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).
Technical bulletin detailing the specifications and performance of the 'AUTOPULSE' fuel pump system.
| Identifier | ExFiles\Box 41\1\ Scan034 | |
| Date | 30th November 1926 guessed | |
| In the "MULTIPLE" INSTALLATION the units are bolted to manifolds by gasketed special cap screws which permit ANY UNIT TO BE REMOVED from the line and REPLACED without disturbing the other units. CAPACITY The AUTOPULSE single unit is adjusted to deliver about seven gallons of gasoline an hour through an orifice 1/8" in diameter while lifting 18" to 20" and operating upon a battery current of the rated voltage as marked upon the base casting (6V or 12V). Under the same conditions, except for a larger orifice or unrestricted delivery, it has a capacity of about 12 gallons an hour. This surplus over the rated capacity is a reserve for possible emergencies, such as: reduced voltage, increased elevation, and restrictions. The operation is satisfactory over the very wide RANGE OF VOLTAGE encountered in vehicle service. The safe operating voltage is at least one-third greater than the rated and the capacity may increase slightly with the increase in voltage. Two-thirds of the rated voltage will deliver 85% capacity, and one-third of the rated voltage will produce sufficient fuel for operation. The VARIATION IN LIFT, represented by the variation in height of the pump over the fuel level, has only a slight effect upon the capacity for any condition encountered upon a vehicle. A change from 1½ feet to 5 feet will reduce the capacity about ½ gallon per hour. The variation in lift, due to grade in the case of an automobile, does not affect the delivery pressure. The suction stroke is magnetic and an increase in suction, due to increased elevation or other causes, is compensated for by an increase in electrical power. The capacity is directly affected by the CHANGE IN PRESSURE UPON the DELIVERY SIDE of the AUTOPULSE. The delivery stroke is spring-actuated and adjusted to raise a column of gasoline to a maximum height of 50" to 60" above the pump outlet. This "head" represents the pressure at which the electrical contacts will be held apart and, therefore, no current is used or fuel pumped. This pressure condition is instantly attained upon the closing of the carburetor float valve when the pump is installed at the same level as the carburetor. The calibration pressure will be directly increased or diminished as the pump is raised or lowered in respect to the carburetor, with change in capacity resulting. When the fuel is flowing, the delivery pressure is governed by the restriction at carburetor valve and the pressure is less than when at rest. It requires a gasoline head of about 40" to force gasoline at a rate of 8 gallons an hour through a round orifice 1/8" in diameter. FOR GREATER CAPACITY than the UNIT rating, additional units are required. Any number of units can be used in multiple or manifolded. The illustration below shows a five combination. When connected in this manner each unit operates independently of every other unit and each will deliver its proportion of the fuel used at all times to the extent of the full capacity of each, and be governed by the same pressure conditions as is each unit. That is, the maximum pressure attained does not increase with the increase in the number of units, but, for any given quantity, the delivery pressure will be maintained at more nearly the maximum, the greater the number of units. The rated capacity of a five-unit pump is 40 gallons of gasoline per hour with an unrestricted delivery of 50 to 60 gallons per hour. This "quintette" is suitable for a "Liberty Twelve" engine. (450 H.P.) LIFE The life of the AUTOPULSE is MEASURED BY THE NUMBER OF GALLONS OF FUEL PUMPED and is practically independent of the time period required. When there are no air or gasoline leaks, there is no waste pumping. Laboratory tests indicate that the life of AUTOPULSE UNIT, when pumping gasoline, is from 10,000 to 20,000 gallons, and a single unit should, therefore, outwear most engines of corresponding capacity. The tests also show that the average duty, without need of adjustment, should be the pumping of more than 6,000 gallons. Few automobiles use more than 1,000 gallons per year and the average is less than 500 gallons. The wearing away of the contact points is compensated for by other characteristics to a great extent. In some cases, however, there may be a capacity loss of 10% during the first 10,000 gallons pumped. PULSE. It is strengthened by overlapping and soldering at the bends, where the greatest strain occurs, thereby causing the flexing to occur at the proper place—in the diaphragms. The process used in producing this bellows has resulted in greater uniformity and several times the life of the usual bellows product. DEFECTS IN MATERIAL AND WORKMANSHIP. The AUTOPULSE is GUARANTEED AGAINST DEFECTS IN MATERIAL AND WORKMANSHIP. EFFICIENCY The AUTOPULSE requires so little power that its amount need not be taken into account in respect to battery capacity. It requires about one ampere to pull the stroke, but, on account of the intermittent action, the ammeter reading or average flow at rated capacity is only ¼ to ½ ampere. About 50 ampere hours are required for pumping 1,000 gallons, or less than ½ a small battery charge for a year or more of hard automobile driving. The values given are for six-volt rating. For twelve volts the current values are reduced nearly one-half. Should AIR BE ALLOWED (See Operation Tests and Checks) to enter the suction line, waste pumping will be caused to an extent represented by the proportion of air entering and the useful life will be reduced in a like proportion. The total air pumping in the life of a vehicle would probably not be an hour. It occurs only for a short period when the system is first supplied with fuel and upon other occasions more or less accidental. The AUTOPULSE operates at a high rate of speed and under a severe strain when upon air alone; but it will withstand several hundred hours of continuous pumping at its rated voltage before rupture of the pumping element occurs. The pumping element or bellows was especially developed for the AUTOPULSE. “Quintette” (½ size) Height, 3½”; width, 5½”; length, 11”. Pump centers, 2 3/16”. All openings ¼” pipe tap. 10 11 | ||