CATALOG OF THE MECHANICAL COLLECTIONS I73 



TILLOTSON CARBURETOR, MODEL V2A, 1927 



U.S.N.M. no. 309614; original; gift of the Tillotsou Manufacturing Co.; not 

 illustrated. 



This carburetor is of the plain-tube type, employing a bypass or 

 low-speed jet, a main fuel nozzle, an economizer, and an accelerating 

 pump. Its operation is in principle the same as that of the preceding 

 Tillotson carburetor model SP-19C. 



BOSCH FUEL INJECTION PUMP FOR OIL-ENGINES, 1935 



U.S.N.M. no. 311017 ; original ; gift of the United American Bosch Corporation ; 

 not illustrated. 



This unit is a cut-away injection system for a solid-injection, 4- 

 cjdinder, oil engine. It comprises four individual pump elements, 

 an injection advance device (timer), a manual fuel-supply priming 

 pump, an idling and maximum speed governor, and one nozzle and 

 nozzle holder. It is the Bosch model P E 4 D, adapted for hand- 

 crank operation in the Museum. 



In this system fuel is supplied to the injection nozzle of each 

 cylinder of the engine at the proper pressure and in the proper 

 amount by a constant-stroke single plunger per cylinder. Each 

 pump element consists of a ground-steel pump plunger and pump 

 barrel. Each element is a self-contained fuel metering device of 

 the plunger-controlled, bypass type, as well as a pump. 



The plunger is girdled with an annular groove with a helical 

 upper edge, which starts just below the head of the plunger and 

 spirals down about half an inch. This groove is connected by a 

 vertical groove with the space above the plunger. The barrel of 

 the pump is pierced with a fuel inlet and a bypass port, which are 

 covered by the plunger as it starts its upward stroke. Fuel is deliv- 

 ered through a third port or delivery valve to the engine cylinder 

 until the helical edge of the groove uncovers the bypass port, when 

 the remaining fuel above the plunger passes down and out through 

 the bypass port. The point in the plunger stroke at which the port 

 is uncovered is adjustable by rotating the barrel about its axis. 

 This places the port at different points about the circumference of 

 the plunger where it will register with differing heights of the helical 

 groove. The position of the barrel is controlled by means of a toothed 

 quadrant on the barrel and a rack that engages quadrants on all the 

 barrels of the unit and is connected to the manual control rod or 

 governor. 



INTERNAL-COMBUSTION ENGINE ACCESSORIES 



The following are internal -combustion engine accessories in the 

 collection not otherwise described: 



