F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
F01N1/00—Silencing apparatus characterised by method of silencing
F01N1/16—Silencing apparatus characterised by method of silencing by using movable parts
F01N1/165—Silencing apparatus characterised by method of silencing by using movable parts for adjusting flow area