COOLANT CIRCUIT IN A VEHICLE

Description

[0001] The invention relates to a coolant circuit in a vehicle, comprising a pump, an engine to be cooled and a radiator.

[0002] To ensure the functionality of a vehicle's engine, it must be continuously cooled once it has reached its operating temperature. For this purpose, typical vehicles are equipped with a coolant circuit, which generally includes a pump, an engine to be cooled, and a radiator. During operation, the pump pumps coolant into the hot engine, where the engine heat is absorbed by the coolant. The heated coolant is then pumped into the radiator, where it is cooled, for example, with air. The cooled coolant is then pumped back to the pump, and the cycle begins again.

[0003] In situations where the engine and coolant are cold (e.g. when starting a vehicle from cold), the rapid warm-up of the engine, which is desired in this situation, is delayed by the coolant circuit described above. For this reason, generic coolant circuits include a thermostat and a bypass line between the engine and the radiator to regulate the coolant temperature, allowing the coolant to bypass the radiator. If the coolant temperature falls below a limit, the main line between the engine and the radiator is closed by the thermostat and the bypass line is opened. This means that the coolant is bypassed the radiator and therefore not cooled. This causes the engine and the coolant to heat up more quickly, which shortens the engine warm-up time.Once the engine and coolant have reached their operating temperature, the thermostat opens the main line at the same rate as it closes the bypass line. As a result, the coolant flows through the radiator, keeping the engine temperature essentially constant.

[0004] DE 100 28 280 A1 discloses a pumping and heating device in a coolant circuit for cooling an engine, in which a thermostatic valve is provided which opens a bypass line when a temperature of the coolant in the thermostatic valve is lower than a certain preset temperature, and closes the bypass line and simultaneously releases a line between the radiator and the engine when the temperature of the coolant in the thermostatic valve is higher than the certain preset temperature.

[0005] In state-of-the-art coolant circuits, a two-way thermostat is typically used to control the coolant temperature as described above. However, the location of such a two-way thermostat in the engine compartment is limited, as it must be located either close to the engine or close to the radiator to simplify the layout of the bypass line.

[0006] EP 0 499 071 A1 discloses a coolant circuit in which a valve is located in the line leading to the radiator and in the bypass. Both valves are electronically controlled. This control works based on the temperature, which is determined by sensors located downstream of the engine and in the cooling circuit.

[0007] EP 1 614 873 A2 shows a coolant circuit with two expansion thermostat valves, each located at the inlet of the lines to the cooler and to the bypass.

[0008] From WO 2014 / 041273 A1, a coolant circuit is known which also teaches valves in the lines to the cooler and in the bypass.

[0009] The object of the invention is to create a simple coolant circuit with an integrated bypass line, which avoids the aforementioned disadvantages of generic coolant circuits.

[0010] This object is achieved according to the invention by a coolant circuit in a vehicle having the features of claim 1.

[0011] In the coolant circuit according to the invention, two spatially separated flow control units are provided instead of a two-way thermostat. This allows for greater design flexibility in the arrangement of components in the engine compartment. The use of two flow control units also makes it possible to control or regulate the coolant flow in the main channel and bypass channel depending on the engine operating condition (coolant temperature, engine speed, etc.).

[0012] A common temperature sensor that measures the coolant temperature in one area for both flow control units simplifies the design of the coolant circuit and minimizes the number of required components. This temperature sensor is preferably an electronic sensor that electronically controls the actuator of each flow control unit.

[0013] According to a further aspect, the first temperature sensor can be arranged in the engine or directly downstream of the engine, where it detects the coolant temperature. By arranging the temperature sensor in the engine or near the engine, it is possible to detect the hottest temperature in the coolant circuit.

[0014] Preferably, the first valve of the first flow control unit is in a maximally closed position at low coolant temperatures, in particular lower than 80°C, and in a maximally open position once an operating temperature of the coolant is reached, in particular above 95°C, wherein the first valve is moved continuously into intermediate positions between the two maximum positions depending on the temperature of the coolant at the first temperature sensor. Thus, at low coolant temperatures, coolant is no longer fed into the radiator, which means that the coolant is not additionally cooled in the radiator, whereby the warm-up time of the engine can be significantly reduced. Once the operating temperature of the coolant is reached, a maximum flow to the radiator is ensured, whereby the coolant is constantly cooled in the radiator and thus a substantially constant operating temperature of the coolant can be ensured.The continuous movement of the first valve in intermediate positions between the two maximum positions also helps to keep the operating temperature of the coolant essentially constant.

[0015] Preferably, the second valve of the second flow control unit is in a maximum open position at low coolant temperatures, in particular lower than 80°C, and in a maximum closed position once an operating temperature of the coolant is reached, in particular above 95°C. At low coolant temperatures, the coolant is thus guided through the bypass channel past the radiator and back to the engine. This short-circuited coolant circuit heats the coolant significantly more quickly and consequently shortens the warm-up time of the engine. Once an operating temperature of the coolant is reached, the bypass channel and thus the short-circuited coolant circuit are closed by the second valve, whereby the maximum available coolant flow can now be guided to the radiator in the main channel.

[0016] According to a further embodiment, the first flow control unit and / or the second flow control unit each have a throttle thermostat. Generally, with a throttle thermostat, the flow of the coolant is throttled until the desired opening temperature specified in the thermostat is reached. Only then does the temperature, in turn, open the valve, allowing the flow of the coolant.

[0017] In another embodiment of the coolant circuit, an oil-coolant heat exchanger is provided. The integration of the oil-coolant heat exchanger can lead to a further improvement in engine warm-up.

[0018] Further advantages and features of the invention will become apparent from the following description and the drawings, to which reference is made. In the drawings: Figure 1a schematic structure of a first embodiment of a coolant circuit, not according to the invention, Figure 2 a schematic structure of a second embodiment of a coolant circuit, not according to the invention, Figure 3 a schematic structure of an embodiment of the coolant circuit according to the invention, and Figure 4 a schematic structure of a further embodiment of a coolant circuit not according to the invention.

[0019] The Figure 1 The coolant circuit 10 shown, not according to the invention, comprises an engine 12, a radiator 14, an oil-coolant heat exchanger 16 and a pump 18. A main channel 20 fluidically connects the engine 12 to the radiator 14, the radiator 14 to the oil-coolant heat exchanger 16, the oil-coolant heat exchanger 16 to the pump 18 and the pump 18 to the engine 12.

[0020] A first flow control unit 22 is provided between the engine 12 and the cooler 14.

[0021] Between the motor 12 and the first flow control unit 22, a bypass channel 24 branches off from the main channel 20. The bypass channel 24 is connected in parallel to the cooler 14 and flows into the main channel 20 after the cooler 14.

[0022] A second flow control unit 26 is arranged in the bypass channel 24.

[0023] The two flow control units 22, 26 are arranged positionally and fluidically distant from each other in the coolant circuit 10.

[0024] In the embodiment shown here, the first flow control unit 22 comprises a first integrated temperature sensor 28, a first actuator 30 and a first valve 32, all of which are integrated in the first flow control unit 22.

[0025] The first temperature sensor 28 can, for example, be an electronic temperature sensor that electronically controls the first actuator 30.

[0026] Optionally, the first temperature sensor 28 can also be part of the first actuator 30, which mechanically or, in particular, thermomechanically controls or regulates the first valve 32, e.g., by a pressure sensor simultaneously acting as the actuator 30. The first temperature sensor 28 is integrated into the first actuator 30, so that the first actuator 30 itself senses the temperature of the coolant, and thus the first temperature sensor 28 is no longer an additional external component. For the sake of simplicity, the actuator and the temperature sensor associated with the actuator are referred to as two separate components in the present application.

[0027] The first valve 32 is coupled to the first actuator 30 and is continuously adjusted by the first actuator 30 depending on the coolant temperature. Since the first valve 32 in the first flow control unit 22 is adjusted based on the coolant temperature measured by the first temperature sensor 28, the first flow control unit 22 is directly dependent on the coolant temperature.

[0028] The first flow control unit 22 can be designed as an expansion thermostat (e.g. wax actuator) and in particular as a throttle thermostat.

[0029] The second flow control unit 26 comprises a second valve 34 which is biased by a spring 36 against a flow direction of the coolant.

[0030] The second valve 34 can be designed as a purely mechanical pressure valve and in particular as a pressure relief valve.

[0031] Since the second flow control unit 26 does not include a temperature sensor that measures the temperature of the coolant and controls or regulates the flow of the coolant based on this temperature, the second flow control unit 26 is indirectly dependent on the temperature of the coolant. In other words, the second flow control unit 26 is influenced by a flow change triggered by the adjustment of the first valve 32 of the first flow control unit 22, which is dependent on the temperature of the coolant, and is a passively operating flow control unit.

[0032] In the Figure 1 In the situation shown, the coolant is cold, as occurs, for example, during a cold start of a vehicle. In the embodiment described here, the first flow control unit 22 comprises an expansion thermostat, in particular a throttle thermostat, e.g., with a wax actuator.

[0033] The first actuator 30 is therefore not controlled externally and detects the temperature of the coolant "by itself" and adjusts the first valve 32 accordingly.

[0034] As long as the coolant temperature is below a certain preset limit (e.g., 80 °C), the first valve 32 is in a fully closed position. Consequently, the flow of coolant to the radiator is blocked, and the coolant accumulates in front of the first valve 32.

[0035] This leads to an increase in pressure upstream of the first flow control unit 22 and upstream of the second flow control unit 26. As soon as the pressure upstream of the first flow control unit 22 exceeds a certain limit value, which can be adjusted, for example, by the preload force of the spring 36, the second valve 34 opens and the coolant can flow through the bypass channel 24.

[0036] After the bypass channel 24, the coolant flows into the main channel 20 after the radiator 14 and is pumped further into the oil-coolant heat exchanger 16. There, a heat exchange between the oil and the coolant can take place.

[0037] The coolant is then directed to pump 18, where it is pumped further into the engine 12. There, heat transfer takes place from the warming engine 12 to the cooler coolant.

[0038] The heated coolant then flows to the first flow control unit 22 and the second flow control unit 26. If the coolant has not yet reached the temperature limit, the first valve 32 remains closed. As long as the first valve 32 is closed, the coolant circulates in the short-circuited coolant circuit via the bypass channel 24 past the radiator 14.

[0039] Once the lower coolant temperature limit is reached, the first actuator 30 continuously opens the first valve 32 of the first flow control unit 22, allowing a partial flow of coolant to the radiator 14. There, the coolant is cooled and mixes with the warmer coolant after the bypass channel 24 opens into the main channel 20. This reduces the heating of the coolant in the short-circuited coolant circuit.

[0040] Once a predetermined operating temperature of the coolant (e.g. 95 °C) is reached, the first valve 32 is in a maximum open position, whereby no more coolant accumulates in front of the first flow control unit 22 and the second flow control unit 26 and, as a result, the pressure in front of the second flow control unit 26 falls below a limit value at which the tension force of the spring 36 is greater than the pressure generated by the coolant on the second valve 34. As a result, the second valve 34 is in a maximum closed position and the flow of the coolant through the second flow control unit 26 is prevented.

[0041] The entire coolant volume flow now flows in the main channel 20 via the cooler 14. The coolant is thus continuously heated in the engine 12 and cooled in the cooler 14, whereby the coolant temperature can be kept constant.

[0042] In Figure 2a non-inventive embodiment of the coolant circuit 10' is shown, which is substantially identical to that shown in Figure 1 Therefore, we will not repeat the explanation of the same components.

[0043] In the coolant circuit 10' from Figure 2 the flow control units 22, 26 are constructed differently.

[0044] In the embodiment shown here, the first temperature sensor 28 is no longer integrated in the first flow control unit 22, but is positioned remote from the first flow control unit 22 in the motor 12.

[0045] It is advantageous to arrange the first temperature sensor 28 in the engine 12 or immediately downstream of the engine 12, since this makes it possible to detect the warmest coolant temperatures.

[0046] The first actuator 30 is electronically controlled by the first temperature sensor 28, which can be designed, for example, as an electronic temperature sensor, via a signal transmission 38, which can in particular be unidirectional.

[0047] The opening and closing of the first valve 32 takes place as already described for the coolant circuit 10 of the Figure 1 described, continuously and directly dependent on the temperature of the coolant.

[0048] In the coolant circuit 10', an electronically controlled pressure valve is used instead of a mechanical pressure valve. In the embodiment shown here, the pressure is measured by a pressure sensor 40 upstream of the second flow control unit 26.

[0049] A second actuator 44 is controlled by the pressure sensor 40 via a signal transmission 42, which can in particular be unidirectional.

[0050] The second flow control unit 26 can be designed such that it operates only in two operating states (open or closed), ie when a certain preset limit value is undershot or exceeded, the second flow control unit 26 is closed or open, respectively.

[0051] Optionally, the second valve 34 of the second flow control unit 26 can be continuously closed or opened between a lower pressure limit and an upper pressure limit.

[0052] The pressure sensor 40 can be freely positioned between the motor 12 and the first flow control unit 22 or the second flow control unit 26.

[0053] The first flow control unit 22 and the second flow control unit 26 can each be designed as an electronically controlled throttle thermostat.

[0054] In the situation shown here, the engine 12 and the coolant are at operating temperature. The flow through the first flow control unit 22 to the radiator 14 is open, and the flow through the bypass channel 24 is closed by the second flow control unit 26.

[0055] The Figure 3 The coolant circuit 10" according to the invention shown is essentially similar to the previously shown coolant circuits 10, 10', which is why a repetition of the explanation of the same components will be omitted below.

[0056] In the embodiment of the coolant circuit 10" shown here, the first temperature sensor 28 is assigned to the first flow control unit 22 and the second flow control unit 26.

[0057] The first actuator 30 and the second actuator 44 are each electronically controlled by a signal transmission 38 from the first temperature sensor 28. The first temperature sensor 28 is positioned in the motor 12 and can be implemented, for example, as an electronic temperature sensor.

[0058] Optionally, the first temperature sensor 28 can be positioned immediately after the motor 12.

[0059] A second temperature sensor 48, which is assigned to the second flow control unit and is also positioned in the motor 12 or immediately after the motor 12, would also be conceivable.

[0060] The first flow control unit 22 and the second flow control unit 26 can each be designed, for example, as a throttle thermostat.

[0061] According to the invention, the two flow control units 22, 26 are in a communication connection 46. This means that the two flow control units 22, 26 can bidirectionally exchange information about their status (e.g. degree of opening).

[0062] This makes it possible to coordinate the opening and closing of one flow control unit with the closing and opening of the other flow control unit. For example, when the first valve 32 of the first flow control unit 22 opens, the second valve 34 of the second flow control unit 26 is closed to the same extent.

[0063] The presence of such a communication connection 46 eliminates the need for both flow control units 22, 26 to be connected to the first temperature sensor 28 via the signal transmission 38. It is sufficient if only one flow control unit is connected to the first temperature sensor 28 via the signal transmission 38 and communicates its status with the other flow control unit via the communication connection 46.

[0064] In the embodiment shown here, the opening and closing of the valves 32, 34 of the flow control units 22, 26 takes place continuously and directly dependent on the temperature of the coolant.

[0065] The Figure 4 The coolant circuit 10‴ shown, not according to the invention, is essentially similar to the previously shown coolant circuits 10, 10', 10", which is why a repetition of the explanation of the same components will be omitted below.

[0066] In the coolant circuit 10‴, the first temperature sensor 28 is integrated into the first flow control unit 22, and a second temperature sensor 48 is integrated into the second flow control unit 26. Both temperature sensors 28, 48 thus measure the temperature of the coolant in the immediate vicinity of the respective flow control unit 22, 26.

[0067] The two flow control units 22, 26 can each be designed as an expansion thermostat (e.g. throttle thermostat).

[0068] The temperature sensors 28, 48 are integrated in the respective actuator 30, 44, so that the actuators 30, 44 sense the temperature of the coolant "themselves" and, depending on this, continuously adjust the valve 32, 34 assigned to them.

[0069] Consequently, the two flow control units 22, 26 are directly dependent on the temperature of the coolant.

Claims

1. Coolant circuit for a vehicle, having a pump (18), an engine (12) to be cooled, and a radiator (14), characterized in that a first flow control unit (22), which comprises a first valve (32) and a first actuator (30) and which, as a function of a temperature of a coolant, in a stepless manner thermostatically controls in an open loop or a closed loop a flow of the coolant, is provided in a main duct (20) between the engine (12) and the radiator (14), and a bypass duct (24), which is fluidically connected in parallel with the radiator (14), and after the radiator (14) opens into the main duct (20), branches off the main duct (20) between the engine (12) and the first flow control unit (22), wherein a second flow control unit (26), which comprises a second valve (34) and is configured such that the second flow control unit opens or closes the bypass duct (24) as a function of the temperature of the coolant, is provided in the bypass duct (24), wherein the first valve (32) is coupled to the first actuator (30) and is adjusted in a stepless manner by the latter as a function of the coolant temperature, and the second valve (34) is coupled to a second actuator (44) and is adjusted in a stepless manner by the latter as a function of the coolant temperature, characterized in that a first temperature sensor (28) is connected to the first flow control unit (22) or the second flow control unit (26) via a signal transmission (38), and the two flow control units (22, 26) are in a communication link (46) and exchange bi-directional information about their condition in order to coordinate the opening and closing of one flow control unit with the closing and opening of the other flow control unit.

2. Coolant circuit according to Claim 1, characterized in that the first valve (32) of the first flow control unit (22) at low coolant temperatures, in particular below 80°C, is in a position closed to the maximum, and upon reaching an operating temperature of the coolant, in particular from 95°C, is in a position opened to the maximum, wherein the first valve (32), as a function of the temperature of the coolant at the first temperature sensor (28), is moved in a stepless manner to intermediate positions between the two maximum positions.

3. Coolant circuit according to one of the preceding claims, characterized in that the second valve (34) of the second flow control unit (26) at low coolant temperatures, in particular below 80°C, is in a position opened to the maximum, and upon reaching an operating temperature of the coolant, in particular from 95°C, is in a position closed to the maximum.

4. Coolant circuit according to one of the preceding claims, characterized in that the bidirectionally exchanged items of information are the degree of opening of the respective valve.

5. Coolant circuit according to one of the preceding claims, characterized in that, when opening one valve (32, 34), the other valve (34, 32) is closed to the same degree.

6. Coolant circuit according to one of the preceding claims, characterized in that the first flow control unit (22) and / or the second flow control unit (26) each has a throttle thermostat.

7. Coolant circuit according to one of the preceding claims, characterized in that an oil-to-coolant heat exchanger (16) is provided.