US 11,815,042 B2
Exhaust catalyst light-off in an opposed-piston engine
Ahmad Ghazi, San Diego, CA (US); Daniel M. Schum, San Diego, CA (US); Fabien G. Redon, San Diego, CA (US); and Samrat M. Patil, San Diego, CA (US)
Assigned to Achates Power, Inc., San Diego, CA (US)
Filed by ACHATES POWER, INC., San Diego, CA (US)
Filed on Jan. 4, 2022, as Appl. No. 17/568,601.
Application 17/568,601 is a division of application No. 16/400,924, filed on May 1, 2019, granted, now 11,242,809.
Prior Publication US 2022/0128012 A1, Apr. 28, 2022
Int. Cl. F02D 41/06 (2006.01); F02D 41/02 (2006.01); F01N 11/00 (2006.01); F02B 25/08 (2006.01); F02B 37/18 (2006.01); F02B 37/24 (2006.01); F02B 75/28 (2006.01); F02D 41/00 (2006.01); F02D 41/40 (2006.01); F02D 41/38 (2006.01)
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
OG exemplary drawing
 
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.