Noise suppression system and method

Abstract

A noise suppression assembly includes a first venturi configured to provide air to a combustion chamber and a second venturi configured to provide air to the combustion chamber. The noise suppression assembly also includes a valve subsystem configured to selectively limit air flow through at least one of the first venturi and the second venturi.

1 . A noise suppression assembly, comprising: 
 a first venturi configured to provide air to a combustion chamber;    a second venturi configured to provide air to the combustion chamber; and    a valve subsystem configured to selectively limit air flow through at least one of the first venturi and the second venturi.    
   
   
       2 . The noise suppression assembly of  claim 1 , wherein the first venturi is sized for greater maximum throughput than the second venturi.  
   
   
       3 . The noise suppression assembly of  claim 2 , wherein the valve subsystem includes a valve configured to selectively close the first venturi.  
   
   
       4 . The noise suppression assembly of  claim 1 , wherein the valve subsystem is configured to close the first venturi during low engine air requirement operation.  
   
   
       5 . The noise suppression assembly of  claim 1 , wherein the valve subsystem is configured to open the first venturi during high engine air requirement operation.  
   
   
       6 . The noise suppression assembly of  claim 1 , wherein the first venturi is positioned in a parallel airflow configuration with the second venturi.  
   
   
       7 . The noise suppression assembly of  claim 1 , further comprising an air box intermediate the combustion chamber and the first and second venturi.  
   
   
       8 . The noise suppression assembly of  claim 1 , wherein the second venturi includes a mouth and a throat, and wherein a cross-sectional area of the throat is at most half a cross-sectional area of the mouth.  
   
   
       9 . The noise suppression assembly of  claim 1  further comprising a filter located upstream of said first venturi.  
   
   
       10 . The noise suppression assembly of  claim 9  wherein said filter is located upstream of said second venturi.  
   
   
       11 . The noise suppression assembly of  claim 1  further comprising a mass air flow sensor.  
   
   
       12 . A noise suppression assembly, comprising: 
 a first passage configured to be positioned intermediate a combustion chamber and an air supply, wherein the first passage includes a first upstream portion, a first downstream portion, and a first throat portion between the first upstream portion and the first downstream portion, wherein a cross-sectional area of the first throat portion is less than a cross-sectional area of the first upstream portion and less than a cross-sectional area of the first downstream portion;    a second passage configured to be positioned intermediate the combustion chamber and the air supply in parallel with the first passage, wherein the second passage includes a second upstream portion, a second downstream portion, and a second throat portion between the second upstream portion and the second downstream portion, wherein a cross-sectional area of the second throat portion is less than a cross-sectional area of the second upstream portion and less than a cross-sectional area of the second downstream portion; and    a valve configured to selectively restrict air flow from the air supply to the combustion chamber through the first passage.    
   
   
       13 . The noise suppression assembly of  claim 12 , wherein the first throat portion has a greater cross-sectional area than the second throat portion.  
   
   
       14 . The noise suppression assembly of  claim 13 , wherein a minimum cross-sectional area of the second throat portion is at most 50% a minimum cross-sectional area of the first throat portion.  
   
   
       15 . The noise suppression assembly of  claim 13 , wherein a minimum cross-sectional area of the second throat portion is at most 25% a minimum cross-sectional area of the first throat portion.  
   
   
       16 . The noise suppression assembly of  claim 13 , wherein a minimum cross-sectional area of the second throat portion is at most 15% a minimum cross-sectional area of the first throat portion.  
   
   
       17 . The noise suppression assembly of  claim 12 , wherein the first passage has a greater maximum throughput than the second passage.  
   
   
       18 . The noise suppression assembly of  claim 17 , wherein the valve is configured to block air flow through the first passage during low engine air requirement operation.  
   
   
       19 . A method of controlling an engine, where the engine includes a first venturi intermediate a combustion chamber and an air supply, wherein the first venturi includes a first throat portion having a smaller cross-sectional area than adjacent upstream and downstream portions of the first venturi, and a second venturi intermediate the combustion chamber and the air supply in parallel with the first venturi, wherein the second venturi includes a second throat portion having a smaller cross-sectional area than adjacent upstream and downstream portions of the second venturi, the engine further including a valve coupled to at least one of the first and second venturi the method comprising: 
 adjusting the valve to adjust an amount of flow through the valve as engine operating conditions vary.    
   
   
       20 . The method of  claim 19 , wherein said adjusting selectively blocks air flow based on engine air requirements.  
   
   
       21 . The method of  claim 20  wherein said selective blocking includes blocking the first venturi during low engine air requirement operation.  
   
   
       22 . The method of  claim 19 , wherein the first venturi has a greater maximum air throughput than the second venturi.  
   
   
       23 . The method of  claim 19 , wherein a cross-sectional area of the first throat portion is less than a cross-sectional area of the second throat portion.  
   
   
       24 . The method of  claim 23 , wherein said adjusting includes closing the first venturi during low engine air requirement operation.