Patent ID: 8196393

Claim:
A reagent dosing system for an internal combustion engine including an exhaust chamber and an injection device to deliver reagent into the exhaust chamber, the injection device comprising: a device inlet, a device outlet, a sub-assembly comprising (i) a valve housing defining a valve seat, (ii) a valve device movable outwardly from the valve housing, away from the valve seat, to permit the reagent to be delivered into the exhaust chamber through the device outlet, whereby a force is applied to the valve device due to reagent delivered to the device inlet which serves to urge the valve device away from the valve seat, (iii) a stop member which is held securely together with the valve device and is engageable with the valve housing to limit outward movement of the valve device, and (iv) a bias device for applying a biasing force to the valve device which serves to urge the valve device against the valve seat so as to prevent delivery of the reagent through the device outlet into the exhaust chamber, and a device housing separate from the valve housing and having a housing bore within which the valve housing is held securely by means of an interference fit so as to hold the sub-assembly securely within the device housing, wherein the stop member includes a sleeve within which the stop member is held securely and wherein a first end of the bias device abuts a surface of the valve housing and a second end of the bias device abuts a surface of the sleeve.