Method for controlling the temperature of a controller

Abstract

A method for controlling the temperature of a controller in a vehicle, in which the controller is actively cooled by means of a cooling circuit, wherein, if there is a request to activate the cooling circuit, firstly at least one measurement variable is employed, and the cooling circuit is activated on the basis of the at least one measurement variable.

Description

[0001] Description

[0002] title

[0003] The invention relates to a method for temperature control of a control unit in a vehicle, in particular a motor vehicle, and to an arrangement for carrying out the method. The method serves in particular to prevent condensation inside the control unit.

[0004] State of the art

[0005] For electronic control units used in vehicles, it must be ensured that they function reliably in all seasons and under varying climatic conditions. This poses a particular challenge in hot and humid regions, as cooling of at least some components is necessary, while condensation on the surface of the components must be avoided.

[0006] Dew formation refers to the precipitation and accumulation of moisture on a surface; this is also known as wetting or covering with dew. Dew, in turn, is water that has condensed due to temperature differences.

[0007] Dew formation can lead to an undesirable effect on the electrical conductivity of the dew-covered surfaces.

[0008] In the field of advanced driver assistance systems (ADAS), the use of water cooling in the electronic control units (ECUs) is regularly required to meet the system's performance requirements. This means that the mechanical design of the ECU must incorporate cooling circuits that allow for optimal cooling of the so-called hot spots, i.e., the components with high power dissipation, thus ensuring functionality throughout the system's lifespan.

[0009] The publication EP 2 863 155 A1 describes a heat pump with a compressor and an electric motor connected to the compressor, which in turn is connected to a power output stage. The heat pump also includes a temperature sensor positioned to detect the temperature of the power output stage. Furthermore, a control unit is provided that controls the power output stage based on a temperature signal representing the detected temperature, such that waste heat can be generated in the power output stage by means of a loss current flowing through it.

[0010] German patent application DE 10 2020 214 861 A1 describes a method for preventing condensation inside an electronic device. The method involves measuring the temperature inside and outside the device's housing. The difference between these temperatures is then calculated, and a heating element is operated based on this difference.

[0011] The German patent application DE 10 2013 225 450 B3 describes a method for preventing condensation in the final stage of a heat pump, in which the temperature of the final stage is detected and a refrigerant flow at the final stage is controlled depending on the detected temperature.

[0012] Disclosure of the invention

[0013] Against this background, a method with the features of claim 1 and an arrangement according to claim 10 are presented. Embodiments are described in the dependent claims and the description. The presented method serves to regulate the temperature of a control unit in a vehicle, particularly in a motor vehicle. A cooling circuit is provided with which the control unit can be actively cooled. If, for example, when the vehicle is started, a request is made to activate the cooling circuit and thus to cool the control unit, at least one measured variable is initially used. Depending on this at least one measured variable, the cooling circuit is then activated. This at least one measured variable can be measured or recorded when the request is made, or it may already be present.If several measured variables are used, at least one of them may already be available and at least one of them may only be recorded upon request.

[0014] In one embodiment, a trigger point is determined based on at least one measured variable, at which the cooling circuit is to be activated. At this trigger point, the cooling circuit is activated and the control unit is cooled. In this embodiment, it is possible to verify at the trigger point whether suitable conditions actually exist. The trigger point is thus verified. Should it turn out that suitable conditions are not yet present, for example, due to the influence of disturbances, the cooling circuit is not activated.

[0015] It is also possible to continuously or at time intervals record measured values ​​and then, when suitable conditions are present, to activate or deactivate the cooling circuit.

[0016] Suitable conditions are conditions, e.g., characterized by temperature(s) and / or, in particular, relative humidity(s), that allow cooling to be activated without condensation occurring.

[0017] By implementing a targeted and controlled activation of the cooling circuit, the risk of condensation within a control unit can be reduced, thus preventing field failures. Since the short-term condensation events for which a coating is designed no longer occur, the need for a conformal coating on the circuit board is often eliminated. This leads to this measure being used less frequently, resulting in reduced development costs. Furthermore, the controlled start can be temperature-controlled in such a way as to also reduce potential temperature fluctuations. This, in turn, has a positive effect on the service life of the solder joints. A conformal coating is a protective coating that can be applied to a circuit board.This coating protects the circuit board from various environmental influences, such as humidity, moisture and contaminants.

[0018] Furthermore, the presented defined start of the cooling circuit can be extended to other products in the vehicle's cooling circuit, or a system strategy can be defined from it that can be offered as a package with the control unit.

[0019] In other words, an "if-then formula" is implemented within the software to start / stop or trigger the water cooling system. This trigger can be set for a defined period, e.g., xx seconds, or based on a limit of relative humidity or temperature, which is determined, for example, by additional humidity sensors on the circuit board or the internal temperature sensors of the components.

[0020] An example is outlined below:

[0021] A vehicle is parked in a cold / damp environment, e.g., 10°C and 90% RH (relative humidity), assuming these conditions also exist inside the vehicle and its control unit. The car is started, and after a delay of, for example, 30 seconds (the exact time can be defined based on measurements), or when the internal temperature sensors detect a defined average value, which depends on the components and their self-heating potential, the cooling system is activated. Again, the delay value is defined based on measurements.

[0022] This results in the internal air temperature rising, or warming up more quickly, and thus being able to absorb moisture from the circuit boards. Additionally, colder areas of the circuit board also warm up, and the microclimates within the control unit are reduced.

[0023] This reduces the risk of dew formation or condensation inside the control unit during startup, as these "overshoots" occur with every startup and are therefore avoided. Furthermore, conformal coating is not required, resulting in cost savings. This process can also be performed during continuous operation. That is, if a defined relative humidity threshold is exceeded during active operation, cooling is stopped for xx seconds. The exact duration is determined based on measurement results.

[0024] If the vehicle has a single cooling circuit, meaning the control unit is located in the same circuit as the battery or electric drive, the control unit requires a "bypass," i.e., a separate cooling circuit. The coolant temperature can be controlled via this bypass or the valve control system.

[0025] The presented arrangement serves to carry out the procedure and includes an evaluation unit for this purpose. The arrangement and / or the evaluation unit can be implemented in hardware and / or software and integrated into a control unit or designed as such.

[0026] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

[0027] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0028] Brief description of the drawings

[0029] Figure 1 shows signal curves in two graphs.

[0030] Figure 2 shows a schematic representation of a printed circuit board for carrying out the presented method in two views.

[0031] Figure 3 shows a block diagram of an embodiment of a cooling circuit for carrying out the presented method.

[0032] Figure 4 shows a possible sequence of the described procedure in a flowchart.

[0033] Figure 5 shows, in a highly simplified, purely schematic representation, a vehicle with an arrangement for carrying out an embodiment of the described method.

[0034] Embodiments of the invention

[0035] The invention is schematically illustrated with reference to embodiments in the drawings and is described in detail below with reference to the drawings.

[0036] Figure 1 shows different trends of measured quantities in two graphs. In a first graph 10, where time is plotted on the abscissa 12 and relative humidity and temperature on the ordinate 14, several humidity trends are plotted at different points.

[0037] In a second graph 30, where time is plotted on the abscissa 32 and relative humidity on the ordinate 34, different temperature profiles are shown at different locations. A highlighted area 40 illustrates a jump in relative humidity caused by a delayed warming of the surrounding air inside the control unit, influenced by the water cooling system activated in parallel with the power dissipation. This is also referred to as overshoot. A curve 42 shows the temperature curve of a measuring point in this enlarged area.

[0038] Figure 2 shows two views of a printed circuit board for carrying out the method, designated by the reference numeral 100. The top view shows the printed circuit board 100 in a top view. The bottom view shows the printed circuit board 100 in a side view.

[0039] The illustration also shows humidity sensors 102, a SoC 104 (System on Chip) representing the hotspot, an area 106 with a thermally conductive material (TIM: thermal interface material), a valve 108 and cooling water 110.

[0040] Figure 3 shows a block diagram of a cooling circuit, designated by the reference numeral 150. The diagram shows a water-cooled control unit 152, a first valve 154, which is triggered by the control unit 152 or humidity sensors and switches a bypass 155, an electric motor 156, a radiator 158, a DC / DC converter 160, a battery 162, a heat exchanger 164, a high-voltage (HV) heating device 166, and a second valve 168.

[0041] Figure 4 shows a possible embodiment of the presented method in a flowchart. In a first step 200, the operation of a motor vehicle is started. Upon starting, a request is made to activate a cooling circuit. A bypass in this cooling circuit ensures that a control unit can be cooled via a separate cooling circuit.

[0042] In step 202, measured values ​​are acquired, in this case temperature and relative humidity, typically at a measuring point (cold spot) within the control unit. Based on these measured values, a trigger point for activating the bypass (reference numeral 155 in Figure 3) is calculated or determined in step 204, thus determining the point at which the control unit should be cooled. Then, in step 206, the separate cooling circuit is activated at the determined trigger point, for example, by actuating a valve. From this point on, there is a brief interruption (xx seconds) of the control unit's cooling. At this time, conditions prevail within the control unit that prevent condensation.

[0043] In principle, it is also possible, if there is a cooling requirement, to continuously or at time intervals record measured values ​​until a condition is detected that indicates that there is no risk of condensation when the cooling is activated.

[0044] Alternatively, once the requirement is met, a trigger time can first be determined and then, at that time before activating the cooling circuit, it can be checked again, typically using at least one measured parameter, whether suitable conditions actually exist.

[0045] Figure 5 shows, in purely schematic form, a vehicle designated as a whole by the reference numeral 300. This vehicle 300 comprises an arrangement 302 for carrying out the method, which in turn includes an evaluation unit 304. The illustration also shows a control unit 306, which is connected to a cooling circuit 308.

[0046] Furthermore, sensors 310 are shown, which provide measured quantities, e.g. temperatures 312 and humidity values ​​314.

Claims

Claims 1. Method for temperature control of a control unit (152, 306) in a vehicle (300) in which the control unit (152, 306) is actively cooled by a cooling circuit (150, 308), wherein, when a request to activate the cooling circuit (150, 308) is present, at least one measured variable is used first, and depending on the at least one measured variable, the cooling circuit (150, 308) is activated.

2. Method according to claim 1, wherein a trigger time is determined depending on the at least one measured variable, at which the activation of the cooling circuit (150, 308) is to take place, and the cooling circuit (150, 308) is activated at the determined trigger time.

3. Method according to claim 1 or 2, wherein a temperature (312) is recorded as a measured quantity.

4. Method according to claim 3, wherein an absolute temperature is recorded as a measured quantity.

5. Method according to claim 3, wherein a temperature difference is recorded as a measured quantity.

6. Method according to any one of claims 1 to 5, wherein relative humidity (314) is measured.

7. Method according to one of claims 1 to 6, which causes a time delay in the cooling of the control unit (152, 306).

8. Method according to any one of claims 1 to 7, which is carried out when the vehicle (300) is started.

9. A method according to any one of claims 1 to 8, wherein the control unit (152, 306) is cooled via a separate cooling circuit.

10. An arrangement for temperature-controlling a control unit (152, 306) in a Vehicle (300) comprising an evaluation unit (304) configured to perform a method according to any one of claims 1 to 9.

11. Arrangement according to claim 10, to which at least one measuring device for determining a measured quantity is assigned.

Images