Estimation method of fuel emissions from civil aviation aircraft

Abstract

The present invention discloses a method for estimating fuel emissions from civil aircraft, comprising: preprocessing QAR data and flight data; searching and matching a database for fuel flow rates and emission coefficients for typical engine models of each aircraft type during each LTO sub-stage; establishing a relationship function between fuel consumption and flight time for each aircraft type during the CCD stage based on the QAR data preprocessed in step 1; calculating the emission coefficient for each aircraft type during the CCD stage based on the fuel flow rate and emission coefficient obtained in step 2 and the relationship function obtained in step 3; calculating the duration of a flight during each LTO sub-stage based on the QAR data preprocessed in step 1; calculating the duration of a flight during the CCD stage based on the flight time in the flight data and the LTO stage duration obtained in step 5; calculating the fuel consumption of the flight during each stage; and calculating the emissions of various emissions during each stage. The method achieves superior estimation accuracy to most fuel estimation methods based on great circle trajectories.

Description

Technical Field

[0001] The present invention belongs to the technical field of civil aviation data, and in particular relates to a method for estimating the amount of fuel emissions from civil aviation aircraft. Background Art

[0002] Frequent aircraft activities not only generate a large amount of greenhouse gas CO2, but also emit gaseous pollutants HC, CO, NO x and SO2, as well as solid pollutants such as nvPM. Currently, emissions are generally calculated based on the flight status, divided into the LTO (Taxi out, Take off, Climb out, Approach, Landing, and Taxi in) phase and the CCD (Climb, Cruise, and Descent) phase. Since the LTO phase is closest to the ground, it has a greater impact on human life and emits the most pollutants per unit mileage. Therefore, previous studies have mostly focused on this phase. However, since the CCD phase accounts for the vast majority of the entire flight, its total emissions account for a higher proportion, and research on this phase is relatively limited. During aircraft flight, the fuel flow rate and emission coefficient vary to varying degrees in different flight phases. Currently, most studies use the average duration of each LTO phase recommended by ICAO: 0.7 minutes for takeoff, 2.2 minutes for climb, 4 minutes for approach, and 26 minutes for taxi. The CCD phase duration is the total flight time minus the LTO phase duration. This time is combined with the corresponding fuel flow rate in the ICAO database to obtain fuel consumption, and the corresponding emissions are calculated accordingly. This rough calculation can introduce large errors in bottom-up calculations. Summary of the Invention

[0003] The purpose of the present invention is to address the deficiencies of the existing technology and provide a method for estimating the fuel emissions of civil aviation aircraft, which can more accurately estimate the fuel consumption and emissions of all stages of flight.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A method for estimating fuel emissions from civil aviation aircraft comprises the following steps:

[0006] Step 1: Preprocess QAR data and flight data;

[0007] Step 2: Search and match the fuel flow and emission coefficient of each LTO sub-stage for the typical engine model of each model in the database;

[0008] Step 3: Based on the QAR data pre-processed in step 1, a function is established to determine the relationship between the fuel consumption of each aircraft type in the CCD stage and the flight time;

[0009] Step 4, calculating the emission coefficient of each aircraft model in the CCD stage based on the relationship function between the fuel flow rate and the emission coefficient obtained in step 2 and step 3;

[0010] Step 5: Calculate the duration of the flight in each LTO sub-stage based on the QAR data pre-processed in step 1;

[0011] Step 6: Calculate the flight time in the CCD phase based on the flight data flight time and the LTO phase duration obtained in step 5;

[0012] Step 7: Calculate the fuel consumption of each LTO substage by using the duration of each LTO substage in step 5 and the fuel flow rate of each LTO substage in step 2, and calculate the fuel consumption of the CCD stage by using the CCD stage duration calculated in step 6 and the relationship function obtained in step 3;

[0013] In step 8, the emission amounts of various emissions in each LTO substage are calculated based on the fuel consumption of each LTO substage obtained in step 7 and the emission coefficient of each LTO substage obtained in step 2. The emission amounts of various emissions in the CCD stage are calculated based on the fuel consumption of the CCD stage calculated in step 7 and the emission coefficient of the CCD stage obtained in step 4.

[0014] Furthermore, in step 1, the preprocessing is to filter out flight information containing a complete operation process from the QAR data, eliminate data of terminated takeoff and data with errors in the decoding process, and interpolate information with a lower recording frequency.

[0015] Furthermore, in step 2, referring to the aircraft engine emissions database provided by ICAO, each aircraft model is matched with its typical engine, and the fuel flow rate and emission coefficient of the engine in each LTO sub-stage are used as the fuel flow rate and emission coefficient of the aircraft model.

[0016] Furthermore, the emission of NO x The emission coefficients of HC, CO and nvPM are directly obtained from the database, and the emission coefficients of CO2 and SO2 are calculated from the fuel consumption.

[0017] Furthermore, in step 3, the duration of the CCD phase is obtained from the pre-processed QAR data, and a linear regression analysis is performed on the fuel consumption recorded in this phase by aircraft type. The formula is as follows:

[0018] F(CCD)=a*T(CCD)+b;

[0019] Where F(CCD) is the fuel consumption during the CCD phase, T(CCD) is the duration of the CCD phase, a and b are the slope and intercept in the regression equation, respectively;

[0020] After performing the above regression analysis, the regression results of slope a and intercept b are obtained. The regression results are evaluated, and the slope a and intercept b that meet the accuracy requirements are selected and substituted into the above formula to obtain the relationship function between the fuel consumption of each aircraft model in the CCD stage and the flight time.

[0021] Furthermore, in step 4, the method for calculating the emission coefficient of each model in the CCD stage is:

[0022] Based on the fuel flow and emission coefficients of each LTO sub-stage obtained in step 2, a relationship function between the fuel flow and each emission component of each aircraft type is established. Subsequently, the fuel flow per unit time of the CCD stage obtained in step 3 is substituted into the relationship function in step 2 to obtain the emission coefficient of the CCD stage. The emission coefficient is then corrected according to the air pressure and temperature of the flight during the CCD stage. Finally, the emission coefficient of each aircraft type in the CCD stage is obtained.

[0023] Furthermore, in step 5, the QAR data and conditional mean estimation method are used to establish a corresponding relationship model between routes, aircraft types and LTO phase duration.

[0024] Furthermore, for a flight with route ij and aircraft type AC, the time for takeoff, climb, approach, and landing is calculated using the following formula:

[0025]

[0026] Where phase is the takeoff, vertical climb, approach and landing phases during flight, ∑T ij，AC (phase) is the total time of all flights with route ij and aircraft model AC in the QAR data in the phase stage, and n is the total number of flights that meet this condition.

[0027] The push-out time and taxi-in time of this flight can be obtained from the flight data, specifically:

[0028] T(taxi out)=t(take off)-t(departure)

[0029] T(taxi in)=t(arrival)-t(landing)

[0030] Where t(take off), t(departure), t(arrival), and t(landing) correspond to the take-off time, departure time, arrival time, and landing time of the flight in the flight data, respectively.

[0031] Furthermore, in step 6, the time of the CCD stage is the total flight time minus the time of the LTO stage.

[0032] Furthermore, in step 8, the amount of emissions generated EM during phase phase of a single flight is j (phase) is calculated as follows:

[0033] EM j (phase)=F(phase)*EF phase (j)

[0034] Where, F(phase) is the fuel consumption, EF phase (j) is the emission coefficient of each emission substance.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1) The impact of routes and airports is taken into account when calculating the duration of each phase. This method uses QAR data to analyze the factors that affect the duration of each LTO sub-phase and compares the impact of these factors on the duration. If the flight data does not contain this information, when calculating the duration of each LTO sub-phase for a particular flight, flights with the same route and aircraft type are selected from the QAR data, and the average of these flights in a particular sub-phase is used as the duration of the flight in that sub-phase.

[0037] 2) A fuel consumption estimation model is constructed based on the duration of the CCD phase. During actual flight, changes in flight trajectory are reflected in flight time. The estimation accuracy is superior to the fuel estimation method based on great-circle trajectories used in most technologies.

[0038] 3) Bottom-up calculations can obtain domestic civil aviation emission information with high temporal resolution, which can be used to assist in the formulation of relevant policies and the evaluation of their effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of a method for estimating fuel emissions from civil aviation aircraft according to an embodiment of the present invention;

[0040] Figure 2 This is a graph of emissions calculated according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0043] The present invention will be further described below with reference to specific examples, but they are not intended to limit the present invention.

[0044] like Figure 1 As shown, an embodiment of the present invention provides a method for estimating the amount of fuel emissions from civil aviation aircraft. The following specifically describes the technical solution of this embodiment by calculating the corresponding information based on QAR data and flight data. The above QAR data are all flights operated by the civil aviation industry at airports in China (excluding Hong Kong, Macao and Taiwan) from July 14, 2021 to July 21, 2021, provided by the China Civil Aviation Flight Quality Monitoring Base Station. The flight data is flight information data from January 2018 to November 2021. The process of the embodiment of the present invention includes the following steps:

[0045] Step 1: Preprocess the QAR data and flight data to make them useful for building fuel and emissions estimation models and calculating actual information.

[0046] QAR data preprocessing primarily involves data screening and interpolation. Data screening involves selecting flights from the QAR data that cover the entire operational process, eliminating flights that aborted takeoffs or encountered errors during decoding. Interpolation is also performed on information recorded less frequently. The QAR attribute fields used in this embodiment and their meanings are shown in Table 1. Attribute data related to total fuel volume is recorded every 4 seconds. To facilitate integrated calculations with other attributes, interpolation is performed at a sampling frequency of 1 second during data preprocessing.

[0047] The preprocessing of flight data is to filter it, that is, to filter out flights containing complete data information, including attribute information such as aircraft model, departure airport, arrival airport, departure time, arrival time, take-off time, landing time, total operating time and total flight time.

[0048] Table 1 QAR data attribute information related to emission inventory calculation

[0049]

[0050]

[0051] Step 2: Search and match the fuel flow and emission coefficient of each LTO sub-stage for the typical engine model of each model in the database;

[0052] Aircraft emissions are directly related to engine model and parameters, and emissions from different engine models can vary significantly. Statistics show that most major aircraft types in domestic civil aviation use the same engine model. For example, among the 286 B737-800 aircraft operated by domestic airlines, as recorded on the Civil Aviation Leisure Station (http: / / www.xmyzl.com), only 17 are powered by the CFM56-7B24E engine; the rest are powered by the CFM56-7B26E. According to records in the ICAO database, the difference in emission coefficients between these two engines is within 10%, and their fuel flow rates are essentially the same. Therefore, when calculating displacement, each aircraft type is matched to its representative engine model, using the corresponding engine's emission coefficient and fuel flow rate information.

[0053] The emission list estimated by this invention includes CO2, SO2, NO x , HC, CO and nvPM, among which NO x Emission coefficients for HC, CO, and nvPM are based on the ICAO Aircraft Engine Emissions Database, which lists fuel flow rates and emission coefficients for each LTO phase (taxi, takeoff, climb, and approach) measured at standard sea pressure. CO2 and SO2 are the primary products of carbon and sulfur in aircraft fuel, respectively. Therefore, their emission coefficients are primarily related to the fuel's content. The coefficients for CO2 and SO2 emissions relative to fuel consumption are 3150 g / kg and 1 g / kg, respectively.

[0054] Step 3: Based on the QAR data pre-processed in step 1, a function is established to determine the relationship between the fuel consumption of each aircraft type in the CCD stage and the flight time;

[0055] First, the duration of the CCD phase is obtained from the QAR data. A linear regression analysis is performed on the fuel consumption recorded during this phase by aircraft type. The formula is as follows:

[0056] F(CCD)=a*T(CCD)+b (1)

[0057] Where F(CCD) is the fuel consumption during the CCD phase, T(CCD) is the duration of the CCD phase, a and b are the slope and intercept of the linear regression equation, respectively. 2 The regression results are evaluated, where the obtained slope a can be considered as the fuel flow rate of this aircraft model during the CCD process.

[0058] The results of several aircraft models with the largest sample size in the QAR data are shown in Table 2. 2 are all above 0.9, and this model can make a relatively accurate estimate of the fuel consumption in the CCD stage.

[0059] Table 2 Fitting results of total fuel consumption in CCD stage

[0060]

[0061] Step 4, calculating the emission coefficient of each model in the CCD stage according to the fuel flow rate in the CCD stage;

[0062] When calculating the emission coefficient of the CCD stage, first, the relationship function between the fuel flow rate and each emission of each model is established based on the fuel flow rate and emission coefficient of each LTO sub-stage obtained in step 2. The fuel flow rate is used as the independent variable and the emission coefficient is used as the dependent variable. The fuel flow rate of the LTO stage of different models is provided by the ICAO database to calculate the NO x , HC, CO and nvPM emission coefficients were fitted respectively. The fitting equation results are shown in Table 3. R 2 Evaluate the fitting effect. In the table, y is the emission coefficient, and x is the fuel flow rate. Substitute the fuel flow rate of the CCD stage obtained in step 3 to obtain the emission coefficient of this stage. Here, the fuel flow rate of the CCD stage is a in Table 2, that is, the slope.

[0063] Table 2 Emission fitting equations and results for some models

[0064]

[0065] It is worth noting that the measured values ​​in the ICAO database are all calculated under standard sea pressure, and different environmental conditions during actual flight will lead to NO x , HC, CO emission coefficients change, so the calculated emission coefficients of the cruise phase need to be adjusted according to its environmental conditions, as shown in Equations (2) to (10).

[0066]

[0067]

[0068]

[0069] H=-19.0×(ω-0.0063); (5)

[0070]

[0071] P V =(0.014504)×10β ; (7)

[0072]

[0073] θ amb =(T amb +273.15) / 288.15; (9)

[0074]

[0075] Where REF(*) is the calculated discharge coefficient under standard sea pressure, EF(*) is the corrected discharge coefficient, is the relative humidity at cruising altitude, P amb is the environmental pressure, T amb is the ambient temperature. The ambient temperature, ambient pressure, and relative humidity in the above formula are all referenced from the China Statistical Yearbook and are calculated accordingly to obtain the corresponding information at cruising altitude, i.e., the CCD stage.

[0076] Step 5: Calculate the flight time in each LTO sub-stage based on the QAR data;

[0077] The duration of each LTO phase is closely related to the departure airport, arrival airport, and aircraft type. For example, takeoff and landing times are largely determined by the flight procedures at the departure and arrival airports, while vertical climb time is significantly influenced by the aircraft type and departure airport. Therefore, this embodiment uses QAR data and conditional mean estimation to establish a correlation model between routes, aircraft types, and LTO phase durations. Considering the differences in flight volume across different routes and to mitigate sample size constraints, the variance analysis results show that departure airport, arrival airport, and aircraft type have varying degrees of influence on the estimated duration of different LTO phases. For example, the influence of the three factors on takeoff phase duration decreases in descending order. For routes with smaller sample sizes, relatively minor factors are ignored when it is difficult to cover the entire sample space.

[0078] Table 3 ANOVA results of LTO duration on airport and aircraft type variables

[0079]

[0080] For a flight with route ij and aircraft type AC, the time for takeoff, climb, approach and landing can be calculated using the following formula:

[0081]

[0082] Where phase is the takeoff, vertical climb, approach and landing phases during flight, ∑T ij，AC(phase) is the sum of the time spent in the phase phase for all flights with route ij and aircraft type AC in the QAR data, and n is the total number of flights that meet this condition;

[0083] The push-out time and taxi-in time of this flight can be obtained from the flight data, as shown in Equations (12) and (13):

[0084] T(taxi out)=t(take off)-t(departure) (12)

[0085] T(taxi in)=t(arrival)-t(landing) (13)

[0086] Where t(take off), t(departure), t(arrival), and t(landing) are the take-off time, departure time, arrival time, and landing time of the flight in the flight data, respectively.

[0087] Step 6: Calculate the flight time in the CCD phase based on the flight data flight time and the LTO phase duration obtained in step 5;

[0088] The time of the CCD stage is the total flight time minus the time of the LTO stage, as shown in formula (14).

[0089] T(CCD)=T(airborne)-∑ LTo T(phase) (14)

[0090] Where T(airborne) is the total flight time of the flight in the flight data, ∑ LTO T(phase) is the duration of each sub-phase calculated by equations (11), (12), and (13).

[0091] Step 7: Calculate the fuel consumption of the flight at each stage.

[0092] When calculating the fuel consumption of each flight phase in this step, the fuel consumption of each LTO sub-phase is calculated by combining the duration of each LTO sub-phase in step 5 and the fuel flow rate of each LTO sub-phase in step 2. The fuel consumption of the CCD phase is calculated by substituting the CCD phase duration calculated in step 6 into the relationship function of fuel consumption of each aircraft type in the CCD phase with flight time obtained in step 3.

[0093] The fuel flow rate in each flight phase is relatively fixed. This embodiment uses the fuel flow rate of each LTO sub-phase recorded in the ICAO database to calculate the total fuel consumption in each phase. For a flight with route ij and aircraft model AC, the fuel consumption is calculated as shown in formula (15):

[0094] F(phase)=T(phase)*FF(phase) (15)

[0095] FF(phase) is the fuel flow rate of each phase in the LTO phase, that is, the fuel flow rate of the pushback, takeoff, vertical climb, approach, landing, and taxi-in phases. T(phase) is the duration of each phase in the LTO phase.

[0096] The fuel consumption in the CCD stage is calculated by substituting the CCD stage duration calculated by formula (14) into formula (1) obtained in step 3 according to the aircraft model.

[0097] Step 8: Calculate the emission of various emissions at each stage of the flight;

[0098] In this step, the amount of emissions generated during phase j of a single flight, EM j (phase) is calculated as shown in formula (16):

[0099] EM j (phase)=F(phase)*EF phase (j) (16)

[0100] Where, F(phase) represents fuel consumption, EF phase (j) Indicates the emission coefficient of each emission substance;

[0101] Among them, the fuel consumption F(phase) of each LTO sub-stage is obtained by formula (15) in step 7, the fuel consumption F(phase) of the CCD stage is obtained in step 7, and the emission coefficient EF of each emission substance in each LTO sub-stage is phas e(j) is obtained from step 2, and the emission coefficient EF of each emission in the CCD stage phas e(j) is obtained from step 4, thus obtaining the final emission of each emission substance in a single flight, see Figure 2 .

[0102] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the present invention specification should be included in the protection scope of the present invention.

Claims

1. A method for estimating fuel emissions from civil aviation aircraft, characterized in that: The steps include: Step 1: Preprocess QAR data and flight data; Step 2: Search and match the fuel flow and emission coefficient of each LTO sub-stage for the typical engine model of each model in the database; Step 3: Based on the QAR data pre-processed in step 1, a function is established to determine the relationship between the fuel consumption of each aircraft type in the CCD stage and the flight time; Step 4, calculating the emission coefficient of each aircraft model in the CCD stage based on the relationship function between the fuel flow rate and the emission coefficient obtained in step 2 and step 3; Step 5: Calculate the duration of the flight in each LTO sub-stage based on the QAR data pre-processed in step 1; Step 6: Calculate the flight time in the CCD phase based on the flight data flight time and the LTO phase duration obtained in step 5; Step 7: Calculate the fuel consumption of each LTO substage by using the duration of each LTO substage in step 5 and the fuel flow rate of each LTO substage in step 2, and calculate the fuel consumption of the CCD stage by using the CCD stage duration calculated in step 6 and the relationship function obtained in step 3; Step 8: Calculate the emission of various emissions in each LTO sub-stage by using the fuel consumption of each LTO sub-stage obtained in Step 7 and the emission coefficient of each LTO sub-stage obtained in Step 2. Calculate the emission of various emissions in the CCD stage by using the fuel consumption of the CCD stage calculated in Step 7 and the emission coefficient of the CCD stage obtained in Step 4. In step 5, the QAR data and conditional mean estimation method are used to establish the corresponding relationship model between routes, aircraft types and the duration of each LTO sub-stage; For a route , the aircraft model is For flights, the time for takeoff, climb, approach and landing is calculated using the following formula: Where, For the takeoff, vertical climb, approach and landing phases of flight, The route in the QAR data is , the aircraft model is All flights in The total time of the stages, The total number of flights that meet this condition; The push-out time and taxi-in time of this flight can be obtained from the flight data, specifically: Where, 、 、 and They correspond to the take-off time, departure time, arrival time and landing time of the flight in the flight data respectively; In step 6, the CCD stage time is the total flight time minus the LTO stage time, and the formula is: Where, is the total flight time of the flight in the flight data, is the duration of each sub-stage.

2. The method for estimating fuel emissions from civil aviation aircraft according to claim 1, characterized in that: In step 1, preprocessing involves filtering out flight information containing complete operation processes from the QAR data, eliminating data on terminated takeoffs and data with errors in the decoding process, and interpolating information with lower recording frequency.

3. The method for estimating fuel emissions from civil aviation aircraft according to claim 1, characterized in that: In step 2, refer to the aircraft engine emissions database provided by ICAO, match each aircraft model with its typical engine, and use the fuel flow rate and emission coefficient of the engine in each LTO sub-stage as the fuel flow rate and emission coefficient of the aircraft model.

4. The method for estimating fuel emissions from civil aviation aircraft according to claim 3, characterized in that: emissions and The emission coefficient is obtained directly from the database. and The emission coefficient is calculated from the fuel consumption.

5. The method for estimating fuel emissions from civil aviation aircraft according to claim 1, characterized in that: In step 3, the duration of the CCD phase is obtained from the pre-processed QAR data. The fuel consumption recorded in this phase is subjected to linear regression analysis by aircraft type. The formula is as follows: Where, is the fuel consumption in the CCD stage, is the duration of the CCD phase, and are the slope and intercept in the regression equation respectively; After performing the above regression analysis, the regression results of slope a and intercept b are obtained. The regression results are evaluated, and the slope a and intercept b that meet the accuracy requirements are selected and substituted into the above formula to obtain the relationship function between the fuel consumption of each aircraft model in the CCD stage and the flight time.

6. The method for estimating fuel emissions from civil aviation aircraft according to claim 1, characterized in that: In step 4, the method for calculating the emission coefficient of each model in the CCD stage is: Based on the fuel flow and emission coefficients of each LTO sub-stage obtained in step 2, a relationship function between the fuel flow and each emission component of each aircraft type is established. Subsequently, the fuel flow per unit time of the CCD stage obtained in step 3 is substituted into the relationship function in step 2 to obtain the emission coefficient of the CCD stage. The emission coefficient is then corrected according to the air pressure and temperature of the flight during the CCD stage. Finally, the emission coefficient of each aircraft type in the CCD stage is obtained.

7. The fuel emission measurement of civil aviation aircraft according to claim 1, characterized in that: In step 8, during a single flight Emissions The amount of generation Calculation is as follows: Where, is the fuel consumption, is the emission coefficient of each emission substance.

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