Patent ID: 9732645
Date: 2017-08-15
CPC Classifications: F01N

Claim:
1. An internal combustion (IC) power plant, said IC power plant comprising: an IC engine having a variable-volume combustion chamber producing a flow of combustion gas products, an exhaust port flowing said combustion gas products from said IC engine, and an exhaust valve disposed at said exhaust port and when closed defining at said exhaust port a velocity node of zero velocity for said flow of combustion gas products; and a branched exhaust system conveying said combustion gas products from said exhaust port of said IC engine to atmosphere, said branched exhaust system including a first branch having a length of exhaust conduit at a first end receiving combustion gas products from said exhaust port, and said length of exhaust conduit terminating at a second end conveying said combustion gas products to atmosphere; a second branch of said exhaust system having a respective second length of exhaust conduit communicating with said first branch adjacent to said first end thereof, and receiving combustion gas products from said exhaust port, said second branch and said respective second length of exhaust conduit dead-ending in a resonant chamber of selected resonant frequency; whereby said second branch of said exhaust system both receives combustion gas products from said exhaust port via said first branch, and returns combustion gas products to said first branch according to said selected resonant frequency; wherein said resonant chamber structure is a Helmholtz resonator chamber, said Helmholtz resonator chamber including a neck portion communicating between said second length of exhaust conduit and a voluminous chamber portion of said Helmholtz resonator chamber, said voluminous chamber portion defining both a length dimension and a selected volume; wherein said Helmholtz resonant chamber further includes a movable actuator along said length dimension of said Helmholtz resonant chamber, whereby movement of said movable actuator toward said neck portion effects an increase in the selected resonant frequency of said Helmholtz resonant chamber; and wherein said actuator is configured to include a poppet valve member sealingly engagable with said neck portion to effectively cut off communication of said selected volume of said Helmholtz resonant chamber with said neck portion thereof, whereby engagement of said poppet valve member of said movable actuator with said neck portion converts said neck portion effectively into a ¼ wave resonate pipe.