Study on Combustion and Emission Characteristics of Ammonia–Diesel Engine Under Diesel Pilot Injection Strategy

Xiaopan Li; Sunchu Wu; Zihui Yang; Gang Yi; Wei Wang; Yaohui Nie; Jiacheng Xiang; Shikai Xing; Jianbing Gao

doi:10.3390/pr14091445

Study on Combustion and Emission Characteristics of Ammonia–Diesel Engine Under Diesel Pilot Injection Strategy

Xiaopan Li
, Sunchu Wu^*
, Zihui Yang^*
, Gang Yi
, Wei Wang
, Yaohui Nie
, Jiacheng Xiang
, Shikai Xing
, Jianbing Gao

^*Corresponding author for this work

School of Mechanical Engineering

National Automobile Inspection & Test Center (Beijing)
Hebei Normal University
Chang An Automobile Co. Ltd
Ningde Normal University

Research output: Contribution to journal › Article › peer-review

Abstract

As a carbon-free fuel, ammonia can substantially reduce the carbon footprint of internal combustion engines. However, its slow flame propagation speed and high ignition temperature present combustion challenges. A dual-fuel engine combining ammonia with diesel can effectively address these issues and enhance combustion performance. This study investigates the effects of diesel split ratio (DSR), start of diesel pre-injection (SODI-pre), and start of diesel main-injection (SODI-main). The results indicate that, compared to single diesel injection, segmented diesel injection significantly improves mixture distribution and reactivity, leading to enhanced flame propagation. With a pre-injection ratio of 10% and SODI-pre advanced to −62 °CA, the indicated thermal efficiency increases from 45.35% to 47.61%. Meanwhile, NH₃ emissions decrease from 1707 ppm to 689 ppm, and greenhouse gas N₂O concentration drops from 370 ppm to 251 ppm. Nevertheless, elevated NO_x emissions remain a significant challenge.

Original language	English
Article number	1445
Journal	Processes
Volume	14
Issue number	9
DOIs	https://doi.org/10.3390/pr14091445
Publication status	Published - May 2026

Keywords

ammonia/diesel dual fuel engines
combustion characteristics
emissions characteristics
indicated thermal efficiency

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10.3390/pr14091445

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@article{8207953906d94b779ba73dbc443a5215,

title = "Study on Combustion and Emission Characteristics of Ammonia–Diesel Engine Under Diesel Pilot Injection Strategy",

abstract = "As a carbon-free fuel, ammonia can substantially reduce the carbon footprint of internal combustion engines. However, its slow flame propagation speed and high ignition temperature present combustion challenges. A dual-fuel engine combining ammonia with diesel can effectively address these issues and enhance combustion performance. This study investigates the effects of diesel split ratio (DSR), start of diesel pre-injection (SODI-pre), and start of diesel main-injection (SODI-main). The results indicate that, compared to single diesel injection, segmented diesel injection significantly improves mixture distribution and reactivity, leading to enhanced flame propagation. With a pre-injection ratio of 10\% and SODI-pre advanced to −62 °CA, the indicated thermal efficiency increases from 45.35\% to 47.61\%. Meanwhile, NH3 emissions decrease from 1707 ppm to 689 ppm, and greenhouse gas N2O concentration drops from 370 ppm to 251 ppm. Nevertheless, elevated NOx emissions remain a significant challenge.",

keywords = "ammonia/diesel dual fuel engines, combustion characteristics, emissions characteristics, indicated thermal efficiency",

author = "Xiaopan Li and Sunchu Wu and Zihui Yang and Gang Yi and Wei Wang and Yaohui Nie and Jiacheng Xiang and Shikai Xing and Jianbing Gao",

note = "Publisher Copyright: {\textcopyright} 2026 by the authors.",

year = "2026",

month = may,

doi = "10.3390/pr14091445",

language = "English",

volume = "14",

journal = "Processes",

issn = "2227-9717",

publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",

number = "9",

}

TY - JOUR

T1 - Study on Combustion and Emission Characteristics of Ammonia–Diesel Engine Under Diesel Pilot Injection Strategy

AU - Li, Xiaopan

AU - Wu, Sunchu

AU - Yang, Zihui

AU - Yi, Gang

AU - Wang, Wei

AU - Nie, Yaohui

AU - Xiang, Jiacheng

AU - Xing, Shikai

AU - Gao, Jianbing

PY - 2026/5

Y1 - 2026/5

N2 - As a carbon-free fuel, ammonia can substantially reduce the carbon footprint of internal combustion engines. However, its slow flame propagation speed and high ignition temperature present combustion challenges. A dual-fuel engine combining ammonia with diesel can effectively address these issues and enhance combustion performance. This study investigates the effects of diesel split ratio (DSR), start of diesel pre-injection (SODI-pre), and start of diesel main-injection (SODI-main). The results indicate that, compared to single diesel injection, segmented diesel injection significantly improves mixture distribution and reactivity, leading to enhanced flame propagation. With a pre-injection ratio of 10% and SODI-pre advanced to −62 °CA, the indicated thermal efficiency increases from 45.35% to 47.61%. Meanwhile, NH3 emissions decrease from 1707 ppm to 689 ppm, and greenhouse gas N2O concentration drops from 370 ppm to 251 ppm. Nevertheless, elevated NOx emissions remain a significant challenge.

AB - As a carbon-free fuel, ammonia can substantially reduce the carbon footprint of internal combustion engines. However, its slow flame propagation speed and high ignition temperature present combustion challenges. A dual-fuel engine combining ammonia with diesel can effectively address these issues and enhance combustion performance. This study investigates the effects of diesel split ratio (DSR), start of diesel pre-injection (SODI-pre), and start of diesel main-injection (SODI-main). The results indicate that, compared to single diesel injection, segmented diesel injection significantly improves mixture distribution and reactivity, leading to enhanced flame propagation. With a pre-injection ratio of 10% and SODI-pre advanced to −62 °CA, the indicated thermal efficiency increases from 45.35% to 47.61%. Meanwhile, NH3 emissions decrease from 1707 ppm to 689 ppm, and greenhouse gas N2O concentration drops from 370 ppm to 251 ppm. Nevertheless, elevated NOx emissions remain a significant challenge.

KW - ammonia/diesel dual fuel engines

KW - combustion characteristics

KW - emissions characteristics

KW - indicated thermal efficiency

UR - https://www.scopus.com/pages/publications/105038607496

U2 - 10.3390/pr14091445

DO - 10.3390/pr14091445

M3 - Article

AN - SCOPUS:105038607496

SN - 2227-9717

VL - 14

JO - Processes

JF - Processes

IS - 9

M1 - 1445

ER -

Study on Combustion and Emission Characteristics of Ammonia–Diesel Engine Under Diesel Pilot Injection Strategy

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Keywords

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