F02D 19/105

Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed simultaneously using pluralities of fuels peculiar to compression-ignition engines in which the main fuel is gaseous {operating in a special mode, e.g. in a liquid fuel only mode for starting}