A Thermodynamically Consistent Workflow for High-Resolution In-Cylinder Pressure Reconstruction from Encoder-Limited Biodiesel Engine Data

A Thermodynamically Consistent Workflow for High-Resolution In-Cylinder Pressure Reconstruction from Encoder-Limited Biodiesel Engine Data | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article A Thermodynamically Consistent Workflow for High-Resolution In-Cylinder Pressure Reconstruction from Encoder-Limited Biodiesel Engine Data Vu Hoang Nguyen, Quan Quoc Nguyen, Minh Quang Duong This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9500964/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In-cylinder pressure analysis is a fundamental tool for understanding combustion thermodynamics, and the CFR-F5 research engine provides an excellent platform for investigating biodiesel combustion. This study presents a validated preprocessing workflow to reconstruct high-resolution pressure traces at 0.1 degrees from hardware-limited 0.5-degree data, which is essential for stable derivative- and integral-based combustion diagnostics. The methodology integrates Piecewise Cubic Hermite Interpolating Polynomials to ensure monotonicity and prevent artificial oscillations, resampling followed by an optimized Savitzky-Golay smoothing. A motoring-based pegging method using least-squares optimization is further employed to ensure thermodynamic consistency. The workflow was rigorously validated using a curated dataset of 330 firing pressure-trace cases and 2 motoring records. The adopted suite polynomial order and the window ( n,m ) = ( 7 , 11) are presented as a reproducible engineering default near a trade-off knee rather than as a unique discrete optimum. This extensive dataset covers a comprehensive matrix of operating conditions, encompassing various biodiesel-diesel blends, compression ratios, injection timings, and fuel flow rates. Results demonstrate high fidelity, indicated mean effective pressure evaluation across all conditions shows a near-zero relative change. Unlike IMEP, the \(\:{0.1}^{\circ\:}\) CA grid does change derivative- and MFB-based diagnostics., the gross-HRR trace becomes continuous and oscillation-free on the uniform grid, and MFB redefines late-burn phasing. The CA5 and CA10 almost const, whereas CA50 and CA90 can change significantly. This standardized workflow ensures reliable calculation of pressure derivatives and heat release parameters, establishing a robust platform for advanced combustion analysis. In-cylinder pressure Savitzky-Golay polynomial order motoring-based pegging Biodiesel combustion Heat Release Rate Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9500964","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":633757768,"identity":"b801111e-002c-40cc-8088-fac4f37a6cf4","order_by":0,"name":"Vu Hoang Nguyen","email":"","orcid":"","institution":"Le Quy Don Technical University","correspondingAuthor":false,"prefix":"","firstName":"Vu","middleName":"Hoang","lastName":"Nguyen","suffix":""},{"id":633757769,"identity":"7f5162be-c520-4682-8084-0ab56cb65ae5","order_by":1,"name":"Quan Quoc Nguyen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBUlEQVRIiWNgGAWjYFADCcYGBoYKCwaGAyAeG0H1BlAtZyQYGI4RrwVIMbYRocWcf/E2iZ87/iRun93c9uDjPAnZvvs9Bgwfyg4zGNxuwKrFcsazMsneMwaJc+4cbDecuU3CeOYxHgPGGeeAWu4cwO6iG2fMJHjbDBJnSCS2SfNuk0jcANTCzNt2mEFyRgJOLZJ/YVr+zoFq+YtPy/keM2m4LYwNUC2MQC38ErhsYSu2lm0zNp4hc7BNsucYyC9pBQd7zqXz4NRy/vDGm2/b5GRnSLc/k/hRYyPbd/jwxgc/yqzl2HBoYZBIMEDhgyIUnAB4sKsHAv4DWLSMglEwCkbBKEAGAB86YtBFpBbOAAAAAElFTkSuQmCC","orcid":"","institution":"Le Quy Don Technical University","correspondingAuthor":true,"prefix":"","firstName":"Quan","middleName":"Quoc","lastName":"Nguyen","suffix":""},{"id":633757773,"identity":"cd999fec-1967-48a6-9878-c8be860a4e32","order_by":2,"name":"Minh Quang Duong","email":"","orcid":"","institution":"University of Transport Technology","correspondingAuthor":false,"prefix":"","firstName":"Minh","middleName":"Quang","lastName":"Duong","suffix":""}],"badges":[],"createdAt":"2026-04-23 01:08:58","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9500964/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9500964/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108948571,"identity":"bb4fc8b1-4862-4220-b5c4-c7cae0a98700","added_by":"auto","created_at":"2026-05-11 06:44:42","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1069538,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript23.4.2026.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9500964/v1_covered_ea0dcb88-59a5-43ba-bc61-1c3356e1b1d8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A Thermodynamically Consistent Workflow for High-Resolution In-Cylinder Pressure Reconstruction from Encoder-Limited Biodiesel Engine Data","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"In-cylinder pressure, Savitzky-Golay, polynomial order, motoring-based pegging, Biodiesel combustion, Heat Release Rate","lastPublishedDoi":"10.21203/rs.3.rs-9500964/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9500964/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn-cylinder pressure analysis is a fundamental tool for understanding combustion thermodynamics, and the CFR-F5 research engine provides an excellent platform for investigating biodiesel combustion. This study presents a validated preprocessing workflow to reconstruct high-resolution pressure traces at 0.1 degrees from hardware-limited 0.5-degree data, which is essential for stable derivative- and integral-based combustion diagnostics. The methodology integrates Piecewise Cubic Hermite Interpolating Polynomials to ensure monotonicity and prevent artificial oscillations, resampling followed by an optimized Savitzky-Golay smoothing. A motoring-based pegging method using least-squares optimization is further employed to ensure thermodynamic consistency. The workflow was rigorously validated using a curated dataset of 330 firing pressure-trace cases and 2 motoring records. The adopted suite polynomial order and the window (\u003cem\u003en,m\u003c/em\u003e) = (\u003cb\u003e7\u003c/b\u003e, 11) are presented as a reproducible engineering default near a trade-off knee rather than as a unique discrete optimum. This extensive dataset covers a comprehensive matrix of operating conditions, encompassing various biodiesel-diesel blends, compression ratios, injection timings, and fuel flow rates. Results demonstrate high fidelity, indicated mean effective pressure evaluation across all conditions shows a near-zero relative change. Unlike IMEP, the \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{0.1}^{\\circ\\:}\\)\u003c/span\u003e\u003c/span\u003eCA grid does change derivative- and MFB-based diagnostics., the gross-HRR trace becomes continuous and oscillation-free on the uniform grid, and MFB redefines late-burn phasing. The CA5 and CA10 almost const, whereas CA50 and CA90 can change significantly. This standardized workflow ensures reliable calculation of pressure derivatives and heat release parameters, establishing a robust platform for advanced combustion analysis.\u003c/p\u003e","manuscriptTitle":"A Thermodynamically Consistent Workflow for High-Resolution In-Cylinder Pressure Reconstruction from Encoder-Limited Biodiesel Engine Data","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-11 06:41:37","doi":"10.21203/rs.3.rs-9500964/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"19628da3-d66f-40df-9e7e-9b6e236c763c","owner":[],"postedDate":"May 11th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"221698291404490508750052696073898733973","date":"2026-05-04T00:13:59+00:00","index":12,"fulltext":""},{"type":"reviewersInvited","content":"6","date":"2026-05-03T18:14:01+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-11T06:41:37+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-11 06:41:37","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9500964","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9500964","identity":"rs-9500964","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}