Vehicle heat dynamic test system and test method

Abstract

The invention relates to the technical field of vehicle engineering, in particular to a vehicle heat dynamic test system and a test method, which can solve the problem of inaccurate test in the running process of a vehicle. A vehicle heat dynamic test system is tested, temperature, pressure and flow data of key nodes are collected under the real vehicle or bench test working condition, and the collected data are combined with a heat flow dynamic model to calculate the heat flow dynamic distribution response of a vehicle in the running process. And evaluating a hot runner transfer path and related laws by comparing and verifying an actual measurement result with a calculation simulation result.

Description

Technical Field

[0001] This invention relates to the field of vehicle engineering technology, and more specifically to a vehicle thermal dynamics testing system and testing method. Background Technology

[0002] Modern integrated powertrains are becoming increasingly complex, with a growing number and variety of key components and sensors. The automation level and complexity of their powertrains are also increasing, thus placing higher demands on the reliability of integrated powertrains. Currently, the main challenges in acquiring auxiliary system parameters lie in the accurate testing of heat under high vibration environments and the dynamic performance testing of high-speed rotating fans. A bottleneck is the inability to install ordinary flow measurement sensors in the limited space of vehicles. Furthermore, accurate testing with small temperature differences is also a major issue affecting the accurate acquisition of vehicle heat. Summary of the Invention

[0003] In view of this, the present invention proposes a vehicle thermal dynamic testing system and testing method, which can solve the problem of inaccurate testing during vehicle movement.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] This invention provides a vehicle thermal dynamic testing system, comprising:

[0006] Embedded flow meter: It adopts a wedge-shaped core structure and uses a diffused silicon pressure sensor to measure the pressure difference before and after the fluid flows through the wedge-shaped core, and calculates the fluid flow rate in the pipeline based on the pressure difference;

[0007] Graded temperature measurement device: includes a conventional temperature sensor and a small temperature difference test module; the small temperature difference test module consists of two thermocouples with the same physical properties connected in reverse series to form a coupler thermocouple, with a total electromotive force output E = E1 - E2, and is connected to an amplifier circuit to convert the millivolt signal into a temperature difference output;

[0008] Vibration signal processing circuit: provides constant current power to the vibration sensor and includes filtering and amplification circuits to convert the vibration signal into a preset voltage range;

[0009] Multi-source information acquisition unit: Equipped with CAN and FlexRay communication interfaces, it is used to collect flow, temperature, pressure, vibration and displacement signals of key nodes in the cooling system, and to obtain the dynamic parameters of the whole vehicle through the vehicle bus, including engine speed, water temperature, gear, generator torque and speed;

[0010] Thermal Flow Dynamic Model Processor: Receives data from the multi-source information acquisition unit and calculates the dynamic distribution response of thermal flow during vehicle operation.

[0011] The calibration method for the small temperature difference test module includes: zero calibration: placing the paired thermocouples in a constant temperature bath, adjusting the amplifier so that the output voltage is 0 when the temperature difference is 0, and repeating this process at different base temperatures; temperature difference calibration: placing the thermocouples in constant temperature baths with a set temperature difference, recording the output voltage, adjusting the temperature so that the output voltage is consistent for the same temperature difference at different base temperatures, thereby achieving the measurement of a temperature difference ≥0.1℃.

[0012] The embedded flow meter satisfies the following:

[0013] The impact on the resistance of the medium system is ≤5%;

[0014] Test accuracy ≥ 98%;

[0015] Operating temperature range: -50℃ to +85℃.

[0016] The key components include cooling fans, radiators, cooling pipes, primary filters, secondary filters, dust extraction devices, exhaust systems, and elastic supports.

[0017] The present invention also provides a method for dynamic testing of vehicle thermal properties, implemented based on any of the systems described in this invention, comprising the following steps:

[0018] Calibration preparation: Calibrate and verify the embedded flow meter, conventional temperature sensor and small temperature difference thermocouple;

[0019] System deployment: Deploy the calibrated sensors to key nodes of the cooling system and connect them to the multi-source information acquisition unit and the vehicle communication interface;

[0020] Dynamic data acquisition: Under actual vehicle or bench conditions, synchronously acquire data on flow rate, temperature, pressure, vibration and displacement at key nodes, as well as dynamic parameters of the whole vehicle;

[0021] Data processing and analysis: Input the collected data into the heat flux dynamic model, calculate the dynamic heat flux distribution response, and compare the measured and simulation results;

[0022] Condition assessment: Based on the heat flow distribution response, assess the heat transfer path law; combine vibration, displacement and vehicle parameters to monitor the health status of elastic support, intake and exhaust systems in real time; establish a real-time heat flow analysis and thermal balance capacity prediction model to guide the cooling system control strategy.

[0023] The calibration of the small temperature difference test module includes: pairing conventional temperature sensors in a constant temperature bath and selecting sensors with consistent readings; performing zero-adjustment calibration and temperature difference calibration on the thermocouples to ensure consistent output of the same temperature difference at different temperatures.

[0024] The vibration signal processing includes:

[0025] The vibration sensor is powered by a constant current source;

[0026] The output signal is filtered and amplified to match the voltage range of the information acquisition device.

[0027] The state assessment includes:

[0028] Based on the vibration displacement data of the elastic support and the engine speed, its working status is determined;

[0029] Evaluate thermal management efficiency by combining exhaust system temperature and pressure data.

[0030] The calibration method for the embedded flow meter is as follows:

[0031] In the flow calibration test bench, its linearity and accuracy were verified to be ≥98.5% using a standard flow meter.

[0032] The thermal balance capability prediction model is used to optimize the multi-objective control strategy of the cooling system.

[0033] Beneficial effects:

[0034] 1. The device of this invention is used to test vehicle thermal dynamics testing systems. Under actual vehicle or bench test conditions, it collects temperature, pressure, and flow data at key nodes. The collected data is combined with a thermal dynamics model to calculate the dynamic distribution response of heat flow during vehicle operation. By comparing and verifying the measured results with the calculated simulation results, the heat flow path and related laws are evaluated.

[0035] 2. This invention addresses the issue of flow meters being unable to be installed due to spatial constraints during vehicle testing. It develops an embedded flow meter and proposes a calibration method for the flow meter, solving the problem of inaccurate flow measurement during actual vehicle testing. It is suitable for vehicle dynamic heat acquisition devices, solving the problems of high difficulty in vehicle dynamic testing and limited sensor spatial layout.

[0036] 3. In this invention, a small temperature difference test method using thermocouples is adopted to solve the problem of inaccurate measurement caused by small temperature differences, and to achieve accurate testing of small temperature differences during actual vehicle testing.

[0037] 4. This invention achieves real-time monitoring of the motion status of various vehicle components by acquiring various dynamic data during actual vehicle testing, and judges the health status of the components.

[0038] 5. The testing method of this invention is applied to vehicle thermal dynamics testing systems. Under actual vehicle or bench test conditions, temperature, pressure, and flow data at key nodes are collected. The collected data is combined with a thermal dynamics model to calculate the dynamic distribution response of heat flow during vehicle operation. By comparing and verifying the measured results with the calculated simulation results, the heat flow path and related laws are evaluated.

[0039] 6. The testing method of this invention solves the problem of accurate heat testing in high-vibration environments and confined spaces. It also utilizes thermocouples to achieve accurate measurement of small temperature differences, and tests the flow rate, temperature difference, temperature, and pressure of each circulation branch of the cooling system. Based on the test data, it establishes real-time heat flow analysis and thermal balance capability prediction analysis to guide the multi-objective control strategy of the cooling system to meet the needs of heat data analysis and acquisition. At the same time, it collects key data on elastic support, intake system, and exhaust system, and then makes real-time judgments on the status of each component. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the logical architecture of the vehicle thermal dynamic testing system according to an embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram illustrating the working principle of the small temperature difference test in an embodiment of the present invention.

[0042] Figure 3 This is a schematic diagram of a coupled thermocouple calibration system according to an embodiment of the present invention.

[0043] Figure 4 This is a schematic diagram of the vibration signal processing circuit according to an embodiment of the present invention.

[0044] Figure 5 This is a schematic diagram of the flow rate collection and calibration results according to an embodiment of the present invention.

[0045] Figure 6 This is a schematic diagram of the vehicle thermal dynamic testing system according to an embodiment of the present invention. Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] This invention discloses a vehicle thermal dynamic testing system, the logical architecture of which is as follows: Figure 1 As shown, the system collects information on flow rate, temperature, pressure, vibration, and displacement during vehicle operation. It also enables data communication with the vehicle to obtain key information such as vehicle speed, gear position, and engine speed from the vehicle's bus. The testing of this invention system considers both accuracy and reliability.

[0048] To accurately measure the coolant flow rate of a vehicle during dynamic driving, this invention employs a self-embedded flow meter. The main structure of this flow meter uses a wedge-shaped core. The pressure gradient generated by the fluid flowing through the wedge core is measured by a diffused silicon pressure sensor, and the pressure difference across the wedge core is calculated. This pressure difference is then used to measure the fluid flow rate within the pipeline. This flow meter meets the requirements of having an impact of no more than 5% on the resistance of the media system, a testing accuracy of no less than 98%, and an operating ambient temperature range of -50 to +85°C.

[0049] To improve temperature measurement accuracy, this invention employs different testing schemes for the measurement medium within different temperature difference ranges. When the temperature difference before and after the test piece is greater than 2.5℃, a traditional thermometer is used to measure the medium. When the temperature is less than 2.5℃, a testing method specifically designed for small temperature differences is used to improve measurement accuracy. Specifically, as follows... Figure 2 As shown. Two thermocouples with identical physical properties are connected in reverse series. The relationship between the total electromotive force of the series-connected thermocouples and the two thermocouples is as follows:

[0050] E = E1 - E2

[0051] An amplifier circuit is used to amplify the millivolt signal output by the thermocouple before processing and converting it into a corresponding temperature difference for output. Therefore, the thermocouple needs to be calibrated. Specific calibration fixtures are as follows... Figure 3 As shown.

[0052] Due to factors such as the imperfect symmetry of the thermocouples, the amplifier output will not be zero when the temperature difference is 0. Therefore, the two thermocouples are placed in a constant temperature bath at the same temperature. After thermal equilibrium is reached, the zero-adjustment potentiometer of the amplifier is adjusted to make the amplifier's output voltage equal to zero. The temperature of the constant temperature bath is changed and adjusted multiple times using the same method until the amplifier output signal is always 0 at the same temperature difference.

[0053] After zeroing, the coupled thermocouples are placed in different constant temperature baths, and the amplifier's output voltage is recorded at a certain temperature difference. Then, the temperature of the heat transfer oil in the constant temperature bath is adjusted so that the amplifier's output voltage is the same at the same temperature difference. This method can achieve a temperature difference of 0.1℃.

[0054] For vibration signals, a dedicated constant current source is required to power them. The sensor output signal needs to be filtered, amplified, and converted to the voltage range required by the data acquisition device. Its measurement circuit is as follows: Figure 4 As shown.

[0055] Before formal testing, the testing equipment in the heat acquisition system needs to be calibrated. On the flow calibration test bench, the accuracy of the embedded flow meter is calibrated and verified using the standard flow meter within the test bench. The specific calibration results are as follows: Figure 5 As shown in the calibration results, the embedded flow meter and the standard flow meter can maintain good linearity under different flow rates. Moreover, the embedded flow meter can maintain an accuracy of over 98.5% throughout the entire flow test range, indicating that the embedded flow meter of the present invention has high accuracy.

[0056] For conventional temperature sensors, calibration is performed by placing them in a constant temperature bath. First, set the constant temperature bath to a specified temperature, then place the sensor in the center of the bath. After the temperature stabilizes, observe the sensor readings. Sensors with the same readings are paired for use, thereby reducing measurement errors and improving accuracy. For small temperature difference tests, place two thermocouples with identical physical properties in the constant temperature bath. Once the temperature in the bath stabilizes, observe the output value of the thermocouple amplifier. When the temperatures of the two thermocouples in the bath are the same, the output voltage of the thermocouple amplifier is 0. If the difference between the two is too large, replace one of the thermocouples and re-pair them before use. After pairing, change the temperature in the constant temperature bath until the thermocouple output voltage values ​​are the same at the same temperature difference. The above method completes the pairing and calibration of temperature sensors.

[0057] After completing sensor pairing and calibration, real-vehicle testing begins. For example... Figure 6 As shown, key node information of critical components in the vehicle cooling system, such as the cooling fan, radiator, cooling pipes, primary filter, secondary filter, dust extraction device, exhaust system, and elastic support, is collected. This key node information includes flow rate, temperature, pressure, vibration, and displacement information. After collection, this information is uploaded to an information collector equipped with CAN and FlexRay communication capabilities, enabling communication with the vehicle. The collector obtains information from the vehicle controller, including engine speed, engine coolant temperature, engine exhaust temperature, gear position, generator speed, generator torque, generator current, and generator voltage. Combined with this information from the vehicle controller, the device can measure the vibration and displacement of the elastic support and, when necessary, measure the temperature and pressure signals of other components. By integrating this vehicle information, the performance status of the key components of the vehicle cooling system is evaluated.

[0058] This invention, a vehicle thermal dynamic testing system, aims to solve the challenge of accurate thermal testing in confined spaces, high-vibration environments, and under small temperature difference conditions during vehicle operation. The system includes an embedded flow meter, a graded temperature measurement device with a small temperature difference testing module, a vibration signal processing circuit, and a multi-source information acquisition unit. In conjunction with the sensor calibration process, it enables the fusion and analysis of real vehicle data.

[0059] Specifically, the embedded flow meter achieves embedded flow measurement. Fluid flowing through a wedge-shaped core generates a pressure gradient, and a diffused silicon pressure sensor measures the pressure difference across the core. The flow rate within the pipeline is calculated based on this pressure difference. This design ensures an impact of ≤5% on the resistance of the media system, a test accuracy of ≥98%, and an operating temperature range of -50 to +85℃, meeting dynamic testing requirements. The flow meter needs to be compared and verified with a standard flow meter on a calibration test bench to ensure linearity and accuracy (e.g., ...). Figure 5 (The calibration results are shown).

[0060] The graded temperature measurement device containing a small temperature difference testing module employs a specialized small temperature difference testing method using coupled thermocouples (such as...). Figure 2 , 3 (As shown). Two thermocouples with identical physical properties are connected in reverse series, with a total electromotive force E = E1 - E2. The tiny millivolt signal is amplified by a dedicated amplifier circuit and converted into a temperature difference output. To eliminate the effects of thermocouple asymmetry and zero-point drift, the calibration process consists of two steps:

[0061] Zeroing: Place the paired thermocouples in a constant-temperature bath to achieve thermal equilibrium, and adjust the amplifier's zero-adjustment potentiometer to make the output voltage zero. Repeat this process at different base temperatures to ensure that the output is zero when the temperature difference at each temperature point is zero.

[0062] Calibration: Place the thermocouples in a constant temperature bath with a set temperature difference and record the amplifier output voltage. Adjust the heat transfer oil temperature to ensure that the output voltage corresponding to the same temperature difference is consistent under different base temperatures. This method can achieve accurate measurement of temperature differences as low as 0.1℃.

[0063] In vibration signal processing circuits, vibration sensors are powered by dedicated constant current sources, and their output signals need to be processed by filtering, amplification, and other circuits (such as...). Figure 4 (As shown), convert it to the voltage signal range required by the information acquisition device to adapt to reliable acquisition in high vibration environments.

[0064] The multi-source data acquisition unit has CAN and FlexRay communication capabilities, and can collect key node information of critical components of the vehicle's cooling system (cooling fan, radiator, cooling pipes, primary filter, secondary filter, dust extraction device, exhaust system, elastic support, etc.) in real time, including flow rate, temperature, pressure, vibration, and displacement. Simultaneously, it communicates with the vehicle controller via the vehicle bus to obtain dynamic operating parameters of the entire vehicle, such as engine speed, coolant temperature, exhaust temperature, gear position, generator speed, torque, current, and voltage.

[0065] The sensor calibration process includes: using a standard flow meter to verify and calibrate accuracy on a flow calibration test bench; setting the temperature in a constant temperature bath and reading the readings after stabilization; pairing sensors with consistent readings to reduce errors; and strictly following the aforementioned zeroing and calibration procedures for pairing and calibration to ensure the matching of thermocouple physical properties and the consistency of output voltage at different temperature differences.

[0066] This invention also provides a method for dynamic testing of vehicle thermal properties, implemented based on the system of this invention, comprising the following steps:

[0067] Calibration preparation: Before the test, all embedded flow meters, conventional temperature sensors (paired), and small temperature difference thermocouples are calibrated and verified to ensure measurement accuracy and reliability.

[0068] System Deployment: Deploy calibrated sensors to pre-defined nodes on key components of the actual vehicle (or test bench) cooling system (e.g., ...). Figure 6 (As shown), connect the information collector and the vehicle communication interface.

[0069] Dynamic data acquisition: Testing is initiated under actual vehicle driving or bench simulation conditions. The information acquisition device synchronously acquires: real-time data from sensors at each node (flow rate, temperature, pressure, vibration, displacement); and dynamic operating parameters of the entire vehicle (vehicle speed, gear, engine speed, coolant temperature, exhaust temperature, generator parameters, etc.) obtained through the vehicle bus.

[0070] Data processing and analysis: The collected multi-source dynamic data (especially temperature, pressure, and flow rate at key nodes) are input into the preset heat flow dynamic model; the model calculates the dynamic distribution response of heat flow during vehicle operation; and the model calculation results are compared and verified with the measured results.

[0071] Evaluation and Application: Based on the comparison of measured and simulation results, the heat transfer path and related laws are evaluated. Combining collected data on vibration, displacement, temperature, pressure, and vehicle information, the motion status of key components such as the elastic support, intake system, and exhaust system is monitored in real time to assess their health. Real-time heat flow analysis and thermal balance capability prediction models are established using test data. This analysis guides the formulation of multi-objective control strategies for the cooling system, meeting its need for accurate thermal data analysis, ultimately improving cooling system efficiency and vehicle reliability.

[0072] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vehicle thermal dynamic testing system, characterized in that, include: Embedded flow meter: It adopts a wedge-shaped core structure and uses a diffused silicon pressure sensor to measure the pressure difference before and after the fluid flows through the wedge-shaped core, and calculates the fluid flow rate in the pipeline based on the pressure difference; Graded temperature measurement device: includes conventional temperature sensors and small temperature difference testing modules; The small temperature difference test module consists of two thermocouples with the same physical properties connected in reverse series to form a coupler thermocouple. The total electromotive force output is E = E1 - E2, and it is connected to an amplifier circuit to convert the millivolt signal into a temperature difference output. Vibration signal processing circuit: provides constant current power to the vibration sensor and includes filtering and amplification circuits to convert the vibration signal into a preset voltage range; Multi-source information acquisition unit: Equipped with CAN and FlexRay communication interfaces, it is used to collect flow, temperature, pressure, vibration and displacement signals of key nodes in the cooling system, and to obtain the dynamic parameters of the whole vehicle through the vehicle bus, including engine speed, water temperature, gear, generator torque and speed; Thermal Flow Dynamic Model Processor: Receives data from the multi-source information acquisition unit and calculates the dynamic distribution response of thermal flow during vehicle operation.

2. The system according to claim 1, characterized in that, The calibration method of the small temperature difference test module includes: zero calibration: placing the paired thermocouples in a constant temperature bath, adjusting the amplifier so that the output voltage is 0 when the temperature difference is 0, and repeating this process at different base temperatures; temperature difference calibration: placing the thermocouples in constant temperature baths with set temperature differences, recording the output voltage, adjusting the temperature so that the output voltage is consistent at the same temperature difference under different base temperatures, thereby achieving the measurement of a temperature difference ≥0.1℃.

3. The system according to claim 1, characterized in that, The embedded flow meter satisfies: The impact on the resistance of the medium system is ≤5%; Test accuracy ≥ 98%; Operating temperature range: -50℃ to +85℃.

4. The system according to any one of claims 1-3, characterized in that, The key components include cooling fans, radiators, cooling pipes, primary filters, secondary filters, dust extraction devices, exhaust systems, and elastic supports.

5. A method for testing vehicle thermal dynamics, characterized in that, The system implementation based on any one of claims 1-4 includes the following steps: Calibration preparation: Calibrate and verify the embedded flow meter, conventional temperature sensor and small temperature difference thermocouple; System deployment: Deploy the calibrated sensors to key nodes of the cooling system and connect them to the multi-source information acquisition unit and the vehicle communication interface; Dynamic data acquisition: Under actual vehicle or bench conditions, synchronously acquire data on flow rate, temperature, pressure, vibration and displacement at key nodes, as well as dynamic parameters of the whole vehicle; Data processing and analysis: Input the collected data into the heat flux dynamic model, calculate the dynamic heat flux distribution response, and compare the measured and simulation results; Condition assessment: Based on the heat flow distribution response, assess the heat transfer path law; combine vibration, displacement and vehicle parameters to monitor the health status of elastic support, intake and exhaust systems in real time; establish a real-time heat flow analysis and thermal balance capacity prediction model to guide the cooling system control strategy.

6. The method according to claim 5, characterized in that, The calibration of the small temperature difference test module includes: pairing conventional temperature sensors in a constant temperature bath and selecting sensors with consistent readings; performing zero-adjustment calibration and temperature difference calibration on the thermocouples to ensure consistent output of the same temperature difference at different temperatures.

7. The method according to claim 5 or 6, characterized in that, The vibration signal processing includes: The vibration sensor is powered by a constant current source; The output signal is filtered and amplified to match the voltage range of the information acquisition device.

8. The method according to claim 5 or 6, characterized in that, The status assessment includes: Based on the vibration displacement data of the elastic support and the engine speed, its working status is determined; Evaluate thermal management efficiency by combining exhaust system temperature and pressure data.

9. The method according to claim 7, characterized in that, The calibration method for the embedded flow meter is as follows: In the flow calibration test bench, its linearity and accuracy were verified to be ≥98.5% using a standard flow meter.

10. The method according to claim 9, characterized in that, The thermal balance capability prediction model is used to optimize the multi-objective control strategy of the cooling system.

Images