THE POWER BEHIND THE ENGINE 



a light was applied to the mixture, an explosion would result. 

 Modern science uses the force of such exploding gases for the 

 accomplishment of work, such as the running of automobiles 

 and launches. 



In connection with the gasoline supply is a carburetor or 

 sprayer, from which the cylinder C (Fig 191) receives a fine 

 mist of gasoline vapor and air. This mixture is ignited by an 



automatic, electric 

 sparking device and 

 the explosion of the 

 gases drives the piston 

 P to the right. In 

 the 4-cycle type of 

 gas engines (Fig. 191) 

 the kind used in 

 automobiles the 



four strokes are as follows : I. The mixture of gasoline and air 

 enters the cylinder as the piston moves to the right. 2. The 

 valves being closed, the mixture is compressed as the piston 

 moves to the left. 3. The electric spark ignites the com- 

 pressed mixture and drives the piston to the right. 4. The 

 waste gas is expelled as the piston moves to the left. The 

 exhaust valve is then closed, the inlet valve opened, and an- 

 other cycle of four strokes begins. 



The use of gasoline in launches and automobiles is familiar 

 to many. Not only are launches and automobiles making use 

 of gas power, but the gasoline engine has made it possible to 

 propel aeroplanes through the air. 



FIG. IQI. The gas engine. 



