US2702029A - Liquid fuel injection pump for internalcombustion engines - Google Patents

Description

Feb. 15, 1955 D. G. BURTON LIQUID FUEL INJECTION PUMP FOR INTERNAL-COMBUSTION ENGINES Filed Dec. 21, 1953 as'itisnot consistent withgoodre tssuchthatwhen theenglneieatjo -resttbeeontrelberoeeupiesalimitpolittcnin United States Patent Ofiice' 2,102,029 Patented Feb. 15, 1955 LIQUID FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES DoIglasGBartom-Breatf Englanflasalperlo QLV.Umited,Aet?:'London,EngI-d Applieatiol December 21, 1953, Serial No. 399,354

Claims priority, application Great Brltfi Deeeniser 23, 1952 1 Claim- (Cl- 123-14.)

This invention relates to liquid fuel injection pumps for internal combustion engines, and has for its object to provide in a simple form a pump of the reciprocatory plunger type having combined with it a governor responsive to the air-pressure in the air-intake manifold of the engine for actuating a slidable control bar, the pump output being variable by relative angular movement of the plunger (or each plunger) and its associated barrel under the action of the said bar.

The invention comprises a pump of the type aforesard of which (1) the governor comprises a chamber divided into two compartments by a spring-loaded flexible diaphragm or piston, one of the compartments being adapted for connection with the air-intake manifold of the engine, and having therein a stabiliser consisting of a spring-loaded movable abutment for steadying the movements of the diaphragm or piston, and of which (2) the spring loaded discharge valve of the pump barrel, or each barrel, is of the poppet type, the closure member of which has combined with it a cylindrical part which (when the valve is closed) occupies a cylindrical bore extending from the valve seatin and which is moved beyond the seating when the cosure member is fully open, the closure member or the barrel having therein also a by-passage arranged to permit a restricted flow of fuel before the closure member is fully opened.

In the accompanying drawings,

Figure l is a part sectional side elevation of a multiplunger fuel injection pump combined with a governor in accordance with the invention.

Figure 2 is a sectional elevation illustrating one of the pgmp plungers and its associated barrel and discharge v ve.

valve.

A pump embodying the invention may so far as the pumping means are concerned, he of any convenient and conventional construction, and it may include a single reciprocatory plunger, or a plurality of such plungers arranged parallel with each other. The output of the pump is variable in known manner by the provision in the plunger a or each plunger of a spill passage b which is brought into action by angular movement of the plunger relatively to discharge ports 0, in the barrel, film movement beingoeitfected by a slldable control bar 41 carried in the y part of the pump. Alternatively the spill may be controlled by angular movement of the barrel by the bar d.

For actuating the control bar d, one end of it is -'con nected to a governor responsive to the air pressure in the air-intake manifold e of the engine, as shown in Figure 1. According to the invention the governor consists of a cylindrical chamber 1 which is divided into two compartments by a flexible diaphragm g (or piston) loaded by a spring h, and one of the compartments is provided with a connection for a pipe i leading to the said manifold at a position between the manifold throttle valve 1 and the engine, the other compartment being open to the atmosphere. In the first mentioned compartment is also contained a stabiliser. Thts consists of a movable abutment I: loaded by a spring m, which when the diaphragm is moved into contact with it serves to supplement the action of the spnpg h acting on the drahragtn and hence prevent hunting. Such an increa e in spring resistance is found to be required at low engine and loads, but is not desirable: tother eondi ons a on.

Thearrangemeut width Figure 3 illustrates an alternative form of the discharge the pump is able to give its maximum output. Movement of the control bar from this position under the action of the governor serves to reduce the pump output.

The second feature of the invention consists in the combmatron with the discharge end of the pump barrel in (Figure 2) or each barrel, of a discharge valve of a poppet type of the following form.

The closure member of the valve (which is loaded by a spring 0) comprises a head p having a frustro-coni-' cal part which co-operates with an annular seating at the outlet end of a cylindrical bush q situated at the discharge end of the barrel. On the stem r of the closure member is formed a short cylindrical land which when the valve is closed lies within the said bush. This land must be moved through the seating by a distance 8",

(Figures 2 and 3) before the full discharge can occur. Also in the stem of the closure member is formed an axial bore r leading to a by-pass passage u of small diameter having its discharge end situated beneath the head of the closure member as shown. The arrangement is such that during the discharge stroke, the initial movement of the closure member allows fuel to pass along the bore 1 and through the passage u at a restricted rate which depends on the speed of the pump. Later and when the land has been moved past the seating a full and unrestricted outflow occurs through the ports v.

In the example shown in Figure 2, the ports v open into an annular groove w around the stem of the closure member. Alternatively and as shown in Figure 3, the ports v may be made of larger diameter than those shown in Figure 2 and arranged to extend to the surface of the stern of the closure member.

If desired the equivalent of the passages t and u may be provided in the bush q instead of in the closure memit has been found that when a pump is provided with a simple governor as above described, the stabiliser tends to exert an excessive resistance to movement of the diaphragm at high pump speeds and thereby interferes with the desired restriction of the pump out-put'at such speeds. To obviate this condition various modifications of the governor have been devised and used but these result in the disadvantage of arelatively complex governor construction. By the combination with the pump of a discharge valve or valves as above described instead of a valve of conventional construction this disadvantage is obviated, and a satisfactory regultaion of the pump output over a wide range of speed and with the throttle in any position, can be obtained with a governor of simple construction.

Having thus described by invention what I claim as new and desire to secure by Letters Patent is:

Means for supplying liquid fuel to an internal combustion engine, comprising in combination a liquid fuel injection pump having at least one reeiprocatory plunger and a barrel in which the plunger is movable, a sltdable central bar for effecting relative angular movement of the plunger and barrel to vary the pump output, a governor having a chamber divided into two compartments by a spring loaded member which is responsive to arr pressure for actuating the control bar, one of the com- .partments being adapted for connection to the air-intake manifold of the engine, a stabiliser consisting of a spring loaded abutment arranged in the chamber to co-operate with the said spring loaded member for steadying the movements thereof. and a spring loaded discharge valve of the poppet type for controlling the delivery of fuel from the barrel by the plunger, the discharge valve comrising a closure member having a cylindrical land, a part having a cylindrical bore which at one end terminates In a seating for the closure member, and which is occuits closed position on the seating, and a byass pase barrel pied by the cylindrical land when the closure member is

Images