Combustion analysis of methane-hydrogen port injection combined with OMEn/Diesel spray injection in an RCCI engine

• Published in: International journal of hydrogen energy Vol. 54; pp. 1319 - 1328
• Main Authors: Navid, Ali, Ghadamkheir, Kourosh, Hasche, Anna, Zareei, Javad, Krause, Hartmut, Eckart, Sven
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 07.02.2024
• Subjects: Diesel; Emission; Hydrogen; Methane; OME; RCCI engine; Methane; Emission; Diesel; RCCI engine; Hydrogen; OME
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2023.11.240

Compressed Natural Gas (CNG) is recognized as an environmentally friendly alternative vehicle fuel, but it has a low flame speed. Combining hydrogen with CNG to create ‘hydrogen compressed natural gas’ (HCNG) allows for faster and leaner combustion. Additionally, OME2−4 with varying cetane numbers, from 63 for OME2 to 90 for OME4, serves as a highly reactive fuel suitable for use in a dual fuel strategy known as RCCI (reactivity-controlled compression ignition). This project investigates the impact of adding OME2−4 to HCNG, focusing on pressure, temperature, and emissions. Results indicate that lengthening the OME chain advances the peak heat release rate but delays the second combustion phase. In diesel+HCNG, the first-phase combustion is 2 °CA shorter than OME2+HCNG, resulting in a 6.5% higher peak pressure than OME2+HCNG and a 20% increase over basic diesel. Lengthening the OME chain from OME2 to OME4 raises the peak pressure by about 6.2%. The addition of gaseous fuels, especially hydrogen, increases peak temperature by 16%. OME4+HCNG has a similar peak temperature to OME3+HCNG, while OME2+HCNG is about 1.5% lower than OME4+HCNG. [Display omitted] •The peak pressure for diesel+HCNG is approximately 20% higher than that of basic diesel (115.0 bar).•Lengthening the OME chain from OME2 to OME4 increases the peak pressure by 6.2% (from 134.9 bar to 143.3 bar).•The OMEn+HCNG configurations decrease soot formation, reducing it from 1466 ppm in basic diesel to 6 ppm for OME2+HCNG.