276 



SCIENCE OF HOME AND COMMUNITY 



this is called the carburetion system. The most common 

 kind of carburetor is the spraying type. The gasoline is 



forced under great pressure 

 through small openings, 

 forming a spray which 

 quickly changes to a vapor. 

 At the same time, it is 

 mixed with air in the pro- 

 portion of about one part 

 of gasoline vapor to six or 

 seven parts of air. This 

 mixture is led into the 

 cylinder and put under 

 pressure before it is ex- 

 ploded. 



When the gases escape from the engine after the explosion, 

 they emit a very loud noise. In order to silence this, a 

 muffler is used. This is cylindrical in shape and is made up 

 of several compartments, separated by partitions in which 

 is a series of holes; through these holes the gases pass, so 

 that they finally leave the muffler with only a slight hissing 



Air fn/et 



FIG. 107. Defining elements of simple 

 float-feed carburetor. 



noise. 



Asbestos Cover Band 



xheust from 

 Engine 



Asbestos Covering 



Outer She// 



Exhaust 

 inner She// 



'Mdd/e She// 



FIG. 108. Muffler. 



The amount of gasoline needed to run the engine varies 

 with the make of the car. Some cars will run from 20 to 25 

 miles on a gallon of gasoline, while others will run only ten 

 miles. 



