The atomising surface (17) comprises a porous element which ducts fuel vapour into the inlet element. The atomiser is in thermal contact with an electric heating element (26) to assist the atomising process during cold starting. When the engine reaches its operating temperature the engine heat ensures good vaporisation. The electric heating system incorporates temperature sensing and temperature control. The atomising element has a cylindrical support shell (19) which is slid inside the heating element. The heating element can be in two separately controlled parts and the injector is also heated by an outer jacket to contain exhaust gasses.
