ALEXANDRIA, Va., Nov. 11 -- United States Patent no. 12,467,399, issued on Nov. 11.
"Variable exhaust control system" was invented by H. Sean Hilbert (Hillsdale, Mich.), Phil McDowell (Hillsdale, Mich.) and Scott Castonguay (Hillsdale, Mich.).
According to the abstract* released by the U.S. Patent & Trademark Office: "An apparatus for adjusting power and noise characteristics of an internal combustion engine comprises a wall configured to define an engine cylinder that includes a bore and a compression relief passage. A compression relief valve is configured to selectively adjust fluid flow capacity of the compression relief passage. A manifold is configured to be in fluid communication with the exhaust passage and includes an exhaust byp...