line 17 and the expansion tank 5 back to the static line 7. In this way conditions are created for using the impeller pump 9 in a cooling mode in which the coolant circuit 20 effects cooling with respect to a component 11 disposed in the coolant circuit 20, such as a retarder or other type of component 11. In such embodiments, the coolant circuit 20 may dispense with a circulation pump 15, or it may comprise a non-positive displacement circulation pump 15 with a free flow path over the circulation pump 15

2 10 shows a hydrodynamic retarder assembly 10 according to some exemplary embodiments. For the sake of simplicity, the hydrodynamic retarder arrangement 10 is sometimes also referred to here as “retarder arrangement 10”. The retarder arrangement 10 has a hydrodynamic retarder 1. The hydrodynamic retarder is set up for braking the rotation of a shaft 6 of a vehicle, as will be explained further below. For the sake of simplicity, the hydrodynamic retarder 1 is sometimes also referred to here as “retarder 1”.

The retarder 1 has a retarder housing 51 with a blade space 52 and a blade arrangement 12 , 53 which is arranged in the blade space 52 . The blade assembly 12, 53 has a bladed stator 53 and a bladed rotor 12 which together form a working space 55. As shown in FIG. The working space 55 can also be referred to as a torus. The retarder 1 also has a coolant inlet 4 and a coolant outlet 33. The retarder 1 also has a coolant circuit 20 which is connected to the coolant inlet 4 and the coolant outlet 33 of the retarder 1. In detail: the coolant circuit 20 has an inlet line 2 which is connected to the coolant inlet 4 of the retarder and an outlet line 56 which is connected to the coolant outlet 33 of the retarder 1 . The inlet line 2 thus forms part of the coolant circuit 20 . Coolant is routed from the inlet line 2 into the working chamber 55 via the coolant inlet 4 of the retarder 1 . The coolant outlet 33 of the retarder 1 is set up for discharging coolant from the working chamber 55 to the coolant outlet 56 of the coolant circuit 20. According to the illustrated exemplary embodiments, the coolant is an aqueous solution, such as a glycol-based water mixture.

According to the 2 In the exemplary embodiments illustrated, the coolant circuit 20 is a retarder circuit which is set up to dissipate heat generated by the retarder 1 . Therefore, the coolant circuit 20 according to the in 2 illustrated embodiments are also referred to as retarder circuit 20 and the coolant of the coolant circuit 20 serves as the working fluid for the retarder 1 during operation of the same. Therefore, in these exemplary embodiments, the term “coolant” can also be replaced by the term “working fluid”. According to some embodiments, the coolant circuit 20 may also be configured to remove heat generated by another component, in addition to the retarder 1, such as a component of an electric drive system, a component of an internal combustion engine or the like.

The coolant circuit 20 has a heat exchanger 3, which is set up to adjust the temperature of the coolant in the coolant circuit 20. The heat exchanger 3 can be a radiator, which is set up to dissipate heat from the coolant in the coolant circuit into the environment. Furthermore, the coolant circuit 20 has an expansion tank 5 and a static line 7 which connects the expansion tank 5 to a first section 2 ′ of the coolant circuit 20 . The first section 2 ′ of the coolant circuit 20 is arranged upstream of the coolant inlet 4 of the hydrodynamic retarder 1 in relation to the direction of flow towards the coolant inlet 4 . According to the exemplary embodiments shown, the coolant circuit 20 has an impeller pump 9 in the static line 7. The impeller pump 9 is set up for pumping coolant in one direction from the expansion tank 5 to the first section 2' of the coolant circuit 20 during operation of the same. That is: the impeller pump 9 has an inlet 9', which is in fluid connection with the expansion tank 5, and an outlet 9", which is in fluid connection with the first section 2' of the coolant circuit 20. The impeller pump 9 can also be referred to as a pressure boosting arrangement 8th.

The coolant circuit 20 also has a brake valve 31. The brake valve 31 is arranged downstream of the coolant outlet 33 of the hydrodynamic retarder 1. The brake valve 31 is set up to restrict the flow of coolant through the coolant outlet 33 in such a way that the braking torque of the retarder 1 is increased. The term "outlet line 56" and the term "coolant outlet 33" as used herein can also be understood as an outlet channel 56, or as a set of outlet channels 56 that extend from the working chamber 54 to the brake valve 31. During braking, coolant flows through the coolant circuit 20 via the brake valve 31 through the heat exchanger 3 and back to the working chamber 55 via the inlet line 2.

According to the illustrated exemplary embodiments, the retarder 1 has a retarder transmission 60 with a set of gear wheels 60', 60". Furthermore, the retarder 1 has a clutch device 14 and an actuator 14', which is mechanically connected to the clutch device 14. The actuator 14 ' is moveable between an actuated position and a non-actuated position for moving the clutch assembly 14 between an engaged condition and a disengaged condition. The clutch assembly 14 is arranged to couple the rotor 12 to the shaft 6 via the retarder transmission when engaged 60, while in the disengaged (switched off) state the rotor 12 is disconnected from the shaft 6. The shaft 6 may be connected to one or more wheels of a vehicle in such a way that the vehicle is braked, ie such that a braking force acts on the vehicle when the retarder 1 brakes the rotation of the shaft 6.

According to the illustrated exemplary embodiments, the retarder transmission 60 has a first gear wheel 60' and a second gear wheel 60". The second gear wheel 60" is arranged on a rotor shaft 61 and the first gear wheel 60' can be connected to the shaft 6 via the clutch device 14.

According to the illustrated exemplary embodiments, the clutch device 14 is set up to connect the first gear wheel 60′ of the retarder transmission 60 to the shaft 6 when it is switched on. Furthermore, the clutch device 14 is set up to separate the first gear wheel 60 ′ of the retarder transmission 60 from the shaft 6 in the switched-off state. Thus, in the illustrated embodiments, the first gear wheel 60' and the second gear wheel 60'' of the retarder transmission 60 do not rotate, or at least they are not driven by the shaft 6, when the clutch device 14 is in the switched-off state. In the switched-on state, the first gear wheel rotates 60' together with the shaft 6 so as to drive the rotor 6 via the retarder transmission 60. The clutch means 14 may comprise a dog clutch, synchronizer, clutch or the like.

During operation of the retarder 1, ie when the rotor 12 rotates, the retarder 1 pumps coolant from the inlet line 2 via the working chamber 55 to the coolant outlet 33. The retarder 1 thus circulates coolant through the coolant circuit 20 during operation and can therefore also be referred to as a circulation pump 1. The inlet line 2 and the coolant outlet 33 can each have a plurality of parallel channels which are set up for supplying or removing coolant into or from the working space 55. For example, the coolant outlet 33, as it is named here, can be integrated into the bladed stator 53 and may have one exhaust port per blade in the bladed stator 53 . In such embodiments, the outlet passages may each extend to a common annular volume within housing 51 .

When braking with the hydrodynamic retarder 1 starts or ends, the coolant circuit 20 and in particular the inlet line 2 are exposed to considerable pressure fluctuations. The pressure fluctuations can cause pressures below a momentary ambient pressure, which causes stresses on the coolant circuit 20 and can cause hoses to flatten, ie collapse. Is a hose or if several hoses are sucked flat, then the flow through the hose/hoses is obstructed, which limits the flow rate and accordingly also the supply of coolant to the retarder 1. Repeated compression/collapses of hoses of the coolant circuit 20 can damage the hoses of the coolant circuit 20.

The retarder assembly 10 has a control assembly 21. The control assembly 21 is connected to the impeller pump 9 and configured to control the operation thereof, ie, to start and stop the impeller pump 9. As explained herein, in some embodiments, the control assembly 21 is configured to control the pumping rate of the impeller pump 9 for setting a fluid pressure in the coolant circuit 20. Furthermore, according to the illustrated exemplary embodiments, the control arrangement 21 is connected to the actuator 14' and set up to control its operation, ie it is set up to control the actuator 14' between the actuated position and an unactuated position to move the clutch assembly 14 between the on condition and the off condition. Furthermore, the control arrangement 21 is connected to the brake valve 31 and set up to control the opening state of the brake valve 31 in order to initiate or terminate braking of the hydrodynamic retarder and to control a braking torque of the retarder 1.

According to some of the exemplary embodiments explained here, the control arrangement 21 is set up to activate the impeller pump 9 in connection with an initiation or termination of braking with the hydrodynamic retarder 1. In this way, pressures below the ambient pressure in the coolant circuit 20 of the hydrodynamic retarder arrangement 10 can be avoided. This is because the fluid pressure in the inlet pipe 2 is increased in connection with the initiation or termination of braking of the hydrodynamic retarder 1. This reduces loads on the coolant circuit 20 and compression/collapse of components of the same can be avoided in a simple, robust and efficient manner. A hydrodynamic retarder arrangement 10 is provided which ensures a supply of coolant to the hydrodynamic retarder in a simple, robust and efficient manner.

As explained herein, the impeller pump 9 is configured to increase fluid pressure in the inlet line 2 by pumping coolant to the inlet line 2. According to some embodiments, the pump 9 is a non-positive displacement pump, such as a non-positive displacement impeller pump, for example a centrifugal pump . A non-positive displacement pump does not block the fluid path across the pump and thus gives more stable pressure levels in the inlet line 2 compared to using a positive displacement pump because of the free flow path across the pump and because a non-positive displacement impeller pump such as a centrifugal pump in is capable of producing a substantially continuous flow of coolant compared to a positive displacement pump such as a piston pump. As explained here, the static line 7 connects the expansion tank 5 to a first section 2' of the inlet line 2. The first section 2' of the inlet line 2 can thus be referred to as a first section 2' of the coolant circuit 20. According to the exemplary embodiments shown the expansion tank 5 has a pressure relief valve 25 which is arranged to open to atmosphere when a pressure inside the expansion tank 5 rises above a threshold value. Thus, in the illustrated embodiments, the coolant circuit 20 is pressurized and arranged to operate at pressure levels below the current ambient pressure even when the impeller pump 9 is inactive. According to the illustrated exemplary embodiments, the pressure relief valve 25 is set up to open to the atmosphere when a pressure in the expansion tank 5 falls below a second threshold value.

According to the exemplary embodiments shown, the coolant circuit 20 has a ventilation line 17 which connects the expansion tank 5 to a second section 23 of the coolant circuit 20 . According to the exemplary embodiments shown, the second section 23 of the coolant circuit 20 is a section of the heat exchanger 3. In this way, the heat exchanger 3 can be efficiently vented, with the vent line 17 being able to be used as a return line for coolant, which is routed through the impeller pump 9 to the inlet line 2 is. Furthermore, according to some exemplary embodiments, the control arrangement 21 can be equipped with a venting mode, in which the control arrangement 21 operates the pump 9 in such a way that coolant flows through the heat exchanger 3 and the venting line 17 even when the retarder is inactive, ie even when the retarder 1 is not used for braking.

Furthermore, according to the exemplary embodiments shown, the ventilation line 17 has a flow resistance 27. Correspondingly 2 the flow resistance 27 can have a valve 27 . The control arrangement 21 can be set up to control an opening state of the valve 27 for further adjusting the fluid pressure in the inlet line 2. In such embodiments, the control arrangement can bring the valve 27 into a more closed state so as to increase the fluid pressure in the inlet line 2 and it can control the valve 27 into a more open state so as to increase the fluid pressure in the inlet line 2 to lower. Furthermore, the control arrangement 21 can control the valve 27 to an open state in the venting mode. According to further exemplary embodiments, the flow resistance 27 can also have another type of device or structure, such as a device or structure with a flow path reduced effective cross-section.

The second section 23 of the coolant circuit 20 can be arranged upstream of the first section 2 ′ of the coolant circuit 20 in relation to the intended direction of flow through the coolant circuit 20 . In other words: according to some embodiments, the second section 23 is arranged upstream of the first section 2' with respect to the desired flow direction through a circular section 20" of the coolant circuit 20 between the first and second sections 2', 23 of the coolant circuit 20. How 2 shows, according to some embodiments of the present description, the coolant circuit 20 has a one-way valve 28 in the circuit section 20" of the coolant circuit 20 between the first and second sections 2', 23. According to the illustrated embodiments, the one-way valve 28 set up to avoid a flow of coolant from the first section 2' to the second section 23 through the coolant circuit 20. In other words: according to the illustrated exemplary embodiments, the one-way valve 28 is set up to avoid a flow of coolant through the circuit section 20" in the forward direction first section 2 'to the second section 23. Thus, a coolant circuit 20 is provided in which the impeller pump 9 can be used to circulate coolant through the working chamber 55 of the retarder 1, ie it causes a flow of coolant through the static line 7 to Inlet line 2, the coolant inlet 4, through the Arbeitsr aum 55 and back to the static line 7 via the outlet line 56, the heat exchanger 3, the vent line 17 and the expansion tank 5. Accordingly, a coolant circuit 20 is provided in which the impeller pump 9 can be used to circulate coolant through the working space 55 of the retarder 1 when the retarder is inactive, such as after a braking application of the retarder 1, so as to cool the retarder 1.

According to the exemplary embodiments shown here, the control arrangement 21 is equipped with a retarder cooling mode, in which the control arrangement 21 actuates the impeller pump 9 to circulate coolant through the working chamber 55 of the retarder 1. The control arrangement 21 can Working cooling mode, ie after stopping braking with the hydrodynamic retarder 1. In the retarder cooling mode, the control arrangement 21 can operate the pump 9 in such a way that a flow of coolant is caused through the working chamber 55 of the retarder 1, through the heat exchanger 3, the vent line 17, the expansion tank 5 and back to the working space 55 via the static line 7 and the inlet line 2.

Because of the one-way valve 28, a backflow of working medium 5 from the static line 7 to the ventilation line 17 is prevented when operating in the retarder cooling mode. According to other embodiments, the retarder circuit 20 may include another type of component, structure and/or piping to prevent reverse flow of working fluid from the static line 7 to the vent line 17 when the retarder is operating in cooling mode.

In some prior art solutions, a rotor of the hydrodynamic retarder is actuated, i.e. rotated, so as to cool the retarder after use. However, by circulating coolant through the working space 55 using the impeller pump 9, the retarder 1 and the working space 55 thereof can be cooled significantly more efficiently compared to such solutions. In exemplary embodiments in which the vent line 17 has the valve 27, the control arrangement 21 can control the valve 27 to an open state when the retarder is operated in the cooling mode. Similarly, the control arrangement 21 can control the brake valve 31 to an open state when operating in the retarder cooling mode.

3 12 shows a vehicle 30 according to some example embodiments. The vehicle 30 has a drive unit 11. The drive unit 11 can be an internal combustion engine or an electric drive unit. The drive unit 11 is driven by a coolant circuit 20 according to the 1 illustrated embodiments cooled. The vehicle 30 also has a hydrodynamic retarder arrangement 10 according to the 2 illustrated embodiments, ie a retarder assembly 10 with a coolant circuit 20, as with reference to 2 is explained. The hydrodynamic retarder arrangement 10 is set up to generate a braking force on the vehicle 30 via wheels 39 of the vehicle 30. Similarly, the drive unit 11 is set up to generate a driving force for the vehicle 30 via wheels 39 of the vehicle 30.

According to the illustrated embodiment, the vehicle 30 is a truck, ie a heavy-duty vehicle. According to other embodiments, the vehicle 30 referred to herein may also be another type of vehicle, be it with or without a driver, for overland travel, such as a truck, a bus, a construction vehicle, a tractor, a passenger car or similar.

The in relation to the 1 and 2 Control arrangement 21 explained may have an arithmetic unit, which may be any suitable type of processor circuit or microcomputer, e.g. a circuit for digital signal processing (digital signal processor, DSP), a central processing unit (CPU), a processing unit, a processing circuit , a processor, application specific integrated circuit (ASIC), microprocessor, or other processor logic capable of interpreting and executing instructions. The term "processing unit" as used herein can mean a processing circuit with a plurality of processor circuits, such as one or some or all of the above types.

The control arrangement 21 can also have a storage unit, wherein the processing unit can be connected to the storage unit, which can supply the processing unit with, for example, stored program code and/or stored data, which the processing unit in turn needs to carry out the calculations. The computing unit can also be set up to store intermediate results or final results of calculations in the memory unit. The storage unit may comprise a physical device used to store data or programs, i.e. sequences of instructions, either temporarily or permanently. According to some embodiments, the memory unit may include integrated circuits with silicon-based transistors. The storage device can be, for example, a memory card, flash memory, USB memory, hard drive or other suitable volatile or non-volatile storage device for storing data, such as ROM (read only memory), PROM (programmable read only memory). EPROM (erasable PROM), an EEPROM (an electronically erasable PROM), etc., depending on the embodiment.

The control arrangement 21 is connected to components of the coolant circuit 20 and/or the hydrodynamic retarder arrangement 10 and/or also to components of a vehicle 30, which has the coolant circuit 20 and/or the hydrodynamic retarder arrangement 10, for receiving and/or sending input or output signals. These input and output signals may take on waveforms, pulses or other properties which the devices receiving the signals can detect as information and which can be converted into signals which can be processed by the control arrangement 21 . These signals can then be fed to the computing unit. One or more devices for sending output signals can be set up to convert calculation results from the calculation unit into output signals for transmission to other parts of the vehicle control system and/or to the component or components for which the signals are intended. Each of the connections to the respective components of the vehicle 3 for receiving and sending input and output signals can have one of the following configurations: a cable, a data bus, e.g. a CAN (control area network) bus, a MOST bus (media related transport system ) or other suitable bus configuration, or it can also be a wireless connection.

In the exemplary embodiments shown, the coolant circuit 20 and/or the hydrodynamic retarder arrangement 10 has a control arrangement 21; on the other hand, the implementation can also take place in whole or in part in the form of two or more control arrangements or in the form of two or more control units.

Control systems in contemporary vehicles generally have a communication bus system with one or more communication buses for connecting a number of electronic control units (ECU), or controllers, to various components on board the vehicle. Such a control system may include a large number of control units and the performance of a particular function may be shared between two or more such units. Vehicles of the type in question are therefore often equipped with significantly more control arrangements than in 1 and in 2 is shown, as a person skilled in the art knows.

It is to be understood that the above illustration explains various exemplary embodiments and that the invention is only limited by the appended patent claims. A person skilled in the art will recognize that the exemplary embodiments can be modified and that various features of the exemplary embodiments can be combined to produce further exemplary embodiments different from those described, without departing from the scope of the present invention as described in the appended claims.

As used herein, the terms "comprising" or "comprises" are open-ended and include one or more of the specified feature, element, step, component, or function, but do not exclude other such feature, element, step, component, function, or group of which are available.

Claims (18)

Vehicle coolant circuit (20), set up to dissipate heat generated by a vehicle component (1, 11), the coolant circuit (20) having: - a heat exchanger (3) which is set up to adjust the temperature of coolant in the coolant circuit (20), - an expansion tank (5), - a static line (7) connecting the expansion tank (5) to a first section (2') of the refrigerant circuit (20), and - an impeller pump (9) arranged in the static line (7). Coolant circuit (20) according to claim 1 , wherein an inlet (9') of the impeller pump (9) is in fluid communication with the expansion tank (5) and an outlet (9''') of the impeller pump (9) is in fluid communication with the first section (2') of the coolant circuit ( 20). Coolant circuit (20) according to one of Claims 1 or 2 , wherein the impeller pump (9) is a centrifugal pump. Coolant circuit (20) according to one of the preceding claims, wherein the coolant circuit (20) further comprises a circulation pump (1, 15) which is set up for circulating coolant through the coolant circuit (20). Coolant circuit (20) according to one of the preceding claims, wherein the coolant circuit (20) has a control arrangement (21) and wherein the control arrangement (21) is set up to control the operation of the impeller pump (9) for setting a fluid pressure in the coolant circuit (20) . Coolant circuit (20) according to claim 5 , wherein the control arrangement (21) is set up for controlling the pumping rate of the impeller pump (9) for setting a fluid pressure in the coolant circuit (20). Coolant circuit (20) according to one of the preceding claims, wherein the expansion tank (5) has a pressure relief valve (25) which is arranged to open to the atmosphere when a pressure in the expansion tank (5) rises above a threshold value. Coolant circuit (20) according to one of the preceding claims, wherein the coolant circuit (20) has a vent line (17) which connects the expansion tank (5) to a second section (23) of the coolant circuit (20). Coolant circuit (20) according to claim 8 , wherein the second section (23) of the coolant circuit (20) is a section of the heat exchanger (3). Coolant circuit (20) according to one of Claims 8 or 9 , wherein the ventilation line (17) has a flow resistance (27). Coolant circuit (20) according to one of Claims 8 - 10 , wherein the vent line (17) has a valve (27). Coolant circuit (20) according to claim 11 , wherein the coolant circuit (20) has a control arrangement (21) and wherein the control arrangement (21) is set up for controlling an opening state of the valve (27) for controlling a fluid pressure in the coolant circuit (20). Coolant circuit (20) according to one of Claims 8 - 12 , wherein the second section (23) upstream of the first section (2') with respect to the desired direction of flow through a circular section (20") of the coolant circuit (20) between the first and second sections (2', 23) of the coolant circuit (20 ) is arranged and wherein the coolant circuit (20) has a one-way valve (28) which is arranged in the circuit section (20"). Coolant circuit (20) according to one of the preceding claims, wherein the coolant circuit (20) is a retarder circuit which is set up to dissipate heat generated by a retarder (1). Coolant circuit (20) according to Claim 14 , wherein the retarder (1) is a hydrodynamic retarder and wherein the first section (2') of the coolant circuit (20) upstream of a coolant inlet (4) of the hydrodynamic retarder (1) in relation to the desired flow direction in the direction of the coolant inlet (4 ) is arranged. Hydrodynamic retarder arrangement (10), comprising: - a hydrodynamic retarder (1) which is set up for braking the rotation of a shaft (6) of a vehicle (30), and - a coolant circuit (20) according to one of the preceding claims, wherein the coolant circuit (20) is arranged to remove heat generated by the hydrodynamic retarder (1). Hydrodynamic retarder arrangement (10) according to Claim 16 , wherein the arrangement (10) has a control arrangement (21) which is set up to actuate the impeller pump (9) in a retarder cooling mode in which the impeller pump (9) coolant through a working space (55) of the hydrodynamic retarder (1) circulates. Vehicle (30) with a coolant circuit (20) according to one of Claims 1 - 15 or a hydrodynamic retarder arrangement (10) according to one of Claims 16 or 17 .

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