FR2521640A1 - FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES - Google Patents

Abstract

A. FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES. B. PUMP CHARACTERIZED IN THAT THE DEFLECTOR BODY 14 CONSTITUTES A REVOLUTION BODY IS FREELY MOUNTED IN THE CASING 1 OF THE INJECTION PUMP SO AS TO BE ABLE TO ROTATE AROUND AT LEAST ONE AXIS EXTENDING FOLLOWING AN ANGLE IN RELATION TO THE JET STOPPING DRILL 6. C. THE INVENTION RELATES TO FUEL INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES.

Description

1.- "Fuel injection pump for internal combustion engines"

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  The invention relates to a fuel injection pump for internal combustion engines, comprising at least one pump cylinder which receives a piston, and on the piston, at least one control edge which cooperates with at least one end drilling. in the cylinder wall, for controlling the end of the pumping conveyance and, in addition, on the side of the piston opposite to the end-of-control bore, a baffle impact body of cavitation resistant material, which has a

  convex surface facing the end of injection piercing.

  Fuel injection pumps, with such impact protection, are known, for example,

  by patents AT-306,445 or DE-22 19,827 the body of

  pact that is provided on the mouth of the piercing end of

  C 8 té Carter control, has the function of pocketing ex-

  metal growth at the points of impact of the jet of fuel

  which is cut off, at the end of the pumping run, at its

  outlet of the discharge chamber of the pump.

  In the majority of these known installations, the outer surfaces of the deflector impact body which

  are exposed directly to the incident jet are

  cellars or planes, on the one hand, for reasons of manufacturing techniques, and, on the other hand, to oppose the impact of the jet of fuel very forcefully cut, on parts 2.-

- of neighboring Construction.

  It has been found, however, that, because of the tendency towards a functioning, at pressures of more than one per cent. In addition to the higher fuel injection system for internal combustion engines, the fuel jets that are cut at the end of the piston delivery stroke reach such high output speeds that the

  jets of fuel reflected by the deflector bodies pos-

  are still sufficient energy to be able to provoke

  cavitation in the construction parts making

  - this to the deflector body It is so also, in par-

  particular, for the control edge of the pump piston which: o is directly concerned at the moment of stopping the jet,

  which naturally presents serious disadvantages.

  In order to avoid these drawbacks, installations of the kind described at the beginning have been proposed by

  For example, patents GB 1 215 584 or DE-OS-

  2 107 266, in which the baffle impact body has, on its face exposed to the cut incident jet, a substantially convex outer surface. On the contrary - constitutions with concave outer surface, in which the incident jet is, to a certain extent, When it is located at a point in front of the deflector body and thus creates an increased risk of cavitation, it is found in the installations mentioned that the incident jet is spread more fanwise, so that the energy of the jet is increased. It is distributed over a considerably larger external surface of the building parts facing the building, and can not degrade the latter. More particularly, in the case of high fuel pressure and large pumping rates, the risks of cavitation - f on the control edges by the cut jet reflected by

  : the deflector body, are deleted.

  9 ,. ' The disadvantage of these known installations> 35 which comprise a baffle impact body in the form of 3.- a spring, which is inserted torus-shaped in an annular groove, and in the form of a coaxial pin at jet cutting piercing and having a

  point on a front face, is that the jet is

  both of the cut-off boring strikes the baffle body in the same place, causing rapid wear

of it.

  The object of the present invention is to provide

  kill a fuel injection pump of the type described at the beginning, in such a way that the disadvantages mentioned

  should be avoided, and that, in particular, the risks of

  vation on the deflector body itself are excluded, or

  their influence on the service reliability of the

be reduced.

  For this purpose, the injection pump according to the invention is characterized in that the deflector impact body, constituted as a body of revolution, is freely mounted in the pump casing, being maintained

  so as to be able to turn about an axis extending

  at an angle to the jet stop hole.

  The outer surface of the deflector body is therefore not exposed by a single c 8 tee to the energetic jet of

  cut-off, and the service life and reliability of the

are increased.

  According to a particular embodiment

  advantage of the invention, the deflector body is

  consisting of a cylindrical axis which is supported

  one of its ends in a transverse bore of the car-

  ter, which provides a very easy manufacturing

and mounting the deflector body.

  In addition, following another method of

  tion, it is possible to constitute the deflector body

  by a sphere that can be loaded by a spring.

  The invention is explained below by means of exemplary embodiments with reference to the drawings in which: FIG. 1 is a partial view in vertical section through a fuel injection pump according to the invention; FIG. 2 is a sectional view through II-II of FIG. 2, FIGS. 3 and 4 show each

  a section through the embodiment of the invention

tion.

  The pump cylinder 1 of the injection pump

  fuel supply, not shown, comprises a piston of

  pump 2 which is movable towards the axis 3 and is ac-

  The pumping piston has control edges 4, 5, one (4) controlling the flow rate and the other (5) controlling

  the end of the transport of fuel by the pumping piston.

  As soon as the control edge 5 releases the

  internal cross-section of the cylinder 6 of a stop control bore 7 disposed in the wall of the cylinder of

  pompel, the excess fuel for the operating state-

  instantaneous flow of the motor, passes, out of the pressure chamber 8 of the pump cylinder and, through milling

  9 of the pump piston 2 It passes into the hole

  7 and then through an outlet port 17 in the suction chamber which surrounds it in the pump housing. In order to avoid tearing of material by the relatively large kinetic energy of the jet on the parts of the fuel injection pump which are in front of the other mouth of the bore 7, it is provided, on the side of the piercing 7 opposite the pump piston 2, a body

  baffle impact device 14 made of a cavitally resistant material

  tion. In the embodiment shown in FIGS. 1 and 2, the deflector body 14 is constituted by a 5-axis 10, which is arranged perpendicular to the axis 15 of the

  piercing 7, in a transverse bore 16 and in a cy-

  lindrique To facilitate the flow of fuel

  cut and already deviated by the deflector body 14, it is pre-

  seen, in the vicinity of the deflector body, an enlarged evacuation bore, which allows an evacuation of the fuel cut in the suction space surrounding above the

deflector body 14.

  Thanks to the convex outer surface of the deflector body 14, turned to the cut hole 7, the cut fuel jet coming out of the bore 7 is enlarged

  in a fan, so

  centering the jet energy on the outer surface

  This is the case in particular

  for the control edge 5 of the pump piston itself.

  same, which, at the opening of the passage section 6 of the cut-out bore 7, is directly in front of the deflector body and which, thanks to the planar and even concave shape, of the surface of the deflector body, is

  more directly subject to the impact of the fuel jet.

  As is particularly shown in FIG. 2, the transverse bore 16 for the cylinder-shaped deflector body 14 is constituted as a blind hole.

  in which is inserted the axis 10 In order to avoid a

  tie and a fall of it, it is expected, on the face

  front of the deflector body 14 which faces the end

  of blind drilling, a pin 18 that opposes a

  sliding in the axial direction The deflector body 14 pre-

  relative to the transverse drilling 16, a sufficient clearance

  to rotate around its axis, such as

  so that the cylindrical outer surface is not always exposed to the same place with the energy-rich jet,

  which increases its life and reliability.

  Advantageously, variants may also be provided, shown in Figures 3 and 4 of the 6.-

  form shown in Figures 1 and 2, variants in the

  the deflector body 14 is formed by a sphere or ball 10 'which is arranged to rotate freely in a suitable insertion piece 20, so that only a certain part (here the lower part) of the

  outside face, be exposed to the fuel jet at

  purpose of the jet cut-off course, the ball 10 'being

  thus born step by step in the direction of the arrow 22 (Figure 3).

  In the example according to FIG. 4, the ball 10 ', in the insertion part 20', is loaded by a spring 21 while being free to turn on itself. Here, too, regular wear of the entire the surface of the ball and thus a longer duration of reliability,

  of the installation with simple means.

  The embodiment of FIG.

  FIG. 3 in that, in this case, the longitudinal axis of the deflector body 14 is shifted upwards with respect to the axis 15 of the bore, so that the rotation pulse of the jet on the ball 10 'is

increased.

  In all the variants of embodiment

  presented, it is provided, on the side of the pump cylinder

  1 opposed to the jet stop piercing 7, a suction hole

  19, which is not open or is only open a certain time after the stop drilling 7, by the control edge 5 of the pump piston 2, so that no deflector body is necessary to this place Modes

  in accordance with the invention are nevertheless possible.

  where both holes are used for

  in which case a baffle body would also be provided for the second piercing, as described. 7.-

Claims (4)

R E V E N D I C A T IO N S   1. Fuel injection pump for mo-   internal combustion engines, with at least one pump cylinder receiving a pumping piston and at least one control edge on the piston, which, together with at least one injection stop hole in the wall of the   pump cylinder, controls the end of the displacement of   a baffle impact body being provided on the stem of the stop hole opposite the piston, the baffle body of a cavitation resistant material having a convex surface facing the stop bore, pump characterized in that the deflector body (14) constituted as a body of revolution is freely mounted in the housing (1) of the injection pump so as to be able to   turn around at least one axis extending   relative to the jet stop hole (6).   2. Pump according to claim 1, characterized   characterized in that the deflector body (14) is constituted by a cylindrical axis (10) which is rotatably supported at both ends in a transverse bore (16) crankcase.   3. Pump according to claim 1, characterized   characterized in that the deflector body (14) is constituted   by a sphere or a ball (10 ').   4 Pump according to claim 3, characterized   characterized in that the ball (10 ') is loaded by a spring (21).