Patent ID: 7591132
Filing Date: 2009-09-22
Classification: F01N,Y02T

Abstract:
1. Apparatus, to inject a reductant into an exhaust gas feedstream of an internal combustion engine, comprising: a source of pressurized fuel; a controllable pressure regulator; a fuel injector; said controllable pressure regulator configured to receive said pressurized fuel and to provide a pressure regulated fuel to said fuel injector; said fuel injector configured to inject said pressure regulated fuel into the exhaust gas feedstream; a control module operatively connected to the controllable pressure regulator and the fuel injector, said control module configured to coordinate control of the controllable pressure regulator and the fuel injector to achieve an effective turndown ratio greater than a turndown ratio achievable through control of the fuel injector alone; wherein the fuel injector is configured to inject said pressure regulated fuel upstream of a selective catalyst reduction device; wherein the control module is further configured to coordinate control of both the controllable pressure regulator and the fuel injector based upon engine-out NO wherein the control module is further configured to coordinate control of both the controllable pressure regulator and the fuel injector based upon a preferred ratio for HC further comprising the control module signally connected to a plurality of sensing devices configured to monitor parameters of the exhaust gas feedstream, and, configured to determine parameters of exhaust gas temperature, flow rate and emissions; and wherein the control module is further configured to coordinate control of both the controllable pressure regulator and the fuel injector using a feed forward control scheme based upon the preferred ratio for HC