DE102018003101A1 - Cooling system for a water retarder - Google Patents

Abstract

Cooling system for a water retarder (6). The cooling system includes a control valve (12) configured to direct cooling liquid to the water retarder (6) via a retarder line (13) or to the water retarder (6) via a retarder bypass line (14) (11) for directing cooling liquid to the control valve (12) located at a downstream end (11b) of the supply line (11) and a return line (17) configured to supply cooling liquid from the retarder line (12). 13) and the retarder bypass line (14), at an upstream end (17a). The cooling system comprises a second retarder bypass line (19) configured to receive cooling fluid from a position (11c) of the supply line (11) located at a distance from its downstream end (11b) and cooling fluid to a position (17c) of the return passage (17) located at a distance from its upstream end (17a).

Description

BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention relates to a cooling system for a water retarder according to the preamble of claim 1.

Heavy vehicles are often equipped with one or more additional brakes to reduce wear on the vehicle's common wheel brakes. Such an additional brake may be a hydraulic retarder. Primary hydraulic retarders are connected to a component in the drive train that is in front of the transmission, and secondary hydraulic retarders are connected to a component in the drive system that is behind the transmission. One type of hydraulic retarder, commonly referred to as a water retarder, uses cooling fluid as the cooling medium and working fluid.

A secondary water retarder is usually located in a position on a rear of the transmission. The coolant lines leading coolant to and from the water retarder often need to be bent and limited due to the lack of space around the transmission. Usually, the coolant flow in this area reaches relatively high pressure drops, which puts a heavy strain on the coolant pump. As a result, the cooling liquid pump has to perform much pumping for the circulation of the cooling liquid through a cooling system comprising a secondary water retarder. Due to this fact, coolant pumps having a relatively high pumping capacity must be used. The operation of such pumps has an effect on the fuel consumption of the internal combustion engine. The existence of long coolant lines to the water retarder causes a large amount of coolant to circulate through the cooling system. After a cold start, it takes a relatively long time to heat such a large amount of coolant to an operating temperature.

DE 196 03 184 shows a cooling system for an internal combustion engine and a water retarder. The water retarder is engaged by means of a clutch by which a rotor of the retarder is releasably connected to an output shaft of a transmission. The cooling system includes a retarder bypass line and a check valve. When the retarder is disengaged, an increased pressure is obtained in the cooling system in a region adjacent to the retarder, which opens the check valve and allows a flow of cooling fluid through the retarder bypass line.

US 4,538,553 shows a cooling system for an internal combustion engine and a water retarder. The cooling system includes a 2/2-way valve which, in an open position, allows coolant flow to the water retarder and, in a closed position, prevents coolant flow to the water retarder. The cooling system includes a retarder bypass line spaced from the 2/2-way valve. When the 2/2-way valve is placed in the closed position, the flow of cooling fluid is directed through the retarder bypass line.

BRIEF SUMMARY OF THE INVENTION

The object of the present invention is to provide a cooling system cooling for a water retarder with a design that ensures relatively low flow losses during operating conditions when the retarder is not activated.

This object is achieved by the features defined in the characterizing part of claim 1. When the control valve is switched from a retarder-on position to a retarder-off position, it stops the flow of cooling fluid to the retarder and the flow of cooling fluid is directed to the first retarder bypass line. It is important that the control valve is located very close to the retarder, so that the coolant supply to the retarder is stopped immediately when the control valve is placed in the retarder-off position. It is also important that the first retarder bypass line be located close to the control valve to minimize the generation of pressure surges and standing waves that can occur when the control valve is switched between the two positions. In the case where the retarder is located at a relatively large distance from the radiator, there is a risk that the supply line, the cooling liquid leads to the water retarder, and the return line, which leads the cooling liquid back from the retarder, a high flow resistance to reach.

According to the invention, when the control valve is placed in the retarder-off position, the existence of the second retarder bypass line makes it possible for part of the coolant flow to take an alternative shorter flow path than the conventional flow path for the first bypass line. The distribution of the cooling liquid flow through the two bypass lines is related to the flow resistance in the two alternative flow paths. It is usually not a problem, the second retarder bypass line in one Position to create an alternative flow path with a substantially lower flow resistance than the conventional flow path, which is defined by the first retarder bypass line. The application of such a second bypass line results in a major portion of the coolant flow being directed by the second bypass line when the control valve is in the retarder-off position. As a result, the existence of the second bypass line can substantially reduce flow losses in the cooling system during operating conditions when the retarder is not activated.

According to one embodiment of the invention, the second retarder bypass line comprises a flow element which allows a flow of cooling liquid from the supply line to the return line, but prevents a flow of cooling liquid in the opposite direction. In any case, it is necessary to prevent a cooling liquid flow in the wrong direction through the second retarder bypass line. A flow element in the form of a check valve may, for example, be used in the second retarder bypass line. Such a flow element is the only component which must be arranged in the second retarder bypass line. Thus, the second retarder bypass line may have a very simple design.

According to one embodiment of the invention, the second retarder bypass line receives cooling fluid from the supply line in a position which is at a smaller flow distance from its upstream end than from its downstream end. In order to minimize the length of a flow path defined by the second retarder bypass line, it is appropriate to arrange an inlet of the second retarder bypass line relatively close to its upstream end.

According to one embodiment of the invention, the cooling system comprises a control unit configured to control the control valve by means of information from a brake activation element. The brake activating element may be a brake pedal or other type of brake activating element by which a driver or a vehicle control system indicates activation of the retarder.

According to one embodiment of the invention, the control valve is a solenoid valve which is in a retarder-in position, in which it directs the flow of cooling fluid to the retarder, and in a retarder-off position, in which the cooling liquid flow to the first retarder bypass line conducts, is switchable. It is of course possible to use other types of valves that control the activation of the retarder.

According to one embodiment of the invention, the retarder conduit includes a flow member disposed in a position behind the retarder and configured to prevent a backward flow of cooling fluid in the retarder conduit toward the retarder. Such a flow element may be a check valve. Furthermore, the retarder conduit may comprise a pressure regulating valve.

According to an embodiment of the invention, the cooling system is also configured to cool an internal combustion engine, and the supply line is a supply line that receives cooling fluid that has cooled the internal combustion engine. It is common to use a common cooling system for the internal combustion engine and the water retarder. The existence of the second bypass line reduces the amount of coolant that must flow through the cooling system when the water retarder is shut off. This leads to a faster heating of the cooling liquid to a desired operating temperature of the internal combustion engine after a cold start.

According to an embodiment of the invention, the supply line receives cooling fluid at an upstream end located on the side of the internal combustion engine that is at the longest distance from the radiator. Usually, cooling liquid enters the internal combustion engine via an intake pipe arranged relatively close to the radiator, and exits the internal combustion engine via an exhaust pipe arranged on an opposite side of the internal combustion engine.

According to one embodiment of the invention, the internal combustion engine is connected to a transmission and the control valve and the water retarder are arranged in a position which is located at a longer distance from the radiator than from the transmission. The cooling system may be disposed in a vehicle, and a rotor unit of the water retarder is connected to a part of the powertrain of the vehicle by means of a motion transmission mechanism. In the case where the water retarder is a secondary retarder, a rotor unit of the water retarder is connected by means of a motion transmission mechanism to a component of the drivetrain of the vehicle that is behind the transmission. The component of the powertrain may be an output shaft of the transmission. In this case the supply line and the return line should be long. Furthermore, coolant lines often have to due to the lack of space in the area around the Be bent and limited. In this case, the use of a second retarder bypass line will be very beneficial in order to reduce flow losses in the refrigeration system during operating conditions when the retarder is not activated.

The invention also relates to a water retarder comprising a cooling system according to the above. The invention also relates to a vehicle comprising a water retarder according to the above.

list of figures

• 1 ein Kühlsystem gemäß einer Ausführungsform der Erfindung zeigt.

Hereinafter, a preferred embodiment of the invention will be described by way of example with reference to the accompanying drawings, in which:

• 1 shows a cooling system according to an embodiment of the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

1 shows a schematically shown vehicle 1 which can be a heavy vehicle. The vehicle 1 is powered by an internal combustion engine 2 driven. The internal combustion engine 2 can be a gasoline engine or a diesel engine. The vehicle 1 includes a powertrain, in addition to the internal combustion engine 2 a clutch mechanism 3 , a gearbox 4 and a transmission output shaft 5 includes. The internal combustion engine 2 includes a motor front 2a and a motor back 2 B that are at a longer distance from a radiator 23 as the engine front 2a located. The gear 4 includes a transmission front 4a and a transmission back 4b extending at a longer distance from a radiator 23 as the transmission front 4b located. The vehicle 1 is with a water retarder 6 equipped, which is a rotor unit 6a and a stator unit 6b includes. The rotor unit 6a and a stator unit 6b define a toroidal space for receiving coolant. The rotor unit 6a and the stator unit 6b each have a plurality of vanes located in the toroidal space. The stator unit 6b is stationary in the vehicle. The rotor unit 6a is by means of a motion transmission mechanism 7 with the drive train of the vehicle 1 by means of the transmission output shaft 6 connected. Thus, the rotor unit becomes 6a rotated by a speed determined by the speed of the transmission output shaft 5 and the gear ratio in the motion transmission mechanism 7 is defined. A control unit 8th is set up to use the retarder 6 using information from a brake activation element 8a which can be a brake pedal to activate.

A cooling system with a circulating coolant is configured to drive the engine 2 and the water retarder 6 to cool. The cooling system includes a coolant pump 9 , which circulates coolant in the cooling system. The coolant pump 9 is in an engine intake line 10 at the engine front 2a arranged. The coolant coming out of the engine intake line 10 exits, circulates through cooling channels in the internal combustion engine. The coolant exits the internal combustion engine 1 and enters a supply line 11 a, the coolant to the retarder 6 passes. The supply line 11 guides the coolant from a downstream end 11a that with the back 2 B of the internal combustion engine is connected to an upstream end 11b that with a control valve 12 connected is. The flow control valve 12 is in a retarder-on position, where it is the coolant to the retarder 6 by means of a retarder line 13 conducts, and in a retarder-off position, in which there is the coolant to the retarder 6 passing by means of a first retarder bypass line 14 conducts, switchable.

The retarder pipe 13 includes a pressure control valve 15 and a second shut-off valve 16 in a downstream position of the retarder 6 are arranged. The cooling liquid coming out of the retarder pipe 13 exits, enters an upstream end of a return line 17 one. The return 17 directs the coolant to a thermostat 18 at a downstream end 17b the return line 17 is arranged. The cooling liquid coming from the first retarder bypass line 14 exit, also enters the return line 17 by means of the upstream end 17a one. The cooling system also includes a second retarder bypass line 19 , the coolant on the retarder 6 passing, at a distance from the first retarder bypass line 14 , The second retarder bypass line 19 takes coolant in one position 11c the supply line 11 which extends at a relatively long distance from its downstream end 11b located. The second retarder bypass line 19 gives coolant to a position 17c the supply line 17 starting at a relatively long distance from its upstream end 17a located. The second retarder bypass line 19 includes a first check valve 20 , which is a cooling liquid flow from the supply line 11 to the return 17 allows and prevents a flow of cooling liquid in the opposite direction.

Thus, the thermostat decreases 18 Coolant from the return line 17 on. The thermostat 18 directs the coolant to a radiator bypass line 21 when the cooling liquid is a lower temperature than a control temperature of the thermostat 18 having. The radiator bypass line 21 guides the coolant to the engine inlet line 10 , The thermostat 18 directs the coolant to a radiator line 22 holding a cooler 23 includes when the cooling liquid has a higher temperature than its control temperature. The coolant is in the cooler 23 cooled by a cooling air flow passing through the radiator 23 by ram air and a radiator fan 24 is driven. The cooling liquid in the cooler 23 has cooled, becomes the engine intake line 10 directed.

The coolant pump 9 starts the circulation of cooling fluid through the cooling system as soon as the internal combustion engine 2 is activated. During operating conditions, when the control unit 8th an information from the brake control unit 8a receives, indicating that the retarder 6 should not be activated, it sets the flow control valve 12 in the retarder-off position. In this position, a first part of the cooling liquid flow in the supply line 11 to the first retarder bypass line 14 passed and a second part of the cooling liquid flow is to the second retarder bypass line 19 directed. The ratio between the parts of the coolant flow is related to the flow resistance in the flow paths coming from the respective retarder bypass lines 14 . 19 To be defined. The flow path of the first retarder bypass line 14 is longer than the flow path of the second retarder bypass line 19 is defined. Furthermore, there is usually a lack of space near the transmission 4 , which complicate the wiring and the flow resistance in the supply line 11 and the return 17 increase in this area. In view of these facts, the flow of cooling liquid through the second retarder bypass line 19 much larger than the cooling liquid flow through the first retarder bypass line 14 be. Consequently, the existence of the second retarder bypass line 19 the flow losses in the cooling system during operating conditions when the water retarder 6 is not in operation, significantly reduce. Furthermore, the shorter flow path leading from the second retarder bypass line 19 is defined for circulating a smaller amount of coolant in the cooling system when the water retarder 6 is not in operation. In view of this fact, the cooling fluid in the cooling system is given a faster heating to a desired operating temperature after a cold start when the retarder is not in operation.

During operating conditions, when the control unit 8th an information from the brake control unit 8a receives, indicating that the water retarder 6 must be activated, it switches the flow control valve 12 in the retarder-a-position. The activated retarder 6 works like a pump and it sucks coolant from the supply line 11 to the retarder 6 , In this case, the cooling liquid flow becomes the second retarder bypass line 19 essentially eliminated. Essentially, the entire flow of cooling liquid is in the supply line 11 to the water retarder 6 what is an efficient braking action of the water retarder 6 by means of the motion transmission mechanism 7 on the transmission output shaft 5 and the drive train of the vehicle 1 ensures. Thus, the existence of the second bypass line affects 19 not at all on the efficiency of the water retarder 6 off when the control valve 12 in the retarder-on position.

It should be noted that the control valve 12 and the first retarder bypass line 14 in positions near the water retarder 6 are mounted. Such mounting positioning of the flow control valve 12 allows the coolant supply to the water retarder 6 then immediately shut down and complete the braking process when the control valve 12 from the retarder-on position to the retarder-off position. The in the retarder 6 During the switching operation to be separated cooling liquid quantity will be relatively low and thereby also the subsequently formed amount of steam in the retarder. It is important to have the amount of steam in the water retarder 6 minimize to reduce drag losses when the water retarder 6 is not in operation. It is also appropriate for other reasons to minimize the amount of steam in the cooling system. For example, it is difficult to design a cooling system that is adaptable to accommodate high volumes of vapor. Furthermore, it is important to have the first bypass line 14 near the control valve 12 to order pressure surges from the control valve 12 to decrease when it is switched between the two positions.

As a result, it is appropriate to use the control valve 12 near the retarder 6 to arrange the steam formation in the water retarder 6 to minimize. Furthermore, it is appropriate to have a first bypass line 14 in a position near the control valve 12 to order pressure surges from the control valve 12 to reduce. Finally, it is appropriate to have a second retarder bypass line 19 at a distance from the first retarder bypass line, which allows a flow path of the cooling liquid with low flow losses when the Wasserretarder 6 is not in operation.

The invention is not limited to the described embodiment but can be freely varied within the scope of the claims. The control valve 12 may, for example, in other positions than in a downstream position of the supply line 11 to be ordered.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19603184 [0004]
• US 4538553 [0005]

Claims (13)

A cooling system for a water retarder (6), wherein the cooling system includes a cooling liquid pump (9) configured to circulate cooling liquid through the cooling system, a radiator (23) in which the cooling liquid is cooled, a radiator bypass line (21), in which the cooling liquid flows past the radiator (23), a supply line (11) configured to direct cooling liquid towards the water retarder (6), a control valve (12) configured to transfer cooling liquid to a retarder Conduit (13) comprising the water retarder (6) or to a retarder bypass conduit (14) passing cooling liquid past the water retarder (6), and a return conduit (17) configured to To receive cooling liquid from the retarder line (13) and the retarder bypass line (14) at an upstream end (17 a) and to guide them in the direction of the radiator (4) and the radiator bypass line (21) characterized gek characterized in that the cooling system comprises a second retarder bypass line (19) configured to receive cooling fluid from a position (11c) of the supply line (11) spaced from its downstream end (11b) and cooling fluid to a position (11c) of the return line (17), which is located at a distance from its upstream end (17a) to deliver. Cooling system after Claim 1 , characterized in that the second retarder bypass line (19) comprises a flow element (20) which allows a flow of cooling liquid from the supply line (11) to the return line (17) and prevents a flow of cooling liquid in the opposite direction. Cooling system after Claim 1 or 2 characterized in that the second retarder bypass line (19) is cooling liquid from the supply line (11) in a position (11c) located at a longer flow distance from its downstream end (11b) than from its upstream end (11a), receives. Cooling system according to one of the preceding claims, characterized in that the cooling system comprises a control unit (8) which is configured to control the control valve (12) by means of information from a brake activation element (8a). Cooling system according to one of the preceding claims, characterized in that the control valve (12) is a solenoid valve which is in a retarder-in position, in which it directs the flow of cooling liquid to the water retarder (6), and in a retarder-off position in that it conducts the flow of cooling fluid to the first retarder bypass line (14) is switchable. Cooling system according to one of the preceding claims, characterized in that the retarder pipe (13) comprises a flow element (16) arranged in a position behind the water retarder (6) and configured to supply a backflow of cooling liquid from the return pipe (17 ) in the direction of the retarder (6). Cooling system according to one of the preceding claims, characterized in that the retarder pipe (13) comprises a pressure regulating valve (15). Cooling system according to one of the preceding claims, characterized in that the cooling system is also configured to cool an internal combustion engine (2), and that the supply line is a supply line (11) which receives cooling liquid, which has cooled the internal combustion engine (2). Cooling system after Claim 8 characterized in that the supply line (11) receives cooling liquid at an upstream end (11a) located on the side (2b) of the internal combustion engine (2) located at the longest distance from the radiator (23). Cooling system after Claim 8 or 9 characterized in that the internal combustion engine (2) is connected to a transmission (4) and that the control valve (12) and the water retarder (6) are arranged in a position which is at a longer distance from the radiator (23) than from the transmission (4). Cooling system according to one of the preceding claims, characterized in that the cooling system is arranged in a vehicle (1) and that a rotor unit (6a) of the water retarder (6) by means of a motion transmission mechanism (7) with a part (5) of the drive train of the vehicle ( 1) is connected. Water retarder, which is a cooling system after one of the previous ones Claims 1 - 11 includes. Vehicle following a water retarder Claim 12 includes.

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