The IC engine has a fuel injection control and uses a selected cylinder to use the fuel vapour from the fuel tank. This is collected in a reservoir with absorbent insert and is released into the inlet manifold by a control valve. The valve is operated for a preset time at the same part of the cycle of the selected cylinder, allowing the engine management system to make appropriate correction to the fuel injection for that cylinder. For a four cylinder IC engine the selected cylinder is 1 or 3 and the part of the cycle used for venting the fuel vapour is the absorption stroke. The period over which the venting valve is open is sufficiently long to enable a usable amount of fuel vapour to enter the inlet manifold.
