SE545818C2

SE545818C2 - Coolant Circuit, Hydrodynamic Retarder Arrangement, and Vehicle

Info

Publication number: SE545818C2
Application number: SE2051001A
Authority: SE
Inventors: Ola Hall; Zoltan Kardos
Original assignee: Scania Cv Ab
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2024-02-13
Also published as: SE2051001A1; DE102021121407A1

Abstract

A vehicle coolant circuit (20) is disclosed configured to remove heat generated by a vehicle component (1, 11). The coolant circuit (20) comprises a heat exchanger (3) configured to regulate temperature of coolant in the coolant circuit (20), an expansion tank (5), a static line (7) connecting the expansion tank (5) to a first portion (2’) of the coolant circuit (20), and an impeller pump (9) arranged in the static line (7). The present disclosure further relates to a hydrodynamic retarder arrangement (10), and a vehicle (30) comprising a coolant circuit (20).

Description

TECHNICAL FIELD The present disclosure relates to a vehicle coolant circuit configured to remove heat generated by a vehicle component. The present disclosure further relates to a hydrodynamic retarder arrangement and a vehicle comprising a coolant circuit.

BACKGROUND Modern vehicles comprise various components which need cooling. Examples are combustion engines, electric machines, propulsion batteries, power electronics, fuel cells, retarders, and the like. Coolant circuits normally comprise coolant channels, one or more heat exchangers configured to regulate the temperature of coolant in the coolant circuit, and a coolant pump configured to circulate coolant through the coolant circuit.

Some coolant circuits utilize an expansion tank, also known as an expansion vessel, to protect the coolant circuit from excessive pressure. An expansion tank allows air and coolant in the coolant circuit to expand with rising temperature and pressure and allow coolant to flow back into the coolant circuit as the temperature and pressure declines. An expansion tank is usually connected to a portion of the coolant circuit via a static line. Such a line is referred to as a static line because during normal operation of the coolant circuit, there is usually substantially no flow of coolant, or at least a low flow rate of coolant, through the static line, and as a result thereof, the pressure in the static line is substantially static, i.e. substantially non-varying, during normal operation of a coolant circuit.

Coolant circuits of various kind are associated with some mutual problems. One problem is that pressure variations can cause pressures in the coolant circuit below a current ambient pressure which put strain on the coolant circuit and can cause hoses to collapse and suck flat. lf one or more hoses is/are sucked flat, the flow through the hose/hoses is obstructed which limits the flow therethrough. l\/loreover, repeated compression/collapsing of hoses may damage the hoses and eventually they may break.

Another problem is cavitation in pumps and other systems and components. Cavitation is a phenomenon in which changes of pressure in a liquid lead to the formation of vapor-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 a coolant circuit.Attempts have been made to prevent the problem of low pressure situations in a coolant circuit by pressurizing the expansion tank using compressed air from a pneumatic system of the vehicle, such as a pneumatic braking system. However, several problems can arise when using external pressurization partly because of sensitive components and systems. Adding air to the system can be troublesome in the sense that coolant can destroy valves and even flow back into compressed air tanks of the pneumatic system.

Another way to prevent the problem of low pressure situations in a coolant circuit with an expansion tank is to increase the temperature in the cooling system. The static pressure will increase as the coolant expands and the air volume becomes smaller in the expansion tank. However, to rely on increased temperatures to create higher static pressures can only be done if the system keeps the temperature on a certain level. ln electrified vehicles this can be difficult due to low heat added to the system.

Moreover, some types of components, such as hydrodynamic retarders, are especially prone to causing high pressure variations in a coolant circuit. Hydrodynamic retarders are devices used on vehicles to augment or replace some of the functions of primary braking arrangements, such as friction-based braking arrangements. Such retarders utilize the viscous drag forces of a coolant in a workspace between a rotor and a stator. The rotor is usually connected to a shaft of the vehicle, such as a shaft of the gearbox of the vehicle, via a retarder transmission. Retarders are capable of providing several advantages. As an example, they are less likely to become overheated in comparison to friction-based braking arrangements, for example when braking a vehicle travelling downhill. Furthermore, when used, retarders lower wear of primary friction-based braking arrangements.

When braking, the workspace of the retarder is filled with a certain volume of coolant and when the braking is cancelled, the workspace is usually emptied of the coolant. As indicated above, a problem associated with hydrodynamic retarders is that they impart significant pressure variations in the coolant circuit thereof, especially upon initiation and cancellation of braking. The pressure variations can cause pressures below the ambient pressure which put strain on the coolant circuit and can cause hoses to suck flat. lf one or more hoses is/are sucked flat, the flow through the hose/hoses is obstructed which limits the flow therethrough and consequently the feed of coolant to the retarder. And as indicated above, repeated compression/collapsing of hoses may damage the hoses and eventually they may break.In addition, generally, on today's consumer market, it is an advantage if products comprise different features and functions while the products have conditions and/or characteristics suitable for being manufactured and assembled in a cost-efficient manner.

SUMMARY lt is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks.

According to a first aspect of the invention, the object is achieved by a vehicle coolant circuit configured to remove heat generated by a vehicle component. The coolant circuit comprises a heat exchanger configured to regulate 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 arranged in the static line.

Since the coolant circuit comprises an impeller pump arranged in the static line, a coolant circuit is provided having conditions for increasing the pressure in the coolant circuit without relying on pneumatic pressurization and without relying on the coolant temperature in the coolant circuit. Accordingly, as a further result thereof, a coolant circuit is provided in which the pressure in the coolant circuit can be regulated, simply by regulating the impeller pump, also when a coolant temperature in the coolant circuit is low, such as for example when the coolant circuit is arranged to cool one or more components of an electric propulsion system.

I\/|oreover, since the coolant circuit circumvents the need for pneumatic pressurization, a reliable and durable coolant circuit is provided. Moreover, since the coolant circuit comprises an impeller pump, i.e. a standardized low cost component, a coolant circuit is provided having conditions for increasing the pressure in the coolant circuit, while having conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner. ln addition, since the coolant circuit comprises an impeller pump, more stable pressure levels can be provided in the coolant circuit as compared to the use of a piston pump because of the relative continuous flow of coolant provided by the impeller pump.

Thus, a coolant circuit is provided having conditions for increasing the pressure in the coolant circuit in a simple, efficient, and reliable manner. As a further result thereof, a coolant circuit is provided in which cavitation and compression/collapsing of hoses of the coolant circuit can be avoided in a simple, efficient, and reliable manner.

Furthermore, a coolant circuit is provided in which the pressure in the coolant circuit can be controlled in an efficient manner simply by controlling the pumping rate of the pump, for example based on a determined pressurization need of the coolant circuit.

Accordingiy, a coolant circuit is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, an inlet of the impeller pump is fluidly connected to the expansion tank and an outlet of the impeller pump is fluidly connected to the first portion of the coolant circuit. According to these embodiments, the impeller pump is thus configured to pump coolant in a direction from the expansion tank towards the first portion of the coolant circuit when activated. Thereby, a coolant circuit is provided capable of increasing the pressure in the coolant circuit simply by activating the impeller pump.

Optionally, the impeller pump is a centrifugal pump. Thereby, a coolant circuit is provided having conditions for increasing the pressure in the coolant circuit in a simple, efficient, and reliable manner, while having conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner. Moreover, since the coolant circuit comprises a centrifugal pump, a free flow path is provided over the pump which provides more stable pressure levels in the coolant circuit as compared to the use of a positive displacement pump, such as a piston pump.

Optionally, the coolant circuit further comprises a circulation pump configured to circulate coolant through the coolant circuit. Thereby, a coolant circuit is provided having conditions for cooling one or more components in an efficient and controlled manner.

Optionally, the coolant circuit comprises a control arrangement, and wherein the control arrangement is configured to control operation of the impeller pump to regulate a fluid pressure in the coolant circuit. Thereby, a coolant circuit is provided capable of obtaining stable pressure levels in a simple, efficient, and reliable manner.

Optionally, the control arrangement is configured to control the pumping rate of the impeller pump to regulate a fluid pressure in the coolant circuit. Thereby, a coolant circuit is provided capable of obtaining even more stable pressure levels at various conditions in a simple, efficient, and reliable manner.

Optionally, the expansion tank comprises a pressure relief valve configured to open to the surroundings when a pressure inside the expansion tank rises above a threshold pressure. Thereby, a coolant circuit is provided capable of operating at static pressures above current ambient pressures also when the impeller pump is inactive. coolant circuit comprises a deaeration line connecting the expansion tank to a second portion of the coolant circuit. Thereby, the coolant circuit can be deaired in an efficient manner. l\/loreover, a coolant circuit is provided in which the deaeration line can be utilized as a return conduit for coolant transferred to the coolant circuit by the impeller pump.

As a further result, even more stable pressure levels can be provided in the coolant circuit.

Optionally, the second portion of the coolant circuit is a portion of the heat exchanger. Thereby, a coolant circuit is provided having conditions for deairing the heat exchanger in an efficient manner while the deaeration line can be utilized as a return conduit for coolant transferred to the retarder circuit by the impeller pump. Moreover, conditions are provided for deairing the heat exchanger in an efficient manner by activating impeller pump.

Optionally, the deaeration line comprises a flow restrictor. Thereby, even more stable pressure levels can be provided in the coolant circuit.

Optionally, the deaeration line comprises a valve. Thereby, coolant circuit is provided in which fluid pressure in the coolant circuit can be further regulated simply by regulating an opening state of the valve.

Optionally, the coolant circuit comprises a control arrangement, and wherein the control arrangement is configured to control an opening state of the valve to regulate a fluid pressure in the coolant circuit. Thereby, coolant circuit is provided capable of obtaining even more stable pressure levels in the coolant circuit at various conditions. second portion is arranged upstream of the first portion relative to an intended flow direction through a circuit section of the coolant circuit between the first and second portions of the coolant circuit, and wherein the coolant circuit comprises a one-way valve arranged in the circuit section. The one-way valve may be configured to prevent flow of coolant through the circuit section in a direction from the first portion towards the second portion of the coolant circuit. Thereby, a coolant circuit is provided in which the impeller pump can be utilized to circulate coolant through the coolant circuit, i.e. cause a flow of coolantthrough the static line to the coolant circuit and components arranged therein, and through the deaeration line and the expansion tank back to the static line. ln this manner, conditions are provided for utilizing the impeller pump in a cooling mode in which the coolant circuit provides cooling of a component arranged in the coolant circuit, such as a retarder.

Optionally, the coolant circuit is a retarder circuit configured to remove heat generated by a retarder. Thereby, a retarder circuit is provided capable of avoiding, or at least alleviating, the problem of pressures below the ambient pressure. This is because the impeller pump can be operated so as to increase fluid pressure in the retarder circuit.

As a further result thereof, a retarder circuit is provided capable of lowering strain on the retarder circuit and avoiding compression/collapsing of components thereof in a simple, robust, and efficient manner. I\/|oreover, a retarder circuit is provided having conditions for ensuring feed of coolant to the hydrodynamic retarder in a simple, robust, and efficient manner.

Optionally, the retarder is a hydrodynamic retarder, and wherein the first portion of the coolant circuit is arranged upstream of a coolant inlet of the hydrodynamic retarder relative to an intended flow direction towards the coolant inlet. Thereby, a retarder circuit is provided capable of avoiding, or at least alleviating, the problem of pressures below the ambient pressure in the retarder circuit. This is because the fluid pressure in an inlet duct connected to the coolant inlet of the retarder can be increased simply by operating the impeller pump, for example in conjunction with an initiation or cancellation of braking of the hydrodynamic retarder.

According to a second aspect of the invention, the object is achieved by a hydrodynamic retarder arrangement comprising a hydrodynamic retarder configured to brake rotation of a shaft of a vehicle and a coolant circuit according to some embodiments of the present disclosure, wherein the coolant circuit is configured to remove heat generated by the hydrodynamic retarder.Since the hydrodynamic retarder arrangement comprises a coolant circuit according to some embodiments, a hydrodynamic retarder arrangement is provided capable of avoiding, or at least alleviating, the problem of pressures below the ambient pressure in the coolant circuit simply by operating the impeller pump, for example in conjunction with an initiation or cancellation of braking of the hydrodynamic retarder.

As a further result thereof, a hydrodynamic retarder arrangement is provided capable of lowering strain on the coolant circuit and avoiding compression/collapsing of components thereof in a simple, robust, and efficient manner. l\/loreover, a hydrodynamic retarder arrangement is provided having conditions for ensuring feed of coolant to the hydrodynamic retarder in a simple, robust, and efficient manner.

Accordingly, a hydrodynamic retarder arrangement is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, the hydrodynamic retarder arrangement comprises a control arrangement configured to operate the impeller pump in a retarder cooling mode in which the impeller pump circulates coolant through a workspace of the hydrodynamic retarder. ln this manner, a hydrodynamic retarder arrangement is provided capable of cooling the workspace of the retarder, as well as other portions of the retarder arrangement and coolant in the coolant circuit, in an energy efficient manner. ln some prior art solutions, a rotor of the hydrodynamic retarder is operated, i.e. rotated, so as to cool the retarder after operation. However, by circulating coolant through the workspace using the impeller pump, the retarder and the workspace thereof can be cooled in a significantly more energy efficient manner as compared to such a solution.

According to a third aspect of the invention, the object is achieved by a vehicle comprising a coolant circuit according to some embodiments of the present disclosure, or a hydrodynamic retarder according to some embodiments of the present disclosure.

Since the vehicle comprises a coolant circuit according to some embodiments of the present disclosure, or a hydrodynamic retarder according to some embodiments of the present disclosure, a vehicle is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS Various aspects of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which: Fig. 1 illustrates a vehicle coolant circuit according to some embodiments, Fig. 2 illustrates a hydrodynamic retarder arrangement according to some embodiments, and Fig. 3 illustrates a vehicle according to some embodiments.

DETAILED DESCRIPTION Aspects of the present invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

Fig. 1 illustrates a vehicle coolant circuit 20, according to some embodiments. The vehicle coolant circuit 20 is in some places herein referred to as the “coolant circuit 20” for reasons of brevity and clarity. The coolant circuit 20 may also be referred to as a vehicle coolant system 20, a vehicle cooling circuit 20, or a vehicle cooling system 20. The coolant circuit 20 is configured to remove heat generated by a vehicle component 11. According to the illustrated embodiments, the vehicle component 11 is a component of an electric propulsion system of a vehicle, such as an electric machine, a propulsion battery, a fuel cell, power electronics, or the like. As an alternative, or in addition, the coolant circuit 20 may be configured to remove heat generated by other type of components, such as a combustion engine, a retarder, or the like. The coolant circuit 20 comprises a heat exchanger 3 configured to regulate temperature of coolant in the coolant circuit 20. The heat exchanger 3 may be a radiator configured to dissipate heat of coolant in the coolant circuit 20 to the surroundings.

The coolant circuit 20 further comprises a circulation pump 15 configured to circulate coolant through the coolant circuit 20. The coolant may comprise an aqueous mixture, such as a glycol based aqueous mixture. l\/loreover, the coolant circuit 20 comprises a bypass line 22 bypassing the heat exchanger 3 and a valve 24 configured to direct coolant to the bypass line 22 and/or to the heat exchanger 3. The valve 24 may be a thermostatic valve configured to direct coolant to the bypass line 22 and/or to the heat exchanger 3 based on thetemperature of coolant pumped to the valve 24. As an alternative, or in addition, the valve 24 may be electronically controlled, for example by a control arrangement 21, based on a temperature of coolant in the coolant circuit 20 and/or a cooling demand of the vehicle component Moreover, the coolant circuit 20 comprises an expansion tank 5 and a static line 7 connecting the expansion tank 5 to a first portion 2' of the coolant circuit 20. According to embodiments herein, the coolant circuit 20 comprises an impeller pump 9 arranged in the static line 7. The impeller pump 9 is configured to pump coolant in a direction from the expansion tank 5 towards the first portion 2' of the coolant circuit 20 during operation. That is, the impeller pump 9 comprises an inlet 9' fluidly connected to the expansion tank 5 and an outlet 9” fluidly connected to the first portion 2' of the coolant circuit 20. Due to these features, a coolant circuit 20 is provided having conditions for increasing the pressure in the coolant circuit 20 without relying on pneumatic pressurization and without relying on the coolant temperature in the coolant circuit 20. Accordingly, as a further result thereof, a coolant circuit 20 is provided in which the pressure in the coolant circuit 20 can be regulated, simply by regulating the impeller pump 9, also when a coolant temperature in the coolant circuit 20 is low, which usually is the case in a coolant circuit 20 configured to cool a component 11 of an electric propulsion system, as the coolant circuit 20 according to the embodiments illustrated in Fig.

Moreover, a coolant circuit 20 is provided having conditions for increasing the pressure in the coolant circuit 20 in a simple, efficient, and reliable manner, simply by controlling the impeller pump 9 as is further explained herein. l\/loreover, due to the impeller pump 9, a coolant circuit 20 is provided in which cavitation and compression/collapsing of hoses of the coolant circuit 20 can be avoided in a simple, efficient, and reliable manner. The wording “increasing the pressure in the coolant circuit 20” as used herein may encompass an increase in fluid pressure of at least a first portion of the coolant circuit According to some embodiments, the impeller pump 9 is a non-positive displacement impeller pump, such as a centrifugal pump. Thereby, a free flow path is provided over the impeller pump 9 which provides more stable pressure levels in the coolant circuit 20 as compared to the use of a positive displacement pump, such as a piston pump. ln addition, more stable pressure levels in the coolant circuit 20 can be provided as compared to the use of a positive displacement pump because a non-positive displacement impeller pump, such as a centrifugal pump, is capable of producing a continuous flow of coolant as compared to a positive displacement pump, such as a piston pump.

According to the illustrated embodiments, the coolant circuit 20 comprises a control arrangement 21. The control arrangement 21 is configured to control operation of the impeller pump 9 to regulate a fluid pressure in the coolant circuit 20. The control arrangement 21 may be configured to control the pumping rate of the impeller pump 9, i.e. the rotation speed of the impeller pump 9, to regulate a fluid pressure in the coolant circuit 20. Thereby, a coolant circuit 20 is provided capable of obtaining stable pressure levels at various operational conditions of the coolant circuit 20 in a simple, efficient, and reliable manner. The impeller pump 9 may be an electrically driven impeller pump According to the illustrated embodiments, the expansion tank 5 comprises a pressure relief valve 25 configured to open to the surroundings when a pressure inside the expansion tank 5 rises above a threshold pressure. Thus, according to the illustrated embodiments, the coolant circuit 20 is a pressurized coolant circuit 20 capable of operating at pressure levels above a current ambient pressure also when the impeller pump 9 is inactive. l\/loreover, according to the illustrated embodiments, the pressure relief valve 25 is configured to open to the surroundings when a pressure inside the expansion tank 5 declines below a second threshold pressure.

According to the illustrated embodiments, the coolant circuit 20 comprises a deaeration line 17. The deaeration line 17 connects the expansion tank 5 to a second portion 23 of the coolant circuit 20. According to the illustrated embodiments, the second portion 23 of the coolant circuit 20 is a portion of the heat exchanger 3. ln more detail, according to the illustrated embodiments, the second portion 23 of the coolant circuit 9 is a portion of an outlet tank of the heat exchanger 3, i.e. a portion downstream of cooling channels of the heat exchanger 3. The deaeration line 17 can be utilized as a return conduit for coolant transferred to the coolant circuit 20 by the impeller pump 9. ln this manner, the pressure in the coolant circuit 20 can be controlled in an improved manner and the heat exchanger 3 can be deaerated in an efficient manner. The connection between the static line 7 and the coolant circuit 20 is thus referred to as a first portion 2' of the coolant circuit 20 and the connection between the deaeration line 17 and the coolant circuit 20 is thus referred to as a second portion 23 of the coolant circuit 20. According to further embodiments, the deaeration line 17 may connect the expansion tank 5 to another portion of the coolant circuit 20 than the heat exchanger 3. As an example, the deaeration line 17 may connect the expansion tank 5 to a high point of a conduit or component, such as the component 11. According to some embodiments, the deaeration line 17 is connected to the static line 7 at a location between the outlet 9” of the impeller pump 9 and the first portion 2' of the coolant circuit 20, i.e. alocation between the outlet 9” of the impeller pump 9 and the connection of the static line 7 and the coo|ant circuit Furthermore, according to the illustrated embodiments, the deaeration line 17 comprises a flow restrictor 27. As indicated in Fig. 1, the flow restrictor 27 may comprise a valve 27. The control arrangement 21 may be configured to control an opening state of the valve 27 to further regulate the fluid pressure in the coo|ant circuit 20. According to such embodiments, the control arrangement 21 may control the valve 27 to a more closed state so as to increase fluid pressure in the coo|ant circuit 20 and may control the valve 27 to a more open state so as to decrease fluid pressure in the coo|ant circuit 20. According to further embodiments, the flow restrictor 27 may comprise another type of device or structure, such as a device or structure comprising a flow path with a reduced effective cross sectional area.

Moreover, according to some embodiments of the present disclosure, the control arrangement 21 may be provided with a deairing-mode in which the control arrangement 21 operates the pump 9 so as to cause a flow of coo|ant through the heat exchanger 3 and the deaeration line 17 also when no pressurization of the coo|ant circuit 20 is determined necessary. According to such embodiment, the control arrangement 21 may control the valve 27 to an open state when operating in the deairing-mode.

The second portion 23 of the coo|ant circuit 20 may be arranged upstream of the first portion 2' of the coo|ant circuit 20 relative to an intended flow direction through the coo|ant circuit 20. ln other words, according to some embodiments, the second portion 23 is arranged upstream of the first portion 2' relative to an intended flow direction through a circuit section 20” of the coo|ant circuit 20 between the first and second portions 2', 23 of the coo|ant circuit 20. As is indicated in Fig. 1, according to some embodiments of the present disclosure, the coo|ant circuit 20 comprises a one-way valve 28 arranged in the circuit section 20” of the coo|ant circuit 20 between the first and second portions 2', 23. According to the illustrated embodiments, the one-way valve 28 is configured to prevent flow of coo|ant from the first portion 2' towards the second portion 23 through the coo|ant circuit 20. ln other words, according to the illustrated embodiments, the one-way valve 28 is configured to prevent flow of coo|ant through the circuit section 20” in a direction from the first portion 2' towards the second portion 23. Thereby, a coo|ant circuit 20 is provided in which the impeller pump 9 can be utilized to circulate coo|ant through the coo|ant circuit 20, i.e. cause a flow of coo|ant through the static line 7 to the coo|ant circuit 20 and components 11 arranged therein, and through the heat exchanger 3 and through the deaeration line 17 and the expansion tank 5 back to the static line 7. ln this manner, conditions are provided for utilizing the impellerpump 9 in a cooling mode in which the coolant circuit 20 provides cooling of a component 11 arranged in the coolant circuit 20, such as a retarder or other type of component 11. According to such embodiments, the coolant circuit 20 may lack a circuiation pump 15 or may comprise a non-positive dispiacement circulation pump 15 comprising a free flow path over the circuiation pump Fig. 2 iliustrates a hydrodynamic retarder arrangement 10 according to some embodiments. The hydrodynamic retarder arrangement 10 is in some places herein referred to as “the retarder arrangement 10” for reasons of brevity and clarity. The retarder arrangement 10 comprises a hydrodynamic retarder 1. The hydrodynamic retarder 1 is configured to brake rotation of a shaft 6 of a vehicle, as is further explained herein. The hydrodynamic retarder 1 is in some places herein referred to as “the retarder 1” for reasons of brevity and clarity.

The retarder 1 comprises a retarder housing 51 with a shovel space 52 and a shovel arrangement 12, 53 arranged in the shovel space 52. The shovel arrangement 12, 53 comprises a shovel-equipped stator 53 and a shovel-equipped rotor 12 together forming a workspace 55. The workspace 55 can also be referred to as a torus. The retarder 1 further comprises a coolant inlet 4 and a coolant outlet 33. l\/loreover, the retarder 1 comprises a coolant circuit 20 connected to the coolant inlet 4 and to the coolant outlet 33 of the retarder 1. ln more detail, the coolant circuit 20 comprises an inlet duct 2 connected to the coolant inlet 4 of the retarder 1 and an outlet duct 56 connected to the coolant outlet 33 of the retarder 1. The inlet duct 2 thus forms part of the coolant circuit 20. Coolant is supplied from the inlet duct 2 to the workspace 55 via the coolant inlet 4 of the retarder 1. The coolant outlet 33 of the retarder 1 is arranged to evacuate coolant from the workspace 55 to the outlet duct 56 of the coolant circuit 20. According to the illustrated embodiments, the coolant is an aqueous mixture, such as a glycol based aqueous mixture.

Thus, according to the embodiments illustrated in Fig. 2, the coolant circuit 20 is a retarder circuit configured to remove heat generated by a retarder 1. Therefore, according to the embodiments illustrated in Fig. 2, the coolant circuit 20 may also be referred to as a retarder circuit 20 and the coolant of the coolant circuit 20 functions as a working fluid for the retarder 1 during operation of the retarder 1. Therefore, according to these embodiments, the wording “coolant” may be replaced with the wording “working fluid”. l\/loreover, according to some embodiments, the coolant circuit 20 may also be configured to remove heat generated by a further component in addition to the retarder 1, such as a component of an electric propulsion system, a component of a combustion engine, or the like.The coolant circuit 20 comprises a heat exchanger 3 configured to regulate temperature of coolant in the coolant circuit 20. The heat exchanger 3 may be a radiator configured to dissipate heat of coolant in the coolant circuit to the surroundings. l\/loreover, the coolant circuit 20 comprises an expansion tank 5 and a static line 7 connecting the expansion tank 5 to a first portion 2' of the coolant circuit 20. The first portion 2' of the coolant circuit 20 is arranged upstream of the coolant in|et 4 of the hydrodynamic retarder 1 relative to an intended flow direction towards the coolant in|et 4. According to embodiments herein, the coolant circuit 20 comprises an impeller pump 9 arranged in the static line 7. The impeller pump 9 is configured to pump coolant in a direction from the expansion tank 5 towards the first portion 2' of the coolant circuit 20 during operation. That is, the impeller pump 9 comprises an in|et 9' fluidly connected to the expansion tank 5 and an outlet 9” fluidly connected to the first portion 2' of the coolant circuit 20. The impeller pump 9 may also be referred to as a pressure increasing arrangement The coolant circuit 20 further comprises 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 arranged to restrict flow of coolant through the coolant outlet 33 so as to increase the braking torque of the retarder 1. The wording “outlet duct 56” and “coolant outlet 33” as used herein, may be defined as an outlet channel 56, or a set of outlet channels 56, extending from the workspace 55 to the brake valve 31. During braking, the coolant flows through the coolant circuit 20, through the brake valve 31, through the heat exchanger 3, and back to the workspace 55 via the in|et duct According to the illustrated embodiments, the retarder 1 comprises a retarder transmission 60 comprising a set of gear wheels 60', 60”. Furthermore, the retarder 1 comprises a coupling device 14 and an actuator 14” mechanically connected to the coupling device 14. The actuator 14” is moveable between an actuated position and an unactuated position to move the coupling device 14 between an engaged state and a disengaged state. The coupling device 14 is configured to, in the engaged state, connect the rotor 12 to the shaft 6 via the retarder transmission 60, and in the disengaged state, disconnect the rotor 12 from the shaft 6. The shaft 6 may be connected to one or more wheels of a vehicle such that the vehicle is braked, i.e. such that a retarding force is applied to the vehicle, when the retarder 1 brakes rotation of the shaftAccording to the illustrated embodiments, the retarder transmission 60 comprises 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' is connectable to the shaft 6 by the coupling deviceAccording to the illustrated embodiments, the coupling device 14 is configured to, in the engaged state, connect the first gear wheel 60' of the retarder transmission 60 to the shaft 6. Moreover, the coupling device 14 is configured to, in the disengaged state, disconnect the first gear wheel 60' of the retarder transmission 60 from the shaft 6. Thus, according to the illustrated embodiments, the first gear wheel 60' and a second gear wheel 60" of the retarder transmission 60 will not rotate, or will at least not be driven by the shaft 6, when the coupling device 14 is in the disengaged state. ln the engaged state, the first gear wheel 60' corotates with the shaft 6 so as to drive the rotor 12 via the retarder transmission 60. The coupling device 14 may comprise a dog clutch, a synchronizer, a clutch, or the like.

During operation of the retarder 1, i.e. during rotation of the rotor 12, the retarder 1 pumps coolant from the in|et duct 2 to the coolant outlet 33, via the workspace 55. The retarder 1 will thus circulate coolant through the coolant circuit 20 during operation and can therefore be seen as, and be referred to as, a circulation pump 1. The in|et duct 2 and the coolant outlet 33 may each comprise a plurality of parallel channels arranged to supply and evacuate, respectively, coolant to and from the workspace 55. As an example, the coolant outlet 33, as referred to herein, may be integrated in the shovel-equipped stator 53 and may comprise one outlet channel portion per shovel of the shovel-equipped stator 53. According to such embodiments, the outlet channel portions may each extend to a common ring-shaped volume arranged in the housing Upon initiation or cance||ation of braking of the hydrodynamic retarder 1, the coolant circuit 20, and especially the in|et duct 2, is subjected to significant pressure variations. The pressure variations may cause pressures below a current ambient pressure which put strain on the coolant circuit 20 and can cause hoses to suck flat, i.e. collapse. lf one or more hoses is/are sucked flat, the flow through the hose/hoses is obstructed which limits the flow therethrough and consequently the feed of coolant to the retarder 1. Moreover, repeated compression/collapsing of hoses of the coolant circuit 20 may damage the hoses of the coolant circuit Moreover, the retarder arrangement 10 comprises a control arrangement 21. The control arrangement 21 is connected to the impeller pump 9 and is configured to control operation thereof, i.e. activate and deactivate the impeller pump 9. l\/loreover, as indicated herein, according to some embodiments, the control arrangement 21 is configured to control the pumping rate of the impeller pump 9 to regulate a fluid pressure in the coolant circuit 20. Moreover, according to the illustrated embodiments, the control arrangement 21 is connected to the actuator 14' and is configured to control operation thereof, i.e. is configured to control the actuator 14' between actuated position and an unactuated position in order to move the coupling device 14 between the engaged state and the disengaged state. Furthermore, the control arrangement 21 is connected to the brake valve 31 and is configured to control the opening state of the brake valve 31 so as to initiate and cancel braking of the hydrodynamic retarder 1 and to control a braking torque of the retarder Moreover, according to some embodiments herein, the control arrangement 21 is configured to activate the impeller pump 9 in conjunction with an initiation or cancellation of braking of the hydrodynamic retarder 1. ln this manner, pressures below the ambient pressure can be avoided in the coolant circuit 20 of the hydrodynamic retarder arrangement 10. This is because the fluid pressure in the inlet duct 2 is increased in conjunction with the of initiation or cancellation of braking of the hydrodynamic retarder 1. As a further result thereof, strain on the coolant circuit 20 is lowered and compression/collapsing of components thereof can be avoided in a simple, robust, and efficient manner. Moreover, a hydrodynamic retarder arrangement 10 is provided having conditions for ensuring feed of coolant to the hydrodynamic retarder 1 in a simple, robust, and efficient manner.

As indicated herein, the impeller pump 9 is configured to increase fluid pressure in the inlet duct 2 by pumping coolant to the inlet duct 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 over the pump and thereby provides more stable pressure levels in the inlet duct 2 as compared to when using a positive displacement pump because of the free flow path over the pump and because of the fact that a non-positive displacement impeller pump, such as a centrifugal pump, is capable of producing a substantially continuous flow of coolant as compared to a positive displacement pump, such as a piston pump. l\/loreover, as indicated herein, the static line 7 connects the expansion tank 5 to a first portion 2' of the inlet duct 2. The first portion 2' of the inlet duct 2 is thus herein referred to as a first portion 2' of the coolant circuit 2. According to the illustrated embodiments, the expansion tank 5 comprises a pressure relief valve 25 configured to open to the surroundings when a pressure inside the expansion tank 5 rises above a threshold pressure. Thus, according to the illustrated embodiments, the coolant circuit 20 is a pressurized coolant circuit 20 capable of operating at pressure levels above a current ambient pressure also when the impeller pump 9 is inactive. l\/loreover, according to the illustrated embodiments, the pressure relief valve 25 is configured to open to the surroundings when a pressure inside the expansion tank 5 declines below a second threshold pressure.Moreover, according to the illustrated embodiments, the coolant circuit 20 comprises a deaeration line 17 connecting the expansion tank 5 to a second portion 23 of the coolant circuit 20. According to the illustrated embodiments, the second portion 23 of the coolant circuit 9 is a portion of the heat exchanger 3. ln this manner, the heat exchanger 3 can be deaired in an efficient manner while the deaeration line 17 can be utilized as a return conduit for coolant transferred to the inlet duct 2 by the impeller pump 9. Moreover, according to some embodiments, the control arrangement 21 may be provided with a deairing-mode in which the control arrangement 21 operates the pump 9 so as to cause a flow of coolant through the heat exchanger 3 and the deaeration line 17 also when the retarder 1 is inactive, i.e. also when the retarder 1 is not used for braking.

Furthermore, according to the illustrated embodiments, the deaeration line 17 comprises a flow restrictor 27. As indicated in Fig. 2, the flow restrictor 27 may comprise a valve 27. The control arrangement 21 may be configured to control an opening state of the valve 27 to further regulate the fluid pressure in the inlet duct 2. According to such embodiments, the control arrangement may control the valve 27 to a more closed state so as to increase fluid pressure in the inlet duct 2 and may control the valve 27 to a more open state so as to decrease fluid pressure in the inlet duct 2. I\/|oreover, the control arrangement 21 may control the valve 27 to an open state when operating in the deairing-mode. According to further embodiments, the flow restrictor 27 may comprise another type of device or structure, such as a device or structure comprising a flow path with a reduced effective cross sectional area.

The second portion 23 of the coolant circuit 20 may be arranged upstream of the first portion 2' of the coolant circuit 20 relative to an intended flow direction through the coolant circuit 20. ln other words, according to some embodiments, the second portion 23 is arranged upstream of the first portion 2' relative to an intended flow direction through a circuit section 20” of the coolant circuit 20 between the first and second portions 2', 23 of the coolant circuit 20. As is indicated in Fig. 2, according to some embodiments of the present disclosure, the coolant circuit 20 comprises a one-way valve 28 arranged in the circuit section 20” of the coolant circuit 20 between the first and second portions 2', 23. According to the illustrated embodiments, the one-way valve 28 is configured to prevent flow of coolant from the first portion 2' towards the second portion 23 through the coolant circuit 20. ln other words, according to the illustrated embodiments, the one-way valve 28 is configured to prevent flow of coolant through the circuit section 20” in a direction from the first portion 2' towards the second portion 23. Thereby, a coolant circuit 20 is provided in which the impeller pump 9 can be utilized to circulate coolant through the workspace 55 of the retarder 1, i.e. cause a flow of coolant through the static line 7 to the inlet duct 2, the coolant inlet 4, through the workspace55 and back to the static line 7 via the outlet duct 56, the heat exchanger 3, the deaeration line 17 and the expansion tank 5. Accordingly, a coolant circuit 20 is provided in which the impeller pump 9 can be utilized to circulate coolant through the workspace 55 of the retarder 1 when the retarder is inactive, such as after a braking event of the retarder 1 so as to cool the retarder According to embodiments herein, the control arrangement 21 is provided with a retarder cooling mode in which the control arrangement 21 operates the impeller pump 9 to circulate coolant through the workspace 55 of the retarder 1. The control arrangement 21 may operate in the retarder cooling mode after a braking event of the retarder 1, i.e. after a cancellation of braking of the hydrodynamic retarder 1. ln the retarder cooling mode, the control arrangement 21 may operate the pump 9 so as to cause a flow of coolant through the workspace 55 of the retarder 1, through the heat exchanger 3, the deaeration line 17, the expansion tank 5 and back to the workspace 55 via the static line 7 and the inlet duct Due to the one way valve 28 a reverse flow of working media from the static line 7 to the deaeration line 17 is prevented during operation in the retarder cooling mode. According to further embodiments, the retarder circuit 20 may comprise another type of component, structure, and/or routing of ducts to prevent a reverse flow of working media from the static line 7 to the deaeration line 17 during operation in the retarder cooling mode. ln some prior art solutions, a rotor of the hydrodynamic retarder is operated, i.e. rotated, so as to cool the retarder after operation. However, by circulating coolant through the workspace 55 using the impeller pump 9, the retarder 1 and the workspace 55 thereof can be cooled in a significantly more energy efficient manner as compared to such a solution. ln embodiments in which the deaeration line 17 comprises a valve 27, the control arrangement 21 may control the valve 27 to an open state when operating in the retarder cooling mode. Likewise, the control arrangement 21 may control the brake valve 31 to an open state when operating in the retarder cooling mode.

Fig. 3 illustrates a vehicle 30 according to some embodiments. The vehicle 30 comprises a propulsion unit 11. The propulsion unit 11 may be a combustion engine or an electric propulsion unit. The propulsion unit 11 is cooled by a coolant circuit 20 according to the embodiments illustrated in Fig. 1. The vehicle 30 further comprises a hydrodynamic retarder arrangement 10 according to the embodiments illustrated in Fig. 2, i.e. a retarder arrangement 10 comprising a coolant circuit 20 explained with reference to Fig. 2. The hydrodynamic retarder arrangement 10 is configured to provide a retardation force onto thevehicle 30 via wheels 39 of the vehicle 30. Likewise, the propulsion unit 11 is configured to provide motive power to the vehicle 30 via wheels 39 of the vehicle According to the illustrated embodiments, the vehicle 30 is a truck, i.e. a heavy vehicle. However, according to further embodiments, the vehicle 30, as referred to herein, may be another type of manned or unmanned vehicle for land based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, or the like.

The control arrangement 21 explained with reference to Fig. 1 and Fig. 2 may comprise a calculation unit which may take the form of substantially 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, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression “calculation unit” may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

The control arrangement 21 may further comprise a memory unit, wherein the calculation unit may be connected to the memory unit, which may provide the calculation unit with, for example, stored program code and/or stored data which the calculation unit may need to enable it to do calculations. The calculation unit may also be adapted to store partial or final results of calculations in the memory unit. The memory unit may comprise a physical device utilised to store data or programs, i.e., sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory unit may comprise integrated circuits comprising silicon-based transistors. The memory unit may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROIVI (Read-Only l\/lemory), PROIVI (Programmable Read-Only Memory), EPROIVI (Erasable PROIVI), EEPROIVI (Electrically Erasable PRONI), etc. in different embodiments.

The control arrangement 21 is connected to components of the coolant circuit 20 and/or the hydrodynamic retarder arrangement 10, and/or to components of a vehicle 30 comprising the coolant circuit 20 and/or the hydrodynamic retarder arrangement 10, for receiving and/or sending input and output signals. These input and output signals may comprise waveforms, pulses, or other attributes which the input signal receiving devices can detect as information and which can be converted to signals processable by the control arrangement 21. These signals may then be supplied to the calculation unit. One or more output signal sendingdevices may be arranged to convert calculation results from the calculation unit to output signals for conveying to other parts of the vehicle's control system and/or the component or components for which the signals are intended. Each of the connections to the respective components of the vehicle 30 for receiving and sending input and output signals may take the form of one or more from among a cable, a data bus, e.g. a CAN (controller area network) bus, a l\/IOST (media orientated systems transport) bus or some other bus configuration, or a wireless connection. ln the embodiments illustrated, the coolant circuit 20 and/or the hydrodynamic retarder arrangement 10 comprises a control arrangement 21 but might alternatively be implemented wholly or partly in two or more control arrangements or two or more control units.

Control systems in modern vehicles generally comprise a communication bus system consisting of one or more communication buses for connecting a number of electronic control units (ECUs), or controllers, to various components on board the vehicle. Such a control system may comprise a large number of control units and taking care of a specific function may be shared between two or more of them. Vehicles of the type here concerned are therefore often provided with significantly more control arrangements than depicted in Fig. 1 and Fig. 2, as one skilled in the art will surely appreciate. lt is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended claims.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components, or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions, or groups thereof.

Claims

A vehicle coolant circuit (20) configured to remove heat generated by a vehicle component (1, 11), wherein the coolant circuit (20) comprises: - a heat exchanger (3) configured to regulate temperature of coolant in the coolant circuit (20), - an expansion tank (5), - a static line (7) connecting the expansion tank (5) to a first portion (2') of the coolant circuit (20), and Man impeller pump (9) arranged in the static line (7 (
The coolant circuit (20) according to claim 1, wherein an inlet (9') of the impeller pump (9) is fluidly connected to the expansion tank (5) and an outlet (9”) of the impeller pump (9) is fluidly connected to the first portion (2') of the coolant circuit (20).
The coolant circuit (20) according to claim 1 or 2, wherein the impeller pump (9) is a centrifugal pump.
The coolant circuit (20) according to any one of the preceding claims, wherein the coolant circuit (20) further comprises a circulation pump (1, 15) configured to circulate coolant through the coolant circuit (20).
The coolant circuit (20) according to any one of the preceding claims, wherein the coolant circuit (20) comprises a control arrangement (21 ), and wherein the control arrangement (21) is configured to control operation of the impeller pump (9) to regulate a fluid pressure in the coolant circuit (20).
The coolant circuit (20) according to claim 5, wherein the control arrangement (21) is configured to control the pumping rate of the impeller pump (9) to regulate a fluid pressure in the coolant circuit (20). j Formatted: Normal, Indent: Left: 0,75 cm, No bullets or numbering . Formatted: Font: (Default) Arial
7. The coolant circuit (20) according to any one of the preceding claims, wherein the expansion tank (5) comprises a pressure relief valve (25) configured to open to the surroundings when a pressure inside the expansion tank (5) rises above a threshold pressure. 5 'f- Formatted: Font: (Default) Arial Formatted: Normal, lndent: Left: -0,63 cm i” Formatted: Normal, lndent: Left: 0 cm, Right: 0 cm, _ _ _ _ Line spacing: single 10 ëšTg§_“NNN______The coolant c|rcu|t (20) according to i wherein the second portion (23) of the coolant circuit (20) is a portion of the heat exchanger (3). _.“__________The coolant circuit (20) according to any one of the *=1_claims-<'-“.~----ïiš-, wherein the deaeration line (17) comprises a valve (27). 20 ______________ “The coolant circuit (20) according to claim wherein the coolant circuit (20) comprises a control arrangement (21), and wherein the control arrangement (21) is configured to control an opening state of the valve (27) to regulate a fluid pressure in the coolant circuit (20). 25 '“ ' ' “ ^ :-::':^:r ._ __________ __The coolant circuit (20) according to any one of the preceding claims, wherein the coolant circuit (20) is a retarder circuit configured to remove heat generated by a retarder (1 ). 35 " ___________ “The coolant circuit (20) according to claim 1 wherein the retarder (1) is a hydrodynamic retarder, and wherein the first portion (2') of the coolant circuit (20) is arranged upstream of a coolant inlet (4) of the hydrodynamic retarder (1) relative to an intended flow direction towards the coolant inlet (4). hydrodynamic retarder arrangement (10) comprising: - a hydrodynamic retarder (1) configured to brake rotation of a shaft (6) of a vehicle (30), and - a coolant circuit (20) according to any one of the preceding claims, wherein the coolant circuit (20) is configured to remove heat generated by the hydrodynamic retarder (1 ). _____The hydrodynamic retarder arrangement (1 0) according to claim wherein the arrangement (10) comprises a control arrangement (21) configured to operate the impeller pump (9) in a retarder cooling mode in which the impeller pump (9) circulates coolant through a workspace (55) of the hydrodynamic retarder (1 ). ._ __________ __A vehicle (30) comprising a coolant circuit (20) acoording to any one the claims1 -or a hydrodynamic retarder arrangement (10) according to claim 1-jlgsš or