This document summarizes the process used to generate a full engine fuel consumption map for a 2020 Ford 7.3L Engine modeled using GT-Power® as documented in the “Engine Efficiency Technology Study” Final Report prepared for Argonne National Laboratory included in this package as 3b- Engine Efficiency Technology Study Final Report for Argonne National Lab.pdf (Thomas E. Reinhart, Engine Efficiency Technology Study: Final Report, SwRI Project No. 03.26457, November 30, 2021). The original GT-Power® model configuration as published in the report was re-run by SwRI using the EPA specified Tier 3 fuel shown in the Fuel Properties section below. The new data was then used to generate this ALPHA engine map which defines the complete operating boundaries of the engine needed for ALPHA modeling including idle, WOT, minimum torque, and maximum speed.
SUGGESTED CITATION:
GT Power Baseline 2020 Ford 7.3L Engine from Argonne Report Tier 3 Fuel - ALPHA Map Package. Version 2023-02. Ann Arbor MI: US EPA National Vehicle and Fuel Emissions Laboratory, National Center for Advanced Technology, 2023.
Engine Physical Characteristics
Set physical characteristics based on published information provided in 3b- Engine Efficiency Technology Study Final Report for Argonne National Lab.pdf. The bore and stroke of the engine are extracted from Ford's website ( Ford Motor Company, “F250 Super Duty 2020 7.3L V8 480 HP Crate Engine,” available at: https://accessories.ford.com/products/7-3l-v8-430hp-super-duty-crate-engine. Accessed January 25, 2023).
engine = [];
engine.name = 'GT Power Baseline 2020 Ford 7.3L Engine from Argonne Report Tier 3 Fuel';
engine.combustion_type = enum_engine_combustion_type.spark_ignition;
engine.displacement_L = 7.293;
engine.num_cylinders = 8;
engine.bore_mm = 107.2;
engine.stroke_mm = 101;
engine.compression_ratio = 10.5;
BSFC Data
Import the GT-Power® modeled Tier 3 fuel data provided in 3c- GT Power Baseline 2020 Ford 7.3L Engine Tier3 Fuel - Test Data File.xlsx. EPA reviews the quality of the test data we import to ensure consistency with expected data trends and emotor system physics. Any data points considered significant outliers are removed from the dataset before generating the final efficiency map. In addition, since many of the datasets are missing low-speed and torque datapoints, occasionally a few “grounding” datapoints are added to help the curve fitting algorithm extrapolate the gradients near the map’s boundaries.
Specifically for this dataset, a few data points are removed to make the map smooth.The BSFC datapoints that lie above 450 Nm and 3500 RPM in the original data set are removed. In addition, three more datapoints (2750 RPM & 9.30556 bar, 3000 RPM & 9.032967 bar, and 500 RPM & 1.0609231 bar) were excluded from the original dataset. An additional grounding point at 600 RPM and 1.0649364 bar was added.
test_data_tab = readmatrix('3c- GT Power Baseline 2020 Ford 7.3L Engine Tier3 Fuel - Test Data File.xlsx','sheet','Steady State','DataRange','A5:D153'); test_data.name = 'Core Test Data'; Idx = ((test_data_tab(:,2) / ( 4 * pi / (engine.displacement_L /1000)*1e-5 ) > 450) & test_data_tab(:,1) > 3500)... | (test_data_tab(:,1) == 2750 & test_data_tab(:,2) == 9.305556)... | (test_data_tab(:,1) == 3000 & test_data_tab(:,2) == 9.032967)... | (test_data_tab(:,1) == 500 & test_data_tab(:,2) == 1.0609231); test_data.speed_rpm = test_data_tab(~Idx,1); test_data.bmep_bar = test_data_tab(~Idx,2); test_data.bsfc_gpkWhr = test_data_tab(~Idx,3); est_data.name = 'Estimated Test Data'; est_data.speed_rpm = [600;600]; est_data.bmep_bar = [1.0649364;1.0649364]; est_data.bsfc_gpkWhr = [582.7180;582.7180];
Maximum Torque (WOT) Curve Data
Import the WOT data extracted from the maximum torque curve provided by Motor Authority (Viknesh Vijayenthiran, August 12, 2019, “2020 Ford Super Duty’s new 7.3-liter V-8 rated at 430 hp and 475 lb-ft” Motor Authority, available at: https://www.motorauthority.com/news/1124338_ford-super-duty-7-3-hp Accessed January 26, 2023).
load('Extracted_WOT_data');
WOT_data.speed_rpm = WOT_Extracted(:,1);
WOT_data.torque_Nm = WOT_Extracted(:,2) * unit_convert.ftlbs2Nm;
Minimum Torque (Zero Accelerator Pedal) Curve Data
Import the minimum torque data provided in 3c- GT Power Baseline 2020 Ford 7.3L Engine Tier3 Fuel - Test Data File.xlsx.
CT_data_tab = readmatrix('3c- GT Power Baseline 2020 Ford 7.3L Engine Tier3 Fuel - Test Data File.xlsx','sheet','Minimum Torque','DataRange','A5:B20'); CT_data.speed_rpm = CT_data_tab(:,1); CT_data.torque_Nm = CT_data_tab(:,2);
Fuel Properties
Load the Tier 3 fuel properties provided by EPA for SwRI to use when generating the GT-Power® modeled data provided in 3c- GT Power Baseline 2020 Ford 7.3L Engine Tier3 Fuel - Test Data File.xlsx.
engine.fuel = class_REVS_fuel('LMDV_TIER_3_REG');
disp(engine.fuel);
class_REVS_fuel with properties:
id: 'LMDV_TIER_3_REG'
description: 'avg Regular Tier 3 Cert fuel for 2027+ LMDV rule'
density_kgpL_15C: 0.7465
energy_density_MJpkg: 41.7870
carbon_weight_fraction: 0.8273
anti_knock_index: 87.7000
research_octane_number: 91.8000
motor_octane_number: 83.6000
alcohol_pct_vol: 9.6900
gCO2pgal: 8.5665e+03
energy_density_BTUplbm: 1.7965e+04
specific_gravity: 0.7472
Idle Speed
Idle speed data was not available in the report so the minimum speed data is assumed to be the idle speed.
engine.idle_target_speed_radps = 500 * unit_convert.rpm2radps ;
Engine Build for Simulation in ALPHA
Construct the ALPHA engine, combining all of the above inputs. Fit the fueling data onto a grid for simple interpolation and establish points that represent the maximum and minimum engine torque versus speed. Confirm the quality of fit between the input data and the resulting engine description by examining the resulting plots.
engine = REVS_build_engine(engine, {test_data, est_data}, 'WOT', WOT_data, 'plot_bsfc', 'plot_efficiency','torque_alpha',0.15);
Idle Fuel Verification
Confirm appropriate fuel consumption near idle conditions.
REVS_check_idle_fuel(engine)
Estimated idle fuel consumption @ 500 RPM & 38.9 Nm: 0.403 g/sec => Indicated Efficiency: 30.5%
Fuel Map Linearity
Confirm expected trends in the output fuel map, specifically in regions where test data is unavailable.
REVS_plot_engine_fuel_linearity(engine)
Model Calibration Options
Calibrate additional properties of the REVS engine model which can be set to match observed behaviors during the validation process.
Note: Default values are used unless properties are specified below, which are derived from the composite set of EPA testing and model validation activities.
Transient Fueling Adjustments
Use the default adjustment factors during the simulation, since there is no transient fueling data available. Additional explanation regarding transient fueling adjustments are provided in Dekraker, P., Stuhldreher, M., and Kim, Y., 2017, "Characterizing Factors Influencing SI Engine Transient Fuel Consumption for Vehicle Simulation in ALPHA," SAE Int. J. Engines 10(2):529-540.
File Description
Generate and write the created ALPHA engine definition into a file for later simulation.
engine.write_mscript('engine_GTP_base_2020_Ford_7L3_report_image_Tier3.m');
Engine Build: engine_GTP_base_2020_Ford_7L3_report_image_Tier3.m
% ALPHA ENGINE DEFINITION % Generated 28-Feb-2023 11:14:48 % Constructor engine = class_REVS_engine(); engine.name = 'GT Power Baseline 2020 Ford 7.3L Engine from Argonne Report Tier 3 Fuel'; engine.source_filename = mfilename;engine.matrix_vintage = enum_matrix_vintage.present; % Physical Description engine.displacement_L = 7.293; engine.num_cylinders = 8; engine.combustion_type = enum_engine_combustion_type.spark_ignition; engine.compression_ratio = 10.5; engine.bore_mm = 107.2; engine.stroke_mm = 101; % Maximum Torque Curve engine.full_throttle_speed_radps = [ 0.0000000000000000 ; 52.359877559829883 ; 104.71975511965977 ; 157.89633786087768 ; 213.97676129357288 ; 259.16778213322823 ; 302.72539261010741 ; 416.51964994299368 ; 451.91020839655323 ; 494.92334871760062 ; 560.25976438055966 ; 588.27275259958765 ; 616.28574081861564 ]; engine.full_throttle_torque_Nm = [ 0.0000000000000000 ; 360.06158081791830 ; 468.50919825431498 ; 555.10454272071195 ; 584.91834195043396 ; 599.11538881530601 ; 600.53509295946594 ; 653.06416798647399 ; 633.18830183332602 ; 628.92918804502801 ; 580.65922680631797 ; 497.70790869112977 ; 0.0000000000000000 ]; % Minimum Torque Curve engine.closed_throttle_speed_radps = [ 0.0000000000000000 ; 60.650191506802955 ; 104.71975511965977 ; 340.33920413889422 ; 471.23889803846896 ; 733.03828583761833 ]; engine.closed_throttle_torque_Nm = [ -58.167200000000008 ; -59.342418368830536 ; -73.094838994814410 ; -104.76327548228690 ; -115.17343884571348 ; -123.76102372227928 ]; % Fuel Map engine.fuel_map_speed_radps = [ 0.0000000000000000 ; 30.325095753401477 ; 60.650191506802955 ; 83.775804095727807 ; 104.71975511965977 ; 130.89969389957471 ; 157.07963267948966 ; 183.25957145940458 ; 209.43951023931953 ; 235.61944901923448 ; 261.79938779914943 ; 287.97932657906438 ; 314.15926535897933 ; 340.33920413889422 ; 366.51914291880917 ; 392.69908169872411 ; 415.21382904945096 ; 443.22636354395996 ; 471.23889803846896 ; 497.41883681838391 ; 523.59877559829886 ; 569.94225820845725 ; 616.28574081861564 ]; engine.fuel_map_torque_Nm = [ -166.10139000000004 ; -53.781170024028533 ; 58.539049951942971 ; 87.476373559214665 ; 116.41369716648636 ; 145.29274199485508 ; 174.17178682322378 ; 203.40355987891314 ; 232.63533293460253 ; 260.69239545085509 ; 288.74945796710762 ; 319.03076641480573 ; 349.31207486250383 ; 378.55062583152096 ; 407.78917680053814 ; 437.50503338313047 ; 467.22088996572279 ; 495.26759615132818 ; 523.31430233693357 ; 604.51583936136558 ; 685.71737638579771 ]; engine.fuel_map_gps = [ -0.099846698760828329 -0.35633784259234147 -0.47111770650844298 -0.52371747344677944 -0.57125707657331082 -0.63046019360519900 -0.68921453379783570 -0.74736456949549479 -0.80485826639957303 -0.86174319434220492 -0.91814498902862274 -0.97424221737225503 -1.0302362667565486 -1.0863146360046390 -1.1426335251307815 -1.1993080253132475 -1.2483665262553463 -1.3098663090449811 -1.3719537391464975 -1.4304581674112327 -1.4893238914773235 -1.5943786810111689 -1.6999086985352476 ; -0.014934570767375061 -0.0097081250912450911 0.032167476286703384 0.067281521127778937 0.10233508728638892 0.15182552337953326 0.20900808978494595 0.27406719407257507 0.34801276477072518 0.43168061602996938 0.52573512029729308 0.63061082472406271 0.74651735365399641 0.87301130387438020 1.0091121353316923 1.1534653818034200 1.2826083498948573 1.4489101631815102 1.6212972742221914 1.7871186666410086 1.9563876707223800 2.2640323714543755 2.5766748328756752 ; 0.20504858032064538 0.37249645618171345 0.52674243541614563 0.61905759662267934 0.74175471222437672 0.94778969237475219 1.1782534508180806 1.3638526976585814 1.5544568190129027 1.7614286834093393 1.9852758700313768 2.2259327857934252 2.5017920391120518 2.8041261377842739 3.1316255402762576 3.4847683786390728 3.7956627049802107 4.1763317461311855 4.5767584956245804 4.9875515428232466 5.4140714607361540 6.1531883337820830 6.8864712631800664 ; 0.19498380318264602 0.40034580398616215 0.61016948766848511 0.77907434188522451 0.94731124557729274 1.1800032161893670 1.4241669673595754 1.6588286963965817 1.8881761659109535 2.1266568606946699 2.3856249104250735 2.6724203655588248 2.9871821406128962 3.3240937574040528 3.6816825063485412 4.0635653601372885 4.4113911000936010 4.8666758904929939 5.3476799021645247 5.8183160623470442 6.2978591260716223 7.1394851255132528 7.9679993063475161 ; 0.19122985261254080 0.44075727025336087 0.69892549778100166 0.91516208348400296 1.1261442299780124 1.4005206001181842 1.6901319673589541 1.9571458920102252 2.2185728950308747 2.4893331926014897 2.7861235298946365 3.1212571391166311 3.4869431284490862 3.8639233360922880 4.2521980791984744 4.6666329384767646 5.0586293194188148 5.5779623190844516 6.1224319265338210 6.6565346478215126 7.1965847522512707 8.1267432529830952 9.0450941763257973 ; 0.20525052939932101 0.50772175979653089 0.81420503454983539 1.0604282501121616 1.2962059104263848 1.6061027724153383 1.9216033082788426 2.2286538736745261 2.5343554421978300 2.8543279724442687 3.2029441174527888 3.5855223145152957 3.9959841479137568 4.4234376092359780 4.8669048610838281 5.3355515794999153 5.7644511957189231 6.3306546946058706 6.9288747640244255 7.5076359251389650 8.0925982153707778 9.1121417949870445 10.120027489027105 ; 0.23404312025884791 0.59160532260061838 0.94033265682689482 1.1980155021707979 1.4588391624120698 1.8069605898687877 2.1649713558886052 2.5060535780775082 2.8536988891631707 3.2221557433461245 3.6239515671348661 4.0596832719019940 4.5234784319264456 5.0079209981889434 5.5041870205416901 6.0210567391173697 6.4929173057176559 7.1035416777990950 7.7459136940948810 8.3681842211417639 9.0021871665514226 10.102518037206263 11.202979999980535 ; 0.26844250680653758 0.66174598431906562 1.0529606974458035 1.3558003193544628 1.6423861027601681 2.0180436962231787 2.4061273932190681 2.7994129545827731 3.2021943735183065 3.6244600480290980 4.0759428653020642 4.5577293267478014 5.0670977707892018 5.5988521275662535 6.1479815304536949 6.7171942926009685 7.2268337125560453 7.8869269337982235 8.5757691100730504 9.2398019539988425 9.9142482002436143 11.115916449996718 12.319233260315755 ; 0.31348854461177017 0.73950327903277169 1.1697643661425461 1.5007915405082404 1.8233033705546577 2.2402152594482603 2.6705435421891730 3.1151430825424558 3.5682516525756145 4.0364188976737916 4.5398735437969524 5.0656567186045223 5.6187628988184137 6.1992695879828679 6.7966463489684648 7.4112751937946619 7.9665315089325164 8.6812447644939894 9.4198850465329791 10.132455910967055 10.855481015461677 12.157934352388040 13.467910459716993 ; 0.37481320970204957 0.83043616790502672 1.2883995013726974 1.6502457972733326 2.0016269132750741 2.4612433824712556 2.9386239030744492 3.4311703855612317 3.9291548584799325 4.4467359693514315 4.9941111688917426 5.5616872432397031 6.1535197628302187 6.7725272840376851 7.4183721281804074 8.0930043464083230 8.6949026680718493 9.4680402835530852 10.264677611688594 11.026419732617141 11.800126798958001 13.197862904545785 14.610979747806383 ; 0.45481166650737176 0.94190367756218074 1.4332058241930388 1.8190023364471977 2.1954380305467751 2.6878553461952404 3.2058449836660703 3.7439773635380513 4.2806784429929934 4.8391465423513269 5.4394989600259027 6.0537665647917409 6.6906746120897020 7.3543973198666137 8.0493243300403279 8.7827737924124172 9.4383156284007903 10.276172844545712 11.136671474096252 11.955053770688185 12.784598346699008 14.282376075666450 15.800734497179244 ; 0.56042247827107594 1.0631221258385488 1.5769978343780895 1.9951456438971478 2.3955597262870572 2.9255298275296426 3.4804015531512977 4.0555159189569014 4.6472007904025201 5.2581909458231735 5.8990336035918087 6.5695513329016135 7.2698739436958011 7.9987507696834417 8.7576091166411416 9.5474061247112036 10.252672375929052 11.164838211792702 12.106298918404088 12.995244561735626 13.892100549014456 15.507538157637454 17.143459822468177 ; 0.67539958902424824 1.2124081999387666 1.7392802696022671 2.1812218169666160 2.6037667418981236 3.1691294115137367 3.7553122098581406 4.3685740713731702 5.0091961921969874 5.6647202053987629 6.3593452042603422 7.0882873786728720 7.8628228951069268 8.6672156666313089 9.4973536201387816 10.330660755566740 11.074914110593745 12.066220585498652 13.110715622642845 14.075054333259336 15.047296454133434 16.792232791987189 18.546671651412112 ; 0.76352980501886447 1.3711137587968378 1.9721591710978466 2.4303250984971263 2.8594700370146358 3.4279512401055623 4.0319989093287383 4.6782229291889417 5.3548751940166506 6.0686100576595150 6.8254849694113666 7.6138779818269740 8.4564957822102542 9.3422724790203553 10.236951464043504 11.115596160116461 11.900566067049802 12.957308813757404 14.083151263850027 15.150583349680449 16.216019174329933 18.087231569954213 19.948380084436589 ; 0.81783742550198180 1.5004477360818327 2.1801672913837544 2.6959956359357347 3.1634909463116432 3.7506382645182090 4.3485457874706110 5.0201682008023578 5.7191690750841078 6.4680379972903390 7.2814732010335002 8.1197951169132239 9.0412466177699198 10.056147151207371 11.094372596793345 11.993073485696064 12.796291091841566 13.952189855651151 15.172509440921012 16.316537560290605 17.451148880419598 19.427549674275980 21.383289503065622 ; 0.83779927208793181 1.6066179125296460 2.3764271542055870 2.9650564161747601 3.4984105915875485 4.1601159624937605 4.8011575498864643 5.4413616720450637 6.1336503046366291 6.9109903536712309 7.7575888455077981 8.6657092718314921 9.6714816604973954 10.794249406923887 11.952671951630103 13.064781425404608 14.008930482477362 15.208421915061601 16.443117557448126 17.610415324463837 18.778100337958673 20.830338246420769 22.866869839137216 ; 0.82705081351117260 1.6894789021192731 2.5530151707178081 3.2151660396359030 3.8222463762899093 4.6077664655043442 5.3172066197986165 5.9021859067400344 6.5857896714612458 7.4074725442231344 8.3044771885059685 9.2644857659040518 10.350637175690308 11.636894639845394 13.012858137916149 14.265766367301477 15.300130138193786 16.558909593789569 17.811875767906642 18.988262116632345 20.170076283858709 22.271740024604828 24.373834897421421 ; 0.79241900580777180 1.7478788792354523 2.7054153178922831 3.4387615511502676 4.1033497668045396 4.9215626002504278 5.6690781695444636 6.3618879337670196 7.0876014052442873 7.9086362722574073 8.8481236312172928 9.9318566372851631 11.179436023522381 12.590239077328446 14.050274939274532 15.411995051311932 16.518400543720734 17.835843119069335 19.121401051559431 20.317724254869457 21.518093301296812 23.662036354779627 25.819770611567115 ; 0.73562746609749974 1.7826778291614154 2.8271823746777875 3.6157858049371314 4.3195101689159383 5.1769171950913613 6.0036134418335658 6.8056544061571245 7.6217951581638488 8.4391392465322745 9.4173140132627289 10.633532671099578 12.032296705653897 13.558130797558924 15.144593243809629 16.560265667071835 17.707189511452690 19.076463510269090 20.408715865462892 21.641705628834373 22.874492888271256 25.072387063110455 27.290325622592967 ; 0.30428653925475496 1.5515278076462213 2.7953017051544706 3.7400388565037734 4.5938141532311869 5.6615320689061921 6.7392899650068943 7.8413359920668730 8.9875446833931676 10.204176557060682 11.523172474311751 12.952343897039341 14.463701552687867 16.026491190593848 17.610826428406575 19.190631911551247 20.533760310057929 22.177722937023322 23.787712862766160 25.267136892820837 26.728851918830557 29.276320474753408 31.802910927602930 ; -0.18075111906533062 1.2686496122714794 2.7194201196697718 3.8279582147925204 4.9113808830168448 6.3168829431891549 7.7450178438629695 9.2003185387132618 10.685877405295706 12.203062187559869 13.751466480202859 15.329436425175491 16.934665037834897 18.564534434702203 20.216215708624052 21.886508232590558 23.333870291182336 25.145595399884915 26.965326148526302 28.669066901550845 30.373296716525431 33.387785057956535 36.397954205833386 ]; % Fuel Properties engine.fuel = class_REVS_fuel('LMDV_TIER_3_REG'); % Idle Speed engine.idle_target_speed_radps = class_REVS_dynamic_lookup; engine.idle_target_speed_radps.axis_1.signal = 'eng_runtime_sec'; engine.idle_target_speed_radps.axis_1.breakpoints = [ 0.0000000000000000 10.000000000000000 ]; engine.idle_target_speed_radps.table = [ 52.359877559829883 52.359877559829883 ]; % Calibration Adjustment Factors engine.variant = 'basic engine';