Air–Fuel Ratio Evaluation in Open-Loop ECU Mapping for a KZR Engine: A Trade-Off Analysis of Power, Torque, and Fuel-Efficiency Potential
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Jun 30, 2026
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Abstract
An open-loop ECU operates without oxygen-sensor feedback, making Air–Fuel Ratio (AFR) control dependent on the preset fuel map. This study evaluated how three AFR settings in open-loop ECU mapping relate to the performance characteristics of a Honda KZR engine. A dynamometer-based experiment was conducted on a Honda Vario 125 KZR engine using Pertalite RON 90 and AFR targets of 11.7, 13.1, and 14.1. The evaluated parameters were engine power, torque response, and fuel-efficiency potential inferred from AFR characteristics. The results showed that AFR 13.1 produced the highest reported power output of 11.0 HP, whereas AFR 14.1 indicated a more favourable fuel-efficiency potential. AFR 11.7 represented an over-rich setting with the least favourable efficiency tendency. These findings indicate a trade-off between performance-oriented and economy-oriented AFR settings in open-loop ECU mapping.
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This work is licensed under a Creative Commons Attribution 4.0 International License.
How to Cite
Ramadhan, M. (2026). Air–Fuel Ratio Evaluation in Open-Loop ECU Mapping for a KZR Engine: A Trade-Off Analysis of Power, Torque, and Fuel-Efficiency Potential. AEEJ : Journal of Automotive Engineering and Vocational Education, 7(1), 57-68. https://doi.org/https://doi.org/10.24036/aeej.v7i1.318
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[16] S. Pukalskas, A. Rimkus, T. Vipartas, S. Stravinskas, D. Kriaučiūnas, G. Mejeras, and A. Ušinskas, “Hydrogen Supplementation in SI Engines: Enhancing Efficiency and Reducing Emissions with a Focus on Knock Phenomena,” Machines, vol. 13, no. 7, Art. no. 571, 2025, doi: 10.3390/machines13070571.
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[18] T. Alsuwian, A. A. Amin, M. S. Iqbal, M. B. Qadir, S. Almasabi, and M. Jalalah, “Design of Active Fault-Tolerant Control System for Air-Fuel Ratio Control of Internal Combustion Engine Using Nonlinear Regression-Based Observer Model,” PLoS ONE, vol. 17, no. 12, Art. no. e0279101, 2022, doi: 10.1371/journal.pone.0279101.
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[20] A. A. D. C. Amaral, N. Saidatin, and H. S. Maulana, “Experimental Study of Spark Ignition Engine Performance under Different Electronic Control Units, Hole Injectors and Spark Plugs,” Journal of Mechanical Engineering, Science, and Innovation, vol. 3, no. 1, pp. 22–29, 2023, doi: 10.31284/j.jmesi.2023.v3i1.2992.
[21] M. Hanifuddin, M. F. Taufiqurrahman, T. A. Setyawan, R. Anggarani, C. S. Wibowo, and B. Sugiarto, “Performance of a Single-Cylinder Four-Stroke Engine with High Concentrations of Gasoline-Ethanol-Methanol (GEM),” Automotive Experiences, vol. 6, no. 2, pp. 407–415, 2023, doi: 10.31603/ae.9322.
[22] A. F. Fauzil, D. Fernandez, H. Maksum, and M. Y. Setiawan, “Pengaruh Penggunaan ECU Racing dan Injektor Racing Terhadap Torsi, Daya dan Konsumsi Bahan Bakar Pada Sepeda Motor Jupiter MX King 150,” JTPVI: Jurnal Teknologi dan Pendidikan Vokasi Indonesia, vol. 2, no. 1, pp. 1–10, 2023, doi: 10.24036/jtpvi.v2i1.122.
[23] M. Ikhwan, R. Saputra, I. Febriansyah, M. S. Firmansyah, R. K. Ramadhan, W. Purwanto, and H. D. Saputra, “Effect of Ignition Timing Variations Using a Programmable ECU on Power and Torque of FI Motorcycle,” BIS Energy and Engineering, vol. 2, Art. no. V225041, 2025, doi: 10.31603/biseeng.366.
[24] T. M. Khadri, T. W. Saputra, and D. S. Wijayanto, “The Influence of Ignition Timing and Injection Duration Using Arduino-Based ECU on the Performance of a 110cc FI Engine,” Scientific Journal of Mechanical Engineering Kinematika, vol. 9, no. 2, pp. 117–128, 2024, doi: 10.20527/sjmekinematika.v9i2.317.
[25] M. Gad and N. M. Ghazaly, “Evaluation of Parameters Affecting the Performance of the Spark Ignition Engine,” SVU-International Journal of Engineering Sciences and Applications, vol. 4, no. 2, pp. 216–224, 2023, doi: 10.21608/svusrc.2023.197849.1113.
[26] J. Zareei and K. Ghadamkheir, “The Effects of Variable Excess Air Ratio and Ignition Timing on the Performance and Exhaust Emissions in a Direct Injection Hydrogen-CNG Fueled Engine,” International Journal of Engine Research, vol. 24, no. 5, pp. 2039–2050, 2023, doi: 10.1177/14680874221107141.
[2] B. P. Maldonado, B. C. Kaul, C. D. Schuman, and S. R. Young, “Reinforcement learning applied to dilute combustion control for increased fuel efficiency,” International Journal of Engine Research, vol. 25, no. 6, pp. 1157–1173, 2024, doi: 10.1177/14680874241226580.
[3] D. R. B. Syaka, A. T. Purwoko, and Sopiyan, “Design and Experiment of a Prototype Electronic Control Unit Direct Injection Fuel System Arduino-Based for 2-stroke Spark Ignition Engine,” Automotive Experiences, vol. 5, no. 1, pp. 49–56, 2022, doi: 10.31603/ae.5472.
[4] M. R. Al-mukharom and S. Hadi, “Performance and Fuel Efficiency Evaluation of an Injection Converter Kit Retrofit on a 100cc Four-Stroke Engine,” AEEJ: Journal of Automotive Engineering and Vocational Education, vol. 6, no. 1, pp. 55–64, 2025, doi: 10.24036/aeej.v6i1.240.
[5] W. D. V. Yansyah, W. Purwanto, H. Maksum, A. Arif, I. W. Kustanrika, and S. B. Ahmad, “Rancang Bangun Sistem Injeksi Sepeda Motor 4 Langkah,” AEEJ: Journal of Automotive Engineering and Vocational Education, vol. 5, no. 1, pp. 29–36, 2024, doi: 10.24036/aeej.v5i1.133.
[6] R. Monasari and I. I. Fatazar, “The Effect of Venturi Size and Compression Ratio on Torque and Specific Fuel Consumption of 2 Stroke Gasoline Motorcycle 149 CC,” AEEJ: Journal of Automotive Engineering and Vocational Education, vol. 5, no. 1, pp. 63–72, 2024, doi: 10.24036/aeej.v5i1.238.
[7] B. U. Wisesa, M. Y. Setiawan, A. Arif, I. Nasution, and A. Aryadi, “The Effect of Citronella Bio-Additive Mixture on RON 90 Gasoline on Engine Performance and Motorcycle Fuel Economy,” AEEJ: Journal of Automotive Engineering and Vocational Education, vol. 4, no. 1, pp. 61–70, 2023, doi: 10.24036/aeej.v4i1.197.
[8] H. Sinkala, S. Özarslan, and A. Benarous, “Effect of Excess Air Ratio on Emissions, Performance and Efficiency of Gasoline Fueled Engines: A Review,” Energy, Environment and Storage, vol. 4, no. 2, pp. 32–45, 2024, doi: 10.52924/PUPX2065.
[9] D. C. Anindito and M. R. Hikmahtiar, “Optimasi AFR pada Gasoline Engine Menggunakan Sistem Controller pada Vehicle Speed Sensor,” Borobudur Engineering Review, vol. 4, no. 1, pp. 01–09, 2024, doi: 10.31603/benr.v4i01.11117.
[10] Mokhtar, D. A. Sumarsomo, A. A. Agama, and M. Adhitya, “Optimizing the performance of gasoline-ethanol-methanol fueled engines with variations in the air-fuel ratio,” Seminar Nasional Tahunan Teknik Mesin, vol. 23, no. 1, pp. 23–31, 2026, doi: 10.71452/638pey73.
[11] D. Wicaksono, A. Muhammad, M. F. Noor, I. N. D. K. Dewi, M. N. Helsinky, D. H. T. Prasetiyo, and W. N. Achmadin, “Investigating Engine Performance Alteration and Emissions Characteristic of ECU Remapping in a 150cc Four-stroke Single Overhead Camshaft Engine System,” IRA Jurnal Teknik Mesin dan Aplikasinya, vol. 5, no. 1, pp. 101–114, 2026, doi: 10.56862/irajtma.v5i1.374.
[12] L. O. I. S. Yunus, F. T. Putri, and R. R. Ismail, “Fuel-Injected Motorcycle Performance Optimization Utilising Pertalite-Ethanol Blends and Deep Neural Network-Based ECU for Efficiency Improvement and Emission Reduction,” Jurnal Rekayasa Mesin, vol. 16, no. 2, pp. 789–799, 2025, doi: 10.21776/jrm.v16i2.1946.
[13] International Organization for Standardization, “ISO 1585:2020 Road vehicles — Engine test code — Net power,” International Organization for Standardization, Geneva, Switzerland, 2020. DOI: not applicable.
[14] A. Rimkus, G. Mejeras, A. Dittrich, S. Pukalskas, and D. Barta, “Effect of the Concentration of Bioethanol Mixed with Gasoline on the Energy and Environmental Performance of a Hybrid Vehicle in the Worldwide Harmonized Light Vehicles Test Cycle (WLTC),” Applied Sciences, vol. 14, no. 23, Art. no. 10858, 2024, doi: 10.3390/app142310858.
[15] F. Catapano, S. Di Iorio, A. Magno, P. Sementa, and B. M. Vaglieco, “A Complete Assessment of the Emission Performance of an SI Engine Fueled with Methanol, Methane and Hydrogen,” Energies, vol. 17, no. 5, Art. no. 1026, 2024, doi: 10.3390/en17051026.
[16] S. Pukalskas, A. Rimkus, T. Vipartas, S. Stravinskas, D. Kriaučiūnas, G. Mejeras, and A. Ušinskas, “Hydrogen Supplementation in SI Engines: Enhancing Efficiency and Reducing Emissions with a Focus on Knock Phenomena,” Machines, vol. 13, no. 7, Art. no. 571, 2025, doi: 10.3390/machines13070571.
[17] Ł. Warguła, P. Kaczmarzyk, B. Wieczorek, Ł. Gierz, D. Małozięć, T. Góral, et al., “Identification of the Problem in Controlling the Air–Fuel Mixture Ratio (Lambda Coefficient λ) in Small Spark-Ignition Engines for Positive Pressure Ventilators,” Energies, vol. 17, no. 17, Art. no. 4241, 2024, doi: 10.3390/en17174241.
[18] T. Alsuwian, A. A. Amin, M. S. Iqbal, M. B. Qadir, S. Almasabi, and M. Jalalah, “Design of Active Fault-Tolerant Control System for Air-Fuel Ratio Control of Internal Combustion Engine Using Nonlinear Regression-Based Observer Model,” PLoS ONE, vol. 17, no. 12, Art. no. e0279101, 2022, doi: 10.1371/journal.pone.0279101.
[19] A. D. Soewono, M. Darmawan, and J. Halim, “Kajian Eksperimental Pengaruh Penggunaan Electronic Control Unit Aftermarket pada Daya, Torsi, Emisi dan Konsumsi Bahan Bakar Sepeda Motor 150cc,” Jurnal Rekayasa Mesin, vol. 14, no. 2, pp. 487–497, 2023, doi: 10.21776/jrm.v14i2.1276.
[20] A. A. D. C. Amaral, N. Saidatin, and H. S. Maulana, “Experimental Study of Spark Ignition Engine Performance under Different Electronic Control Units, Hole Injectors and Spark Plugs,” Journal of Mechanical Engineering, Science, and Innovation, vol. 3, no. 1, pp. 22–29, 2023, doi: 10.31284/j.jmesi.2023.v3i1.2992.
[21] M. Hanifuddin, M. F. Taufiqurrahman, T. A. Setyawan, R. Anggarani, C. S. Wibowo, and B. Sugiarto, “Performance of a Single-Cylinder Four-Stroke Engine with High Concentrations of Gasoline-Ethanol-Methanol (GEM),” Automotive Experiences, vol. 6, no. 2, pp. 407–415, 2023, doi: 10.31603/ae.9322.
[22] A. F. Fauzil, D. Fernandez, H. Maksum, and M. Y. Setiawan, “Pengaruh Penggunaan ECU Racing dan Injektor Racing Terhadap Torsi, Daya dan Konsumsi Bahan Bakar Pada Sepeda Motor Jupiter MX King 150,” JTPVI: Jurnal Teknologi dan Pendidikan Vokasi Indonesia, vol. 2, no. 1, pp. 1–10, 2023, doi: 10.24036/jtpvi.v2i1.122.
[23] M. Ikhwan, R. Saputra, I. Febriansyah, M. S. Firmansyah, R. K. Ramadhan, W. Purwanto, and H. D. Saputra, “Effect of Ignition Timing Variations Using a Programmable ECU on Power and Torque of FI Motorcycle,” BIS Energy and Engineering, vol. 2, Art. no. V225041, 2025, doi: 10.31603/biseeng.366.
[24] T. M. Khadri, T. W. Saputra, and D. S. Wijayanto, “The Influence of Ignition Timing and Injection Duration Using Arduino-Based ECU on the Performance of a 110cc FI Engine,” Scientific Journal of Mechanical Engineering Kinematika, vol. 9, no. 2, pp. 117–128, 2024, doi: 10.20527/sjmekinematika.v9i2.317.
[25] M. Gad and N. M. Ghazaly, “Evaluation of Parameters Affecting the Performance of the Spark Ignition Engine,” SVU-International Journal of Engineering Sciences and Applications, vol. 4, no. 2, pp. 216–224, 2023, doi: 10.21608/svusrc.2023.197849.1113.
[26] J. Zareei and K. Ghadamkheir, “The Effects of Variable Excess Air Ratio and Ignition Timing on the Performance and Exhaust Emissions in a Direct Injection Hydrogen-CNG Fueled Engine,” International Journal of Engine Research, vol. 24, no. 5, pp. 2039–2050, 2023, doi: 10.1177/14680874221107141.