Partial flow sampling prejudgment control system and method based on carbon balance

Abstract

The invention provides a partial flow sampling prejudgment control system and a partial flow sampling prejudgment control method based on carbon balance, and aims to improve the measurement precision of a shunting dilution system in a laboratory environment on real-time exhaust flow and compensate lag time. The partial flow sampling pre-judgment control system based on carbon balance comprises an air flow meter, an oil consumption meter, a sensor, a data acquisition module, a rack measurement and control system, a direct sampling analyzer and a partial flow dilution system, sampling exhaust flow can be obtained through cooperation of the air flow meter and the oil consumption meter, and calculated exhaust flow is obtained through calculation of a carbon balance method of the direct sampling analyzer. By aligning the time of sampling the exhaust flow and the time of calculating the exhaust flow, the pre-judgment control time can be obtained, the control precision of a partial flow dilution system is improved, sampling flow fluctuation caused by exhaust flow deviation is prevented, the sampling PM quality is prevented from being influenced, and it is ensured that the ratio of the sampling flow to the exhaust flow is kept synchronous; the measurement precision of the partial flow dilution system on the real-time exhaust flow is improved, and the lag time is compensated.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile emission detection, and in particular to a partial flow sampling prediction control system and method based on carbon balance. Background Art

[0002] The main pollutant emitted by diesel engines is particulate matter, and its particulate matter emission is 30 to 60 times that of gasoline engines. At present, there are two main methods for the detection of particulate matter in diesel engines in China: full-flow dilution sampling and partial-flow dilution sampling. The full-flow constant volume system refers to the exhaust gas discharged by the engine being diluted by clean fresh air to keep the flow state of the diluted mixture constant and input into the analysis system at a fixed volume flow rate. After all the exhaust gas is diluted, the specific emission of particles is calculated based on the mass of the particulate matter sampling filter paper, the total mass of the diluted exhaust gas during the entire test process and the actual cycle work of the entire cycle; the partial-flow sampling system refers to extracting a certain proportion of gas from the engine exhaust for analysis. For gaseous pollutants, samples are taken directly from the original exhaust in proportion, while for particulate matter, it is usually analyzed after dilution. To ensure the accuracy of the partial-flow sampling system, it is necessary to ensure that the ratio of the total exhaust flow rate to the sampling flow rate of the engine under different states remains unchanged.

[0003] Due to the complex structure, large size and high cost of the full-flow dilution sampling system, it is seldom used. In contrast, the partial-flow dilution sampling system has been widely used due to its small footprint, low cost and easy operation. The core of the partial-flow dilution system is that the ratio of the sampling flow to the exhaust flow is constant. The system needs to process two dynamic signals, the exhaust flow and the sampling flow, at the same time. In transient tests, due to the rapid changes in engine operating conditions, the system cannot control the sampling flow in a timely and accurate manner, resulting in inaccurate measurement results. Summary of the invention

[0004] The present invention provides a partial flow sampling prediction control system and method based on carbon balance, which aims to improve the measurement accuracy of the partial flow dilution system for real-time exhaust flow and compensate for the lag time in the laboratory environment. In order to achieve the above purpose, the technical solution adopted is as follows: A partial flow sampling prediction control system based on carbon balance, characterized by comprising: An intake pipe is connected to the engine air intake port and is provided with an air flow meter and an intake temperature, humidity and pressure sensor; A fuel consumption meter, wherein the fuel outlet of the fuel consumption meter is connected to the fuel inlet of the engine, and the fuel outlet of the engine is connected to the fuel inlet of the fuel consumption meter, and is used to measure the fuel consumption mass flow of the engine; An exhaust straight pipe section, one end of which is connected to the engine exhaust port; A partial flow dilution system, wherein a sampling tube of the partial flow dilution system is connected to the exhaust straight pipe section through a sampling probe, and a sampling flow meter is provided on the sampling arm of the partial flow dilution system; A direct sampling analyzer, wherein the sampling probe of the direct sampling analyzer is connected to the exhaust straight pipe section and is used to measure the concentrations of CO, CO2 and HC in the exhaust gas; The sampling probe of the partial flow dilution system and the sampling probe of the direct sampling analyzer are located at the same section with the same cross-sectional area on the exhaust straight pipe section, and the two are spaced apart; A dynamometer, wherein the output shaft of the dynamometer is drivingly connected to the input shaft of the engine; The measurement and control system, the air flow meter, the intake air temperature, humidity and pressure sensor, the intake air pressure sensor, the fuel flow sensor in the fuel consumption meter, and the sampling flow meter are all connected to the signal input end of the measurement and control system, and the oil pump and dynamometer in the fuel consumption meter are all connected to the signal output end of the measurement and control system; And an atmospheric humidity sensor and an atmospheric pressure sensor connected to the signal input end of the measurement and control system.

[0005] Furthermore, L≥12D, wherein L is the length of the exhaust straight pipe section, and D is the diameter of the exhaust straight pipe section.

[0006] Furthermore, the measuring point positions of the sampling probe of the partial flow dilution system and the sampling probe of the direct sampling analyzer are greater than 3D from the inlet or outlet of the straight pipe section of the exhaust pipe, and the distance between the measuring point of the sampling probe of the partial flow dilution system and the measuring point of the sampling probe of the direct sampling analyzer is 4 to 6D.

[0007] Furthermore, an on-off oil valve is provided between the fuel consumption meter and the oil inlet of the engine, and the on-off oil valve is connected to the signal output end of the measurement and control system.

[0008] Furthermore, an air intake butterfly valve is provided on the air intake pipe, and the air intake butterfly valve is connected to the signal output end of the measurement and control system.

[0009] Furthermore, an end of the exhaust straight pipe section away from the engine exhaust port is connected to an exhaust butterfly valve, and the exhaust butterfly valve is connected to a signal output end of a measurement and control system.

[0010] Furthermore, it also includes a data acquisition module, and the air flow meter, intake temperature, humidity and pressure sensor, intake pressure sensor, atmospheric humidity sensor, atmospheric pressure sensor, fuel consumption meter, and sampling flow meter are all connected to the signal input end of the measurement and control system through the data acquisition module.

[0011] A partial flow sampling prediction control method based on carbon balance, based on the partial flow sampling prediction control system based on carbon balance according to any one of claims 1 to 4, characterized in that it comprises the following steps: S1. Check whether the equipment meets the linear correlation requirements; S2. Perform a transient experiment to obtain bench test data of the target engine required for carbon balance calculation, and obtain the time trajectory of the measured exhaust flow before time alignment based on the fuel consumption and intake flow time trajectory; S3. Calculate the exhaust flow rate by carbon balance according to the bench test data obtained from the transient experiment in step S2, and obtain the time trajectory of the calculated exhaust flow rate signal; S4. Based on the time trajectory of the calculated exhaust flow, time align the measured exhaust flow of the engine to obtain the predicted control value ; S5. Based on the predicted control value Adjusting the time trajectory of the measured exhaust flow before time alignment so that the exhaust flow of the partial flow dilution system coincides with the time trajectory of the corrected measured exhaust flow, thereby obtaining the corrected time trajectory of the measured exhaust flow, and the partial flow dilution system controls the sampling flow at a fixed sampling rate according to the corrected measured exhaust flow; S6. The partial flow dilution system uses the corrected measured exhaust flow time trajectory to conduct transient experiments, obtain the sampling flow time trajectory of the partial flow dilution system, and perform correlation analysis with the measured exhaust flow.

[0012] Furthermore, in step S1, the inspection includes performing a linearization inspection on the air flow meter and the fuel consumption meter, performing a correlation inspection on the air flow and the output analog quantity of the air flow meter, and performing a correlation inspection on the fuel consumption and the output analog quantity of the fuel consumption meter.

[0013] Furthermore, in step S2, the engine bench test data includes time, intake air temperature, intake air humidity, atmospheric pressure, atmospheric humidity, fuel consumption, intake air flow, exhaust CO2 wet basis concentration, exhaust CO wet basis concentration, exhaust HC wet basis concentration, and background CO2 wet basis concentration.

[0014] The beneficial effects of the present invention are: 1. The exhaust flow can be measured by the intake flow meter and the fuel consumption meter. The exhaust flow can be calculated by the carbon balance method of the direct sampling analyzer. The time of the measured exhaust flow and the calculated exhaust flow can be aligned to obtain the predicted control time, improve the control accuracy of the partial flow dilution system, prevent the sampling flow fluctuation caused by the exhaust flow deviation, prevent the quality of the sampled PM, and ensure that the ratio of the sampling flow to the exhaust flow is synchronized, effectively improve the measurement accuracy of the partial flow dilution system for the real-time exhaust flow, and compensate for all lag times; 2. In the partial flow sampling prediction control system based on carbon balance, the sampling probe of the partial flow dilution system and the sampling probe of the direct sampling analyzer are set in the same section of the exhaust straight pipe section, and the distance between the two sampling probes and the inlet and outlet positions of the end of the exhaust straight pipe section are reasonably limited to avoid the two being too close to cause mutual interference and too far to cause time error. In addition, the two sampling probes are kept at a certain reasonable distance from the end of the exhaust straight pipe section to avoid the inlet and outlet vortex affecting the sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the partial flow sampling prediction control system based on carbon balance of the present invention. Figure 2 This is a flow chart of the steps of the partial flow sampling prediction control method based on carbon balance of the present invention. Figure 3 To predict the control value Calculation diagram of Figure 4 Schematic diagram of correlation analysis between sampling flow and intake flow Among them: 1-engine, 2-exhaust straight pipe section, 3-intake butterfly valve, 4-universal coupling, 5-intake pipe, 6-intake temperature, humidity and pressure sensor, 7-dynamometer, 8-air flow meter, 9-measurement and control system, 10-data acquisition module, 11-atmospheric pressure sensor, 12-atmospheric humidity sensor, 13-partial flow dilution system, 14-exhaust butterfly valve, 15-direct sampling analyzer, 16-fuel consumption meter, 17-oil pump, 18-sampling probe of direct sampling analyzer, 19-switching oil valve, 20-sampling flow meter, 21-sampling probe of partial flow dilution system. DETAILED DESCRIPTION

[0016] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0017] In the description of the invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the viewing direction or positional relationships and are only for the convenience of describing the invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention.

[0018] In this embodiment, for the convenience of description, the length direction of the bed, that is, the processing sequence direction, is taken as the front-to-back direction, and the width direction of the bed is taken as the left-to-right direction.

[0019] like Figure 1 A partial flow sampling prediction control system based on carbon balance is shown, including an engine 1, an intake pipe 5, an exhaust straight pipe section 2, an air flow meter 8, a fuel consumption meter 16, a partial flow dilution system 13, a direct sampling analyzer 15, a data acquisition module 10 and a measurement and control system 9.

[0020] Specifically, one end of the intake pipe 5 is connected to the air intake port of the engine 1, and an air flow meter 8 is arranged on the intake pipe 5 to measure the air mass flow passing therethrough and output the signal to the data acquisition module 10; an intake butterfly valve 3 is also arranged on the intake pipe 5, and the intake pressure on the intake pipe 5 is adjusted by the intake butterfly valve 3, and an intake temperature, humidity and pressure sensor 6 is also arranged on the intake pipe 5. The intake temperature, humidity and pressure sensor 6 adopts an integrated temperature, humidity and pressure sensor, which can simultaneously measure the intake temperature, intake humidity and intake pressure data; in addition, the air flow meter 8 and the intake temperature, humidity and pressure sensor 6 are connected to the signal input end of the measurement and control system 9 through the data acquisition module 10, and the intake butterfly valve 3 is connected to the signal output end of the measurement and control system 9.

[0021] The oil outlet of the fuel consumption meter 16 is connected to the oil inlet of the engine 1, and the oil outlet of the engine 1 is connected to the oil return port of the fuel consumption meter 16, wherein the fuel consumption meter 16 has a fuel flow sensor and an oil pump 17, and the fuel consumption meter 16 is signal-connected to the measurement and control system 9. The fuel flow sensor in the fuel consumption meter 16 can measure the mass flow of the fuel passing through, and output an analog signal of the fuel consumption to the measurement and control system 9. The oil pump 17 can provide the oil inlet pressure required by the engine 1, and the start and stop of the oil pump 17 can be controlled by the measurement and control system 9. Moreover, a switch oil valve 19 is also provided on the connecting oil pipe between the fuel consumption meter 16 and the oil inlet of the engine 1, and the switch oil valve 19 is connected to the signal output end of the measurement and control system 9, and the on and off of the switch oil valve 19 can be controlled by the measurement and control system 9.

[0022] The output shaft of the dynamometer 7 is connected to the input shaft of the engine 1 through a cross-axis universal coupling 4. In the present embodiment, the center coaxiality error between the connecting disk of the engine 1 and the connecting disk of the dynamometer 7 is less than 0.01 mm. The signal output end of the measurement and control system 9 is connected to the dynamometer 7 for controlling the start and stop of the dynamometer 7.

[0023] The direct sampling analyzer 15 is connected to the exhaust straight pipe section 2 through the direct sampling analyzer sampling probe 18. The direct sampling analyzer sampling probe 18 is connected to the exhaust straight pipe section 2 and the sampling port is arranged to face the exhaust air. The direct sampling analyzer 15 can measure the concentrations of CO, CO2 and HC in the exhaust gas, among which CO and CO2 use non-dispersive infrared analysis (NDIR), and HC uses a hydrogen flame ion analyzer (FID). Moreover, the direct sampling analyzer 15 is connected to the signal input end of the measurement and control system 9, and the data of the direct sampling analyzer 15 can be transmitted to the measurement and control system 9 in real time.

[0024] One end of the exhaust straight pipe section 2 is connected to the exhaust port of the engine 1, and the other end is connected to the exhaust butterfly valve 14, and the exhaust butterfly valve 14 is connected to the signal output end of the measurement and control system 9. The measurement and control system 9 can control the on and off of the exhaust straight pipe section 2, and the partial flow dilution system 13 is connected to the exhaust straight pipe section 2 through a sampling arm, and one end of the sampling arm is provided with a partial flow dilution system sampling probe 18 located inside the exhaust straight pipe section 2, and the sampling arm is also provided with a sampling flowmeter 20 for measuring the sampling flow, and the sampling flowmeter 20 is connected to the signal input end of the measurement and control system 9, and can output the sampling flow-time state.

[0025] In addition, the partial flow dilution system sampling probe 21 and the direct sampling analyzer sampling probe 18 are arranged at the same cross-sectional position of the exhaust straight pipe section 2. Specifically, the exhaust straight pipe section 2 has a length of L and a diameter of D, and L≥12D. The distance between the partial flow dilution system sampling probe 21 and the direct sampling analyzer sampling probe 18 is between 4 and 6D to avoid sampling interference caused by the two being too close, and to avoid time errors caused by too long a distance; and the distance between the partial flow dilution system sampling probe 21 and the direct sampling analyzer sampling probe 18 and the end of the exhaust straight pipe section 2 in the length direction (i.e., the inlet end or the outlet end) is greater than 3D to avoid the inlet and outlet vortices affecting the sampling results.

[0026] In this embodiment, an atmospheric pressure sensor 11 and an atmospheric humidity sensor 12 are also included, both of which are connected to the data acquisition module 10. The pressure and humidity measured in the current atmospheric environment can be transmitted to the data acquisition module 10. The data acquisition module 10 is connected to the signal output end of the measurement and control system 9. The sensor signal is collected by the data acquisition module 10 and transmitted to the measurement and control system 9, and each component is controlled by the measurement and control system 9.

[0027] Partial flow sampling predictive control method based on carbon balance, such as Figure 2 As shown, the following steps are included: S1. Check whether the equipment meets the linear correlation requirements; Before the test, prepare the air flow meter 8, fuel consumption meter 16, data acquisition module 10, direct sampling analyzer 15 and partial flow dilution system 13, perform linearization check on the air flow meter 8 and fuel consumption meter 16, perform correlation check between air flow and output analog quantity on the air flow meter 8, perform correlation check between fuel consumption and output analog quantity on the fuel consumption meter, and perform linearization check and leakage check on the direct sampling analyzer. The linearization check calculation formula is: y=a1x+a0, In the formula: y is the actual value, a1 is the slope of the regression line, x is the reference value, and a0 is the intercept of the regression line.

[0028] S2. Conduct transient experiments to obtain the bench test data of the target engine required for carbon balance calculation, based on the fuel consumption and intake flow time trajectory, namely Figure 3 Curve 1 in the figure obtains the time trajectory of the measured exhaust flow before time alignment, that is, Figure 3 Curve 3 in Among them, the calculation formula for measuring exhaust flow is: q mea ==q oil +q air , Where: q mea To measure the exhaust flow, q oil is the fuel consumption, q air is the intake air flow rate; The engine bench test data include time, intake temperature, intake humidity, atmospheric humidity, atmospheric pressure, fuel consumption, intake flow, exhaust CO2 wet basis concentration, exhaust CO wet basis concentration, exhaust HC wet basis concentration, background CO2 wet basis concentration, and are exported through the bench measurement and control system or analyzer.

[0029] S3. According to the bench test data obtained in the transient experiment in step S2, the exhaust flow rate is calculated by carbon balance, and the time trajectory of the calculated exhaust flow rate signal is obtained, that is, Figure 3 Curve 2 in Among them, the calculation formula for carbon balance calculation exhaust flow is: , in: q exh To calculate the exhaust mass flow rate, kg / s; q oil is the fuel mass flow rate, kg / s; H a is the absolute humidity of the intake air, g water / kg dry air; WBET is the carbon content of fuel, mass percentage; W ALF is the hydrogen content of fuel, mass percentage; W DEL is the fuel nitrogen content, mass percentage; W EPS is the oxygen content of fuel, mass percentage; C co2d is the dry basis CO2 concentration, %; C co2d,a is the ambient dry basis CO2 concentration, %; C co is the CO concentration on a dry basis, ppm; C HCw is the HC concentration on a wet basis, ppm.

[0030] S4. Based on the time trajectory of the calculated exhaust flow, time align the measured exhaust flow of the engine to obtain the predicted control value ; The analog signals of the air flow meter 8 and the fuel consumption meter 16 are connected to the partial flow dilution system 13, and the equipment controls the sampling flow in real time according to the measured exhaust flow; Due to the actual working mode of the engine, that is, air and fuel enter the engine first and then flow out of the exhaust pipe after working, the calculated exhaust flow must lag behind the sampled exhaust flow. Therefore, the time trajectory of the calculated exhaust flow lags behind the measured exhaust flow before time alignment. , based on the time trajectory of the calculated exhaust flow, the engine measured exhaust flow is time-aligned to obtain the predicted control value .

[0031] S5. Based on the predicted control value Adjusting the time trajectory of the measured exhaust flow before time alignment so that the exhaust flow of the partial flow dilution system coincides with the time trajectory of the corrected measured exhaust flow, thereby obtaining the corrected time trajectory of the measured exhaust flow, and the partial flow dilution system controls the sampling flow at a fixed sampling rate according to the corrected measured exhaust flow; Since the time trajectory of the calculated exhaust flow rate does not match the measured exhaust flow rate, the sampling flow rate of the partial flow sampling system does not match the actual exhaust flow rate, causing the sampling flow rate to deviate from the measured exhaust flow rate; therefore, the control value is predicted , adjust the time trajectory of the measured exhaust flow of the partial flow dilution system, such as Figure 3As shown, the measured exhaust flow of the partial flow dilution system is made to coincide with the time trajectory of the actual exhaust flow (i.e., the corrected measured exhaust flow), thereby achieving a precise control effect. The analog signals of the air flow meter and the fuel consumption meter are connected to the partial flow dilution system. At this time, the partial flow dilution system can control the sampling flow in real time according to the measured exhaust flow by setting the sampling rate.

[0032] S6. The partial flow dilution system uses the corrected measured exhaust flow time trajectory to conduct transient experiments, obtain the sampling flow time trajectory of the partial flow dilution system, and perform correlation analysis with the measured exhaust flow; In this embodiment, if the correlation between the sampled flow rate and the measured exhaust flow rate is greater than 0.95, it is considered that the predictive control of the partial flow dilution system has a significant effect, and the sampling of the partial flow dilution system is in line with reality and has good accuracy, wherein the correlation coefficient calculation formula is: , Where: x, y are the measurements to check for correlation.

[0033] The PM sampling flow of the partial flow sampling system was corrected by delay time, and the WHTC transient test was carried out by predictive control. The test results are shown in Table 1: Table 1 The correlation analysis of the sampling flow and measured exhaust flow during the entire transient process is carried out, such as Figure 4 As shown, the correlation coefficient between the sampled flow and the measured exhaust flow after time alignment reaches 0.9911. It can be seen that the ratio of the sampled flow to the exhaust flow remains synchronized. The partial flow dilution system improves the measurement accuracy of the real-time exhaust flow, compensates for all lag times, and meets the sampling requirements of the partial flow system.

[0034] This solution can obtain the measured exhaust flow through the cooperation of the air flow meter 8 and the fuel consumption meter 16, and can calculate the calculated exhaust flow through the carbon balance method of the direct sampling analyzer 15. By aligning the time of the measured exhaust flow and the calculated exhaust flow, the predicted control time can be obtained, thereby improving the control accuracy of the partial flow dilution system, preventing sampling flow fluctuations caused by exhaust flow deviations, preventing the quality of sampled PM, ensuring that the ratio of the sampling flow to the exhaust flow remains synchronized, improving the measurement accuracy of the partial flow dilution system for real-time exhaust flow, and compensating for all lag times.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principle of the present invention. These improvements should also be regarded as the protection scope of the present invention.

Claims

1. A partial flow sampling prediction control system based on carbon balance, characterized in that: include: An intake pipe is connected to the engine air intake port and is provided with an air flow meter and an intake temperature, humidity and pressure sensor; A fuel consumption meter, wherein the fuel outlet of the fuel consumption meter is connected to the fuel inlet of the engine, and the fuel outlet of the engine is connected to the fuel inlet of the fuel consumption meter, and is used to measure the fuel consumption mass flow of the engine; An exhaust straight pipe section, one end of which is connected to the engine exhaust port; A partial flow dilution system, wherein a sampling tube of the partial flow dilution system is connected to the exhaust straight pipe section through a sampling probe, and a sampling flow meter is provided on the sampling arm of the partial flow dilution system; A direct sampling analyzer, wherein the sampling probe of the direct sampling analyzer is connected to the exhaust straight pipe section and is used to measure the concentrations of CO, CO2 and HC in the exhaust gas; The sampling probe of the partial flow dilution system and the sampling probe of the direct sampling analyzer are located at the same section with the same cross-sectional area on the exhaust straight pipe section, and the two are spaced apart; A dynamometer, wherein the output shaft of the dynamometer is drivingly connected to the input shaft of the engine; The measurement and control system, the air flow meter, the intake air temperature, humidity and pressure sensor, the intake air pressure sensor, the fuel flow sensor in the fuel consumption meter, and the sampling flow meter are all connected to the signal input end of the measurement and control system, and the oil pump and dynamometer in the fuel consumption meter are all connected to the signal output end of the measurement and control system; And an atmospheric humidity sensor and an atmospheric pressure sensor connected to the signal input end of the measurement and control system.

2. The partial flow sampling prediction control system based on carbon balance according to claim 1 is characterized in that: L≥12D, where L is the length of the exhaust straight pipe section and D is the diameter of the exhaust straight pipe section.

3. The partial flow sampling prediction control system based on carbon balance according to claim 2 is characterized in that: The distance between the measuring point of the sampling probe of the partial flow dilution system and the sampling probe of the direct sampling analyzer and the inlet or outlet of the straight pipe section of the exhaust pipe is greater than 3D, and the distance between the measuring point of the sampling probe of the partial flow dilution system and the measuring point of the sampling probe of the direct sampling analyzer is 4 to 6D.

4. The partial flow sampling prediction control system based on carbon balance according to claim 1 is characterized in that: An on-off oil valve is also provided between the fuel consumption meter and the oil inlet of the engine, and the on-off oil valve is connected to the signal output end of the measurement and control system.

5. The partial flow sampling prediction control system based on carbon balance according to claim 1 is characterized in that: The air intake pipe is provided with an air intake butterfly valve, and the air intake butterfly valve is connected to the signal output end of the measurement and control system.

6. The partial flow sampling prediction control system based on carbon balance according to claim 1 is characterized in that: An end of the exhaust straight pipe section away from the engine exhaust port is connected to an exhaust butterfly valve, and the exhaust butterfly valve is connected to a signal output end of a measurement and control system.

7. The partial flow sampling prediction control system based on carbon balance according to claim 1 is characterized in that: It also includes a data acquisition module, and the air flow meter, intake temperature, humidity and pressure sensor, intake pressure sensor, atmospheric humidity sensor, atmospheric pressure sensor, fuel consumption meter and sampling flow meter are all connected to the signal input end of the measurement and control system through the data acquisition module.

8. A partial flow sampling prediction control method based on carbon balance, based on the partial flow sampling prediction control system based on carbon balance according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Check whether the equipment meets the linear correlation requirements; S2. Perform a transient experiment to obtain bench test data of the target engine required for carbon balance calculation, and obtain the time trajectory of the measured exhaust flow before time alignment based on the fuel consumption and intake flow time trajectory; S3. Calculate the exhaust flow rate by carbon balance according to the bench test data obtained from the transient experiment in step S2, and obtain the time trajectory of the calculated exhaust flow rate signal; S4. Based on the time trajectory of the calculated exhaust flow, time align the measured exhaust flow of the engine to obtain the predicted control value ; S5. Based on the predicted control value Adjusting the time trajectory of the measured exhaust flow before time alignment so that the exhaust flow of the partial flow dilution system coincides with the time trajectory of the corrected measured exhaust flow, thereby obtaining the corrected time trajectory of the measured exhaust flow, and the partial flow dilution system controls the sampling flow at a fixed sampling rate according to the corrected measured exhaust flow; S6. The partial flow dilution system uses the corrected measured exhaust flow time trajectory to conduct transient experiments, obtain the sampling flow time trajectory of the partial flow dilution system, and perform correlation analysis with the measured exhaust flow.

9. The partial flow sampling prediction control method based on carbon balance according to claim 8 is characterized in that: In the step S1, the inspection includes linearization inspection of the air flow meter and the fuel consumption meter, correlation inspection of the air flow and output analog quantity of the air flow meter, and correlation inspection of the fuel consumption and output analog quantity of the fuel consumption meter.

10. The partial flow sampling prediction control method based on carbon balance according to claim 8, characterized in that: In step S2, the engine bench test data includes time, intake air temperature, intake air humidity, atmospheric pressure, atmospheric humidity, fuel consumption, intake air flow, exhaust CO2 wet basis concentration, exhaust CO wet basis concentration, exhaust HC wet basis concentration, and background CO2 wet basis concentration.

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