152 BULLETIN 173, U. S. NATIONAL MUSEUM 



engine of 1872, he redesigned the engine to use petroleum. The re- 

 sulting engine, the one described in this patent, is considered to be 

 the first safe and practical oil engine. 



The model (wooden) shows an engine that resembles the earlier 

 gas engine in arrangement. It consists of a vertical cylinder closed 

 at both ends, cast integral with a tall, heavy tank. The rod from 

 the piston extends upward to a bell crank at the top of the tank. 

 The other arm of the bell crank drives, through a long connecting 

 rod, a crankshaft running under the cylinder. Cams on the crank- 

 shaft operate the intake or carburetor valve and the petroleum pump. 



In operation, air is drawn into the upper part of the cylinder, 

 compressed, and stored in the receiver tank. Petroleum is pumped 

 under pressure into the carburetor, which is one of the most inter- 

 esting features of the engine. It consists of a chamber containing 

 a porous material into which jets of petroleum and air impinge, the 

 air acting to break up or pulverize the petroleum. A lift valve 

 admits air to the carburetor from the receiver, which dilutes the 

 mixture in the carburetor and continues, through a wire-gauze di- 

 aphragm, into a chamber in which a flame burns continuously. The 

 mixture is ignited and issues into the cylinder as a flame. The wire 

 gauze prevents the striking back of the flame as in a safety lamp. 

 Combustion continues for about one-third of the stroke when the 

 air valve closes. The air and petroleum valves operate at the proper 

 time, and the cycle is repeated. 



DAIMLER GAS ENGINE, 1875 



U.S.N.M. no. 308689 ; original patent model ; transferred from the United States 

 Patent Office ; not illustrated. 



This model was submitted with the application for Patent no. 

 168623, issued to Gottlieb Daimler, of Muelheim-on-the-Rhine, Prus- 

 sia, October 11, 1875. 



Daimler, who was managing director of Otto's Gas Moteren 

 Fabric, 1872-1882, introduced this engine as an improvement over 

 the Langen and Otto engine of 1866. The engine is of the double- 

 acting, free-piston, atmospheric type. 



A water-jacketed cylinder open to the atmosphere at both ends 

 contains a working piston and two other pistons, one on each side 

 of the working piston, which are loose or unconnected and operate 

 in conjunction with the working piston in the following manner: 

 With the working piston at the end of its back stroke, a charge of 

 gas and air is drawn into the space between it and the front loose 

 piston and is exploded. The said loose piston is thrown to the 

 front end of the cylinder (without doing work) where it is held 

 by a wedge device, whereupon a partial vacuum being formed in 

 the cylinder by the expansion and cooling of the gaseous products 



