CPC F02D 41/0245 (2013.01) [F01N 11/00 (2013.01); F02B 25/08 (2013.01); F02B 37/18 (2013.01); F02B 37/24 (2013.01); F02B 75/282 (2013.01); F02D 41/0007 (2013.01); F02D 41/0255 (2013.01); F02D 41/401 (2013.01); F02D 2041/389 (2013.01)] | 8 Claims |
1. A method of operating an opposed-piston engine comprising a cylinder, an intake port near a first end of the cylinder, an exhaust port near a second end of the cylinder, a supercharger configured to pump air to the intake port, an exhaust passage configured to transport exhaust from the exhaust port, a turbocharger comprising a turbine in the exhaust passage and a compressor on an upstream side of the supercharger, a backpressure valve in the exhaust passage on a downstream side of the turbine, and a catalytic aftertreatment device in the exhaust passage, the catalytic aftertreatment device comprising a catalyst having a light-off temperature, the method comprising:
initiating compression-ignited combustion in the cylinder by cranking the opposed-piston engine;
when cranking ceases as compression-ignited combustion continues, elevating a catalyst temperature of the catalytic aftertreatment device by:
regulating the turbine and the supercharger to increase mass airflow into the intake port; and,
closing the backpressure valve;
determining an exhaust gas condition indicative of the catalyst temperature;
as an indicated catalyst temperature approaches the light-off temperature, transitioning the engine to a normal operating condition.
|