US3035592A - Fuel control governors - Google Patents

Description

May 22, 1962 P. B. KAHN FUEL CONTROL GOVERNORS Filed Jan.- 11, 1961 United States Patent 3,035,592 FUEL CONTROL GOVERNORS Peter Bruno Kahn, Loughton, England, assignor to The Plessey Company Limited, London, England, a British company Filed Jan. 11, 1961, Ser. No. 82,136 Claims priority, application Great Britain J an. 28, 1960 4 Claims. (Cl. 13754) This invention relates to speed-responsive spill-type flow-control governors and is particularly, though not exclusively, applicable to fuel-control governors for an internal combustion engine which in response to the speed of the engine vary the amount of fuel delivered from a positive-displacement fuel pump to the injection device of the engine by opening a spill aperture when the speed rises above a predetermined value.

A spill-type governor has previously been proposed in which the governor shaft contains a bore communicating with the delivery side of the fuel pump and having a radial outlet which is controlled by a valve element which rotates with the shaft about the axis of the shaft and is resiliently held on its seat by a leaf spring extending longitudinally of the shaft, the centrifugal action of the valve element and its mounting producing the governor action by overcoming, at a predetermined speed, the action of the spring. In the previously proposed construction the governor shaft is constituted by one of the shafts, or an extension of one of the shafts, of a geartype fuel pump.

The present invention has for an object to provide an improved governor of this kind which when used as a fuel governor of an internal-combustion engine, permits either of two different predetermined engine speeds to be selectively maintained.

According to the invention the governor shaft is provided with two radial spill outlets each controlled by a separate spring-loaded valve element which rotates with the shaft about the axis of the shaft and is resiliently held on its seat, the spring loading of the two valve elements being respectively so arranged that the two valves will respectively open at two predetermined speeds of rotation of the shaft, and an externally operable valve is provided, by which the spring-loaded valve opening at the lower speed can be cut off from communication with the pump delivery, means being provided which prevent the valve element responsive to the lower speed from moving outwardly to an excessive extent when the shaft runs at the higher speed for which the other valve is set. Each valve spring is preferably a leaf spring extending longitudinally of the shaft. More than two valves, each set for a difierent speed, may be used, in conjunction with means for successively rendering, when required, all valves except that for the highest speed inoperative, on a single governor shaft if desired, more particularly to allow more than two speeds of an internal combustion engine to be selectively maintained within narrow limits, but alternatively in an arrangement having only two valve elements responsive to different predetermined speeds, intermediate speeds may be maintained by placing the cut-off valve element in intermediate positions in which the flow to the valve element responsive to the lower speed is progressively throttled. The drawing accompanying the specification is a sectional elevation illustrating a fuel pump equipped with a governor equipped for two preset speeds and embOdying one form of the invention.

Referring to the drawing, the governor is mounted on a gear-type fuel pump having a housing 1 and pumping gears 2 and 3, one mounted on a drive shaft 4 coupled to the engine to which the fuel is to be supplied and the other on an idler shaft 5. The idler shaft 5 has an axial bore 6 communicating with the delivery side of the gear pump and is coupled in a fluid-tight manner with a governor shaft 7 which forms a coaxial extension of the shaft 5 and has an axial bore 8 which forms an extension of, or communicates with, the bore 6 of the shaft 5. Two valve seats 9 and 10 are arranged at the outer ends of two bores 9a and 10a which are longitudinally spaced along the shaft and extend in diametrically opposite directions from the central bore 8, and each valve seat 9 and 10 is normally closed by a valve element 11 or 12 of hemispherical shape. Each valve element is mounted in a valve support member 13 or 14, and each support member is carried by a leaf spring 15 or 16 which extends longitudinally of the shaft and is fixed to a spring carrier 17 or 18. The spring carriers 17 and 18 are respectively mounted in direct diametric opposition to the valve seats 10 and 9 so as to dynamically balance the masses of the valve seats and valveelernent assemblies.

The spring 15 is stronger than the spring 16 so that the valve 9, 11 will not open until the higher one of two predetermined engine speeds, generally the normal or the maximum running speed of the engine, is reached, while the valve assembly 10, 12 will open at a lower predetermined speed, for example at the idling speed of the engine to which the shaft 4 is coupled. The admission of fuel from the bore 8 to the seat 16 of the lastmentioned valve 10, 12 is controlled by a spring type piston type slide valve 19 which operates in a wider counter-bore part 8a of the bore 8, and which can, against the action of the pressure operating in bore 8a, be moved to cut off the bore 10a leading to seat 10 by means of a speed-control lever 20, which acts on the piston 19 through a pin 21. A spring 22, interposed between the lever 20 and the pin 21, makes it possible, by a suitable movement of the lever 20, to maintain the valve 19 in an intermediate position in such manner as to maintain a predetermined pressure drop at the inlet to bore lila, according to the loading which is applied to the spring 22.

When the valve 19 is closed, the governor valve 12 responsive to the lower one of the predetermined speeds is ineffective for controlling the engine speed, allowing this speed to rise well above that at which the valve element 12 will be lifted off the seat 10 even in the absence of pressure in the seat. In order to avoid the risk of the valve element 12 and its support moving under these circumstances so far outwardly as to foul the housing 23 in which the governor is enclosed, a stop member 24 is secured on the governor shaft 7, which limits the outward movement of the spring 16. No such stop will generally be required for the valve element 11 which opens at the highest engine speed, because its seat passage 9a always communicates with the bore 8, and opening of valve 11 will therefore always be effective to prevent any rise of engine speed beyond the range in which the pressure acting in here 8 is required in addition to centrifugal action for opening valve 11 against the pressure of spring 15.

The fact that the slide-valve piston 19 is arranged coaxially in the rotary member carrying the governor valves greatly reduces sealing difiiculties.

The apparatus illustrated may be modified in various respects without exceeding the scope of the invention. The piston-type slide valve 19 could, for example, be replaced by a poppet-type valve.

Furthermore the governor arrangement described may be used generally for the control of the flow of any liquid or gaseous fluid whenever one outlet is required to be opened at one speed, and a second outlet is required to be opened at a higher speed, means being provided for selectively preventing the first outlet from becoming effective. The rotation of the governor shaft may be derived from an engine shaft or from any variable-speed shaft. Thus an additional advantageous use of the present invention is for the control of the combustion-air supply to an internal-combustion engine.

What I claim is:

1. A speed-responsive spill-type flow-control governor, which comprises a governor shaft provided with two radial spill outlets which communicate with a common inlet for connection to the delivery port of a positivedisplacement pump, each spill outlet being controlled by a separate spring-loaded valve element which rotates with the shaft about the axis of the shaft and is resiliently held on its seat, the spring loading of the two valve elements being respectively so arranged that the two valves will respectively open at two predetermined speeds of rotation of the shaft, and an externally operable valve by which the spring loaded valve opening at the lower one of said speeds can be cut ofl? from communication with the 20 common inlet, and means limiting the outward movement of the valve element responsive to the lower speed so that such valve element is prevented from moving outwardly (1;. to an excessive extent when the shaft runs at the higher speed for which the other valve is set.

2. A governor as claimed in claim 1, wherein each valve spring is a leaf spring extending longitudinally of the shaft.

3. A governor as claimed in claim 1, comprising on a single governor shaft more than two valves, each set for a different speed, in conjunction with means for successively rendering inoperative, when required, all valves except that for the highest speed.

4. A governor as claimed in claim 1, having only two valve element's responsive to different predetermined speeds, wherein means are provided for placing the cutoif valve element in intermediate positions in which the flow to the valve element responsive to the lower speed is progressively throttled.

References Cited in the file of this patent UNITED STATES PATENTS 1,491,883 Priess Apr. 29, 1924 2,779,582 Hopper Jan. 29, 1957 2,896,653 Marlin July 28, 1959

Images