CHAPTER LVI 



GASOLINE AND OIL ENGINE OPERATION (Continued) 



Ignition. The burning of the fuel in a steam plant is 

 continuous from the time of kindling the fire until the plant is 

 shut down. In the gasoline engine the fire is quickly extin- 

 guished, lasting but a part of one stroke of the piston, necessi- 

 tating the igniting of additional fuel as it is taken into the 

 cylinder. It is easy to see that if for any reason there is a 

 failure to ignite the fresh fuel, no power will be obtained from 

 that particular cylinder. As in the case of failure to secure 

 the proper mixture and compression, the gas engine will not 

 operate unless each charge is successfully ignited. 



Development. As indicated, the firing of the charge in 

 the cylinder is spoken of as the ignition, and the devices that 

 accomplish it, the ignition system. One of the principal diffi- 

 culties encountered by the early inventors in developing the 

 gas engine was that of securing ignition. The early attempts 

 consisted largely in carrying an open flame into the cylinder 

 by means of suitable valves. Later, the hot tube was used 

 generally, and is to some extent at the present time. The 

 hot-tube igniter consisted of a short length of pipe screwed 

 into the compression space and kept at red heat by means of 

 an outside flame. During compression the unburned gases 

 pushed the burned gases up into the tube until the fresh fuel 

 came in contact with the hot surface of the tube, causing 

 ignition. It is not possible to regulate the time of the ignition 

 with the hot tube as accurately as desired, and when used with 

 a small engine, at least, the fuel required to keep the tube hot 

 is often an important part of the entire cost of operation. 



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