CN209385257U - A kind of engine EGR orifice flowmeter - Google Patents

Abstract

The utility model relates to an engine EGR orifice flowmeter, which comprises an inlet section, an orifice plate and an outlet section. The orifice flow orifice is provided with a bellows, and the orifice flow inlet section is provided with a first meter for measuring the inlet pressure. Pressure port, the inlet section of the orifice flow is provided with a second pressure tap for measuring the outlet pressure, and also includes a differential pressure sensor connected to the first pressure tap and the second pressure tap of the orifice flow, and also includes a pressure sensor connected to the orifice plate The front straight pipe connected to the flow inlet section, the rear straight pipe connected to the outlet section, the length of the straight pipe before the orifice flow is 2.5 to 3 times the inner diameter of the orifice flow inlet section, and the straight pipe after the orifice flow The length is 2.5 to 3 times the inner diameter of the orifice flow outlet section, and the distance from the first pressure-taking port of the orifice flow along the airflow direction to the orifice flow outlet is greater than half of the inner diameter of the orifice flow inlet section. Ensure that the gas flowing into the orifice flowmeter is stable without disturbance, avoiding the unstable air flow at the mouth, and improving the measurement stability and accuracy.

Description

An engine EGR orifice flowmeter

technical field

The utility model relates to the technical field of engine flow measurement, in particular to an engine EGR orifice flowmeter.

Background technique

With the continuous upgrading of emission regulations, the EGR system needs closed-loop control to meet the requirements of emission regulations after the National 6 stage. The exhaust gas flow measurement of the EGR system is divided into two types, the Venturi tube exhaust gas flow meter and the orifice plate exhaust gas flow meter. The Venturi tube exhaust gas flowmeter can only measure the exhaust gas flow in the forward direction, while the orifice flowmeter can measure the exhaust gas flow in the forward and reverse directions, and can simultaneously monitor whether the exhaust gas flows from the intake side to the exhaust gas side. For example, Chinese patent CN105547381A includes an orifice plate, the orifice plate has a throttling hole connected with the intake pipe of the engine, and the upstream and downstream of the throttling hole are respectively provided with a first detection port and a second detection port. The detection port is used to detect the inlet pressure of the orifice and the gas temperature at the inlet, and the second detection port is used to detect the outlet pressure of the orifice, and then according to the inlet pressure, the outlet pressure and The gas temperature at the inlet is used to calculate the intake air flow. The downstream pipeline layout on the orifice plate has little influence on the measurement, and the structure of the orifice plate is simple, especially the axial dimension is small, and the requirements for installation space are low and the required installation space is small, which is better suitable for the engine Measurement of intake air flow. However, due to the structural size setting problem of the device, the axial size is small, the gas flowing into the orifice flowmeter is unstable, there is turbulence, the detection data of the detection port is unstable, and the measurement accuracy is not high.

Utility model content

The utility model provides an engine EGR orifice flowmeter, which solves the problem of air flow instability when the existing EGR orifice flowmeter measures EGR flow, reduces exhaust pulses, and improves measurement accuracy.

The technical scheme of the utility model is as follows:

An engine EGR orifice flowmeter, comprising an inlet section, an orifice plate, and an outlet section sequentially connected along the airflow direction, the orifice plate is provided with a bellows, and the inlet section is provided with a first valve for measuring the inlet pressure A pressure port, the outlet section is provided with a second pressure tap for measuring the outlet pressure, and also includes a differential pressure sensor connected to the first pressure tap and the second pressure tap, and also includes a pressure sensor connected to the inlet section The connected front straight section pipe and the rear straight section pipe connected to the outlet section, the length of the front straight section pipe is 2.5 to 3 times the inner diameter of the inlet section, and the length of the rear straight section pipe is 2.5 to 3 times the inner diameter of the outlet section 2.5 to 3 times the inner diameter, and the distance from the first pressure tapping port to the bellows along the gas flow direction is greater than half of the inner diameter of the inlet section. The front and rear straight pipes with long lengths are set to ensure that the gas flowing into the orifice flowmeter is stable without turbulence; Steady airflow improves measurement stability and accuracy.

Preferably, the inner diameter of the bellows is 0.4 to 0.75 times the inner diameter of the inlet section, and a larger inner diameter of the bellows is selected to avoid turbulent flow, improve airflow stability, and further improve measurement stability and accuracy .

Preferably, the inlet section and the outlet section have the same inner diameter and use the same size to reduce production and processing costs.

Preferably, the distance from the second pressure-taking port to the bellows along the gas flow direction is greater than half of the inner diameter of the outlet section, avoiding unstable airflow at the bellows, and improving measurement stability and accuracy.

Preferably, the inner diameters of the first pressure tapping port and the second pressure tapping port are both 4-5 mm. Larger pressure taps are used to prevent carbon deposits from the engine from clogging the pressure taps, improving the reliability of the device and causing less interference to the airflow.

Preferably, the measuring range of the differential pressure sensor is 25-35kPa. Selecting a range that is closer to the measured pressure avoids the reduction of measurement accuracy due to the measurement pressure difference being too small and the range selection being too large.

Description of drawings

Fig. 1 is a schematic diagram of the internal structure of an engine EGR orifice flowmeter according to the present invention.

Fig. 2 is a schematic diagram of the installation structure of an engine EGR orifice flowmeter described in the present invention.

In the figure: 1. Inlet section; 11. First pressure-taking port; 2. Orifice plate; 21. Roar port; 3. Exit section; 31. Second pressure-taking port; 4. Differential pressure sensor; 5. Front straight section Tube; 6. Rear straight section tube; 7. Interface flange.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further:

As shown in Fig. 1 and Fig. 2, a kind of engine EGR orifice plate flow meter comprises the inlet section 1 that is connected successively along the airflow direction, orifice plate 2, outlet section 3, and described orifice plate 2 is provided with mouthpiece 21, so The inlet section 1 is provided with a first pressure tapping port 11 for measuring the inlet pressure, and the outlet section 3 is provided with a second pressure tapping port 31 for measuring the outlet pressure. The differential pressure sensor 4 connected to the second pressure taking port 31 also includes a front straight pipe 5 connected to the inlet section 1, a rear straight pipe 6 connected to the outlet section 3, and the inlet section 1 and the front straight pipe 6. The section pipe 5 is connected by an interface flange 7, and the outlet section 3 and the rear straight section pipe 6 are connected by an interface flange 7,

Both the inner diameter D1 of the inlet section 1 and the inner diameter D2 of the outlet section 3 are 35mm,

The inner diameter d of the mouth 21 is 14mm;

The length of the front straight pipe 5 and the rear straight pipe 6 is 70mm;

The distance L2 from the first pressure-taking port 11 to the bellows 21 along the airflow direction is 17.5mm; the distance L1 from the second pressure-taking port 31 to the bellows 21 along the airflow direction is 17.5mm;

The inner diameters of the first pressure-taking port 11 and the second pressure-taking port 31 are both 4mm;

The measuring range of the differential pressure sensor 4 is 25-35kPa.

Example 2:

The difference between this embodiment and the above-mentioned embodiment 1 is:

Both the inner diameter D1 of the inlet section 1 and the inner diameter D2 of the outlet section 3 are 40mm,

The inner diameter d of the mouth 21 is 24mm;

The length of the front straight pipe 5 and the rear straight pipe 6 is 120mm,

The distance L2 from the first pressure-taking port 11 to the bellows 21 along the airflow direction is 24mm; the distance L1 from the second pressure-taking port 31 to the bellows 21 along the airflow direction is 24mm;

The inner diameters of the first pressure-taking port 11 and the second pressure-taking port 31 are both 5mm;

Example 3:

The difference between this embodiment and the above-mentioned embodiment 1 is:

Both the inner diameter D1 of the inlet section 1 and the inner diameter D2 of the outlet section 3 are 40mm,

The inner diameter d of the mouth 21 is 30mm;

The length of the front straight pipe 5 and the rear straight pipe 6 is 140mm;

The distance L2 from the first pressure-taking port 11 to the bellows 21 along the airflow direction is 32mm; the distance L1 from the second pressure-taking port 31 to the bellows 21 along the airflow direction is 32mm;

The inner diameters of the first pressure tapping port 11 and the second pressure tapping port 31 are both 4.5 mm.

The working principle of the utility model is: measure the inlet pressure through the first pressure taking port 11, collect the outlet pressure through the second pressure taking port 31, calculate the volume flow of the exhaust gas, and then calculate the temperature and pressure of the exhaust gas. The mass flow rate of the exhaust gas. Applicable to EGR rate of 20% to 25%.

Claims (6)

1. A kind of engine EGR orifice flowmeter, comprises the inlet section (1) that is connected successively along the airflow direction, orifice (2) and outlet section (3), and described orifice (2) is provided with roar port (21 ), the inlet section (1) is provided with a first pressure tapping port (11) for measuring the inlet pressure, and the outlet section (3) is provided with a second pressure tapping port (31) for measuring the outlet pressure, It also includes a differential pressure sensor (4) connected to the first pressure taking port (11) and the second pressure taking port (31), characterized in that it also includes a front straight section connected to the inlet section (1) Pipe (5), the rear straight pipe (6) connected to the outlet section (3), the length of the front straight pipe (5) is 2.5 to 3 times the inner diameter of the inlet section (1), the The length of the rear straight pipe (6) is 2.5 to 3 times the inner diameter of the outlet section (3), and the distance from the first pressure-taking port (11) to the mouth (21) along the airflow direction is greater than that of the inlet Half the inner diameter of section (1). 2 . The engine EGR orifice flowmeter according to claim 1 , characterized in that: the inner diameter of the bellows ( 21 ) is 0.4 to 0.75 times the inner diameter of the inlet section ( 1 ). 3. The engine EGR orifice flowmeter according to claim 1 or 2, characterized in that: the inner diameters of the inlet section (1) and the outlet section (3) are the same. 4. A kind of engine EGR orifice flowmeter as claimed in claim 1 or 2, is characterized in that: the distance from the second pressure-taking port (31) to the mouth (21) along the airflow direction is greater than the Half of the internal diameter of the outlet section (3). 5. A kind of engine EGR orifice flowmeter as claimed in claim 1 or 2, characterized in that: the inner diameters of the first pressure taking port (11) and the second pressure taking port (31) are both 4 to 5 mm . 6. The engine EGR orifice flowmeter according to claim 1 or 2, characterized in that: the range of the differential pressure sensor (4) is 25-35 kPa.