CN201622082U - On-line measurement device for cooling air volume of automobile radiator - Google Patents

Abstract

The utility model relates to an on-line measuring device for the cooling air volume of an automobile radiator. The impeller is equipped with at least one miniature photoelectric sensor, and the signal of the miniature photoelectric sensor passes through the photoelectric sensor interface circuit to the impeller speed frequency counting circuit and then is input into a single-chip microcomputer. The single-chip microcomputer is collected by the communication interface circuit. The data is sent to the PC, and the working power of the whole device is provided by the standard vehicle power supply through the power conversion circuit. This device overcomes the defects of poor air direction directivity of pressure or hot wire sensors and inability to measure online. The impeller speed is measured by the photoelectric sensor, and the cooling air volume is converted from the relationship between the impeller speed and air flow rate. It is simple, powerful and reliable. It is an ideal tool for realizing on-line measurement of the cooling air volume of automobile radiators.

Description

On-line measurement device for cooling air volume of automobile radiator

technical field

The utility model relates to a flow measuring device, in particular to an on-line measuring device for the cooling air volume of an automobile radiator.

Background technique

The car radiator is an indispensable and important part of the car cooling system. Its function is to transfer the excess heat carried by the coolant in the engine water jacket through secondary heat exchange, and dissipate the excess heat to the in the air. Therefore, the performance of the radiator in the cooling system directly affects the heat dissipation effect of the automobile engine and its power, economy and reliability, and even produces safety.

However, in recent years, on the one hand, the engine speed and power have continued to increase, and the heat load has increased accordingly. On the other hand, in order to reduce the air resistance when the car is running and pursue a perfect appearance, the amount of air flowing into the radiator and condenser There is a clear tendency to decrease. Under the above unfavorable conditions, in order to ensure the cooling performance, it is of great significance to accurately measure the cooling wind speed and the distribution of the wind speed of the radiator.

At present, common methods for measuring the cooling air volume of automobile radiators include: using CFD (Computational Fluid Dynamics) to simulate the air volume of the engine compartment, and using pressure or hot-wire sensors for direct measurement. The simulation calculation using CFD is more complicated, and the calculation results still need to be further verified by the performance test of the car radiator; it is a more traditional method to use the pressure sensor to measure the pressure difference to calculate the cooling air volume, but when the air volume is small, the pressure difference does not change much. The measurement error is large and the accuracy is reduced; the hot wire sensor can measure the fluid flow rate on the metal surface by using the physical properties of metal resistance. The hot wire sensor has high measurement sensitivity, but the hot wire is difficult to install and is also damaged. It should not be carried out under real vehicle driving test.

Contents of the invention

The utility model aims at the shortcomings and deficiencies in the measurement of the cooling air volume of the automobile radiator, and proposes an on-line measuring device for the cooling air volume of the automobile radiator. The device is light and portable, has strong anti-interference, high measurement accuracy, and is easy to operate. It can be loaded on a real vehicle to complete online measurement. It can not only measure the total air volume, but also obtain detailed distribution information of the air volume, and the measured air volume has a good direction sex.

The technical scheme of the utility model is: an on-line measuring device for the cooling air volume of an automobile radiator, including an impeller, a data acquisition circuit, a single-chip microcomputer, a communication interface circuit, a PC and a power conversion circuit, and the data acquisition circuit includes a miniature photoelectric sensor and a photoelectric sensor interface Circuit, impeller speed and frequency counting circuit, at least one micro photoelectric sensor is installed on the impeller, the signal of the micro photoelectric sensor is input to the single chip microcomputer after passing through the photoelectric sensor interface circuit to the impeller speed frequency counting circuit, the single chip microcomputer sends the collected data to the PC through the communication interface circuit, the whole The working power of the device is provided by the standard vehicle power supply through the power conversion circuit.

The impeller includes a blade, an outer frame, a bracket and a bearing. Several circular holes of equal size are evenly distributed on the rotating shaft of the blade, and the distance between each circular hole is 45°. The miniature photoelectric sensor is fixed at the opening of the bracket, and is facing the Hole center.

The single-chip microcomputer can input 18 data acquisition signals at most.

The communication interface circuit selects RS-232 communication interface.

The impeller is a light and thin impeller with a thickness of 10mm, which is installed between the car radiator and the condenser.

The beneficial effect of the utility model is that: the utility model automobile radiator cooling air volume on-line measurement device overcomes the defects such as poor air direction directivity of the pressure or hot wire sensor and inability to measure on-line. The relationship between the cooling air volume is converted to the cooling air volume, which is simple, powerful, and reliable. It is an ideal tool for online measurement of the cooling air volume of automobile radiators.

Description of drawings

Fig. 1 is the structural block diagram of the utility model automobile radiator cooling air volume online measuring device;

Fig. 2 is the photoelectric sensor interface circuit diagram of the utility model automobile radiator cooling air volume online measuring device;

Fig. 3 is the impeller rotation speed frequency counting circuit diagram of the utility model automobile radiator cooling air flow online measuring device;

Fig. 4 is the power conversion circuit diagram of the utility model automobile radiator cooling air flow online measuring device;

Fig. 5 is the communication interface circuit diagram of the utility model automobile radiator cooling air volume online measuring device;

Fig. 6 is a graph showing the relationship between the measured value of the air volume and the deflection angle of the wind direction of the on-line measuring device for the cooling air volume of the automobile radiator of the present invention.

Detailed ways

The utility model indirectly measures the cooling air volume of the automobile radiator through the relationship between the impeller speed and the air flow rate. The sensor interface circuit 2 and the impeller speed frequency counting circuit 3 are connected to the single-chip microcomputer 4, and the single-chip microcomputer 4 sends the collected data to the PC 7 by the serial port interface circuit 6, and the working power of the whole device is provided by the standard vehicle power supply through the power conversion circuit 5.

The impeller 1 is assembled from a blade, an outer frame, a bracket and a bearing. Eight circular holes of equal size are evenly distributed on the rotating shaft of the blade, and the distance between the circular holes is 45°. The miniature photoelectric sensor is fixed at the opening of one of the brackets, and is facing the center of the circular hole. Its interface circuit 2 is shown in Figure 2 shown. When air flows through the impeller, the rotation of the impeller drives the circular hole on the rotating shaft to rotate accordingly, and the infrared rays from the emitting end of the photoelectric sensor alternately pass through the circular hole area of the rotating shaft and the non-transparent area of the rotating shaft, thereby outputting current signals with high and low changes. The larger the air volume, the higher the speed of the impeller, and the higher the frequency of output signal changes. Conversely, the smaller the air volume, the lower the speed of the impeller, and the lower the frequency of output signal changes. Since the rotation of the impeller is the result of the flow of air parallel to the axis of the impeller, the measurement of the air volume through the rotation of the impeller has a good directivity of the wind direction and is not easily affected by the change of the direction of the flowing air.

The impeller rotational speed frequency counting circuit 3 is shown in Fig. 3 . The current signal output by the photoelectric sensor interface circuit 2 passes through the impeller speed frequency counting circuit 3 to obtain a regular rectangular square wave signal. The single-chip microcomputer indicates the number of impeller rotation frequencies by recording the number of rising edges of the rectangular square wave signal per unit time, thus reflecting the current The flow of cooling air through the car radiator at all times.

In the actual measurement process, the single-chip microcomputer can process the signals of up to 18 photoelectric sensors at the same time, and the signals of each sensor are independent of each other without interfering with each other.

The power conversion circuit 5 is shown in Figure 4. The standard vehicle power supply is used as the external power supply of the entire device. After passing through the power conversion circuit 5, the input 12V DC voltage is converted into a 5V DC voltage output, which provides normal operation for the electronic components of the device. Voltage.

The serial port interface circuit 6 provides a powerful communication function for the single-chip microcomputer 4 and the PC 7, and its interface circuit is shown in FIG. 5 . The single-chip microcomputer 4 sends the rotation frequency of each impeller to the PC 7 through the serial port interface circuit 6 through the RS-232 serial port, and the PC 7 side realizes the conversion, display, and storage of the air volume through professional software. The 232 serial port sends operation instructions to the online measuring device of the cooling air volume of the car radiator, and sets parameters such as sampling interval and measurement time.

Through the relationship between the impeller speed and the air flow rate, the cooling air volume of the car radiator is indirectly measured, which not only has high measurement accuracy, but also has more powerful functions and features, including:

1) On-line measurement function: This device uses a special thin impeller with a thickness of only 10mm, which can be installed between the car radiator and the condenser, and uses the standard vehicle power supply as the external power supply of the device, so that the car can be used during the driving test. The measurement can be realized, the measurement environment is closer to the real working conditions, and the measurement results are more instructive.

2) Low pressure loss: The impeller uses very thin spokes and low-resistance bearings, so that the pressure loss generated is small. Compared with the pressure loss caused by the radiator, the pressure loss caused by the impeller is very small and can be ignored.

3) Strong anti-interference: The electromagnetic interference near the car engine is relatively strong, and the ambient temperature is high. Since the high-temperature-resistant reflective photoelectric sensor is used to measure the impeller speed, the measurement results are not affected by the high temperature and electromagnetic noise inside the car.

4) Good directivity of wind direction: Since the impeller only detects the air volume perpendicular to the surface of the car radiator, the measurement result is not affected by the change of wind direction and the air flow in other directions, and can accurately measure the effect on the car radiator. The effective air volume in the direction parallel to the impeller axis.

5) Rich measurement information: The device adopts multi-point distribution measurement, which can not only measure the total air volume, but also obtain the distribution information of the air volume, providing a richer basis for judging the cooling performance of the automobile radiator.

6) Communication function: through the RS-232 interface, the communication between the single-chip microcomputer and the PC is completed, and data collection and measurement parameter setting are realized.

7) Simple and easy to operate: the device only needs to be installed at the designated location, connected to the vehicle power supply, and operated through a PC-friendly man-machine interface to realize online measurement of the cooling air volume of the car radiator.

Claims (5)

1. An on-line measuring device for cooling air volume of an automobile radiator is characterized in that it comprises an impeller, a data acquisition circuit, a single-chip microcomputer, a communication interface circuit, a PC and a power conversion circuit, and the data acquisition circuit includes a miniature photoelectric sensor, a photoelectric sensor interface circuit, The impeller speed and frequency counting circuit, the impeller is equipped with at least one miniature photoelectric sensor, the signal of the miniature photoelectric sensor is input to the single-chip microcomputer after passing through the photoelectric sensor interface circuit to the impeller speed and frequency counting circuit, and the single-chip microcomputer sends the collected data to the PC through the communication interface circuit, and the whole device works The power supply is provided by the standard vehicle power supply through the power conversion circuit. 2. The on-line measuring device for the cooling air volume of the automobile radiator according to claim 1, wherein the impeller comprises a blade, an outer frame, a support and a bearing, and several circular holes of equal size are evenly distributed on the rotating shaft of the blade, each The distance between the circular holes is 45°, and the miniature photoelectric sensor is fixed at the opening of the bracket, facing the center of the circular holes. 3. The on-line measuring device for the cooling air volume of the automobile radiator according to claim 1, wherein the single-chip microcomputer can input 18 data acquisition signals at most. 4. The on-line measurement device for cooling air volume of an automobile radiator according to claim 1, wherein the communication interface circuit is an RS-232 communication interface. 5. The on-line measuring device for the cooling air volume of the automobile radiator according to claim 1, wherein the impeller is a light and thin impeller with a thickness of 10 mm, which is installed between the automobile radiator and the condenser.

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