A Design of an Engine Speed Measurement System Based on Cigarette Lighter Signal Analysis in Vehicles

This study proposes a non-contact engine speed measurement system using vehicle electrical characterization to address the limitations of traditional contact-type methods and optical methods. The developed system collects coupled AC signals through a cigarette lighter interface and extracts the AC f...

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Main Authors: Xuelian Li, Xuanze Wang, Jinping Yin, Da Liu, Zhongsheng Zhai
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/15/10/5387
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author Xuelian Li
Xuanze Wang
Jinping Yin
Da Liu
Zhongsheng Zhai
author_facet Xuelian Li
Xuanze Wang
Jinping Yin
Da Liu
Zhongsheng Zhai
author_sort Xuelian Li
collection DOAJ
description This study proposes a non-contact engine speed measurement system using vehicle electrical characterization to address the limitations of traditional contact-type methods and optical methods. The developed system collects coupled AC signals through a cigarette lighter interface and extracts the AC features for frequency analysis through a signal conditioning circuit. The system employs a hybrid algorithm combining Fast Fourier Transform (FFT) and phase difference compensation to estimate the coarse frequency in the 1-second FFT analysis via sinusoidal least squares fitting and phase difference calculation. The STM32F4-based hardware integrates dual-channel acquisition and adaptive signal conditioning. The experimental results demonstrate high measurement accuracy with errors below 0.4%, real-time performance (1 Hz update rate), and operational portability. Validation tests show a 33-fold improvement in accuracy over the pure FFT method under transient conditions. Key innovations include (1) phase-difference-enhanced frequency resolution (0.1% error), and (2) optimized computational efficiency for embedded deployments. The system’s portability and robustness make it suitable for on-site diagnostics, meeting the automotive industry’s need for non-intrusive, high-precision speed measurements.
format Article
id doaj-art-debb0e7d38cc443fa89739cf47ac57b1
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issn 2076-3417
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publishDate 2025-05-01
publisher MDPI AG
record_format Article
series Applied Sciences
spelling doaj-art-debb0e7d38cc443fa89739cf47ac57b12025-08-20T03:14:35ZengMDPI AGApplied Sciences2076-34172025-05-011510538710.3390/app15105387A Design of an Engine Speed Measurement System Based on Cigarette Lighter Signal Analysis in VehiclesXuelian Li0Xuanze Wang1Jinping Yin2Da Liu3Zhongsheng Zhai4School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, ChinaSchool of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, ChinaSchool of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, ChinaSchool of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, ChinaSchool of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, ChinaThis study proposes a non-contact engine speed measurement system using vehicle electrical characterization to address the limitations of traditional contact-type methods and optical methods. The developed system collects coupled AC signals through a cigarette lighter interface and extracts the AC features for frequency analysis through a signal conditioning circuit. The system employs a hybrid algorithm combining Fast Fourier Transform (FFT) and phase difference compensation to estimate the coarse frequency in the 1-second FFT analysis via sinusoidal least squares fitting and phase difference calculation. The STM32F4-based hardware integrates dual-channel acquisition and adaptive signal conditioning. The experimental results demonstrate high measurement accuracy with errors below 0.4%, real-time performance (1 Hz update rate), and operational portability. Validation tests show a 33-fold improvement in accuracy over the pure FFT method under transient conditions. Key innovations include (1) phase-difference-enhanced frequency resolution (0.1% error), and (2) optimized computational efficiency for embedded deployments. The system’s portability and robustness make it suitable for on-site diagnostics, meeting the automotive industry’s need for non-intrusive, high-precision speed measurements.https://www.mdpi.com/2076-3417/15/10/5387engine rotation speedspectral analysisphase-difference compensation algorithmsinusoidal least-squares fitting
spellingShingle Xuelian Li
Xuanze Wang
Jinping Yin
Da Liu
Zhongsheng Zhai
A Design of an Engine Speed Measurement System Based on Cigarette Lighter Signal Analysis in Vehicles
Applied Sciences
engine rotation speed
spectral analysis
phase-difference compensation algorithm
sinusoidal least-squares fitting
title A Design of an Engine Speed Measurement System Based on Cigarette Lighter Signal Analysis in Vehicles
title_full A Design of an Engine Speed Measurement System Based on Cigarette Lighter Signal Analysis in Vehicles
title_fullStr A Design of an Engine Speed Measurement System Based on Cigarette Lighter Signal Analysis in Vehicles
title_full_unstemmed A Design of an Engine Speed Measurement System Based on Cigarette Lighter Signal Analysis in Vehicles
title_short A Design of an Engine Speed Measurement System Based on Cigarette Lighter Signal Analysis in Vehicles
title_sort design of an engine speed measurement system based on cigarette lighter signal analysis in vehicles
topic engine rotation speed
spectral analysis
phase-difference compensation algorithm
sinusoidal least-squares fitting
url https://www.mdpi.com/2076-3417/15/10/5387
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