Patent ID: 8069651

Claim:
An engine system comprising: an engine having an exhaust system coupled therewith; a compressor configured to supply intake air to said engine; a flow restriction device disposed in said exhaust system, said flow restriction device having a first configuration with a relatively larger flow area, and a second configuration with a relatively smaller flow area; a compressed air subsystem having an inlet configured to receive compressed air from said compressor, a first passage fluidly connected with the inlet for returning compressed air to said compressor, and a second passage fluidly connected with the inlet for supplying compressed air to an air actuated element; a pressure control device configured to selectively fluidly connect the inlet of said compressed air subsystem with said compressor when said flow restriction device is in said second configuration; an indicating device configured to output a signal indicative of exhaust back pressure in said exhaust system upstream said flow restriction device, wherein said pressure control device is operably coupled with said indicating device; and a valve positioned fluidly between the inlet and the second passage.