Higher fuel anti-knock quality will be required as spark ignition engines are designed for higher efficiency in the future.
The demand for fuels with high anti-knock quality has historically been rising, and will continue to increase with the development of downsized and turbocharged spark-ignition engines.
Gasoline anti-knock quality, defined by the research and motor octane numbers (RON and MON), is important for increasing spark ignition (SI) engine efficiency.
The anti-knock quality of gasoline fuels is a significant contributing factor to the indicated thermal efficiency (ITE) of spark ignition (SI) engines.
This is because the octane rating of the fuel was high and in order to differentiate their anti-knock quality, a higher compression ratio than 11.5 1 was needed.
Historically, the anti-knock quality of gasoline is characterised by two parameters, research octane number (RON) and motor octane number (MON), which are measured in cooperative fuel research engines (CFR) using iso-octane and n-heptane as the primary reference fuels (PRFs).
This arises as the addition of CNG increases the overall anti-knock quality of the fuel, and therefore enrichment is not required.
It means when operating on natural gas, we have greater anti-knock quality, so it can maintain the exhaust gas temperature lower, so it does not need to retard the spark to avoid knock.
