Combustion analysis of methane-hydrogen port injection combined with [formula omitted] spray injection in an RCCI engine.

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, OME 2 − 4 with varying cetane numbers, from 63 for OME 2 to 90 for OME 4 , 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 OME 2 − 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 OME 2 + HCNG , resulting in a 6.5% higher peak pressure than OME 2 + HCNG and a 20% increase over basic diesel. Lengthening the OME chain from OME 2 to OME 4 raises the peak pressure by about 6.2%. The addition of gaseous fuels, especially hydrogen, increases peak temperature by 16%. OME 4 + HCNG has a similar peak temperature to OME 3 + HCNG , while OME 2 + HCNG is about 1.5% lower than OME 4 + 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 OME 2 to OME 4 increases the peak pressure by 6.2% (from 134.9 bar to 143.3 bar). • The OME n + HCNG configurations decrease soot formation, reducing it from 1466 ppm in basic diesel to 6 ppm for OME 2 + HCNG. [ABSTRACT FROM AUTHOR]