Abstract: A liquid injection device comprising a housing; a liquid bore in the housing; an orifice in the housing through which the liquid is injected; a liquid chamber arranged upstream of the orifice; a valve which is normally arranged to close the orifice; the valve being adapted to be moved electrically away from the orifice, and the valve being a close fit in the liquid chamber so that substantially no liquid can pass directly from the liquid bore to the orifice by passing between the valve and the walls of the liquid chamber; an annular liquid passage surrounding the liquid chamber; first passage means by which the liquid can pass to the annular liquid passage; and second passage means arranged downstream of the first passage means; the liquid injection device being such that when the valve is moved away from the orifice, the liquid in the annular liquid passage passes through the second passage means for injection through the orifice and also forces the valve towards the bore whereby the nearer the valve moves t