US1225345A - Controlling the supply of liquid fuel to internal-combustion engines. - Google Patents

Description

J. IVIcKECHNlE.

CONTROLLING THE SUPPLY OF LIQUID FUEL TO INTERNAL COMBUSTION ENGINES. APPLICATION FILED Nov. 7. I9I6.

l gQ5 3%5o Patented May 8, 1917 IUD ran enarns rniranr oration.

JAMES MQKECHNIE, OF EARROW-IN-FURNESS, ENGLAND, ASSIGNOR TO VICKERS LIMITED, 01? LONDON, ENGLAND.

CONTROLLING THE SUPPLY OF LIQUID FUEL T0 INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented May e, ism.

Application filed November 7, 1916. Serial N 0. 129,953.

To all whom it may concern:

Be it known that I, JAMES MoKEoHNIE, a subject of the King of Great Britain, residing at Naval Construction Works, Barrow-in-Furness, in the county of Lancaster, England, have invented certain new and useful Improvements in Controlling the Supply of Liquid Fuel to Internal-Combustion Engines, of which the following is a specification.

This invention relates to internal combustion engines of the type in which liquid fuel is injected into the working cylinder by means of a pump and the chief object of the invention is to provide improved means by which the supply of fuel may be controlled so as to give maximum efficiency for varying load on the engine.

According to this invention the power of the engine is controlled through both the fuel pump suction valve and the injection valve by simultaneously varying by .a common control gear the efiective clearance between levers effecting the operation of the two valves and their respective cams. For this purpose the -two valve levers are preferably mounted upon eccentric pivots, which are moved simultaneously so as to alter the position of the two axes. The pump (one being employed for each cylinder in a multi-cylinder engine) acts as a measuring pump to determine the quantity of fuel injected for each working stroke of the engine, while the injection valve serves to time the injection and to maintain a high injection pressure as the power is reduced. A resilient accumulator may be interposed between the pump and the injection valve and the pump may discharge part or all of its charge into this accumulator before the injection valve opens.

The form of the injection valve cam is so related to the eccentric displacement of the lever axis that the opening of the valve is timed to give the best result for all variations in power given by the adjustment of the suction valve lever, so that separate timing gear is not necessary. The displacement of the end of the lever is both radial and circumferential to the cam to allow the cam to be given a practicable shape for correct timing. The reduction of duration of opening of the injection valve as the clearance is increased prevents excessive fall of injection pressure at reduced powers. The cam operating the pump suction valve is preferably made with a steep leading edge giving mechanical opening of the valveearly in the suction stroke of the pump plunger. The following edge has a much more gradual slope so that the position of closing of the suction valve may be varied over as wide a range as may be desired during the discharge stroke of the pump, by variation of the clearance between the cam and the valve lever, as already described. The quantity of fuel delivered depends upon the length of the effective portion of the discharge stroke, that is, the portion during which the suction valve remains closed.

The shaft of the common control gear may be turned under both hand and governor control, a clutch being fitted which disengages the governor from the shaft upon operation of the hand control, thus rendering it unnecessary to overpower the governor.

In order that the said invention may be clearly understood and readily carried into effect, the same will be described more fully with reference to the accompanying drawings, in which Figure 1 shows part of one element of a multi-cylinder engine fitted with a separate fuel pump for each cylinder and with a governor controlled fuel injection device according to this invention; and

Fig. 2 is a detail view of a slight modification.

A. is the fuel injection valve in the cylinder cover B. G is the high pressure fuel oil pump driven ofi' the cam shaft D. 1 E is a rockshaft through which the control of the injection valve and fuel pump is efiected, this rockshaft being actuated by means of the centrifugal overnor F through the oil operated relay in known manner, or, if desired, alternatively by hand gearing such as the lever H, connected directly to the rock-shaft. The gear is shown approximately in its normal iunning position.

The rockshaft E is controlled from the governor through the lever J which is free to turn on the pin it, on which the hand lever H is keyed. This lever J has secured to it the quadrant 7', and the hand lever H engages this quadrant through the pawl h I v gaged the lever H inoves with the lever J.

Kim.

The link (3 and lever e transmit the motion of the'lever H to the rockshaft E, so that for anymovement of the governor due to a variation in the speed of the engine a correspondingmovement of the rockshaft Eis obtained] Whenthe lever H is gripped ifor hand regulation of-the engine the grip lever h? withdraws the pawl iz/ from the quadrant .notch so that thegovernor. is disconnected and the rockshaft E can be turned without requiring the'governor to be overpowered, either at starting or during runn ng I. The'injection valve A is operated by the cam K- on the cam shaft D through the valve lever L, in the end of which is-the cam roller Z. This lever is mounted upon aneccentric fulcrum pin M which is adapted to be partly rotated by' the rockshaft E through levers m and m and link m m is-theeccentric portion of the fulcrum pin M, shown. in dotted'li'nes. Upon this pin being. partly rotated by thev rockshaft E it imparts to the roller Z a radial displacement relatively to i the cam K, thus altering thev clearance 00 between the cam roller Z and cam K, this either increasing or decreasing the angle 00 of duration of injection according to the direction of rotation of the rockshaft E, causing the roller to work on I the lower or. higher part of the cam.

The-center of the eccentric m is so chosen that it gives to ,the roller Z, upon partial rotation-of the fulcrum pin M, a tangential as well as a radial displacement about the center of the camshaft D, and the leading edge of the cam is so correlated to the total displacement imparted to the roller Z that, for

all adjustments of the fulcrum pin M, the point of opening of the injection valveA is either maintained practically-constant for' a constant speed engine such-as a dynamo r engine or advanced and delayed for a variable, speed engine such as a marine engine,

insuch'a'imanner that the valve is timed to open always at the point in the /engine" stroke which gives the best result forfany variation in power given;by the adjustment of the suction valve lever, so that separate timing gear is not necessary. v

The Plunger c of the fuel pump C is driven ofi'fthe camshaft D by the 'eccentric d and strap d, 0% showing the center of the eccentric. Fig. 1 shows the pump G in section-through the valve boxes. I N is the suction valve, and thefuel supply to the 'pump passes through the'pipe n into the fine strainer n, and thence to the suction valve N. O is the delivery valve which is normally held upon its seat by the' spring o, the fuel assing through the delivery pipe, 0" to the injection valve A. In this pi e 0 may befitted "a resilient accumulator of fiatpin Thelever g' is mounted upon 3.111

eccentric e on .the rockshaft E and is connected to the lever g by the link 9 so that upon partial rotation of the rockshaft E and the eccentric e the vertical distance v between the roller 9 and. the point of con- .tact g of the tappet end of lever Q can be elther increased or decreased. The push 1 vrod n? keeps'the roller 9 up to the profile of the cam K by means of the spring a 5.

The suction valve N is normally maintained upon its'seat by the light spring a andin the illustration the push rod 01. is shown just leaving the suction valve N on its seat, that is to say the valve is just closing during the delivery stroke of the pump plunger 0, giving an effective delivery stroke measured by the angle 00 at the cam shaft D. By suitably choosing the size of the eccentric e and by so shaping 1 the closing face 9 of cam Q wecan arrange for the valve N to close at any desired angle on the delivery stroke of the plunger 0, giving-a predetermined effective delivery of oil, for each position of the rockshaft E. The leading face 9 of the-cam gives mechanical opening of the suction valve early in the pump suction stroke. The angles'w, and m are not usually equal or 00- incident, the angle 01: measuring the efiFective stroke of the pump and hence the amount of the fuel charge, which is stored by the accumulator P and is then injected through a period measured by the smaller angle 2?. The two angles, however, increase 11 0 and decrease together. I

As hereinbefore set forth the angle m shows the angle of duration of the opening of the injection valve A, which can be either increased or decreased by partial rotation of the rockshaft E (acting through its connection to the fulcrum pin M), so that according to the ratio of the levers g and g and the size of the eccentric m that is selected, each angular position of the rockshaft E from its maximum to its out out position gives a definite angle of duration m ,1 and the closing face 9 of the cam Q, is. so correlated as to close the suction valve N at a predetermined position of the pump plunger 0 on its delivery stroke which gives a charge of oil corresponding with the amount required for the angle of duration :12, for all adjustments of the rockshaft E. The throw of the cam Q isfmade large enough to insure a suficient opening of the valve N when the rockshaft E is at its maximum power adjustment- R is a lever by which each individual pump-can be cut out independently through the bell crank lever 1', which depresses the suction valve N independently of the common control gear and thus renders the pump inoperative.

Fig. 2 shows an alternative arrangement of the rockshaft E and pin 9 upon which levers g and g are mounted. The cam lever g is in this case mounted on the eccentric e of the rockshaft E so that the roller 9 is displaced both radially and circumferentially of the cam Q. In this arrangement the opening or leading edge 9 of the cam Q is so shaped and the eccentric is so chosen that the tangential displacement imparted to the roller 9 upon partial rotation of the rockshaftE maintains the timing of the opening of the suction valve N practically constant for all adjustments of the rockshaft E. That is, the path of adustment of the roller 9 follows substantially the outline ,of the leading edge 9 of the cam.

What I claim and desire to secure by Letters Patent of the United States is 1. In an internal combustion engine, a fuel injection valve by which liquid fuel is sprayed into the cylinder, a fuel pump including a mechanically controlled suction valve, a pair of adjustable lever and cam de- "lces' for operating the said injection and suctlon valves and a common control gear adapted simultaneously to vary the adju stment of the lever and cam devices for both of the said valves.

2. In an internal combustion engine, a fuel injection valve by which liquid fuel is sprayed into the cylinder, a fuel pump-including a mechanically controlled suction valve, a pair of adjustable lever and cam devices for operating the said injection and suction valves, means for varying the effective clearance between the valve levers and their respective cams and a common control gear adapted simultaneously to actuate the said varying means of the lever and cam devices of both of the said valves.

3. In an internal combustion engine, a fuel injection valve by which liquid fuel is sprayed into the cylinder, a fuel pump including a mechanically controlled suction valve, a cam for operation of the injection valve, an injection valve lever mounted on an eccentrically adjustable pivot, a cam for operating the pump suction valve, an eccentrically pivoted suction valve lever actuated by the said cam and a common control efjection valve lever and engine regulating mechanism operatively connected to the said rockshaft for simultaneous adjustment of the two levers.

- 5. In an internal combustion engine, a fuel injection valve by which liquid fuel is sprayed into the cylinder, a fuel pump including a mechanically controlled suction valve, a pair of adjustable lever and cam devices for operating the said injection and suction valves, an engine governor, hand regulating mechanism, control gear adapted for operation by both the governor and the hand regulating mechanism and adapted to vary the adjustment of both of the lever and cam devices simultaneously and means for disconnecting the hand regulating mecha nism from the governor.

6. In an internal combustion engine, a fuel injection valve by which liquid fuel is sprayed into the cylinder, a fuel pump including a mechanically controlled suction valve, a pair of adjustable lever and cam devices for operating the said injection and suction valves, an engine governor, a hand regulating lever normally operated by the governor mechanism, control gear connected to and operated by the said lever and adapted to vary the adjustment of both of the valve lever and cam devices simultaneously and means for disconnecting the said hand i ture. v JAMES. MoKEGI-INIE.

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