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).
Installation, operation tests, service, and capacity information for the Autopulse electric fuel pump.
| Identifier | ExFiles\Box 41\1\ Scan008 | |
| Date | 23th September 1925 guessed | |
| For TRIPLEX and QUADRUPLEX installations, two 1/8" tubes or one 3/8" tube is desirable. For the QUINTETTE, or SEXTETTE, two 3/8" tubes for suction and one 1/8" tube or two 1/8" tubes for delivery. All outlets in multiple pump fittings are 1/4" pipe tap. Note: FOR HIGH-POWERED VEHICLES, in which the AUTOPULSE is replacing a high-pressure air feed system, it is advisable to use the two-unit or duplex installation. The carburetor float valve opening and the screen surfaces are apt to be small; also the delivery line, which becomes the SUCTION LINE of the AUTOPULSE, is usually 1/4" tubing. OPERATION TESTS AND CHECKS (1) When the AUTOPULSE is used in replacing other devices, it is advisable to partially drain the carburetor so that the float valve will be open for release of air from the system. Then, when the ignition or controlling switch is closed (do not crank the engine), the AUTOPULSE will stroke at a high rate until the system is filled with fuel, and, if conditions are perfect, the stroking will come to a complete stop in a few seconds. Continued stroking at a slow rate will indicate leakage, either external to the AUTOPULSE upon the delivery side or through the suction valve which may not be seating perfectly. If the stroke occurs at intervals of a few seconds and is due to valve leakage, it can be disregarded. It will not amount to much in capacity loss; but the carburetor and connections thereto should be carefully examined to make sure the indication is not for an external leak. (2) Crank the engine and allow it to idle. Should there be no SUCTION LEAK the AUTOPULSE will stroke with fair uniformity, but in case of air leak it will speed up and increase in noise, at intervals. In case engine noise drowns out the AUTOPULSE, the effect can be noted by feeling the vibration with the hand against the case. An air bubble will accumulate in a pipe line from a suction leak and when this air bubble goes through the AUTOPULSE it causes an increase in the sound and in the speed for a few strokes, thereby indicating the leakage condition at the time it occurs. It is quite a common occurrence, upon vehicles, for feed pipes to wear through or break. The AUTOPULSE is the only fuel feed device which will expose faulty conditions in a suction pipe. The leakage of fuel from a delivery pipe is readily observed; but air leakage into a suction pipe, of metal, is an unknown quantity and usually can only be discovered when so serious as to cause operation failure. “Duplex” (1/2 size) Height, 3 1/2"; width, 5 1/8"; length, 4 1/2". Bracket holes center distance, 2 7/8". (Add 2 3/16" to length and bracket centers, for each unit added—Triplex, Quadruplex, etc.) Gasoline gauges of the dash indicating type, which use air for transmission of pressure and make use of the intermittent suction action of the vacuum feed system for correction of the transmission pressure, will not function accurately, if at all, when the AUTOPULSE or any other feed system is used. Most of these gauges RESTRICT THE SUCTION LINE and also ALLOW AIR TO ENTER THE SUCTION PIPE to the extent of 15% of the volume of the fuel in some designs and 60% or more in others. This condition will reduce the capacity of any feed system, and, in the case of the AUTOPULSE, will result in considerable waste pumping, and PRACTICALLY INVALIDATE THE AIR LEAK TEST. (3) A RESTRICTION IN THE SUCTION PIPE will be indicated by the ammeter deflections. Normally the ammeter deflection cannot be noticed as the AUTOPULSE makes its stroke (3/4 ampere). In case of restriction the current builds up, supplying more power to overcome the resistance, and for a serious obstruction the current may build up to 3 or 4 amperes and the throw of the ammeter needle at each stroke will be very apparent. Restrictions may develop in service due to screens clogging or the tube may get pinched through accident. (4) EACH UNIT OF THE MULTIPLE INSTALLATION MAY BE INDIVIDUALLY TESTED by removing the clamping screw, disconnecting the wires at the terminal cluster and connecting the common terminal clip to one of the unit terminal clips. A run may be made with the vehicle, increasing the power delivery until lack or a sufficient supply of fuel is indicated with each unit; thus comparing their capacity and functioning. Instead of operating the vehicle, the same test may be made by removing the pipe plug (ignition switch off) in the end of the delivery manifold and connecting a short piece of pipe for delivery, or, if both ends of the manifold are pipe connected to the carburetor, one may be disconnected at the carburetor. Place a vessel under the end of this pipe to catch the fuel and turn on the switch. SERVICE In case of accident to the AUTOPULSE, it is generally advisable to replace it with a new unit. It is so small in size and weight that it can readily be carried in the tool receptacle or car pocket. Its very rugged and reasonable handling will not affect its calibration. Replacement service is as simple and convenient with the AUTOPULSE as with a spark plug. Only the upper chamber of the AUTOPULSE normally contains fuel (indicated by arrows in diagram illustration). Should a leak occur, possibly due to defective material, the fuel will drain down and onto the breaker contacts. In time the contacts will become carbonized or greasy and will cause the operation to become more or less erratic or even fail. A leak will develop gradually and this warning is given while it is still so small that it will cause very little inconvenience. Operation for considerable traveling can be obtained, after this warning is given, by observing the following instructions: (1) Sharply rap the top of the AUTOPULSE with a block of wood while the current is applied. This will usually produce results and may be all that is required. (2) In case it cannot be kept going, the remedy (1) being insufficient, CUT OFF THE IGNITION SWITCH, loosen the pipe connections and turn the AUTOPULSE bottom side up. Then tighten the pipe connections, remove the cap screw (13) (See diagram cut), the magnetic shell (15) and allow the fuel to dry off somewhat. Clean the contacts with a file or a LINEN cloth (no fuzz). Replace shell, driving spring and screw. The fuel will not drain onto the contacts and it should now give considerable service. The bottom side up installation is not specified as a regular mounting because it is desirable to have this warning given, in time, when a leak occurs and also to prevent water and dirt collecting in chamber (17). The agitation of the pumping element or bellows does not permit this accumulation when right side up. Note: The AUTOPULSE will not operate without the magnetic shell (15). The AUTOPULSE is practically SEALED AGAINST OUTSIDE FUEL LEAKAGE and there is no danger of fire from an inside leak. It is almost impossible to fire gasoline under the condition maintained within the AUTOPULSE, and, even if it were possible, there could be no harm, as there is very little air to support the combustion. A large mesh screen is provided to prevent fuzz and coarse particles of metal or dirt from getting into the valves. See (7) (on diagram cut). CAP SCREW (8) SHOULD NOT BE REMOVED unless the ammeter indicates a restriction. See (3) under Operation Tests and Checks. In case it is removed, the gasket (9) must be carefully replaced and preferably shellaced. A leak at this gasket will allow air to enter. If suction valve (6) is removed, attention must be given to properly replacing the cork gasket (5) and the other parts in order. The spring should be placed within the pronged cap with the small hole up. The boss, at the center of the valve, should be placed in the hole with the polished seat up. The assembly is completed by snapping the cap over the end of the cage. Delivery valve (4) (See diagram cut) SHOULD NEVER BE REMOVED. The screw directly above the valve holds it in place and the loosening of this screw may result in the displacement and loss of the valve. In the “MULTIPLE” INSTALLATION the units are connected together by fittings which are clamped together by bolts and gasketed with cork. ANY UNIT MAY BE REMOVED from the line and REPLACED without disturbing the other units. CAPACITY The AUTOPULSE unit is adjusted to deliver about eight gallons of gasoline an hour through an orifice 1/16" 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. The rated capacity is 8 gallons per hour. This 50% surplus over the rated capacity is a reserve for possible emergencies, such as: reduced voltage, increased elevation, valve leakage, restrictions and general deterioration. 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 | ||