JPS59185863A - Fuel jet apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a fuel injection device for an internal combustion engine, in which a plurality of fuel metering valves are provided in a fuel supply conduit, and the nuclear fuel metering valve is a movable metering valve portion. and one regulating valve is assigned to each of the fuel metering valves, the movable regulating valve part of which is controlled on one side by the fuel pressure downstream of the fuel metering valve and on the other side. The present invention relates to a type in which one side is loaded with fuel pressure in a differential pressure control line, which differential pressure control line is on the one hand limited by a control pressure valve and on the other hand can be relieved via a control throttle.

Fuel injection systems are already known in which all fuel supply lines are shut off after shutting down the internal combustion engine and pressure relief in the fuel injection system is stopped. However, in this known fuel injection device, there is a risk that the fuel upstream of the injection valve is heated by the heat of the internal combustion engine and the fuel pressure increases, causing the injection valve to open and fuel to be undesirably injected.

In a fuel injection device of the above/h type, the connecting pipe between the fuel supply conduit and the control pressure valve is connected to the connecting pipe which is opened when fuel is being fed under pressure to the fuel supply pipe and when the fuel feeding is interrupted. The fuel injection device according to the present invention, which is characterized by being provided with a cutoff valve that shuts off the flow, has the following advantages compared to known ones. That is, in the fuel injection device of the present invention, the fuel pressure downstream of the fuel injection valve can be lowered after the internal combustion engine is stopped, so that the injection valve is prevented from opening due to a pressure increase due to heating when the internal combustion engine is stopped. Ru.

Advantageous embodiments of the fuel injection device according to the invention are possible with the measures specified in the dependent claims. It is particularly advantageous, for example, if a pressure regulating valve is used as the shutoff valve, which regulates the fuel pressure in the fuel supply line. Similarly, in the V-combustion engine, it is advantageous if a solenoid valve is used as the shut-off valve, which closes the connection between the control pressure valve of the differential pressure control line and the fuel supply line when the internal combustion engine is stopped.

Embodiments of the invention will now be explained with reference to the drawings.

In the illustrated exemplary embodiment of the fuel injection system, a metering and distribution valve is designated by 1, one metering valve for each cylinder of an internal combustion engine with ignition, not shown in this case. is assigned, and at this metering valve, fuel is metered at a predetermined ratio to the amount of air sucked in by the internal combustion engine (C).
It has two metering valves (of which 2" are shown in the drawing) and is therefore intended for use in VC four-cylinder internal combustion engines. The cross section of all metering valves are movable together. By means of the control spool 2, which acts as a metering valve part of the fuel supply, the arrangement is varied in a known manner in relation to the operating characteristic values of the internal combustion engine. A check valve 7 is disposed in the fuel supply conduit 3 and opens the fuel tank 6 in the pumping direction by the fuel pump 5 driven by the electric motor 4.
sent via.

A branch line 22 branches off from the fuel supply line 3 and leads to a pressure regulating valve, a cut-off valve 9, which, in relation to the fuel pressure in the fuel supply line 3, maintains a predetermined fuel pressure of at least approximately 3 bar. Released when exceeds. A connecting line 25 leads downstream of the shut-off valve 9 into a line 19 arranged at the inlet of the control pressure valve 2o. Branch conduit 22 and connection conduit 2
5 and the conduit 19 form a connecting pipe between the fuel supply conduit 3 and the control pressure valve 20. This connecting pipe should be at least approximately 3
If the voltage drops below the bar, the shutoff valve 9 shuts off.

The shutoff valve 9 also serves at the same time as a pressure regulating valve, which constantly regulates the fuel pressure in the fuel supply line 3, the so-called system pressure, to a pressure of about 5 par.

For example, the illustrated pressure regulating valve (shutoff valve 9) has a regulating piston 4
0, and this adjusting piston 40 has an adjusting spring 41
is displaced by the fuel pressure in the branch conduit 22 against the force of the control piston 40, so that the fuel flows from the branch conduit 22 into the return conduit 49 and back into the fuel tank 6 via the control lip 42 in the sliding hole 43 of the regulating piston 40. . The opening of the adjusting piston 40 simultaneously causes the impulse valve 44 to open. For this purpose, an operating pin 45 is engaged with the adjusting piston 4o, which opens when the fuel cylinder//'5 is actuated, and this operating pin 45 controls the movable valve part 46 of the impact valve 44 against the cover of the impact spring 47. Move it in the opening direction against the When the internal combustion engine is stopped, the fuel pump 5 can no longer pump fuel.
Instead, the pressure regulating valve 9 is closed.

At the same time, the movable valve part 46 of the impulse valve 44 is brought into the closed position by the impulse spring 4.7 acting on one operating pin 45.

At the end of the adjusting piston 40 on the branch conduit 22 side, a small-diameter step 48 having an adjusting surface 50 is provided. This step 4.8 K forms a conical part 5 with a sealing ring 52.
1 follows, and this conical part 51 cooperates with a conical part 53 of the slide hole 43, which serves as a valve seat. A hole 54 is provided in the area of the sliding hole located between the contact line of the conical part 53 and the ring 52 of the pressure regulating valve 9 and the regulating lip 42 when the pressure regulating valve 9 is closed. td extends from this hole 571. As a result, when the shutoff valve 9, which acts as a pressure regulating valve, is opened, the connecting conduit 25 and the conduit 19 are
At the inlet of the αi-controlled pressure valve 20, the fuel pressure in the fuel supply line 3 also occurs. When the shut-off valve 9 is closed, the fuel supply line 3 is isolated from the connecting line 25 and the line 19.

A solenoid valve 9', shown in broken lines, can also be provided as a shut-off valve 9' in the connecting line between the fuel supply line 3 and the inlet of the control pressure valve 20.

This shutoff valve 9' is disposed in a conduit 19' shown by a broken line between the fuel supply conduit 3 and the conduit 19, and is controlled by the weight Wa control device 32 when the fuel pump 5 is operated, for example. Then, the conduit 19' is opened. The isolation valve 9' is closed in the absence of current. In an embodiment of a fuel injection device with such a cut-off valve 9', the blank connecting line 25 between the pressure regulating valve 9 and a line is omitted.

A conduit 11 is provided downstream of each metering valve, via which the metered fuel quantity reaches a regulating chamber 12 of a regulating valve 13 assigned individually to each metering valve. Regulating valve 1
The regulating chamber 12 of No. 3 is separated from the control chamber 15 of the regulating valve 13 by a movable regulating valve part, for example a diaphragm 14 . The diaphragm 14 of the regulating valve 13 is the regulating chamber 2
It cooperates with an immovable valve seat 16 provided in the valve seat 16.

The metered fuel flows from the regulating chamber 12 via this valve seat 16 into the individual injection valves 10 (only one of which is shown in the drawing) in the intake pipe of the internal combustion engine. . A closing spring 17 is arranged in the control chamber 15 .

Conduit 191d is connected to the inlet of a control pressure valve 20, which is configured as an electrohydraulic transducer of the nozzle-baffle construction type, via which differential pressure control line 2 is connected.
It opens at 1. The differential pressure control conduit 21 downstream of the pressure control valve 20 has a regulating valve 13! A lil control chamber 15 and a control throttle 23 are arranged downstream of this control chamber 15. Fuel flows from differential pressure control conduit 21 to outlet conduit 24 via control restriction 23 . The control pressure valve 2oi/i of the nozzle/baffle construction type is known per se, so its function and mode of action will only be briefly described.

The control pressure valve 20, which is an electro-hydraulic converter, has a rotating plate 26 in the form of a scene, and this rotating plate 26 has a variable turning moment via a coil 27, 28ffi, for example, in an electromagnetic manner.
Since the 'al-load is applied, the rotating plate 261d is deflected to some extent about the rotating shaft 29. At the nozzle 30 of the control pressure valve 20, the conduit 19 opens toward the baffle plate 31 attached to the rotating plate 26. In other words, when the deflection moment acting on the rotating plate 26 is constant, the nozzle 30 and A pressure drop is created between the baffle plate 31 and the pressure drop, which creates a constant pressure difference between the fuel pressure in the conduit 19 and the fuel pressure in the differential pressure control conduit 21, which is related to the deflection moment. The 4j control of the control pressure valve 20 is related to appropriate input internal combustion engine operating characteristic values such as the number of rotations 33, the throttle valve position #34, the temperature 35, the exhaust gas composition 36, etc. This is done via the electronic control unit 32.

The control of the control valve 20 by the electronic control unit 32VrC takes place in this case in an analog 1lfll III manner or in a clock-controlled manner. In the de-energized state of the limiting pressure valve 20, a base moment is generated on the pivot plate 26 by means of a suitable spring casing 1d and a permanent magnet 27. This pace moment is set in such a way that even in the event of a failure of the electrical control system, a pressure difference is generated that guarantees emergency operation of the internal combustion W8 engine.

For example, when a signal occurs that indicates a characteristic of internal engine braking operation, such as a rotation speed above idling speed and the closing of the throttle valve, the control pressure valve 20
is excited, and the fuel pressure in the differential pressure control conduit 21 is
It increases so much that the regulating valve 13 closes and fuel injection at the injection valve 10 is interrupted.

The metering and distribution valve 1 has a metering sleeve 55 in which a control spool or a control spool is axially displaceably mounted in a guide hole 56 . Control (2 spools per spool,
One ff1. It has one groove 57 on the open side that is limited by an edge 58. Control edge 58 when sliding upwards!
The control openings 59, which are, for example, control slits, are opened by more or less than d, and the fuel is metered and flows out into the conduit 11 through these control openings 59. Control edge 58 of control stool 2
together with one control opening 59 each form a metering valve, of which two of the four metering valves are shown in the plane of the drawing, not shown. The remaining two metering valves are not located in the plane of the drawing, but are offset by 90[deg.] with respect to the illustrated canning valve. On the operating side of the control spool 2, an air measuring device (not shown) is arranged, for example in a known manner, on the sweeping end 60, and the side spool 2 is connected to the control spool 2 in relation to the amount of air sucked in by the internal combustion engine.
Move and tighten. A step 61 is formed at the transition to the operating end 60 with a small cross section. Operation end 60
is surrounded by a radially extending wall 62;
The guide hole 56 of the trench wall 62 is closed downward and I
nru. An elastic sealing ring 63 is arranged on this radial wall 62, against which the step 61 rests in the rest position of the control spool 2 and is thus sealed against the outside. . control spool 2
in the working position device, the step 61 and the radial wall 62
A leak chamber 64 is formed between the control spool 2 and the control spool 2, and the leak chamber 64 collects fuel flowing out from the control groove 57 via the outer peripheral surface of the control spool 2. Leak room 6 /1. K leak conduit 65
is connected. The return force acting on the control spool 2 against the operating force acting on the operating end 60 is produced by the fuel.

For this purpose, an end face 70 of the control spool 2 is formed at the end of the control spool opposite to the working end 60, and the end face 70 of the control spool 2 protrudes into a pressure chamber 69. It is connected via a loose restrictor 68 to a conduit 71, which itself opens into a return force control conduit 72.

The return force control conduit 72 is connected to the fuel supply conduit 3 VC via the shutoff throttle shifter 3 at one end, and the pressure d circumferential control valve 74 at the other end.
It is fully limited by. The pressure regulating valve 74 has a working chamber 75 which is connected to the return force jli control line 72 and separated from the spring chamber 77 by a valve diaphragm 76 . The inside of the spring chamber 77 is at atmospheric pressure, and a pressure spring 78 that loads the spring chamber 77Vc (d valve diaphragm 76 in the valve closing direction) is provided.

In the working chamber 751fC, the valve seat 79 that cooperates with the valve diaphragm 76 enters the chamber. Fuel exiting via the valve seat 79 enters a conduit 80 which, like the leakage conduit 65 extending from the metering and dispensing valve 1, passes through the conduit 81 into the valve chamber 82 of the impulse valve 44. It opens upstream of the impact valve seat 83. The movable valve portion 46 of the impact valve 44 is connected to the impact valve seat 83.
Once lifted from the valve chamber 82, the valve chamber 82 connects with the return conduit 49 leading to the suction leg of the fuel pump 5, for example to the fuel tank 6.

The outflow conduit 24 is also connected to the suction side of the fuel pump 5 in an unpressurized state downstream of the control restrictor 23, for example, through the sluice hole 43 of the shutoff valve 9.
It leads to a return conduit 49 through the. Fuel supply lead/position 3
The fuel pressure in the fuel supply conduit 3 is interrupted by stopping the fuel pump 5, and the fuel pressure in the fuel supply conduit 3 is approximately 2.8-3.2
When it becomes a pearl, the shutoff valve 9 is completely closed and the same
Shigeko 44 will also be closed. This fuel pressure rr-1 of approximately 2.8 to 3.2 bar is below the opening pressure of the injector 10 [ω] and is above the entire fuel vapor pressure divided by the fuel temperature in question, so that this regenerates the internal combustion engine. Bubble formation that makes starting difficult or prevents is avoided. If, as in one embodiment of the invention, the conduit 19 leading to the inlet of the control pressure valve 20 is connected to the fuel supply conduit 3 via the connecting conduit 25 and the shutoff valve 9, the connection to the fuel supply conduit 3 is interrupted. The pressure in the differential pressure control line 21 is then reduced via the control throttle 23. As a result, the pressure created by the fuel pressure in each control chamber 15 and the diaphragm 14 during which the VC acts
If the force of Pressure equilibrium between the downstream injection conduit and the fuel supply conduit 3 is achieved via the minimally opened control opening 59 in the metering and distribution valve 1, and therefore the internal combustion) Even if the fuel along the upstream side of 10 heats up, undesired injection can be prevented.

A similar mode of action is provided in another embodiment of the invention l+1-1, in which a solenoid valve (shutoff valve 9
′) is also provided. In this case, the connecting line 25fd between the line 19 and the shutoff valve 9 is omitted.

[Brief explanation of the drawing]

The drawings are diagrams schematically showing two embodiments of the fuel monitoring device according to the present invention. ■...Metering and distributing valve, 2. Control spool, 3. Fuel co-feeding conduit, 1. Electric motor, 5 Fuel pump, 6.Fuel tank, 7.Check valve, 9.9'.Shutoff valve, 10.Injection valve, 11.Conduit, 12.Adjustment chamber, 13.Adjustment valve, 1
4.Diaphragm, 15.Control room, 16 Valve, ]7
Close button spring, 19, 1.9' conduit, 20-control pressure valve, 21...differential pressure control conduit, 22-branch conduit, 23 control throttle, 24-outflow conduit, 25...connection conduit, 26
Swivel plate, 27.28...Coil, 29...Swivel axis, 3
0 nozzle, 31, baffle plate, 32...'Sakiko control device,
33-・Rotation speed, 34・・Throttle valve position, 35
...Temperature, 36 Exhaust gas composition, 37 Permanent magnet, 40.
・Adjustment piston, 41 Kotomisaki adjustment spring, 42・Adjustment edge,
43... Slip hole, 44... Mieko, 45... Operating pin, 46... Valve part, 47... Impact spring, 48... Step part, 49... Return conduit, 50... Adjustment surface, 51 Conical part, 52...Seal 1]ng, 53 Conical part, 5
4., Hole, 55 ・Measuring sleeve, 56 ・Guide hole, 5
7 ・Hou! Mizo, 58 control wlP, 59-ill'
d open D, 60 operating end, 61/stepped section, 62 wall, 63-
・Seal ring, 64・Leak chamber, 65・Leak conduit 568
・Buffer throttle, 69・Pressure chamber, 70・End face, 71・Conduit, 72・Return force control conduit, 73・Shutoff throttle, 74 Pressure adjustment valve, 75 Working chamber, 76・Valve diaphragm, 7
7 chamber 42, 78 pressure spring, 79...valve pressure, 80
．． 81 Conduit, 82 Valve chamber, 83 Valve valve seat

Claims (1)

[Claims] ] A fuel injection device for an internal combustion engine, comprising a fuel metering valve in a fuel supply conduit VC, the fuel metering valve having a movable metering valve portion. 1 each to the same fuel metering valve.
One regulating valve is assigned, the movable regulating valve part of which is loaded on one side by the fuel pressure downstream of the fuel metering valve and on the other side by the fuel pressure in the differential pressure control conduit. Well, the differential pressure control conduit is 10,000 yen! fi
1. Control pressure valve control indenter] In the type in which the pressure is limited and on the other hand can be relieved via a control throttle, the connection pipe l'i:+1 between the fuel supply conduit (3) and the control pressure valve (20) (22,25°19.19'), the fuel supply conduit (
3) when feeding fuel under pressure to the connecting pipes (22, 25, 19,'
19') and interrupt the fuel pressure feeding.
2,25゜19.19')
)' is arranged and is a fuel injection device. 2. The fuel injection device according to claim 1, wherein the VC cutoff valve (9, 9') is opened when the fuel pressure in the fuel supply conduit (3) exceeds a predetermined fuel pressure twice. 3. The fuel injection device according to claim 2, wherein a pressure regulating valve capable of regulating the fuel pressure in the fuel supply conduit (3) to a predetermined pressure is used as the cutoff valve (9). 4. The fuel injection device according to claim 1, wherein a solenoid valve is used as the cutoff valve (9').