The importance of double bond position and cis-trans isomerisation in diesel combustion and emissions

► Four octene isomers were tested as single component fuels in a single cylinder diesel engine. ► Engine tests were conducted using a novel low volume fuel system. ► Moving the double bond towards the centre of the molecule had a non-linear effect on ignition delay. ► Ignition delay of the cis isomer was shorter than the equivalent trans isomer. ► Emissions levels were primarily driven by duration of ignition delay.