US3465969A - Liquid fuel injection nozzles - Google Patents

Description

3 Sheets-Sheet l SePt- 9,1969 1'. PRIEDE ETAL LIQUID FUEL INJECTION NOZZLES Filed aan. 9, 1967 SePt- 9, 1969 T. PRIEDE ETAL 3,465,969

LIQUID FUEL INJECTION NOZZLES Filed Jan. 9, 1967 5 Sheets-Sheet 2 Sept- 9, 1969 T. PRIEDE ETAL 3,465,969

LIQUID FUEL INJECTION NOZZLES Filed Jan. 9, 1967 ,x 3 Sheets-Sheet 5 United States Patent Office Patented Sept. 9, 1969 3,465,969 LIQUID FUEL INJECTION NOZZLES Teodore Priede, Southampton, and Jan Wilkins, London, England, assignors to C.A.V. Limited, London, England Filed Jan. 9, 1967, Ser. No. 607,931 Claims priority, applicati??1 /Great Britain, Jan. 7, 1966,

Int. Cl. B05b 1/30, 1/32 U.S. Cl. 239-533 1 Claim ABSTRACT OF THE DISCLOSURE This invention relates to liquid fuel injection nozzles of the type intended to be mounted in the body of an internal combustion engine and through which fuel is supplied to a combustion space of the engine by a fuel pump, whith the nozzle comprising a nozzle head having a fuel discharge orifice, a valve member for controlling the fiow of fuel through said orifice, and resilient means for biasing the valve member towards a position in which the flow of fuel through the orifice is prevented.

The object of this invention is to provide such a nozzle in a form in which the emission of noise therefrom when in use, is minimized.

In the accompanying drawings:

FIGURE l is a sectional side elevation of one example of a liquid fuel injection nozzle which may incorporate the invention and,

FIGURES 2, 3, 4, 5, 6 and 7 are views and an enlarged scale of part of the nozzle of FIGURE l and showing respectively various embodiments of the invention.

One example of a liquid fuel injection nozzle to which the invention may be applied is shown in FIGURE l and in which there is provided an elongated body part 10 which is adapted to be mounted within a bore formed in the cylinder head of a compression ignition engine. Mounted on one end of the body part is a cylindrical nozzle head 11, the free end of which in use, extends into a combustion space of the engine. Moreover, in the free end of the nozzle head is formed a fuel discharge orifice 12 and within the head is formed a cylindrical bore which contains a slidable valve member 13. Also formed in the nozzle head is a seating with which the valve member co-operates to prevent the iiow of fuel through the orifice. Fuel is supplied to the orifice through passage 14 formed in the nozzle head and body part from a fuel supply pump and the arrangement is such that when fuel is supplied by the pump the valve member will be lifted from its seating to allow fuel to be discharged into the combustion space through the orifice.

The valve member is urged onto its seating by a coiled compression spring 15 which is accommodated in a chamber defined at the end of the body part remote from the nozzle head. The spring acts upon the valve member through a push rod and this is constituted by a spring abutment 16 which is mounted upon a rod 17. As shown in FIGURE 2, the rod 17 is provided with a blind bore 17a extending from the end of the rod remote from the abutment. Within the bore 17a are three struts defined by three substantially equal lengths of piano wire 18 which bear against the end of the 4bore and upon an extended portion of the valve member 13. The end of the bore 17a adjacent the -valve member is enlarged and the tip of said extended portion enters therein but does not contact any part of the rod. The size of the bore in the rod is chosen to permit limited buckling of the wires under the applied load.

In a modification seen in FIGURE 3, the bore 17a is constant in diameter throughout its length and the open end thereof is closed by a slidable plug 20. Furthermore, the end of he rod is rolled over to prevent the plug falling out. The operation of this modification is as described. In this example and the earlier example, the wires 18 are replaced by a large number of wires 19.

In a further modification seen in FIGURE 4, the lengths of wire are replaced by a plurality of Belleville washers 21 disposed Within the bore 17a in the rod 17 and which are slightly smaller in diameter than the bore. In use, the washers flatten out as the valve member moves against the action of the spring and in so doing, the edges thereof contact the wall of the bore to limit the deflection.

In another modification seen in FIGURE 5, the bore i 17a is filled behind the plug 20, with an insert 22 of a hard synthetic resin material such for instance as nylon which can be compressed to a limited extent by a load applied thereto.

In a further modification shown in FIGURE 6, the bore 17a in the rod 17 accommodates a bar 23 of rectangular section. The narrower edges of the bar are shaped in a manner complementary to the wall of the bore. Moreover, the opposite ends of the bar 23 are formed with integral plugs 24, 25 respectively. The plug 24 is located at the inner end of the bore and is a tight fit while the plug 25 is a sliding fit in the bore. Moreover, the plug 25 is formed integrally with a cap 26 which engages over the reduced end of the valve member 13. In use, the bar is able to buckle a limited extent to provide the required resilience.

In a further modification shown in FIGURE 7 there is mounted within the bore 17a in the rod 17 a bar `27 complementary in shape to the 4bore and which is a sliding fit therein. Moreover, the outer end of the bore 17a is of enlarged diameter and accommodates a plug 28 formed integrally with the bar 27. In this case the slight clearance between the bar 27 and the wall of the bore enables the bar to be compressed slightly under the applied load and thereby provides the required resilience.

It has been found that by using the constructions described the radiations of noise created by the impact of the valve member upon its seating when the nozzle is in use is minimized. It will be appreciated that in the constructions shown in FIGURES 3, 4, 5, 6 and 7 relative movement occurs between parts which are in contact with each other and it is thought that this also helps to reduce the noise emitted by providing a measure of damping. Moreover, the rate of the resilient member, that is to say, the force required to compress the member for a unit deflection, be it constituted by wires, rods, spring Washers or a synthetic resin insert, is arranged to be high as compared with the rate defined in like manner, ofthe spring 15.

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

1. A liquid fuel injection nozzle of the type intended to be mounted in the body of an internal combustion engine and through which fuel is supplied to a combustion space of the engine, the nozzle comprising a nozzle head having a fuel discharge orifice, a valve member for controlling the flow of fuel through said orifice and a spring for biasing the valve member towards a position in which the flow of fuel through the orifice is prevented, with the valve member being movable against the action of said spring by fuel under pressure acting on the valve member, the improvement comprising a push rod located between the spring and valve member, said push rod having a bore therein and a resilient means disposed within said bore and serving to transmit the force exerted by said spring to said valve member, with the force required to compress the resilient means for a unit of deection being greater than that of the spring and the deflection of said resilient means under load being limited.

References Cited UNITED STATES PATENTS 1,301,719 4/1919 Lloyd 239-533 1,525,156 2/1925 Teufl 239-533 1,755,192 4/1930 Scott 239-533 2,750,957 6/1956 Tavola 239-533 X 2,957,631 10/1960 Armstrong 23 9-533 3,124,305 3/1964 Evans 29-533 3,175,771 3/1965 Breting 29-533 3,342,422 9/1967 Millington etal 239-533 FOREIGN PATENTS 504,483 3/ 1927 Germany 736,794 9/1955 Great Britain. 808,206 1/1959 Great Britain. 329,505 4/ 1958 Switzerland.

EVERETI W. KIRBY, Primary Examiner U.S. Cl. XR.

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