US2891415A - Control means for liquid fuel injection pumps for internal combustion engines - Google Patents

Description

June 23, 1959 M EVANS 2,891,415

' CONTROL ME IS FOR LIQUID F L'INJECTION PUMPS FOR TERNAL. COMBUS N ENGINES Filed May 13, 1957 2 Sheets-Sheet 1 June 23, 1959 2,891,415

F. M. EVANS CONTROL MEANS FOR LIQUID FUEL. INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES Filed May 13, 1957 2 Sheets-Sheet 2 CONTROL MEANS FOR LIQUID FUEL INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES Fraser Mackie Evans, Acton, London, England, as'signor to C.A.V.- Limited, Acton, London, England Application M y 13, isspseria No. 658,604 1 Claim. c1. 74-603) This invention relates'to liquid fuel injection pumps for internal combustion engine's of the kind having .one or more reciprocatory plungers', and in which the effective length of the plunger strokes is variable by a spring-loaded and endwise movable control bar responsive to the action of a speed governor or other automatic means, or the driver.

To enable a supply of fuel in excess of the normal maximum to be obtained temporarily when starting the engine a control device operable by the driver "is required, and the object of the present invention is to enable such a device to be provided in a convenient form.

A control device in accordance with the invention comprises the combination of a hollow body part adapted to be secured to the pump housing around one end of the control bar, a push piece operable by the driver, a cam pivotal-1y mounted on the push piece and serving as a stop to determine the normal maximum and the extra supply positions of the control bar, and a spring acting on both the cam and the push piece, the cam having formed on it a finger like extension which in one position of the cam can enter a recess in the adjacent end of the control bar and a lobe which can slide along a groove in the body part, or in an insert in the body part, the device being adapted to operate as herein described.

In the accompanying drawings, Figures 1 and 2 are sectional side elevations illustrating a control device in accordance with the invention, Figure 1 showing the device in the condition in which it determines the normal maximum fuel supply, and Figure 2 showing the device in the condition in which it enables an extra fuel supply to be obtained when starting the engine. Figure 3 is a similar view to Figure 1 illustrating a modified construction of the device. Figure 4 is a diagrammatic part sectional side view illustrating the device shown in Figures 1 and 2 applied to a fuel injection pump provided with a speed responsive governor.

Referring to Figures 1 and 2, the control device there shown is provided with a hollow cylindrical body part a, adapted to be secured to the pump housing b around one end of the spring-loaded and endwise movable control bar c. The said body part is adapted for screw-thread connection with an externally threaded end of a bush d, surrounding the control bar, and also is provided with a thin flange e which canabut against the adjacent face of the pump housing. This flange is slit to form a tongue j, which can be pressed into a recess g, in the said face of the housing to lock the said body permanently to the pump housing. On the outer end of the body part is attached an adjustable sleeve h, in screw-thread connection with the body part a. Within the body part is contained a slidable cylindrical push piece i, on which is formed a stem 1' extending through a central hole in the outer end of the sleeve h. Across the portion of the push piece which lies within the body part is formed a transverse slot, and in this slot a cam k is secured by a pivot m.

a shoulder u, on the push piece. ;spring can bear onlthercam. v -Afte'r the device has..been placed 'in position .on the 2,891,415 Patented June 23, 1959 positions of the cam can abut against the base of the slot in the push piece and so hold the cam against undesired rotation. 1

.The push piece is loaded by a spring I, contained in the body part, one end of the spring being supported by The said end of the pump, and -the.necessary,.initial adjustment has beer made to determine the normal maximumlfuel supply position of the push piece suitable for the engine which the pump is required to supply, it is desirable to lock the sleeve to prevent unauthorised interference with the adjustment. This provision may be made in any convenient manner, but preferably it consists of an outer sleeve v. which is pressed tightly on to or is otherwise non-remov' ably secured to the other sleeve h, and in the outer end of the additional sleeve is formed a polygonal or other non-circular hole through which the stem of the push piece extends, the said stem being made to a section conforming with the shape of the hole.

The arrangement is such that during normal running conditions of the engine the cam occupies a position in which the axis of the finger piece n, is inclined to the axis of the control bar as shown in Figure 1. In this position the finger piece serves to determine the normal maximum fuel supply position of the control bar c, movement of the bar from this position having the effect of reducing the rate of fuel supply to the engine. This movement of the control bar may be effected by a speed governor as, for example, in Patent No. 2,795,219. Thus, in Figure 4 such a governor is indicated by 5, and is connected by a lever 6 and link 7 to the control bar 0 of the pump 8, the latter and the governor being of well known form, and the spring loading of the control bar being effected in this embodiment by the springs 9 of the governor. Alternatively, the movement of the control bar may be efiected by other automatic means or by hand. When an extra supply of fuel is required for starting the engine, the driver pushes the push piece 1', inwardly against the action of the spring I. The first efiect of this is to push the control bar c in the same direction until the lobe p, on the cam reaches the inner end of the groove q, in the body part, and the engagement of the lobe with the end of the groove causes the cam to be turned to the position in which the finger piece is opposite the recess 0, in the control bar. The latter can then return (under the action of its spring) until it abuts against the portion of the cam at the root of the finger piece. On release of the pressure on the outer end of the push piece, both control bar and push piece return together until the push piece is arrested by the outer end of the sleeve h, as shown in Figure 2. When the control bar is in this position it enables the pump to give the desired extra fuel. On'starting the engine, and when sufiicient speed has been attained, the control bar is moved by its actuating means to a position in which it is clear of the finger piece n. The cam is then turned by the asso-v ciated spring t, to the position in which it restores the initial inclined position of the finger piece. If the driver actuates the push piece while the engine is running and holds it in he thereby merely reduces the fuel supply below the normal maximum. The device therefore can effectively frustrate any :attempt by -the driver to obtain extra fuelfromthupumpexcepting When-starting the engine.

The modified construction shown in Figure 3 is essentially the same: as the --construct,ion above described, -but ditfers in thatthe body-part wisext'ended and the part h is inserted inscr'ew thread connection with the-interior of the body part a, the grooveiq in'whieh the lobe p of the cam can 'slide being provided in the part h. The sleeve v is non-removably secured to thebody part by a tongue piece w, on the sleevewhich engages a groove x in the body part.

Having thus described my invention what I claim as newand desire' to securebykettersifat'ent' is:

Control means for a liquid fuel injectionr-pump of the kind-having at-least oneirecipmc atory plufiger,=arid a spring-loaded andiendwisemo'vableeontrol "bar for varying the :effective lengthmfiithexplunger' stroke; and thereby varying the pump outpug 'ieomprising:in combination with the control barwhich atfonwend zis-provided with a central recess, a relatively=stationary:hollow:body into which the recessedend inf-the control':bar-':extends, and which has 'a longitudinaltgroove -thereinpa slidable and manually operable push piece carried by the body, a cam pivotally-mounted-on thepush-piec'e to serveasa-stop for limiting movement of the control bar in the direction for increasing the pump output," the cam being provided with a lobe which is slidable along the groove in the body, and also with a finger-like extension which in one position of the cam can enter the'recess -in the end' of the control bar for enabling the portion of the cam at the root of the finger-like extension to serve asthe stop, and a spring actingon both the camand the-push piece and serving normally to retain the cam in another position in which the outer end of its finger-like extension is out of alignment with the recess in the end of the control bar and can serve as the stop, the cam being movable'fi'om the second mentioned position to the first mentioned position by contact of the lobe on the cam with one end of the groove in the body in response to actuation of the push piece, and being returnable by the spring to the second mentioned position followingr'elease of the push piece and'retraction ofthe control bar from the earn.

No references cited.

Images