FR2541378A1 - FUEL INJECTOR - Google Patents

Abstract

THE INVENTION AIMS AT A FUEL INJECTOR 4 IN WHICH A PLUNGER PLACES IN A DRUM, PUSHES AND LIFTS TO DISTRIBUTE FUEL, IS DRIVEN BY A CRANKSHAFT 50. THIS INJECTOR MAKES A REMARKABLE INCREASE IN THE PRESSURE AND THE INJECTION FLOW RATE.

Description

Fuel injector.

  The present invention relates to a fuel injector

  for compression ignition engine.

  In the usual known injection devices of the prior art, of the unit injector or jerky type, a plunger is raised by the rotation of a camshaft to compress and send the fuel to inject it as well

  by a nozzle in an engine combustion chamber.

  In this structure of the prior art, however, the pres-

  injection and injection rate are necessarily low at low engine speeds so that the performance and thermal efficiency of the engine at low speeds,

are not satisfactory.

  In order to improve the combustion efficiency, shorten the fuel injection period and increase the isochoric degree in order to improve the thermal efficiency over the whole range of rotational speeds, and the whole range of loads, it is necessary to increase the injection pressure and flow rate It is however difficult to use the above devices to increase the pressure and the

injection rate.

  To solve this problem, several devices have been developed.

  fuel injection devices of the accumulation type, some of which have practical value but do not have

been commonly used.

  One reason for this is that although an information device

  accumulation type fuel junction not using a booster is simple in construction and low cost, there is a surface pressure between the cam and the roller which makes it difficult to raise the injection pressure up to at 1000 atmospheres In addition, although a booster type fuel injection device can inject fuel at high pressure for a short period of time by electronic control, it is expensive and poorly stable due to its complicated structure. In known fuel injection devices, the plunger is always driven by cooperation of the cam and a cam roller. Consequently, the contact between the cam and the roller is of the linear type so that the stress

  of Hertz on the linear contact area is increased as a function

  increase in injection pressure until the contact surfaces of the cam and the roller drop

  finally due to fatigue This stops the development

  injection devices which generate pressures

  high at high injection rates.

  It is therefore an object of the invention to produce a high pressure fuel injector which generates pressures

  significantly higher fuel injection.

  Another object of the present invention is to provide a fuel injector which can be easily adapted for use on diesel engines at slow speed and

  medium but also at high speed.

  The present invention provides a fuel injector of the accumulation type in which the injection of fuel is initiated by a drop in pressure in a fuel passage, from a fuel injection pump of the non-accumulation type to a accumulation chamber and is stopped

  by a drop in pressure in the accumulator chamber

  lation, and in which the plunger of the injection pump

  is driven by a crank mechanism.

  The invention is particularly useful when applied

  a distribution type fuel injector.

  A fuel injector for a diesel engine is inherently complicated in structure and requires high precision machined parts because it carries fuel under high pressure and therefore it is very expensive and adds considerably to the price of the diesel engine.

  In this regard, a fuel injector of the dispenser type

  The advantage is that it has a smaller number of parts and is light, small and inexpensive.

  such injector must deliver fuel to each of the cylinders

  dres on an engine cycle, so that an in-

  plunger training consisting of a cam with a roller

  spring and spring driven at a high speed corresponding to the number of engine cylinders is subjected to a high degree of stress Therefore, the injection pressure must be limited so that its

  application to fuel injectors of the dispenser type

  tion by cam drive is effectively limited to the diesel engine of the auxiliary chamber type in which

  high injection pressure is not necessary.

  The current situation is that the auxiliary chamber type diesel engines are gradually being replaced by the direct injection type fuel injectors.

  due to the higher thermal efficiency of the latter.

  Thus, in order to further improve the thermal efficiency of diesel engines of the direct injection type, efforts have been made to increase the injection pressure and flow rate.

  so as to shorten the injection period.

  However, to date, no direct injection type diesel engine capable of operating at the desired injection pressure (e.g. 2000 atm) is commercially available due to the high price.

  and unsatisfactory reliability.

  The present invention provides a fuel injector of the

  distribution type which can distribute and deliver a

  running at a supply pressure as high as 2000 atmospheres to the different cylinders of an engine by means

  of a diver and which is light, small, inexpensive and high

  highly reliable. The present invention therefore provides a fuel injector for a compression ignition engine comprising a fuel injection pump comprising an anti-valve

  return arranged in a high pressure fuel passage

  sion communicating with a barrel in which a diver is fitted; and a fuel injection valve of the type

  with storage comprising a fuel injection valve

  rant having a needle valve whose opening is com-

  driven by the fuel pressure and by a spring and an injection light which is opened and closed by said needle valve, and a storage chamber arranged

  in part of said high pressure fuel passage

  so that said needle valve is opened by a drop in pressure in said high pressure fuel passage to thereby initiate fuel injection and is closed by a drop in pressure in said accumulation chamber to thereby stop fuel injection, said plunger being driven by a crankshaft and a

transmission rod.

  Other characteristics of the invention will become apparent from

  during the description which follows, given as an ex-

  non-limiting example, with reference to the attached drawings and

  that will make it clear how the invention can be made

read. On the drawings

  Figure i is an elevational view showing an injec-

  fuel teur and crank drive;

  Figure 2a is a sectional view of a fuel injector

rant; -

  Figure 2b is an enlarged view of the control valve shown in Figure 2a; Figure 3 is a sectional view of the injector drive; Figure 4 is an elevational view of another embodiment of the injector and the drive

  Figure 5 is a sectional view of a fuel injector

  distribution type crank driven; Figure 6 is a sectional view along line A-A of Figure 5; Figure B-B of Figure Figure form of Figure C-C of Figure D-D of Figure l 7 is a sectional view taken along line l Figure 5; B 8 is a sectional view of part of another embodiment of the injector; B 9 is a sectional view taken along line 1 in Figure 8; 3 10 is a sectional view taken along line 1 in Figure 8; and, 11 is a graph representing the relationship between the geometrical location of the movement of the lateral light, the relative position of the sliding face of the adjustable part and the adjustment of time and flow.

of the injection.

  In FIG. 1, a piston 2 is housed in a cylinder block 1 having an upper face provided with a cylinder head 3 in which the injection lumen of an injector is formed

  fuel 4 of the accumulation type.

  Referring to FIG. 2, the injector 4 comprises an injection pump 4 A and an injection valve 4 B of the accumulation type which is connected to the downstream end of the

  pump and fitted with an injection valve 4 b.

  In the injection valve 4 B of the storage type, a thread formed in the upper end of a nut 6 is screwed onto a thread formed on the lower end of a sleeve 5 of the injection pump 4 A In the nut 6, a control valve member 7 is mounted in leaktight manner,

  a spacer 8, an accumulation cylinder 9, a

  height rod 10 and a needle valve member 11 which are arranged in the order listed. The needle valve member 11 is formed at its downstream end with an injection lumen 11a whose opening and

  closure are controlled by cooperation of the headquarters of

  pope on the inner wall of the downstream end of the organ of

  valve and the valve face of a needle valve 12.

  The needle valve 12 has its upper half or part of larger diameter adapted in the needle valve member 11 so as to be axially movable At the upper end of the part of larger diameter is fixed

  a spring seat 13 on which elastic is mounted

a spring 14.

  The needle valve member 11 has a fuel passage 11a which is in communication with a space 15 surrounding the outer circumference of a portion of

  smaller diameter of the needle valve.

  The spacer 10 also includes a fuel passage 1 ia which has its upper part in communication with an accumulation chamber 16 in the accumulation cylinder 9 and its lower part in communication with the passage 11a. The spacer 8 has passages 8 b and 8 c to ensure

  a communication between a fuel passage 8 a which comprises

  fitted with the atmospheric pressure side of the needle valve 12 and the accumulation chamber 16 The spacer 8 at its lower end bears against one end of the

spring 14.

  The fuel passage 8 a is in communication with a fuel passage 7 a of the control valve member

  7 and with fuel passages 7 b and 7 c connected to -

  this passage 7 a This passage 7 a further communicates with a fuel passage 5 has the barrel 5 In addition, the pas-

  of fuel 8 a, 7 a and 7 b are made for commu-

  connect with the atmospheric pressure side of the needle valve 12 and an injection end control valve

  17 is arranged between these passages and the fuel passage

  rant 8 b communicating with the accumulation chamber 16 The end of injection control valve 17 has its part of larger diameter adapted in the valve member

  control 7 so as to be able to move vertically.

  The face 17 a of this control valve is biased downwards by a compression spring 18 which is disposed

  in the sleeve 5, and the spacer 8 acts as a stop.

  As shown in Figure 2B, moreover, this valve face can come when it is raised in abutment against

  the valve seat 7 d of the control valve member 7.

  Between the passage 7 c and the passage 8 c, is fixed to the control valve member 7, a control valve 20 which is authorized to block the flow of fuel from the passage 8 c to the passage 7 c by action d '' a compression spring

  19 housed in the spacer 8 In addition, the fuel flows

  lant sliding faces of the valve member

  demand 7 and the control valve 17 for the end of injection is returned to the atmospheric pressure side by means of a return passage 22 in communication with a side light 21 in the injection pump 4 A. We will now describe the internal structure of the pump

  4 A fuel injection valve 24

  return, to prevent any leakage while being adapted with play in a suction valve member 23

  can function as a check valve thanks to a

  compression spell 25 and has its valve head adjusted by

the action of a stopper 26.

  In addition, the plunger 28 is adapted so that it can slide

be in a drum 27.

  In the barrel 27 is interposed between a fuel inlet 29 and a fuel passage 30, a check valve 31 which has the function of a non-return action by means of a spring so as to block the reverse flow of fuel from the passage 30 towards entrance 29 Barrel 27 is formed with

  the lateral lumen 21 in its middle part and the pas-

  fuel return sage 22 prevents the establishment of a back pressure in the control valve 17 to return fuel from this valve through the return light 32 to a fuel tank (not shown) or the inlet 29 Let l fuel inlet 29 and the return light 32, that is, the return light and the atmosphere, must be suitably prevented from leaking by means of an O-ring

or the like.

  For example, the barrel 27 and the non-return valve member 23 are mounted in the wall 5 by means of a

thread 33.

  The plunger 28 having the same construction as those of the Bosch type, has a passage 28 a. The fuel supply by the injector ends when the notched face 28 b of the plunger 28 communicates with the lateral light 21, which has the effect that the subsequent fuel delivery

  by the head of the diver is made by the side light

  and by the fuel return light 32.

  An adjustment rod 34 is housed so as to be able to slide in the sheath 5 and comprises a rack 34 a which is in gear contact with a pinion 28 c formed on the

diver 28.

  By way of example, the position of the adjustment rod 34 is determined by equilibrium with the oil pressure, which is communicated by an oil pressure inlet 36 and acts against the force of a spring 35, which determines the duration of the injection. For the structure of the drive mechanism of the injector plunger 28, reference will now be made to FIG. 3 A stock 37 which is housed so as to be able to move vertically in the hollow part of the upper end of the sheath 5 has one of its ends connected to the plunger 28 in free rotation and its other end fixed to an axis 38 To this axis 38, is connected by a pad 40 the lower end of a link 39 whose upper end is connected by a bearing 41 and a pin 42 at the left end of a rocker arm 43 This rocker arm 43 is articulated, by means of a bushing 44 which is fixed therein 1 to a rocker arm shaft 46 which is fixed in a console 45 making protrusion of cylinder head 3 (which is shown on

  FIG. 1) and carries an axis 47 at its other end.

  On this axis 47, is mounted by means of a bearing 48 the former

  upper end of a connecting rod 49 which has its lower end articulated on a crankshaft 51 by means of bearings 52 and 53, the crankshaft being eccentric relative to the axis of a camshaft 50 for actuating the valves intake and exhaust, as shown in Figure 1 Bearings 52 and 53 are attached to the connecting rod

  49 by a cap 54 fixed by means of bolts 55 -

  The operation of the injector according to the present invention

will now be described.

  The fuel is sent through inlet 29, the check valve

  nude 31 and passage 30 in a barrel chamber 27.

  In synchronism with the downward movement of the plunger 28 from its top dead center, the check valve 31 is closed so that the pressure in the chamber rises, the non-return suction valve 24 is pushed towards the

  low and fuel is pumped to the passages E S 5 a, 7 a and 8 a.

  At this time, the end of injection control valve 17 is pushed down by the spring 18 and at its valve surface 17 is spaced from the valve seat 7d from the control valve member 7, as shown in Figure 2B

so that it is open.

  The fuel sent in passage 7 a is then pumped

  in passage 7b, the valve 17 for controlling the end of

  jection and passage 8 b inside the battery chamber

mulation 16.

  Fuel is a compressible fluid, as is well known in the art, so that it is stored in the accumulation chamber 16 while its volume is reduced

when the pressure rises.

  When the pressure in the accumulation chamber 16 reaches

  a certain level, for example 1000 atm, the com-

  injection stop 17 is pushed up by compressing the spring 18, so that the valve surface 17 a is brought into contact with the valve seat 7 d and

  blocks communication between passages 7b and 8b.

  Then, the check valve 20 is opened so that the fuel having followed the passages 7 a and 8 c is compressed and accumulated under higher pressure in the chamber.

  of accumulation, this pressure being applied by the steps

  fuel wise 1 Oa and linked to the bottom of the

needle valve 12.

  The fuel in passage 8a, as in the delivery chamber

  accumulator 16, is at high pressure, and this is applied

  quée on the upper face of the part of larger diameter 1 i 1

  of the needle valve In this state, the force of the res-

  sort 14 plus the pressure multiplied by the area of the larger diameter part of the needle valve is

  equal to the pressure pushing down the air valve

  guille 12, and the pressure multiplied by the cross section of the larger diameter part of the needle valve minus the area of the smaller diameter part of the needle valve is equal to the force pushing up the needle valve 12, so that the valve surface is forced into contact with the valve seat this

  which prevents fuel from leaking through the injection light

tion lia.

  As the engine continues to run, the plunger 28 is

  core pushed down until the maximum pressure

  on the high pressure side of the injection system at the flow rate

  maximum jection reaches up to 2000 atm.

  At this time, the communication between the passage 28 a and the lateral lumen 21 is established by the notched surface 28 b of the plunger 28 The high pressure fuel flows through the passage 28 a until it overflows through the light

  lateral 21 in the return light 32.

  At this time, the non-return valve 24 closes and presses it.

  sion in passages 5 a, 7 a and 8 drops sharply as a result of the operation of this valve so that the pressure on the atmospheric pressure side pushing down the larger diameter portion of the needle valve

12 disappears.

  However, the valve surface continues to be applied to its seat, while the injection end control valve 17 is pushed upward because the pressure

  is equal to or greater than 1000 atm for example so that -

  the high pressure fuel in the accumulation chamber 16 is prevented by the check valve 20 from flowing

  back in passages 5 a, 7 a and 8 a.

  At this time, the force of the pressure exerted on the needle valve (the area of the larger diameter portion minus the area of the smaller diameter portion) pushes the needle valve 12 'against the force of the spring. compression 14, which establishes between the valve surface

  and siege an interval by which fuel is injected

  tee of injection light 11a in the combustion chamber

  tion of the engine Depending on the course of the injection -

  of fuel, the pressure of the fuel having been compressed in the accumulation chamber 16 continues to drop to 1000

  atm for example Then the valve 17 for controlling the end of

  jection is pushed down and opens, as shown

  in Figure 2B So the fuel in the chamber-

  accumulation 16 flows through passages 8 b and 7 b in

passages 7 a and 8 a.

  At this time, the non-return valve 24 is in its closed state.

  so that fuel cannot flow from the lu-

  lateral material 21 and the fuel passage 8 a takes na-

  the same pressure as the pressure chamber

  cumulation 16, which pressure is applied to the atmospheric pressure side at the upper part of the needle valve, which abruptly closes this needle valve 12. Thus, in accordance with the present invention, by means of the end control valve 17 injection, pressures

  are applied to both the top and bottom side

  of the needle valve 12 simultaneously with the opening of this control valve 17, so that the needle valve 12 is accelerated towards the valve seat llb

  by the force of spring 14 without being influenced by the pressure

  accumulation chamber 16 So it is possible

  * increase the valve closing speed to connect

  shorten the fuel injection period, which produces

higher injection rate.

  The plunger drive member 28 will now be described. As shown in FIG. 1, the crank pin 51 causes the rod 49 to reciprocate during the rotation of the camshaft 50 so that the rocker arm 43 follows the movements. from the lower end of the connecting rod

  49 to swing around the tree 46 The swinging movement

  rocker rocker 43 raises and lowers the butt 37 by means of the rod 39 to drive the plunger 28

  which has the possibility of turning relative to the butt 37.

  When the crank pin 51 turns from bottom dead center to top dead center, by rotation of the shaft 50, the connecting rod 49 rises and this movement is transmitted by the axis 47 to the rocker arm 43 so that the latter turns in contrary

  clockwise around axis 46.

  As a result, the axis 42 at the other end of the balance is

  moved down to push butt 37 through

  middle of the link 39 and the axis 38.

  The plunger 28 connected to the butt 37 raises the pressure of the fuel in the barrel 27 as it moves down and opens the non-return valve 24, which pumps

fuel in passage 8 a.

  Pressure is applied to the upper side of the base.

  needle valve 12, which opens the needle valve and

the check valve 20.

  When the crankpin 51 continues to rotate, the plunger 28

  continues to descend to increase the pressure in passage 8 a, which pumps the fuel in passage 7 c, the check valve 20 and passage 8 c until it accumulates

in the accumulation chamber 16.

  When the crankpin 51 continues to rotate to approach the top dead center, the plunger 28 continues to descend so that its grooved surface passes in front of the side light 21 to open the passage between the side light 21

  and the interior of the barrel 27 through passage 28 a.

  As the side light 21 communicates through the fuel inlet 32 with the low pressure side, the fuel in

barrel 27 flows through there.

  At this time, the non-return valve 24 closes and lowers the pressure in the passage 8 a by its return movement.

  Fuel under high pressure in the accumulator chamber

  lation 16 is blocked by the check valve 20 so

  that it cannot flow through passage 8 a.

  When the pressure in passage 8 has dropped, the pressure

  bent in the lower part of the needle valve 12 by the passage 11a lifts and opens the needle valve 12 against the force of the spring 14, which injects the fuel

through the light lia.

  Simultaneously with the injection of fuel, the pressure in the accumulation chamber drops so that the needle valve closes to stop the injection when the force of the

  spring 14 exceeds the pressure applied to the lower part

of the needle part.

  When crankpin 51 continues to rotate past neutral

  up, towards bottom dead center, the plunger 28 moves smoothly

  in order to approach the bottom dead center So the extreme

  upper part of the plunger opens the side light 21 so that the fuel is sucked in to prepare the cycle

next operation.

  The bearings 40, 41, 44 and 48 of FIG. 3, the bearing 52 (represented in FIG. 1) or the corresponding axes 38, 42, 46 and 47 or the crank pin 51 are designed and calibrated so that the surface pressure that they receive either about 300 atm when the plunger 28 compresses the fuel to 2000 atm, and are made to guarantee a reliable resistance to such pressures The injection pressure can

  be high, if necessary, by increasing the proportions

  pump drive system.

  Another embodiment of a set of fuel pumps

  jection 4 Aa which is connected by means of a pipeline

  high-pressure to the injection valve 4 b battery type

  mulation shown in Figure 2 will now be

  described with reference to Figure 4.

  A characteristic of the assembly 4 Aa is that it comprises a plunger 56 driven by means of a crankshaft 60 by a connecting rod 59 which is rotatably mounted on the axis 58 of a stock 57 For the rest, the structure of the injection pump 4 Aa is the same as that of the Bosch type or that

  the injection pump 4 A shown in FIG. 2 Ex-

  narrowest end of the connecting rod 59, is fixed a cushion

  net which serves as a bearing for the axis 58 The widest end is rotatably mounted by means of a bearing on the crankpin 61 of the crankshaft, and a yoke 62 is fixed thereto

  by bolts 63 The plunger 56 is moved alternately-

* ment up and down by the rotation of the shaft 60 and the pump assembly 4 Aa is connected by a high pressure pipe 64 with the fuel passage 8 a of the injection valve 4 B of the accumulation type , thanks to

of a fitting 65.

  In the operation of the injection pump assembly 4 Aa, the injection valve of the accumulation type 4 B operates in the same way as in the embodiment of FIG. 2 and has the same structure as that of the Bosch type

  with the exception of the plunger drive mechanism 56.

  The injection pump 4 Aa works in the same way as the injection

  jector shown in Figure 2 so that the butt 57 and the plunger 56 are moved up and down - by the rotation of the shaft 60 to send fuel at high pressure through the line 64 to the valve 4 B -in-

accumulation jection -

  In the structure thus described, the injection rate of

  the accumulator type injector is determined exclusively

  by the pressure in the accumulation chamber and by the diameter of the injection lumen and is not

  depending on the speed of the diver.

  Therefore, the diver can be driven by a

  crank mechanism and its speed varies sinusoi-

dale.

  In addition, the pre-

  invention is of the positive transmission type and does not

  no spring required, avoiding the risk of a break

  ture of the spring by constraint or by pumping The making and manufacturing of the high pressure injector having a

  identical injection capacity can be facilitated by adopting

  both the diver who is the least prone to leaks and who

has a small diameter.

  In accordance with the present invention, the drive system

  the diver has no part in point or line contact

  area and as the diver is driven by a crankshaft and

  not by a cam, the high pressure injection may be

  without using a pressure booster, so that

the injection can be simplified.

  The distribution type injector to which a crank drive can be applied will now be described in

referring to Figures 5 to 11.

  As shown in FIG. 5, a body 101 and a barrel 102 are connected by several bolts 103 In the body 101, having a flange 104 for mounting on the motor, is arranged a drive shaft 107 which is rotatably mounted by means 105 and 106.

  The drive shaft 107 carries on its outer end

  eure a pinion 108 which is driven with a reduction ratio predetermined by the crankshaft (not shown) of the engine At its other internal end, is fixed a conical drive pinion 113 by means of bearings 109 and 110, and bolts 111 Ce bevel gear 113 is carried by a

  bearing 112 which is fixed to the barrel 102.

  An intermediate bevel gear 114 meshes at right angles

  with pinion 113 This pinion 114 is carried by rollers

  elements 117 and 118 in a support 116 which is mounted in the

  body 101 by means of several bolts 115.

  An accelerating bevel gear 119 is mounted in the body

  by means of bearings 120 and 121 which surround the drive shaft

  drag 107 The bevel gear 119 meshes with the intermediate bevel gear 114 to drive the latter towards

  opposite to that of the drive shaft 107.

  A crankshaft 122 is carried by the drive shaft 107

  at right angles to the axis thereof in parts

  simple liers 123 and 124 The crankshaft 122 carries at one of its ends a driven conical pinion 122 which meshes with the conical pinion 119 Consequently, the crankshaft 122 rotates horizontally, as represented in FIG. 5, by rotation of the shaft 107 and around its axis by action

bevel gears 119 and 125.

  A connecting rod 126 has its wide end articulated on the crankpin 127 of the crankshaft 122, as shown in FIGS. 5 and 7, and its narrow end connected by a pin 129 to the buttstock 128, which is mounted so that it can slide

  and turn in the barrel 102, to limit the revolution-

  tion of the stock 128 and transmit the revolution of the drive shaft 107 to the stock 128 to move them alternately. A plunger 130 is formed with a distribution groove 131 at its upper periphery and with a bore 132 in

  its center This bore 132 has at its lower end

  behind a lateral light 132 a The lower end of the plunger 130 is fixed to the stock 128 The plunger 130 slides into the bore 135 of a barrel 134 which is fixed to the barrel 102 by means of several bolts 133 An adjustment piece 137 is inserted in a room 136 which is

  formed transversely to bore 135.

  In the bole 134, are formed at equal distances,

  oil supply passages 138 a to 138 b in corresponding number

  corresponding to the number of engine cylinders (4 in this case) as shown in detail in Figure 6 These oil supply passages 138a to 138b are connected to fuel injection nozzles not shown mounted

on the corresponding cylinders.

  The adjustment piece 137 has on its lateral surface a hole 139 oriented at right angles to the plunger, as shown in FIG. 5 In this hole is inserted the rounded end 141 a of an adjustment lever 141 which is rotatably mounted on the barrel 102 by means of an axis 140, so that a lever 142 fixed to one end of this axis moves the adjustment piece 137 up or down by means of the adjustment lever 141 to adjust the duration

  fuel injection as follows.

  Specifically, one end of the lever 142 is connected by a rod 143 to a lever 146 of a regulator 145

  which responds to the speed of rotation of the intermediate bevel gear

  diary 114 corresponding to the speed of rotation of the motor and to the position of an output adjustment lever 144 As a result, the movements of the regulator 147 are transmitted by

  lever 146 and rod 143 to lever 142, from where it

  sult that the adjustment piece 137 is moved upwards

  and down to vary the distance between the light

  lateral era 132 of said plunger 130 and the lower end surface 137a of the adjustment piece 137 for adjusting the

duration of injection.

  Fuel line 147 establishes communication

  between a fuel tank not shown and the regu-

  lator 145 The fuel is measured by the regulator 1.45 as a function of the position of the adjusting lever 141 and the speed of rotation of the engine so that the measured fuel is delivered by a line 148 inside

of room 136.

  FIGS. 5 to 8 show the injector of the present invention applied to a four-cylinder engine with the same ignition interval When the drive shaft 107 is rotated by the pinion 108 which is driven with a reduction ratio predetermined by a gear not shown

  attached to the engine crankshaft, the drive pinion

  track 113 fixed on the shaft 107 drives the bevel gear

  that intermediate 114 which in turn drives the bevel gear

  that of acceleration 119 which is mounted in the body 101, at the

  same angular speed as the shaft 107 but in opposite direction.

  As a result, the drive bevel gear 125 which meshes with the bevel gear 119 and has half the teeth

  that the pinion 119 is driven to rotate the vile-

brequin 122.

  Thus, the conical pinion 125 rotates in mesh with the bevel pinion 119 around the crankshaft 122, the axis of which rotates horizontally as a function of the rotation of the shaft 107 Consequently, if the shaft 107 rotates once, the angular speed is doubled by the ratio of the teeth to the bevel gear 119 and finally quadrupled because the angle gear 119 rotates in opposite directions and at the same angular speed as the drive shaft 107 Thus, the crankshaft 122 makes four turns during a revolution of

the drive shaft 107.

  During the revolutions of the crankshaft 122, the connecting rod 126 is driven to perform a partial revolution of 900 and an alternating movement of the plunger 130 which is fixed to the stock 128, by means of the axis 129 in the bore 135 of the barrel 134, for each partial revolution of the tree

107 of 90.

  At the same time, regulator 145 is driven by the pi-

  intermediate conical pin 114 so that the fuel is measured according to its speed of rotation and the position of the adjusting lever 144, the fuel being supplied

  to chamber 136 via line 148.

  As a result, during the downward movement of the plunger 130, the fuel from the chamber 136 is sucked in through the side lumen 132a from the plunger 130 through the bore 132 in the

  upper part of the bore 135 of the barrel 134 This fuel

  rant begins to be compressed when the light 132 A is closed by the lower surface 137 a of the adjustment piece 137, as a result of the rise of the plunger 130-and its pressure gradually increases When this pressure reaches a predetermined level, it that is to say when the groove 131 comes into alignment with the distribution passage 138, for example the fuel is sent to the injection valve of one of the four cylinders, until it is injected

in the corresponding cylinder -

  When the plunger 130 is then moved upward

  so that the lateral light 132a goes beyond the face of

  upper part 137 b of adjustment piece 137, the commu-

  connection between chamber 136 and bore 135 in the barrel

  134 is re-established by the bore 132 so that the fuel

  rant in bore 135 flows to stop fuel injection.

  In an injector for six-cylinder interval engine

  equal ignition, the reduction ratio of the bevel gear

  that 119 at pinion c 8 nique 113 can be chosen at a value of 1.5 and six oil supply passages at intervals

equal can be expected.

  When the fuel injection time must be adjusted, the adjustment lever 141 is turned in one direction or the other by the rod 143 and the lever 142 by turning the lever 146 of the regulator 145 in the same direction as the lever 141 so that the adjustment piece 137 is moved up or down by the end 141 a, thereby making it possible to delay or advance the time during which

  the lateral light 132a of the plunger 130 is closed, that is

ie the duration of injection.

  Another embodiment of an injector according to the invention

  tion will now be described with reference to FIGS. 8 to 11 which represent an example in which the adjusting part functions to regulate both the flow rate and the

duration of injection.

  In FIGS. 8 and 9, the elements having the same functions

  tions than those of the embodiment of Figure 5,

  are designated by the same references and symbols.

  In FIG. 8, an adjustment piece 371 which is made to be able to slide and rotate with the plunger 130 has an upper end surface 371 b which is inclined relative to the axis of the plunger 130 and a lower end surface 371 a which forms a right angle with respect to the same axis Consequently, the adjusting part 371 has its sliding surface with the plunger 130 limited and is formed with sliding surfaces bl and b 2 and so on.

  number equal to the number of cylinders in an engine.

  The adjustment part 371 has on one side a cavity 391 into which is inserted the rounded end 411 a of a lever 411 This lever is fixed on an axis 400 which is

  mounted so that it can slide and turn in the drum 102.

  At one end of the axis 400, is fixed a lever 149 comprising

  as a sloping groove 150 around a boss 149 a In the groove 150 is adjusted the end 152 a of a lever 152

  which is mounted on a axle 151 fixed in the barrel 102.

  FIG. 11 is an exploded view showing the sliding parts of the internal face of the adjustment piece 371 and of the plunger 130 of the embodiment shown in FIGS. 8 to 10 A dashed line has

  generally following a sinusoid indicates the geometrical place

  side light displacement sensor 132a, the sliding surface bl, which is surrounded by the dashed lines

  full of the upper end surface 371 b and the over-

  bottom end face 371 a indicate a position

  for a large injection rate; a sliding surface

  cement, which is surrounded by a mixed line at a single point, indicates a position for a low injection rate; a sliding surface d which is surrounded by a mixed line with double dots indicates a position for an injection period in advance Correlatively, the positions in which the lateral lumen 132 a is closed by the sliding surface are indicated by W and X while the positions in which this light is open are indicated by Y and Z. The operation of the embodiment shown

  in Figures 8 to 11 is the following.

  When the lever 52 is turned clockwise around the axis 151, as shown in FIG. 9, the end 152a of the lever 152 raises the axis 400 in the inclined groove 150 so that the end 411 a of the lever 411 rotates the adjustment piece 371 anticlockwise from which it follows that the sliding surface of the adjustment piece 371 changes its position relative to the lateral light 132 a

  of the solid line bl appearing on the explo-

  Figure 11 at position c indicated by the broken line at a single point On the line

  full bl, the side light 132 a closes at X to dampen

  cer the injection and opens in Z to stop the injection and the effective stroke of the plunger, which is proportional to the fuel injection rate, is expressed by the literate

  If the sliding surface is moved to the position indicated

  quée by the dashed line at a single point c, the injection is started in X and is completed in Y so that the effective stroke of the plunger is expressed by the

  letter m to reduce the injection rate.

  As a result, the injection rate can be adjusted by turning

  the adjustment part 371-around the axis of the plunger 130.

  On the other hand, if the lever 149 is turned anti-clockwise as in the embodiment shown in Figure 5, the adjustment piece 371 is

  lowered by lever 411, so that the sliding part

  ment bl is moved to position d, which is indicated by the broken line at double dots in Figure 11, which advances the fuel injection start period by N. Thus, the adjustment piece 371 can adjust not only

  the injection but also the injection period.

  As shown in Figure 10, the reason why the groove 150 is inclined relative to the axis 400 is that it is made to correspond to the line in line

  interrupted at or at the geometrical place of the lateral light

  rale, as shown in figure 11, so that the

  injection rate is not changed when the injection period

jection is set.

  When the present invention is used in combination

  with an accumulator type fuel injector, the a-

  negative clearance is sufficient, for which the upper end surface-371 b of the adjustment piece 371 is arranged at right angles to the axis of the plunger, the lower end surface being inclined by

relation to this axis -

  As described, fuel can be dispensed and sent to multiple cylinders using a single plunger so that the complete injection pump can be simpler, smaller and lighter and can be produced at a lower cost In addition, as the plunger 130 is driven by the crankshaft 122 and the connecting rod 126, the injection pressure is not limited by Hertz constraints as is the case when a cam and a roller lubricated by a compressible fluid as in

  prior art injection pumps As a result, the pressure

  The injection pressure can easily be increased by properly selecting the surface pressure of the crankshaft and the

  connecting rod bearings lubricated by the fluid.

  In the design shown in FIG. 5, the surface pressure of the bearing at the widest end of the connecting rod is 500 kg / cm 2 for a fuel injection pressure of 2000 kg / cm 2 and is equal to that of the bearings

  simple conventional diesel engines.

  On the other hand, no spring is used so that the stroke of the plunger can be increased without limitation

from the use of a spring.

  In addition, the diameter of the plunger can be reduced without affecting

  affect the injection flow by lengthening the stroke of the plunger, and the loads to be borne by the various component parts are reduced so that the noise and the size of the drive mechanism can be reduced in such a way that leaks in the interval

  between the barrel and the plunger can be reduced.

  Thus, in accordance with the present invention, a fuel injector can have its high injection pressure

  not only to increase performance and make it

  thermal motor but also to achieve a cons-

  simpler truction and a reduction in weight, size

  noise, production cost.

Claims (4)

Claims   1 Fuel injector of the accumulation type in which the fuel injection is initiated by a pressure drop in a fuel passage (8 A) of an injection pump (4 A) of the non-accumulation type to a chamber accumulation (16) and is stopped by a pressure drop in the accumulation chamber, and into which the plunger (28) of the injection pump is driven by means of a crank mechanism (49, 50).   2 Fuel injector for a compression ignition engine comprising an injection pump (4 A) comprising a   non-return valve (24) arranged in a fuel passage   high pressure rant (8a) communicating with a barrel (5) in which is fitted a plunger (28) and a fuel injection valve of the accumulation type comprising a fuel injection valve having a needle valve ( 12), the opening of which is controlled by the fuel pressure and by a spring (14), and an injection port (11 a) which is opened and closed by said needle valve, and an accumulation chamber (16 ) disposed in a portion of said high pressure fuel passage so that said needle valve is opened by a drop in pressure in said high pressure fuel passage (8a) so as to thereby initiate fuel injection, and is closed by a drop in pressure in said accumulation chamber (16), so as to stop the injection of fuel, said plunger being driven by a crankshaft and a connecting rod.   3 Fuel injector including a manual mechanism   calella driven from a drive shaft (107) by a gear acceleration mechanism, a plunger (130) provided for a reciprocating movement in a barrel (134), by means of said mechanism crank and formed with a fuel distribution groove (131); the barrel in which slides   said plunger being formed with feed passages (138)   number of fuel corresponding to the number of   engine cylinders, said plunger in its movement al-   ternative being rotatable in the barrel to align its fuel delivery groove (131) with each fuel supply passage in turn to deliver   fuel to each corresponding cylinder in turn.   4 fuel injector according to claim 3, wherein the plunger is provided with a fuel inlet bore (132) opening through a side light (132 a) and wherein an adjustable element (137) can block the light ( 132 a) lateral to an adjustable point in the stroke   of the plunger to adjust the injector injection time.