From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
From AC Spark Plug Company introducing a new fuel pump and explaining how it works.
| Identifier | ExFiles\Box 27a\2\ Scan009 | |
| Date | 12th August 1926 guessed | |
| AC SPARK PLUG COMPANY AC FUEL PUMP 1. INTRODUCTION "I want to show you our new fuel pump. We have been working for many years to get a gasoline system which will give the real answer to the manufacturers and we have made and tested every possible type of mechanical and electrical pump and from the knowledge of everything we made and everything we tested, we developed this new pump which has been a satisfactory job from the first pump we made about eighteen months ago. In fact none of the pumps we have made to date have had any failures whatever and this test has been in both laboratory and on the road for very long mileage. It has been so satisfactory that we have decided to go ahead with the manufacturing of this model which is good for all types and sizes of engines. 2. HOW IT WORKS (Refer to diagram) The AC Fuel Pump is of small dimensions, approximately 5" in height 4" in width, and so designed that it becomes part of the engine and is driven by any convenient method which will give reciprocal motion of from 3/16 to 1/4" maximum. It can be operated from the push rods, tappets or eccentrics located either on the cam shaft, or any other rotating shaft such as generator, oil pump, etc. This particular design shown is adapted to be bolted on to the cam shaft side of the case by means of two cap screws and reciprocal motion of about 1/4" maximum is imparted to lever (D) by a small eccentric (H) mounted on to the cam shaft (G) The AC Fuel Pump is of the diaphragm type and this diaphragm is composed of several layers of especially treated flexible cloth material, which is absolutely impervious to gasoline and benzol. This cloth material (A) is held between two metal discs (B) and is pushed upward by a pump spring (C). This diaphragm in its upward position almost fills the pump chamber (M) so that in its downward movement a very high vacuum is obtained, thus assuring high pumping capacity even at low speed. The repeated 1/4" movement of the diaphragm is possible indefinitely without any injury, due to the extreme flexibility of this material. Further, the extreme movement of the diaphragm occurs only when the carburetor is empty. When the carburetor is full this movement is greatly diminished, being directly proportional to the amount of gasoline used by the engine. This means that in practically all normal driving conditions this diaphragm is pulsating in movement of about .003 inch maximum. This movement is controlled by linkage (F), because when the diaphragm is in the depressed position due to sufficient fuel in the carburetor the reciprocal movement of the lever (D) will merely cause a movement of the linkage (F) to the right as shown by the arrow. Following is a description of a complete cycle in the movement of the fuel pump: | ||