Abstract: A method for operating an exhaust aftertreatment system injector to prevent coking includes steps of injecting fuel for heating the aftertreatment devices, when not injecting fuel, flowing air to purge and cool the nozzle to prevent carbon deposits when exhaust gas temperature is low, and substantially stop air flow to allow passive heating of the nozzle by the exhaust for oxidation of any accumulated carbon when exhaust temperature is high enough to support oxidation. Preferably, the nozzle has a catalytic material coating to reduce the temperature necessary for oxidation of the coking material.

Abstract: A valve actuation system and method for use in an internal combustion engine including at least one combustion cylinder having a piston and an engine valve. The valve actuation system includes a hydraulic pump, a high-pressure reservoir, and an electro-hydraulic valve actuator. The hydraulic pump is configured to produce a hydraulic output based on a valve-piston clearance profile of at least one cylinder of the combustion engine. The high-pressure reservoir is coupled with the hydraulic pump. The electro-hydraulic valve actuator is coupled with the high-pressure reservoir via a first control valve and configured to actuate at least one engine valve of the combustion engine according to an output of the hydraulic pump.