Reductant injection in an exhaust system

An engine exhaust system comprises: an exhaust pipe (18) having a bend routing an exhaust flow in a curved path, the exhaust pipe having an interior surface and being in fluid communication with a catalyst (22) downstream of the bend. An injector (12) mounted to the exterior of the exhaust pipe (18) and having an injector tip (28) which is disposed within the interior of the exhaust pipe at the bend, for injecting liquid reductant into the exhaust pipe. A shield member (4) mounted in the exhaust pipe and spaced apart from the interior surface of the exhaust pipe, the shield member comprising a generally tubular or frustoconical structure having an open proximal end (14) and an open distal end (16), the proximal end (14) being disposed such that the injector tip (28) is inside the shield member (4), the distal end (16) being disposed at or towards a centre line (26) of the exhaust pipe. A vane (6) mounted in relation to the shield member (4), the vane being arranged and adapted to direct a proportion (24) of exhaust flow from upstream of the bend (30) in a substantially actuate path into the proximal end (14) of the shield member (4).