Liquid pump, assembly and method

Abstract

A liquid pump (12), in particular for supplying a transmission of an electric or hybrid drive module of a motor vehicle, is proposed, comprising a pump housing (16), in which a pump chamber (18) and a pump rotor (20) are arranged, wherein a first temperature sensor (24) and a second temperature sensor (26) are arranged in a flow path of a liquid flowing through the liquid pump (12), wherein the temperature sensors (24, 26) each have different non-linear temperature characteristic curves. A component comprising the liquid pump (12) and a method for determining the temperature of a liquid conveyed by the liquid pump (12) are also proposed.

Description

Technical Field

[0001] The present invention relates to a liquid pump, particularly a liquid pump for supplying power to the transmission of an electric or hybrid drive module of a motor vehicle, an assembly including a liquid pump and a measuring unit, and finally a method for determining the temperature of a fluid delivered by the liquid pump. Background Technology

[0002] A liquid pump used to supply power to the drivetrain of an electric or hybrid drive module in a motor vehicle typically includes a pump housing comprising a pump chamber and an outlet passage. A pump rotor is disposed within the pump chamber, and a temperature sensor is disposed within the outlet passage. The temperature sensor is used to monitor the temperature of the liquid being supplied, which is typically a hydraulic fluid, such as oil.

[0003] For example, a temperature sensor is an NTC sensor, meaning a temperature sensor with an NTC thermistor as its main component. This type of temperature sensor is particularly cost-effective. However, a drawback of this type of temperature sensor is that, due to their non-linear characteristic curves, they do not have the same high resolution across the entire measurement range of -40°C to 150°C.

[0004] Alternatively, active temperature sensors can be used, which offer good resolution across the entire measurement range. However, active temperature sensors are relatively expensive.

[0005] Technical content

[0006] Therefore, the object of the present invention is to measure the temperature of hydraulic fluid in a liquid pump with the highest possible accuracy in a measurement range of at least -40°C to 150°C in a cost-effective manner.

[0007] According to the invention, this objective is achieved by a liquid pump, particularly for supplying power to the transmission of an electric or hybrid drive module in a motor vehicle. The liquid pump includes a pump housing, a pump chamber, and a pump rotor arranged within the pump housing. A first temperature sensor and a second temperature sensor are arranged in the flow path of the liquid flowing through the pump, each temperature sensor having a different nonlinear temperature characteristic curve. This allows for the use of signals from different temperature sensors within different temperature ranges, specifically, in each case, to provide a range of temperature characteristic curves with higher resolution.

[0008] In particular, each of the two temperature sensors covers a different temperature range, thus enabling the measurement of the temperature of the liquid flowing through the liquid pump with sufficiently high accuracy throughout the measurement range.

[0009] The measurement range extends from -40°C to 150°C.

[0010] For example, the first temperature sensor has a higher resolution than the second temperature sensor over a first continuous temperature range, and the second temperature sensor has a higher resolution than the first temperature sensor over a second continuous temperature range. The first and second temperature ranges are specifically different. That is, the first and second temperature ranges do not overlap, but are preferably directly adjacent to each other. This allows for overall coverage of a particularly wide temperature range.

[0011] Each temperature sensor preferably covers a measurement range that extends over a temperature difference of 80 to 120°C.

[0012] According to one embodiment, each temperature sensor includes an NTC thermistor. This type of temperature sensor is particularly cost-effective and provides sufficiently accurate measurements, at least within a specific temperature range.

[0013] For example, NTC thermistors are the same. This can also help save costs because fewer different components need to be stored, which is advantageous in terms of storage costs.

[0014] Each temperature sensor's NTC thermistor can be connected in series with two different additional resistors. By properly designing the additional resistors, the temperature characteristic curve of each temperature sensor can be shifted to the desired range.

[0015] The two temperature sensors are preferably arranged in the outlet channel connected to the pump chamber, particularly at a maximum distance of 5 mm. Therefore, the two temperature sensors measure the liquid temperature directly adjacent to each other. This allows the measurements from the first and second temperature sensors to be correlated. In other words, the two temperature sensors can replace a single active temperature sensor due to their direct proximity.

[0016] Alternatively, the temperature sensor is housed on a printed circuit board arranged within the wet chamber of the fluid pump. The printed circuit board is submerged in the hydraulic fluid, thus improving and increasing the accuracy of temperature measurement. Placing the temperature sensor directly on the printed circuit board allows for a more compact fluid pump.

[0017] Temperature sensors can be housed in a common housing. As a result, the temperature sensors can be processed as individual units during assembly, simplifying the assembly process. Furthermore, housing temperature sensors in a common housing allows them to be arranged directly adjacent to each other.

[0018] According to a preferred embodiment, the fluid pumped is oil, such as dielectric oil. Other types of liquids are also possible.

[0019] According to the invention, this objective is also achieved by a component comprising such a liquid pump and including a measuring unit configured to capture measurements from two temperature sensors and, based on the number of measurement points provided by each temperature sensor, to consider the measurement from the temperature sensor with the higher resolution within the current measurement range. As already described in conjunction with the liquid pump according to the invention, this enables the determination of the temperature of the liquid flowing through the liquid pump over the entire measurement range with a high level of accuracy.

[0020] According to the invention, this objective is also achieved by a method for determining the temperature of a liquid pumped by means of components according to the invention, wherein a first temperature sensor provides a greater number of measurement points within a first temperature range, and a second temperature sensor provides a greater number of measurement points within a second temperature range, wherein the measurement unit takes into account the measurements of the first temperature sensor within the first temperature range and the measurements of the second temperature sensor within the second temperature range.

[0021] Therefore, as explained in conjunction with the components, the measurement from the temperature sensor with higher resolution in the current temperature range is used.

[0022] According to one embodiment, one of the two temperature sensors measures the voltage across an NTC thermistor, and the other measures the voltage across an additional resistor. This affects the voltage value measured in each case, and therefore the temperature characteristic curve of the respective temperature sensor. In particular, the measurement of the voltage across the additional resistor causes a shift in the temperature characteristic curve compared to the measurement of the voltage at the NTC thermistor. Attached Figure Description

[0023] Further advantages and features of the invention will become apparent from the following description and the accompanying drawings, which are taken into reference. In the drawings:

[0024] Figure 1 The schematic diagram illustrates an assembly according to the invention, including a liquid pump according to the invention.

[0025] Figure 2 A housing for accommodating two temperature sensors is shown.

[0026] Figure 3 A circuit diagram of a measuring device including first and second temperature sensors is shown.

[0027] Figure 4 The characteristic curves of two temperature sensors are shown.

[0028] Figure 5 A diagram illustrating the measurement resolution of the first and second temperature sensors is shown, and

[0029] Figure 6 The schematic diagram illustrates an assembly including different liquid pumps according to the present invention. Detailed Implementation

[0030] Figure 1 The assembly 10, including a liquid pump 12 and a measuring unit 14, is shown.

[0031] The liquid pump 12 is suitable for supplying hydraulic fluid to the transmission of an electric or hybrid drive module of a motor vehicle, for example, to lubricate bearing points, provide a coolant flow for a clutch, or generate a pressure medium flow for activating an actuator.

[0032] The liquid pump 12 has a pump housing 16, a pump chamber 18 and a pump 20 arranged in the pump housing.

[0033] The pump rotor 20 includes a rotor 19 of an electric motor 21, a shaft 22 driven by the rotor 19, and a pump impeller 23, which is placed on the shaft 22 and hydraulic fluid is transported by the rotation of the pump impeller 23.

[0034] The first temperature sensor 24 and the second temperature sensor 26 are arranged in the outlet channel 25 connected to the pump chamber 18.

[0035] The measurement unit 14 is configured to evaluate the temperature signals from the temperature sensors 24 and 26, as will be explained in detail below.

[0036] The basic function of this liquid pump 12 is well known, which is why its detailed description is omitted for simplicity. For example, the corresponding liquid pump 12 is described in DE 10 2020 106 849 A1.

[0037] Figure 2 The housing 27 is shown, in which two temperature sensors 24 and 26 are housed.

[0038] exist Figure 2 It can also be seen that the two temperature sensors 24 and 26 are arranged so that they are directly adjacent to each other.

[0039] Figure 3 A circuit diagram of a measuring device for measuring temperature signals provided by temperature sensors 24 and 26 is shown.

[0040] from Figure 3 It is clear that each temperature sensor 24, 26 includes NTC thermistors 28, 29 and additional resistors 30, 31.

[0041] The NTC thermistors 28 and 29 of temperature sensors 24 and 26 and the other resistors 30 and 31 are each connected in series.

[0042] For example, NTC thermistors 28 and 29 are identical. However, it is also conceivable that the two NTC thermistors 28 and 29 are different.

[0043] In an exemplary embodiment, the nominal resistance of each NTC thermistor is 10 kiloohms.

[0044] In an exemplary embodiment, the additional resistor 30 of the first temperature sensor 24 is 1000 ohms, while the additional resistor 31 of the second temperature sensor 26 is 22 kiloohms.

[0045] For example, during operation, there is a voltage of 5 volts at each temperature sensor 24, 26.

[0046] The measuring unit 14 measures the voltage value of the first temperature sensor 24 across the NTC thermistor 28 and the voltage value of the second temperature sensor 26 across the additional resistor 31.

[0047] Figure 4 The diagram shows the corresponding temperature characteristic curve 32 of the first temperature sensor 24 and the temperature characteristic curve 34 of the second temperature sensor 26. Specifically, in... Figure 4 The graph shown plots the voltage distribution with respect to temperature for each temperature sensor 24, 26.

[0048] exist Figure 4 As can be seen, the two temperature sensors 24 and 26 each have different, nonlinear temperature characteristic curves. Consequently, for each of the two temperature sensors 24 and 26, the high-resolution region of the temperature characteristic curve lies within a different temperature range.

[0049] Within a temperature range of -40°C to 45°C, the temperature characteristic curve 34 of the second temperature sensor 26 has a larger gradient in absolute value than the temperature characteristic curve 32 of the first temperature sensor 24. This means that the second temperature sensor 26 has a higher resolution than the first temperature sensor 24 within this temperature range.

[0050] Within a temperature range of 45°C to 150°C, the temperature characteristic curve 32 of the first temperature sensor has a larger gradient in absolute value than the temperature characteristic curve 34 of the second temperature sensor. Therefore, the first temperature sensor 24 has higher resolution within this temperature range.

[0051] This is from Figure 5The diagram clearly shows that, for each temperature sensor 24, 26, multiple measurement points provided by the corresponding temperature sensor 24, 26 are plotted at 5°C temperature differences. The bars on the left of the diagram indicate the number of measurement points from the first temperature sensor 24 in each case, and the bars on the right indicate the number of measurement points from the second temperature sensor 26 in each case.

[0052] The second temperature sensor 26 provides more measurement points than the first temperature sensor 24 in the temperature range of -40°C to 45°C, and the first temperature sensor 24 provides more measurement points than the second temperature sensor 26 in the temperature range of 45°C to 150°C.

[0053] This means that at a temperature of approximately 45°C, a change occurs to achieve the following: the resolution of the first temperature sensor 24 exceeds that of the second temperature sensor 26; below this threshold, the temperature sensor 26 has a higher resolution.

[0054] For example, a 12-bit A / D converter with 4096 steps can be used to capture temperature signals.

[0055] Measurements from two temperature sensors, 24 and 26, were continuously captured.

[0056] However, the measuring unit 14 only considers the measurements from the temperature sensors 24, 26 that provide a higher number of measuring points.

[0057] Specifically, the measurement unit 14 compares the number of measurement points from the first temperature sensor 24 with the number of measurement points from the second temperature sensor 26, and only forwards the measurement values ​​from the temperature sensor that provides a higher number of measurement points for processing.

[0058] To this end, the measurement unit 14 is accordingly configured to capture measurement values ​​from the two temperature sensors 24, 26, and to consider the measurement value from the temperature sensor with higher resolution in the current measurement range, based on the number of measurement points provided by each temperature sensor 24, 26.

[0059] Alternatively, a fixed temperature limit value can be stored in the measuring unit 14, reflecting a temperature beyond which a higher resolution “changes” from one temperature characteristic curve to another. The measuring unit 14 then considers the temperature characteristic curve with higher resolution below the temperature limit value and the other temperature characteristic curve above the temperature limit value.

[0060] Figure 6Another type of liquid pump 12 is schematically shown, which is intended for use in motor vehicles to deliver hydraulic fluid to transmission components. The hydraulic fluid can perform lubrication or cooling functions or be used to actuate actuators.

[0061] The liquid pump 12 has a pump housing 16, a pump chamber 18, and a pump rotor 20 arranged within the pump housing. The pump rotor 20 includes a rotor 19 of a motor 21, a shaft 22 driven by the rotor 19, and a pump impeller 23, which rests on the shaft 22 and hydraulic fluid is transported by the rotation of the pump impeller 23. The liquid pump 12 can be a rotary pump, a vane pump, or other types of pump.

[0062] The liquid pump 12 draws in hydraulic fluid through the inlet channel 33 and delivers hydraulic fluid through the outlet channel 25.

[0063] The liquid pump 12 is driven by an electric motor 21. The electric motor 21 is arranged in a wet chamber 34, that is, the area within the housing 16 that is at least substantially filled with hydraulic fluid during operation. The wet chamber 34 is hydraulically connected to the pump chamber 18. In other words, fluid from the pump chamber 18 can flow within the wet chamber 34.

[0064] Inside the wet chamber 34 is a circuit board 35, which houses various electronic or electrical components 24, 26, and 36. These components are used to control the motor 21 and are connected to the control unit. One of the components, 36, is a Hall sensor, which can be used to detect the rotation of the shaft 22.

[0065] The main difference from the previous embodiments is that a first temperature sensor 24 and a second temperature sensor 26 are housed on the printed circuit board 35. The printed circuit board 35 is submerged in hydraulic fluid, thus improving and making the temperature measurement more accurate.

[0066] Temperature sensors 24 and 26 are electrically connected to a measurement unit 14, which may be designed separately from or integrated into a printed circuit board 35. The measurement unit 14 is configured to evaluate the temperature signals from the temperature sensors 24 and 26.

[0067] Operation and information about temperature sensors 24 and 26 Figures 1 to 5 The operations described are the same, only the positions are different.

Claims

1. A liquid pump (12), particularly for supplying power to the transmission of an electric or hybrid drive module of a motor vehicle, said liquid pump comprising a pump housing (16), a pump chamber (18), and a pump rotor (20) arranged within said pump housing, wherein, A first temperature sensor (24) and a second temperature sensor (26) are arranged in the flow path of the liquid flowing through the liquid pump (12), wherein the temperature sensors (24, 26) each have different nonlinear temperature characteristic curves.

2. The liquid pump according to claim 1, characterized in that, The first temperature sensor (24) has a higher resolution than the second temperature sensor (26) in a first continuous temperature range, and the second temperature sensor (26) has a higher resolution than the first temperature sensor (24) in a second continuous temperature range.

3. The liquid pump (12) according to any one of the preceding claims, characterized in that, Each temperature sensor (24, 26) includes an NTC thermistor (28, 29).

4. The liquid pump (12) according to claim 3, characterized in that, The NTC thermistors (28, 29) are identical.

5. The liquid pump (12) according to claim 3 or 4, characterized in that, The NTC thermistor (28, 29) of each temperature sensor (24, 26) is connected in series with an additional resistor (30, 31), wherein the two additional resistors (30, 31) are different.

6. The liquid pump (12) according to any one of the preceding claims, characterized in that, Both temperature sensors (24, 26) are arranged in the outlet channel (25) connected to the pump chamber (18).

7. The liquid pump (12) according to any one of the preceding claims, characterized in that, The temperature sensors (24, 26) are housed in a common housing (27).

8. The liquid pump (12) according to any one of claims 1 to 5, characterized in that, The temperature sensors (24, 26) are housed on a printed circuit board (35), which is arranged inside the wet chamber (34) of the liquid pump (12).

9. A component (10) comprising a liquid pump (12) according to any one of the preceding claims, and comprising a measuring unit (14) configured to capture measurements from two temperature sensors (24, 26) and, depending on the number of measurement points provided by the respective temperature sensors (24, 26), to consider the measurement from the temperature sensor (24, 26) having a higher resolution in the current measurement range.

10. A method for determining the temperature of a liquid delivered by a liquid pump (12) using the component (10) according to claim 9, wherein, The first temperature sensor (24) provides a greater number of measurement points within a first temperature range, and the second temperature sensor (26) provides a greater number of measurement points within a second temperature range, wherein the measurement unit (14) considers the measurement values ​​from the first temperature sensor (24) within the first temperature range and the measurement values ​​from the second temperature sensor (26) within the second temperature range.

11. The method according to claim 10, used for determining the temperature of a liquid delivered by the liquid pump (12) according to claim 5, characterized in that, One of the two temperature sensors (24, 26) measures the voltage across the NTC thermistor (28, 29), and the other of the two temperature sensors (24, 26) measures the voltage across the additional resistor (30, 31).

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