University of Oulu

Gharehghani, A., Salahi, M. M., Andwari, A. M., Mikulski, M., & Könnö, J. (2023). Reactivity enhancement of natural gas/diesel RCCI engine by adding ozone species. Energy, 274, 127341.

Reactivity enhancement of natural gas/diesel RCCI engine by adding ozone species

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Author: Gharehghani, Ayat1; Salahi, Mohammad Mahdi2; Mahmoudzadeh Andwari, Amin2;
Organizations: 1School of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran
2Machine and Vehicle Design (MVD), Materials and Mechanical Engineering, University of Oulu, P.O. Box 4200, FI-90014, Oulu, Finland
3School of Technology and Innovation, Energy Technology, University of Vaasa, Wolffintie 34, FI-65200, Vaasa, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link:
Language: English
Published: Elsevier, 2023
Publish Date: 2025-03-27


Reactivity controlled compression ignition (RCCI) is an alternative combustion strategy with the potential of significant advantages in terms of increasing thermal efficiency together with reduction of NOx and soot emissions. The RCCI engines have been encountered not to be applicable broadly since they suffer from some difficulties mainly contributed to the controllability of combustion and limited operating ranges. The difficulties become even worse where low-reactivity fuels like natural gas (NG) are applied. Ozone gas, a chemical species with an extreme level of reactivity, can improve the combustion efficiency along with the advancement of combustion phasing in the RCCI engine. In this study a multidimensional computational fluid dynamic (CFD) which is coupled with proper detailed chemical kinetic mechanisms is employed to investigate the influence of ozone addition (i.e., 10, 100 and 1000 ppm) to air-fuel mixture with different initial conditions (e.g., intake temperature and equivalence ratio), on the performance and emissions characteristics of the RCCI engine. The results imply that the addition of even low concentrations of ozone (10 ppm) have considerable influences on the RCCI combustion characteristics. Addition of ozone by a distinct quantity not only can enhance the combustion phasing controllability, but also can extend the operating range of the RCCI engine in both lower intake air temperature and the lower fraction of the high-reactive fuel. From the results it is conceived that by adding 1000 ppm ozone into the air-fuel mixture, it is possible to reduce the diesel fuel fraction from 20% to 10% and intake air temperature from 355 K to 335 K, respectively.

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Series: Energy
ISSN: 0360-5442
ISSN-E: 0360-5442
ISSN-L: 0360-5442
Volume: 274
Article number: 127341
DOI: 10.1016/
Type of Publication: A1 Journal article – refereed
Field of Science: 214 Mechanical engineering
Copyright information: © 2023. This manuscript version is made available under the CC-BY-NC-ND 4.0 license