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Technology for Enhancing Thermal Efficiency of Gasoline Engine by Pre-chamber Jet Combustion

Article of Honda R&D Technical Review Vol.30 No.2


A two-point increase in brake thermal efficiency was achieved over an engine with a brake thermal efficiency of 45% from a previous study by using a single-cylinder gasoline engine adopting pre-chamber jet combustion. These results were achieved with a mechanical compression ratio of 16:1 by optimizing the pre-chamber design, coating the pre-chamber inner walls with thermal insulation, and optimizing the combustion chamber shape, including compression ratio settings. The resulting configuration also achieved NOx emissions of 30 ppm and hydrocarbon emissions of 2000 ppm, which puts it in compliance with SULEV20 emission regulations. In addition, combustion stability was kept to a CPmi of 3% or lower, the rate of in-cylinder pressure increase to 300 kPa/deg or lower, and noise vibration requirements for actual vehicles were satisfied.


(1) Tagishi, R., Ikeya, K., Takazawa, M., Yamada, T.: Technology for Realization of Gasoline Engine Brake Thermal Efficiency of 45%, Honda R&D Technical Review, Vol. 27, No. 2, p. 1-11
(2) Hanabusa, H., Kondo, T., Hashimoto, K., Sono, H., Furutani, M.: Study on Homogeneous Lean Charge Spark Ignition Combustion, SAE Technical Paper, doi:10.4271/2013-01-2562, (2013)
(3) Nakata, K., Nogawa, S., Takahashi, D., Yoshihara, Y., Kumagai, A., Suzuki, T.: Engine Technologies for Achieving 45% Thermal Efficiency of S.I. Engine, SAE Technical Paper, doi:10.4271/2015-01-1896, (2015)
(4) Kohda, Y., Suganami, T., Kobayashi, H., Ogawa, K.: Development of High-performance and Low-emission Direct Injection Gasoline Engine, Honda R&D Technical Review, Vol. 16, No. 1, p.39-46
(5) Takeori, H., Wada, K., Matsuo, Y., Morita, T., Konomoto, T., Murata, Y., Kimura, M., Miyauchi, A.: Study of an Aftertreatment System for HLSI Lean-burn Engine, SAE Technical Paper, doi:10.4271/2018-01-0945, (2018)

Author (organization or company)

Hiroki KOBAYASHI(Automobile R&D Center)、Kiminori KOMURA(Automobile R&D Center)、Keitaro NAKANISHI(Automobile R&D Center)、Atsushi OHTA(Automobile R&D Center)、Hiroki NARUMI(Automobile R&D Center)、Noriyuki TAKEGATA(Automobile R&D Center)

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