{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:08:45Z","timestamp":1787029725143,"version":"build-2736575974"},"reference-count":40,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T00:00:00Z","timestamp":1777334400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003052","name":"Ministry of Trade, Industry and Energy of Korea","doi-asserted-by":"publisher","award":["KM260157"],"award-info":[{"award-number":["KM260157"]}],"id":[{"id":"10.13039\/501100003052","id-type":"DOI","asserted-by":"publisher"}]},{"award":["KM260157"],"award-info":[{"award-number":["KM260157"]}],"id":[{"id":"https:\/\/ror.org\/008nkqk13","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003695","name":"Korea Institute of Industrial Technology","doi-asserted-by":"crossref","award":["EH260002"],"award-info":[{"award-number":["EH260002"]}],"id":[{"id":"10.13039\/501100003695","id-type":"DOI","asserted-by":"crossref"}]},{"award":["EH260002"],"award-info":[{"award-number":["EH260002"]}],"id":[{"id":"https:\/\/ror.org\/04qfph657","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Continuous monitoring of vehicle engine vibration is a key enabler of real-time diagnostics, yet conventional accelerometers require an external power supply and fit poorly into the distributed sensor networks envisioned for next-generation vehicles. Triboelectric nanogenerators offer an attractive self-powered alternative, but their direct application to the vibration of a running passenger vehicle engine, and the explicit link between sensor design parameters and individual engine operating states, remains largely unexplored. Here, we address this gap by co-tuning the air gap and the substrate rigidity of a contact-separation triboelectric vibration sensor to the vibration spectrum of an automotive engine. A systematic 3 \u00d7 3 design sweep across three gap distances and three substrate types identifies a single configuration that simultaneously resolves the low-frequency idle band and the higher-frequency acceleration band of a four-cylinder gasoline engine. A frequency-amplitude response map confirms that the real engine operating points fall within the sensitive region of the optimized device, and an on-vehicle test demonstrates clean discrimination of all seven operating states, from ready to shut-down, without any external power. The results establish design guidelines for source-matched triboelectric vibration sensors and outline a practical path toward self-powered, wireless-ready engine health monitoring in future vehicles.<\/jats:p>","DOI":"10.3390\/s26092726","type":"journal-article","created":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T13:26:41Z","timestamp":1777382801000},"page":"2726","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Self-Powered Triboelectric Vibration Sensor with Gap-and-Substrate-Tuned Design for Real-Time Monitoring of Automotive Engine Operating States"],"prefix":"10.3390","volume":"26","author":[{"given":"Min Seok","family":"Jang","sequence":"first","affiliation":[{"name":"Korea Additive Manufacturing Technology Innovation Center, Korea Institute of Industrial Technology, Siheung 15014, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8428-2118","authenticated-orcid":false,"given":"Jiyong","family":"Park","sequence":"additional","affiliation":[{"name":"Advanced Packaging Integration Center (APIC), Korea Institute of Industrial Technology, 156, Gaetbeol-Ro, Yeonsu-Gu, Incheon 21999, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7345-9486","authenticated-orcid":false,"given":"Young Won","family":"Kim","sequence":"additional","affiliation":[{"name":"Korea Additive Manufacturing Technology Innovation Center, Korea Institute of Industrial Technology, Siheung 15014, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,28]]},"reference":[{"key":"ref_1","unstructured":"Heywood, J.B. (1988). Internal Combustion Engine Fundamentals, McGraw-Hill."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Pulkrabek, W.W. (2004). Engineering Fundamentals of the Internal Combustion Engine, Pearson. [2nd ed.].","DOI":"10.1115\/1.1669459"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1109\/7361.983469","article-title":"Overview of automotive sensors","volume":"1","author":"Fleming","year":"2001","journal-title":"IEEE Sens. J."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"628","DOI":"10.1016\/j.apenergy.2011.11.079","article-title":"The engine knock analysis\u2013An overview","volume":"92","author":"Zhen","year":"2012","journal-title":"Appl. Energy"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"104103","DOI":"10.1016\/j.nanoen.2019.104103","article-title":"Embedded self-powered sensing systems for smart vehicles and intelligent transportation","volume":"66","author":"Askari","year":"2019","journal-title":"Nano Energy"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1802906","DOI":"10.1002\/aenm.201802906","article-title":"Triboelectric nanogenerator: A foundation of the energy for the new era","volume":"9","author":"Wu","year":"2019","journal-title":"Adv. Energy Mater."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"328","DOI":"10.1016\/j.nanoen.2012.01.004","article-title":"Flexible triboelectric generator","volume":"1","author":"Fan","year":"2012","journal-title":"Nano Energy"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"9533","DOI":"10.1021\/nn404614z","article-title":"Triboelectric nanogenerators as new energy technology for self-powered systems and as active mechanical and chemical sensors","volume":"7","author":"Wang","year":"2013","journal-title":"ACS Nano"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"453","DOI":"10.1016\/j.nanoen.2018.10.044","article-title":"Rotation sensing and gesture control of a robot joint via triboelectric quantization sensor","volume":"54","author":"Pu","year":"2018","journal-title":"Nano Energy"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3688","DOI":"10.1002\/adfm.201500428","article-title":"Stretchable-rubber-based triboelectric nanogenerator and its application as self-powered body motion sensors","volume":"25","author":"Yi","year":"2015","journal-title":"Adv. Funct. Mater."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3954","DOI":"10.1021\/acsnano.8b01532","article-title":"Self-powered wind sensor system for detecting wind speed and direction based on a triboelectric nanogenerator","volume":"12","author":"Wang","year":"2018","journal-title":"ACS Nano"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"480","DOI":"10.1016\/j.joule.2017.09.004","article-title":"Reviving vibration energy harvesting and self-powered sensing by a triboelectric nanogenerator","volume":"1","author":"Chen","year":"2017","journal-title":"Joule"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.nantod.2018.08.001","article-title":"Piezoelectric and triboelectric nanogenerators: Trends and impacts","volume":"22","author":"Askari","year":"2018","journal-title":"Nano Today"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"107292","DOI":"10.1016\/j.nanoen.2022.107292","article-title":"Machine condition monitoring enabled by broad range vibration frequency detecting triboelectric nano-generator (TENG)-based vibration sensors","volume":"98","author":"Mehamud","year":"2022","journal-title":"Nano Energy"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"107219","DOI":"10.1016\/j.nanoen.2022.107219","article-title":"Triboelectric nanogenerator as next-generation self-powered sensor for cooperative vehicle infrastructure system","volume":"97","author":"Pang","year":"2022","journal-title":"Nano Energy"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Du, T., Zuo, X., Dong, F., Li, S., Mtui, A.E., Zou, Y., Zhang, P., Zhao, J., Zhang, Y., and Sun, P. (2021). A self-powered and highly accurate vibration sensor based on bouncing-ball triboelectric nanogenerator for intelligent ship machinery monitoring. Micromachines, 12.","DOI":"10.3390\/mi12020218"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"880","DOI":"10.1007\/s12274-013-0364-0","article-title":"Harvesting vibration energy by a triple-cantilever based triboelectric nanogenerator","volume":"6","author":"Yang","year":"2013","journal-title":"Nano Res."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"847","DOI":"10.1021\/nl4001053","article-title":"Toward large-scale energy harvesting by a nanoparticle-enhanced triboelectric nanogenerator","volume":"13","author":"Zhu","year":"2013","journal-title":"Nano Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3918","DOI":"10.1002\/adma.201400172","article-title":"Transparent flexible graphene triboelectric nanogenerators","volume":"26","author":"Kim","year":"2014","journal-title":"Adv. Mater."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"5037","DOI":"10.1002\/adma.201401184","article-title":"Hydrophobic sponge structure-based triboelectric nanogenerator","volume":"26","author":"Lee","year":"2014","journal-title":"Adv. Mater."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"11088","DOI":"10.1039\/c1jm11445j","article-title":"Electrical power generator from randomly oriented electrospun poly(vinylidene fluoride) nanofibre membranes","volume":"21","author":"Fang","year":"2011","journal-title":"J. Mater. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2159","DOI":"10.1002\/marc.200700544","article-title":"Polymorphism control of poly(vinylidene fluoride) through electrospinning","volume":"28","author":"Zheng","year":"2007","journal-title":"Macromol. Rapid Commun."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"272","DOI":"10.1007\/s11664-005-0213-3","article-title":"Characterization study of time- and temperature-dependent mechanical behavior of polyimide materials in electronic packaging applications","volume":"34","author":"Kuo","year":"2005","journal-title":"J. Electron. Mater."},{"key":"ref_24","unstructured":"Callister, W.D., and Rethwisch, D.G. (2018). Materials Science and Engineering: An Introduction, Wiley. [10th ed.]."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"3576","DOI":"10.1039\/c3ee42571a","article-title":"Theoretical study of contact-mode triboelectric nanogenerators as an effective power source","volume":"6","author":"Niu","year":"2013","journal-title":"Energy Environ. Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"8376","DOI":"10.1038\/ncomms9376","article-title":"Standards and figure-of-merits for quantifying the performance of triboelectric nanogenerators","volume":"6","author":"Zi","year":"2015","journal-title":"Nat. Commun."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"700","DOI":"10.1016\/j.nanoen.2018.11.062","article-title":"A general optimization approach for contact-separation triboelectric nanogenerator","volume":"56","author":"Zhang","year":"2019","journal-title":"Nano Energy"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1426","DOI":"10.1038\/s41467-019-09464-8","article-title":"Integrated charge excitation triboelectric nanogenerator","volume":"10","author":"Liu","year":"2019","journal-title":"Nat. Commun."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Randall, R.B. (2011). Vibration-Based Condition Monitoring: Industrial, Aerospace and Automotive Applications, Wiley.","DOI":"10.1002\/9780470977668"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1016\/j.nanoen.2018.04.022","article-title":"On-vehicle triboelectric nanogenerator enabled self-powered sensor for tire pressure monitoring","volume":"49","author":"Qian","year":"2018","journal-title":"Nano Energy"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"107094","DOI":"10.1016\/j.nanoen.2022.107094","article-title":"Magnetic-assisted self-powered acceleration sensor for real-time monitoring vehicle operation and collision based on triboelectric nanogenerator","volume":"96","author":"Lu","year":"2022","journal-title":"Nano Energy"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"101100","DOI":"10.1016\/j.eml.2020.101100","article-title":"Triboelectric mechanical sensors\u2014Progress and prospects","volume":"42","author":"Gao","year":"2021","journal-title":"Extrem. Mech. Lett."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"016101","DOI":"10.1063\/5.0242816","article-title":"Sustainable polymer materials for triboelectric and hybrid energy harvesting","volume":"1","author":"Pace","year":"2025","journal-title":"APL Electron. Devices"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"288","DOI":"10.1039\/C5GC01008J","article-title":"CHEM21 selection guide of classical- and less classical-solvents","volume":"18","author":"Prat","year":"2016","journal-title":"Green Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"2213407","DOI":"10.1002\/adfm.202213407","article-title":"Boosting the durability of triboelectric nanogenerators: A critical review and prospect","volume":"33","author":"Zhao","year":"2023","journal-title":"Adv. Funct. Mater."},{"key":"ref_36","first-page":"68","article-title":"Spontaneous ordering of identical materials into a triboelectric series","volume":"646","author":"Sobarzo","year":"2025","journal-title":"Nature"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"104272","DOI":"10.1016\/j.nanoen.2019.104272","article-title":"On the first principle theory of nanogenerators from Maxwell\u2019s equations","volume":"68","author":"Wang","year":"2020","journal-title":"Nano Energy"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1016\/j.mattod.2019.05.016","article-title":"On the origin of contact-electrification","volume":"30","author":"Wang","year":"2019","journal-title":"Mater. Today"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"eadp8681","DOI":"10.1126\/sciadv.adp8681","article-title":"Multi-receptor skin with highly sensitive tele-perception somatosensory","volume":"10","author":"Du","year":"2024","journal-title":"Sci. Adv."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"eady5008","DOI":"10.1126\/sciadv.ady5008","article-title":"Hypersensitive pressure sensors inspired by scorpion mechanosensory mechanisms for near-body flow detection in intelligent robots","volume":"11","author":"Wang","year":"2025","journal-title":"Sci. Adv."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/9\/2726\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T04:15:37Z","timestamp":1777522537000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/9\/2726"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,28]]},"references-count":40,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["s26092726"],"URL":"https:\/\/doi.org\/10.3390\/s26092726","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,28]]}}}