US3511087A - Apparatus for testing fuel injection nozzles of compression ignition engines - Google Patents

Description

May 12, 1970 R. s. EMERSON L 87 APPARATUS FOR TESTING FUEL INJECTION NOZZLES OF COMPRESSION IGNITION ENGINES Filed May 20, 1968 71 All? llVAfT Invenlow, I

A ttorneys I United States Patent 3,511,087 APPARATUS FOR TESTING FUEL INJECTION NOZZLES OF COMPRESSION IGNITION ENGINES Reginald S. Emerson and Cecil I. Taylor, both of Tingewick Road, Buckingham, Buckinghamshire, England Filed May 20, 1968, Ser. No. 730,410 Int. Cl. G01m 15/00 U.S. Cl. 73-119 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to apparatus for testing the fuel injection nozzles of compression ignition engines. More specifically, it is concerned with apparatus for testing the inclination or angular position of the spray hole or holes in such nozzles.

The fuel injection nozzles used in compression ignition engines generally have an axial bore one end of which is connected to a fuel supply passage and the other end of which terminates in a number of small spray holes in the extreme tip of the nozzle. These spray holes extend from the axis of the bore at a predetermined inclination or angular position so as to ensure that the fuel ejected by the nozzle does not impinge on vital parts of the combustion chamber of the engines such as the cylinder valves and piston. It is therefore important that the inclination or attitude of these spray holes be carefully checked for accuracy, and the main object of the present invention is to provide apparatus by which such checking can be done in an effective way.

According to the invention, apparatus for testing the fuel injection nozzles of compression ignition engines comprises nozzle-holding means for holding a fuel injection nozzle and a liquid supply passage for supplying liquid to the nozzle, in which the nozzle-holding means are arranged to so hold the nozzle that it sprays liquid upwards on to a vertically-adjustable target whereby the inclination or attitude of the spray hole or holes in the nozzle can be ascertained, the supply of liquid to the nozzle being effected by liquid supply means which cause liquid to be forced from a container into the said passage leading to the nozzle by means of pressure exerted on the liquid in the container.

Preferably the apparatus comprises a cylindrical chamber which is open at its upper end and which has a horizontal partition located somewhere between its upper and lower ends. An axially-movable tubular stem passes up wards through a central hole in the partition and is urged upwards by a spring so as to press against a nozzle to be tested. The nozzle is located in a hole provided in a bracket or other holder so that its spray holes are arranged to direct liquid in an upward direction. The target takes the form of an open-ended cylinder provided with a ring of holes or windows, the target being supported on a ring which is vertically adjustable so that the target can be adjusted vertically in relation to the nozzle being tested. This allows the target to be adjusted so that the ring of holes or windows provided in it are positioned to receive the jets of liquid issuing through the spray holes of the nozzle during the testing procedure. As already indicated, liquid is supplied to the nozzle by pressure exerted on 3,51 1,087 Patented May 12, 1970 liquid in the cylinder chamber, the pressure being obtained by supplying air under pressure through a pipe which leads to an inlet in the lower compartment of the chamber, that is to say the part of the chamber below the partition previously mentioned.

In order that the invention may be thoroughly understood, an example of apparatus in accordance with it will now be described with reference to the accompanying drawing which shows the apparatus in vertical section.

The apparatus shown in the drawing comprises a cylindrical chamber 1 which is closed at the bottom end and is open. at the top end, the chamber being divided in two by a horizontal partition 2 so as to form a closed lower compartment 5 and an open upper compartment 6. The partition 2 is provided with a central bore 3 and a ring of other holes 4, and includes a hollow spigot portion 7 which extends downwards from the partition and is provided externally with a liquid filter 8 and a flange 9. A disc-shaped valve 10 surrounds the spigot 7 and is arranged for limited axial movement between the bottom face of the partition 2 and the flange 9. A tubular stem 11 passes upwards through the bore 3 in the partition 2, the lower portion of the tubular stem within the hollow spigot 7 having a head portion 12 which is slidable within the spigot. The outer surface of the head portion 12 is provided with knurles so as to provide communication between the spaces above and below the head and to prevent any tendency for the head to seal those spaces from one another. It will be seen that the head portion 12 is cup-shaped so as to form an annular duct 13 which communicates through a passage 13a with the bore 14 of the tubular member 11. A helical spring 15 urges the member 11 upwards towards the open upper end of the chamber 1, and an orifice 16 in the wall of the spigot 7 communicates between the hollow interior of the spigot and the clean side of the filter 8.

Extending upwards from the partition 2 towards the open end of the chamber 1 are two pillars 17 and 17a. A bracket 18 is vertically slidable on these two pillars and is provided with several spokes 18a carrying a ring 19 which is provided with a machined recess in which an open-ended cylindrical target 20 can be rotated by hand. A second bracket 22 which is also slidable on the pillars 17 and 17a has a conical bore 23 adapted to receive and locate an injector nozzle 24 to be tested. A pin 25 or other suitable latch locates the bracket 22 on the pillar 17 in a fixed vertical position, while a removable distance piece 21 sets the vertical position of the target-supporting ring 19 so that a ring of holes or windows 26 in the target 20 are brought into the desired angular relationship with the inclined holes 27 in the injector nozzle 24.

The apparatus also includes an upstanding pipe 28 which communicates with the closed compartment 5 and which is provided with an orifice 29 arranged to direct air under pressure into the open end of an exhaust duct 30. In addition, an air supply duct 31 communicates with the closed compartment 5 and is provided with a control valve 32 having an open and closed position as indicated.

The apparatus described above is used in the following manner:

The upper compartment 6 is partially filled with an appropriate liquid testing medium such as oil to an approximate level indicated at 33. The oil is poured into the open compartment 6 and then passes through the holes 4 in the partition 2 into the closed compartment 5. When the level in the closed compartment 5 reaches the valve 10, the valve (having a lower specific gravity than the oil) floats up on the surface of the oil so as to close the holes 4.

In order to position the injector to be tested, the pin 25 is withdrawn and the injector-holding bracket 22 re- 3 moved from the pillar or post 17. The injector nozzle is then placed over the top of the hollow stem -11 and the bracket 22 replaced on the pillar 17 and pushed down on to the shoulder 34 on the pillar. The pin 25 is now reinserted. In this position the central stem 11 is pushed downwards against the spring 15 which thereby exerts an upwardly-directed force through the stem 11 in sealing engagement with the injector nozzle. Assuming now that the spray holes 27 in the injector nozzle to be tested are intended to lie on the surface of a cone having an included angle of 120, a distance piece 21 is selected of such a length that the target holes 26 each subtend an angle of 120 at the apex of the spray holes 27. The control valve 32, hitherto in the closed position, is now moved to the open position so that air is admitted at a suitable pressure, for example in the region of 100' lb. per square inch, into the lower compartment 5. As a result of this air pressure, oil in the compartment passes through the orifice '16 into the interior of the hollow spigot 7, and thence past the knurls 12 and through the opening 13a and the bore 14 of the stem 11 into the central chamber of the injector nozzle 24. From here the oil passes through the spray holes 27, thereby forming jets which impinge on the inner face of the target 20. The target 20 is rotated by hand until each of the jets passes through a hole or window 26 in the target. If the spray holes of the nozzle are accurate and at the correct angle of inclination, the jets will all pass through the holes or windows 26. If however one or other of the jets does not pass through its appropriate window, then this will indicate that the particular spray hole or holes is worn or incorrectly formed, or is corroded or partially blocked with carbon deposits. Irrespective of whether or not the jets of oil pass through the holes or Windows 26, the oil drops down under gravity and collects in the lower portion of the upper compartment above the partition 2.

We have found that the jets of oil impinging either on the target or on the inner face of the compartment surrounding the target cause a considerable mist. This mist is accordingly extracted from the compartment 6 by being induced up the duct 30 and away from the apparatus by an air jet issuing from the orifice 29 of the pipe 28. As air from the air supply passage 31 begins to fill the top of the lower compartment 5, the valve does not drop down since there is now a differential pressure across it due to the presence of the holes 4 in the partition 2. The valve 10 therefore remains closed as the oil in the lower compartment 5 is pushed up the bore 14 of the stem 11. At the termination of the test when it is decided whether the injector nozzle 24 has passed the test or not, the aircontrol valve 32 is returned to the closed position and the air pressure in the compartment 5 is exhausted through the orifice 29. Once the pressure in the compartment 5 has fallen to atmospheric pressure there is no longer any differential pressure acting across the valve 10 so that it therefore drops on to the shoulder 9 of the spigot 7. The oil contained in the compartment 6 now passes downwards through the holes 4 and refills the lower compartment 5 until the valve 10- once more floats and blocks the holes 4.

It is to be noted that, if the valve 32 is moved to the open position when no injector nozzle is fitted, the delivery of oil through the bore ;14 of the stem 11 is prevented by the spring which causes the enlarged lower end of the stem to abut the underside of the partion 2, thereby preventing any oil from passing through the opening 13a and out of the top of the stem.

Although the target is shown as having only one ring of holes 26, in practice it will have two or more rings of holes at different levels with the rings having different numbers of holes. Preferably there is at least one ring of holes which is spaced the same distance from the upper end of the target as the holes 26 are from the lower end. This enables a single target to be suitable for at least two different forms of injector nozzle, the target being simply turned upside down. Further, an alternative site 35 and 36 is provided for the distance piece 21 which, in conjunction with two further rows of holes in the target, provides for two more types of injector nozzle by locating the target at a different axial position. Other alternative sites for the distance piece 21 can also be provided, or use can be made of a set of distance pieces of different lengths.

It will therefore be seen that the apparatus described above is both versatile and simple to use and operate. The use of air pressure to effect the supply of liquid to the injector nozzle is simpler and gives a smoother flow than a mechanical pump, although it will of course be appreciated that mechanical pressure provided for example by a piston can be used instead of air to apply pressure to the liquid in order to displace it from the compartment 5.

Another practical advantage is that the injector nozzle under test sprays upwards and is easy to see. Moreover, the tip of the nozzle is readily accessible for cleaning with a soft wire brush while spraying is in progress. Thus, it may well be found that a nozzle under test which does not function properly at first is subsequently found to be perfectly in order after it has been cleaned by a soft wire brush. In this way the inadvertent discarding of a good injector nozzle is prevented.

Finally, the use of an axially-adjustable and rotatable target 20 having one or more rings of windows or holes 26 allows many different types of injector nozzle to be tested on the same apparatus. This is important as the spray holes of injector nozzles can be at many different inclinations according to the design of the engine or engines with which the injectors are used.

It is to be understood that the specific apparatus described above is given by way of example only and that the scope of the invention is not to be limited to that particular construction but is defined solely by the appended claims.

We claim:

1. Apparatus for testing the inclination of inclined spray holes in the fuel injection nozzles of compression iginition engines, said apparatus comprising, a cylindriwl chamber which is open at its upper end and has a transverse partition located between its upper and lower ends, nozzle-holding means arranged above the said transverse partition and adapted to hold a fuel injection nozzle So that the nozzle points upwardly, a liquid supply passage in the form of a tubular stem passing upwards through a central hole in the partition and adapted to supply liquid to a nozzle from the space in the chamber below the partition when the nozzle is held in said nozzleholding means, the said tubular stem being axially movable and being urged upwards by a spring so as to press against a nozzle to be tested, a Vertically-adjustable target extending above the level of the nozzle-holding means whereby liquid issuing under pressure from the inclined spray holes of the nozzle impinges on said target, and means for applying pressure to a liquid in the space in the chamber below the partition so as to cause the liquid to be forced from said space into said liquid supply passage and thence into the nozzle to be tested.

2. Apparatus according to claim 1, in which said pressure-applying means include an air supply passage leading to an inlet in that part of the chamber below the transverse partition so that air pressure can be used to force liquid out of the chamber space below the partition into the tubular stem.

3. Apparatus according to claim 1, in which the target takes the form of an open-ended cylinder provided with a ring of windows which receive the jets of liquid issuing through the spray holes of the nozzle during the testing procedure.

4. Apparatus according to claim 3, in which the target is rotatably supported on a ring which is vertically adjustable so that the target can be adjusted vertically in relation to the nozzle being tested and can be ro-' tated in order to bring the windows into line with the side, the hole or holes being opened and closed by a spray holes of a nozzle to be tested. disc valve which floats in the space below the partition.

5. Apparatus according to claim 1, in which the lower end of the tubular stem has a head poriton which References Cited slides within a hollow spigot extending downwards from th trans e s p t't' th h 110w sp'got b 5 UNITED STATES PATENTS e v r e ar 1 ion, e o 1 eing in communication with the interior of that part of the cy- 2629255 2/1953 Harmdge' lindrical chamber which lies below the partition and being surrounded by a liquid filter. OTHER REFERENCES 6. Apparatus according to claim 1, in which the trans- 10 verse partition has one or more holes for the passage of liquid from one side of the partition to the other JERRY MYRACLE, Pflmafy EXamlner 1,104,198 4/1961 Germany.

Images