Exhaust System for Internal Combustion Engines

Abstract

A dynamic exhaust system including a down-pipe ( 1 ) to receive exhaust gases from the engine and delivering the gases to an exhaust pipe ( 3 ). The system further includes a valve member ( 11 ) with one end extending through the exhaust pipe inlet and into the down-pipe ( 1 ). The valve ( 11 ) is movable to reduce or increase the area of the inlet port ( 2 ) of the exhaust pipe ( 3 ).

1 . A dynamic exhaust system for a vehicle powered by an internal combustion engine, the exhaust system comprising a down-pipe connected to receive exhaust gases from the engine and to deliver these gases to an exhaust pipe having at one end an inlet port for receiving the exhaust gases from the down-pipe and at its other end an outlet port for delivering exhaust gases to atmosphere, a valve member positioned at least partially within the exhaust pipe with one end extending through the inlet port and into the down-pipe, and means operable to bias the valve member towards the down-pipe, the valve member being so shaped that movement of it towards the down-pipe progressively reduces the area of the inlet port, and movement of the valve member towards the outlet port increases the area of the inlet port. 
     
     
         2 . A system according to  claim 1 , wherein the valve member has a generally conical nose whose cross-sectional area decreases in a direction towards the down-pipe of the internal combustion engine. 
     
     
         3 . A system according to  claim 1 , wherein the valve member is biased towards the inlet port by a spring. 
     
     
         4 . A system according to  claim 3  wherein the spring is a coil spring. 
     
     
         5 . A system according to  claim 1 , wherein one or more hollow baffle pods are positioned within the exhaust pipe to define a flow passageway for exhaust gases passing through the exhaust pipe, the or each baffle pod comprising a casing formed with a plurality of apertures through which exhaust gases can pass. 
     
     
         6 . A system according to  claim 5  wherein at least one baffle pod includes sound-deadening material. 
     
     
         7 . A system according to  claim 6 , wherein the or each baffle pod comprises an apertured inner drum assembled within an outer drum. 
     
     
         8 . A system according to  claim 7 , wherein the sound deadening material is provided between the outer surface of the Inner drum and the inner surface of the outer drum. 
     
     
         9 . A system according to  claim 1 , wherein the spring is positioned between the end face of the valve member positioned within the exhaust pipe and the opposed surface of the baffle pod closest to the inlet port. 
     
     
         10 . A system according to  claim 1 , wherein the spring is positioned between a stop positioned at or close to the outlet port of the exhaust pipe and an end face of the baffle pod closest to that stop. 
     
     
         11 . A system according to  claim 1 , wherein the valve member is produced from stainless steel. 
     
     
         12 . A system according to  claim 1 , wherein the valve member is produced from titanium or other like material. 
     
     
         13 . A system according to  claim 1 , wherein the or each baffle pod is produced from stainless steel. 
     
     
         14 . A system according to  claim 1 , wherein the coil spring comprises case hardened sprung steel. 
     
     
         15 . (canceled)