CATALOGUE OF THE MECHANICAL ENGINEERING COLLECTION. 43 



valves located in the cylinder head. To the rear of the engine proper 

 is an air tank with air under pressure as great as 60 pounds a square 

 inch, maintained by the engine itself, A suitable valve regulates the 

 amount of air passing out of the tank to the intake pipe. Surround- 

 ing the intake is an annular space stuffed with some absorbent mate- 

 rial which is saturated at each revolution with a prescribed quantity 

 of oil, the saturation being accomplished by a suction and force 

 pump operated by a cam and connecting rod on the main shaft. 



Above the intake pipe and the surrounding annular chamber is a 

 circular opening in which is placed a wire gauze diaphragm on the 

 upper surface of which gas is constantly burning, the gas being sup- 

 plied from an outside source. 



To operate the engine the gas above the wire diaphragm is ignited 

 and the intake valve opened. Air from the tank enters the intake 

 pipe and in passing upward permeates the absorbent material charged 

 with oil through holes in the walls of the intake pipe. The oil now 

 vaporized and mixed with air continues upward, passes through the 

 wire-gauze diaphragm, and is ignited. The resultant expansion 

 moves the piston upward and the impetus of the flywheel returns it. 

 Should the temperature of the air be too low to vaporize the oil, its 

 pressure is sufficient to drive the oil out of the absorbent in the form 

 of a tine spray which upon striking the wire-gauze diaphragm is 

 instantly vaporized, mixes with air, and is ignited as under normal 

 conditions. Cat. No. 251, 281 U.S.N.M. 



Model of N. A. Otto Gasoline Engine. 1J. S. Patent, No. 194047, August 

 14, 1877. Transferred from United States Patent Office. 



In gas-motor engines constructed before the invention of Doctor 

 Otto, an explosive mixture of combustible gas and air was intro- 

 duced into the engine cylinder where it was ignited, resulting in a 

 sudden development of heat and expansion of the gases. A great 

 portion of the useful effect was lost, however, by the absorption of 

 heat, because no special provision was made for allowing the gases 

 to expand rapidly. In the Otto engine, however, an intimate mix- 

 ture of combustible gas or vapor and air is introduced into the cylin- 

 der, together with a separate charge of air or gas that may or may 

 not support combustibles, in such a manner and in such proportions, 

 that the particles of the combustible gaseous mixture are more or less 

 dispersed in an isolated condition in the air or other gas, so that on 

 ignition, instead of an explosion ensuing, the flame will be communi- 

 cated gradually from one combustible particle to another, thereby 

 effecting a gradual development of heat and a corresponding gradual 

 expansion of the gases which will enable the motive power so pro- 

 duced to be utilized in the most effective manner. 



