Abstract: A system is described for storing ammonia and injecting it into the exhaust gas stream of an engine to reduce nitrogen oxides. The ammonia is stored as a liquid mixture (70) of ammonia and water in a container (50). In one system, the mixture passes through a hot nozzle and is injected into an upstream portion of the exhaust gas pipe.

Abstract: A system is provided that reduces nitrogen oxides in the exhaust gases of an engine by converting nitric oxide (NO) in the exhaust gases to nitrogen dioxide (NO2) prior to injecting ammonia (NH3) into the exhaust gases, and then passing the exhaust gases through a vehicle catalytic converter. Much of the nitric oxide (NO) is converted to nitrogen dioxide (NO2) by passing the exhaust gases first through a catalyzed particulate filter (CPF) such as one containing a nitric oxide catalyst. In cases where the exhaust gases must pass from the exhaust gas manifold through an exhaust conduit portion of a length of at least one-eighth meter before reaching the catalyzed particulate filter, that exhaust conduit portion is heavily insulated to result in a high exhaust gas temperature at the downstream end of that conduit portion by at least 30° C. over the temperature without insulation.

Abstract: An engine assembly of the type that includes a conduit (16) extending from the exhaust manifold outlet (14) to the atmosphere (20), an ammonia injection station (22) along the conduit, and a catalytic assembly (24) lying along the conduit and downstream of the ammonia injection station. The catalytic assembly includes a surface wash coat (50) of a nitric-oxide catalyzing material that converts nitric oxide (NO) to nitrogen dioxide (NO2), and passages coated with SCR (selective catalyst reduction) catalyst that reacts ammonia with NO2 to produce nitrogen and water. The catalytic assembly includes multiple elements such as fibers, coated with the SCR catalyzing material, with the elements lying in a mass and with passages, or pores lying between the elements. The mass lies in a tube (90) of the conduit, and has conical inside and outside surfaces (42, 40) to provide a large area through which gasses flow.