FR2618487A1 - HYDRAULIC CONTROL INJECTION POINT FILLER FOR FUEL INJECTION PUMP - Google Patents

Abstract

The invention relates to injection pumps for injection engines. This corrector comprises a primary part 3 coupled to the engine and a secondary part 4 coupled to the camshaft of the pump. Pistons 6 loaded both by pressurized oil and by centrifugal force and returned by a spring 15 are supported by an inclined plane 9 against fingers 11 integral with the primary part, parallel to the axis of the shaft with cams and fitted with a bearing or a smooth ring 10. Main applications: Diesel engines.

Description

Hydraulically controlled injection point corrector

  for fuel injection pump.

  The invention relates to a corrector of

  hydraulically controlled injection point for injection pump

  fuel injection, which controls the start of injection according to the various operating parameters of an internal combustion engine with ignition injection

  by air compression, and which includes a primary part

  mayor entrained by the internal combustion engine and a rigidly secured secondary portion of the shaft to

  injection pump cams, as well as at least one

  your slidable in a cylindrical recess against a restoring force when loaded

  by pressurized oil, and having a strong flat surface

  inclined plane that is in constant contact with a

  bearing surface of an abutment point stop

Eject.

  It is known from German Patent No. 39 45343

  injection point rector with which the injection point can be varied according to the

  speed of rotation and load as well as

  other conditions. The relative displacement of the abutment with respect to the primary part is

  controlled by a piston sliding in axial translation

  in the primary part and by a stop which is

  by a finger rigidly mounted in the secondary part

  and radially oriented. When loaded by the pressure or relieved of this pressure, the piston slides on this finger by its inclined plane surface, the inclined plane surface having its direction of action

  in the circumferential direction of the primary part

mayor.

  The invention is intended to improve

  a hydraulically controlled injection point corrector

  whereas, in comparison with the embodiment according to German Pat. No. 3,345,343, it is possible to obtain a simplified construction and also a

  correction of the injection point with hy-

  reduced hydraulics. According to the invention, this problem is solved by the fact that the piston has a single flat forming

  inclined plane, which extends parallel to the axis of the

  camber, and which rests against the integral stop of

  the primary part and constituted by a bearing with

guilles or a smooth ring.

  Thanks to this orientation of the management of ac-

  piston, it is possible to order the correct

  hydraulically controlled injection point engine with low pressure, for which the engine oil pressure is sufficient, since the piston is assisted

  in the radial component of its movement, by the

  these centrifuges that grow with the increase of the speed of rotation. Another advantage is provided by the fact that, in case of failure of the increase of

  the pressure, the corrector has a command of se-

  course ensured by centrifugal force.

  It is already known, from German Patent No. 2649986, a hydraulically controlled injection point corrector comprising a piston which describes radial movements,

  but this piston is not stressed by the centrifugal force

  ge; on the contrary, it acts against the central forces

  trifuges, together with a spool valve that controls the oil under pressure. When speed

  of rotation, the joint translation of the two organizations

  nes occurs radially inwards, towards the axis

of the drive shaft.

  The subject of the invention is described in the following

  in more detail about examples of how

shown in the drawing.

  In this drawing, FIG. 1 represents, by a sectional view taken along line I-I of FIG. 2, a corrector

  injection point with two pistons

  plates forming inclined planes, planar configuration; FIG. 2 represents the injection point corrector in longitudinal section; Figure 3 shows the point corrector

  injection molding which has a piston flat of a

  different management; Figure 4 shows the injection point corrector provided with hollow pistons; FIG. 5 represents the injection point corrector provided with pistons offset with respect to each other; Figure 6 shows the point corrector

  Injection equipped with three pistons.

  An injection point corrector 1 with hydraulic control, intended to control the point or moment

  Injection engines in internal combustion engines

  air-compression ignition system, which is

  floating head on the camshaft 2 of an injection pump

  usually not represented, is composed of one

  element 3 coupled to the engine and a secondary part

  4 coupled to the injection pump, which is connected

  integrally in rotation with the camshaft 2 and which pre-

  two cylindrical recesses 7 diametrically oppo-

  intended to receive pistons 6 urged by the centrifugal force, recesses whose axes extend

  perpendicular to the axis 8 of the camshaft (FIG.

  res 1, 3, 4) or approximately perpendicular to the axis 8 of the camshaft (Figure 5). In the first case, the movement of the pistons 6 is carried out exclusively in the

  radial direction while in the other case the movement

  pistons 6 is decomposed into a component of

  radial motion and a circumferential motion component

  -competitive. The pistons 6 according to FIG.

  offset with respect to each other. With this

  particular, it may be possible to reduce the

  fluence of centrifugal forces. Each piston 6 is provided with a flattened flattened flattened plane 9 parallel to the axis 8 of the camshaft 2 and, more precisely, inclined on

  the longitudinal median plane of the point corrector

  jection 1 which passes through the piston 6.

  In order to obtain a determined correction characteristic, it is possible to replace, in place of the planar plane flat surface 9 provided on the piston according to FIG. 1, an inclined flat surface which has a curved profile adapted to the needs of the combustion engine.

  internal, such as that shown in Figure 3.

  FIG. 4 shows an embodiment in which the pistons 6 are hollowed out

  to ensure a better basic correction of the

tor.

  Pistons 6 are associated with stops 10 which are in the form of roller bearings, plain rings or needle bearings and which are mounted on a finger 11 extending parallel to the axis 8 of the shaft. cams. For their part, these fingers

  are rigidly screwed into the driving wheel 12 of the

  primary tie 3 which is rotatably mounted (Figure 2). The

  fixation may possibly be effected by

  by force of the fingers in the driving wheel.

  The primary part 3 and the secondary part 4 are provided with recesses 13, 14 arranged opposite one another, in which return springs 15 are guided which

  take support. These jurisdictions have an antago-

  piston movement 6 when the pistons

  are loaded with pressure, and they bring back the pis-

  6 tones at their starting position when these pistons

are relieved of pressure.

  The arrival of the control and lubrication oil

  cation is made through the inlet bores 16 which start from the injection pump, an annular space annular 17, and a throttling hole 18 made in the camshaft 2 and passing by a radial bore 19 made in the secondary part 4, to finally end in a pressure chamber 20 which is delimited by the cylindrical recess 7 and

by the radial piston 6.

  The arrival and the flow of the oil under pressure

  which have the effect of modifying the injection point

  are controlled by a servo valve controlled by an electro-

  regulator, and which is part of the oil circuit.

  the internal combustion engine (this device being

not shown in the drawing).

  Strangulation 18 provided in the corrector serves to dampen the oscillations that occur during corrections of the start of injection of the corrector of

injection place.

  Replacing two pistons 6, we can also

  slide in the point-of-care

  jection 1 three or more pistons which are

  tis in a symmetrical disposition with respect to a point.

R E V E ND I C A T I ON

  1 - Command injection point corrector

  hydraulic pump for fuel injection pump

  internal combustion engine with com-

  air pressure, comprising a primary entraining part

  an internal combustion engine and a secondary part rigidly secured to the camshaft of the injection pump, and comprising at least one piston which moves against a restoring force when is loaded by the pressurized oil and which slides in a cylindrical recess, describing a movement which has a radial component and which is assisted

  by the centrifugal force, this piston cooperating with a bu-

  injection point corrector unit for correcting the start of injection, characterized in that the piston (6) has a single flat (9) forming an inclined plane, which extends parallel to the axis (8) of the camshaft (2),

  and which bears against the stop (10), which is

  of the primary part and consisting of a wheel

  needle or a smooth ring.

  2 - Injection point corrector according to the

  claim 1, characterized in that the rolling bearing

  guilles is mounted on a finger (11) rigidly secured

of the primary part (3).

  3 - Injection point corrector according to one

  Claims 1 and 2, characterized in that the

  flat (9) forming an inclined plane carried by the piston (6)

  has a curved profile determined.

  4 - Injection point corrector according to one

  of the preceding claims, characterized in that the

  piston (6) is drilled with a hole on the loaded side

by the pressure.

  - Injection point corrector according to one

  of the preceding claims, characterized in that the

  piston (6) is constituted by a radial piston whose di-

movement rection is radial.

  6 - Injection point corrector according to one

  of the preceding claims, characterized in that the

  piston (6) also has a motion component

  circumference in addition to its component of

radial effect.