DE2404369A1 - FUEL INJECTION DEVICE FOR A COMBUSTION ENGINE - Google Patents

Description

Fuel injection device for an internal combustion engine

The invention relates to a fuel injection device for an internal combustion engine, with a fuel pump, the one outlet connected or connectable to one or more fuel injection nozzles a fuel flow supplies, with an operationally interposed between the fuel pump and the outlet and in a time-dependent manner from the crankshaft or another rotating output member of the engine drivable metering device for Dispensing a measured amount of fuel to the outlet during each working cycle of the motor, and with a sensor device for controlling the metering device and for scanning of parameters with a view to achieving a for a range of engine loads and a Range of external operating conditions appropriate air-fuel ratio are selected.

One field of application of the invention is a fuel injector of this type for use in connection with an engine with one or more cylinders and one Ignition device for igniting the air-fuel mixture

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in the cylinder or cylinders by spark discharge. The fuel is a volatile one that is flammable in this way Hydrocarbon such as gasoline.

For exact regulation of the air-fuel ratio, it is necessary that with the sensor device more than a parameter is scanned.

However, it is not always possible to make these parameters more convenient Way to be scanned with a single sensor that controls the dosing device as a mechanical output variable in the form of either a force or an adjustment or a combination of both manifestations.

The invention is based on the object of a fuel injection device to provide with a device that the output variables of a plurality of sensors for influencing the dosing device combined to the above-described difficulty or analogous problems overcome or mitigate.

This object is achieved with a fuel injection device of the type mentioned at the outset, which is according to the invention characterized in that the sensor device has sensors, each of which supplies a mechanical output variable and is connected to a drive member of an adding device, the output member of which controls the metering device.

The sensors can be temperature sensors, one of which is arranged at a point at which it determines the intake air temperature receives, and the other the temperature in the engine compartment containing cooling water or others selected Temperature parameter scans.

In the preferred embodiment according to the invention, the adding device comprises axially adjustable relative to one another

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Elements which are rotatably coupled to one another for rotation about an axis and of which one element is attached to the housing is connected via a device that causes a step-by-step rotation when the element is axially adjusted, and the other element is connected to the metering device via a device which, upon axial adjustment of the Element causes a step-by-step rotation, the feelers connected to the elements of the adding device are to adjust them axially.

An embodiment that is expedient for sampling an air pressure parameter of a sensor is an expandable evacuated pressure cell. The accuracy of the output quantity it delivers depends on a spring, the spring stiffness of which is selected exactly and which is expediently located in the interior of the pressure cell itself is arranged to support their enlargement when the outside air pressure drops. Because such a feather After the pressure cell has been adjusted, it cannot be readjusted or replaced without difficulty, support is provided the enlargement of the pressure cell according to a further feature of the invention with a spring device that has a Has arranged outside the pressure cell spring. Such a spring arranged outside can counteract the effect of the inside arranged spring, which is stronger than them. The externally arranged spring can, however, be used for the exact Readjust or replace the definition of the overall spring characteristics.

The invention is described below with reference to schematic drawings several embodiments explained with further details. In the drawing shows:

1 shows a schematic representation of the main components of a fuel supply system of an internal combustion engine with a fuel injection device in an embodiment according to the invention,

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Fig. 2 is a sectional view of the fuel injection device in this form of training,

3 shows a schematic representation to explain the Mode of operation of the switching and distribution valve assembly of the fuel injection device,

Pig. 4 is a schematic illustration to explain the mode of operation of the adding device, which the The output variables of the two temperature sensors belonging to the sensing device are added together, and

5 shows a side view in a vertical sectional plane a part of the fuel injection device shown in FIG. 2 in a modified form Form of training.

Fig. 1 shows a complete system with an integrated fuel injection device for supplying an internal combustion engine with fuel and air. The system v / eist a fuel tank 10, which is via a pipeline 11 and a fuel filter 12 to the inlet of a Low pressure fuel pump 13 and further via a pipe 14 is connected to the inlet of the fuel injection device designated in its entirety by 15.

The fuel injection device 15 is directly on one Intake pipe 16 of an internal combustion engine 17, referred to below for short as an engine, is arranged, which is shown in FIG Example has six cylinders in a V-arrangement.

The fuel injection device includes as main units or main assemblies one with its inlet to the pipeline 14 connected high pressure pump 18, a metering device with a switching and distribution valve assembly 19 and a metering unit 20. The drive of the high pressure pump 18 and the

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Switching and distribution valve assembly 19 takes place at half the crankshaft speed from a drive shaft 21 Via toothed pulleys 22 and 23, which are arranged on the drive shaft 21 and on a driven shaft 24 of the motor and on which a belt 25 provided with internal teeth engages.

From the outlet of the pump 18, fuel under high pressure can be conveyed through switching holes of the switching and distribution valve assembly 19 to the metering unit 20 and from there back to the distribution holes of the valve assembly 19 and then passes through a pipe 27 which leads to outlets supplied by the valve assembly 19 are connected to injection nozzles 26 so that they receive fuel in the required order. In Pig. 1 only three injection nozzles are drawn. These are received in recesses in the intake pipe 16 of the engine 17.

The fuel injector also includes one Sensing or regulating device 29 for controlling the metering unit 20 in order to control the air-fuel ratio supplied to the engine to be able to determine. The fuel injector has an air flow passage through which air is entrained Regulation by a manually operated valve, for example a throttle valve, can flow to the intake pipe 16. The term “manually operated valve” is of course intended to include a “foot operated valve”.

The fuel injection device is also provided with a carburetor starting device 30 and a blow-off valve 31, by the excess fuel supplied by the high pressure pump 18 via a pipe 32 to the fuel tank is traceable.

Fig. 2 shows an embodiment of the fuel injection device described above, where the already mentioned

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Main units or assemblies are denoted by the same reference numerals as in FIG. 1.

A housing 33 of the fuel injection device is off an upper housing part 33a and a lower housing part 33b assembled. The upper housing part 33a forms a chamber of predominant longitudinal extent, in which the high pressure pump 18, the switching and distribution valve assembly 19 and the Dosing unit or device 20 are housed. The lower housing part 33b can be integral with the upper housing part be formed, has a substantially rectangular box shape and forms a chamber 34, which with a channel 35 in a sleeve-shaped throttle valve carrier 36 communicates. The throttle valve carrier 36 contains a manually operable throttle valve 37, which is attached to a rotatable Shaft 38 is attached.

The chamber 34 is on three sides, namely, corresponding to Pig. 2, open to the front and back and also at the bottom. The throttle valve support 36 is attachable to each of these sides, one of the remaining open sides with one plate is closed and the other is connected to the inlet port of the engine intake manifold. This training grants a certain freedom in terms of attaching the fuel injection device to any engine the mounting position, so that it is optimally adapted to the throttle linkage and with the best possible utilization the engine compartment with regard to the installation of additional devices, such as an air filter, can be selected.

The chamber 34, which in this way forms part of an air inlet duct extending from an air inlet 39 to Open side of the chamber 34 extends, is used to accommodate the main components of the control device 29, which are used to control of the metering devices 20 and 19 scans the parameters absolute pressure and temperature of the inlet air. The housing parts 33a and 33b can be cast from a light metal alloy, for example from an aluminum alloy.

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The high-pressure pump 18 is designed as a flying wheel pump and has a rotor 40 which is arranged between two stator plates 41 held at a distance from one another by a ring 41a and / carries radial vanes 42 ^{made from r fStle.} The rotor is fastened to the drive shaft 21, which is rotatably supported at one end in a ball bearing 43 and at its other end in a bearing 44 received on one of the 3ator plates 41. Fuel, for example gasoline, flows through an inlet (not shown) into a space 45 and through a recess in the adjacent stator plate 41 and is then dispensed by the pump at an opening (not shown) in the left ai stator plate 41, so that in a space 46 there is a fuel supply under high pressure.

Before the detailed description of the structure of the dosing device, i.e. that of the dosing piston and cylinder existing unit or the device 20 and the switching and distribution valve unit 19 »is for the better Understanding referred to Fig. 3, in which the general structure and mode of operation of the metering device is shown are.

The switching and distribution valve assembly is a revolving assembly with a fixedly arranged on the drive shaft 21 circumferential support 47, which has a flat cylindrical recess 47a for receiving a circumferential valve disk 48, on which a circumferential valve disc 49 designed with a larger diameter is attached (see also Fig. 2). To a form-fitting To ensure entrainment of the valve disks 48 and 49 by the carrier 47, the valve disk 48 has at one Side has a flat surface 48a which engages a flat surface in the carrier 47. The valve disks 48 and 49 are at the front cemented together or otherwise attached to one another.

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The running valve disk 49 is supported by a spring 58 (Fig. 2) on the opposite end face of a dosing cylinder block 50 held pressed, in which a metering cylinder 51 extends transversely to the axis of rotation of the revolving valve disks.

In the dosing cylinder 51 is a freely movable or reciprocating one adjustable between stops 54 and 55 Piston 52 housed. The dosing cylinder block has outlets g1 to g6, to which associated pipelines 27 leading to the injection nozzles 26 (Pig. 1) can be connected. These Outlets are provided via channels extending axially through the cylinder block with corresponding passages f1 to f6 in connection, over which an opening d, which is formed in the circumferential valve disk 49, passes one after the other is, which thus acts as a distributor.

The task of passages el and e2 in the cylinder block 50, which are connected by channels 51a and 51b with cylinder chambers S1 and S2 above or below the piston 52, consists in in connection with passages c1 to c6 in the valve disk 49 and with passages b1, b3 and b5 in the valve disk 48 and together with a flat one formed in the left end face of the valve disk 48, the disk thickness does not penetrating T-shaped channel with legs b2, b4 and b6 to form a switching device that occurs with each passage the opening d at one of the passages f1 to f6 a stroke of the piston 52 from its upper stop to the lower The stop causes or vice versa and thereby a fuel quantity measured as a function of the stroke length of the piston 52 at the corresponding one of the outlets g1 to g6.

Solid arrow lines 56 represent the flow of fuel in the upper cylinder space S1 of the cylinder 51 during the downward stroke of the piston 52, with which this corresponding dashed arrow lines 57 fuel from the pushes out the lower cylinder chamber S2 and releases it via the outlet g6.

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It can be seen that fuel delivered by the high-pressure pump through the passages a1, b1, d and el into the cylinder chamber S1 flows. Fuel emerging from cylinder space S2 flows through passages e2 and c4, legs b4 and b6, opening d, passage f6 and outlet g6. After a further rotation of the drive shaft by 60, corresponding to a rotation of the engine crankshaft by 120 °, flows through the high pressure pump delivered fuel the passages a5 » b5i c5 (in this pail in the lowest position) and e2 and enters the cylinder space S2. In the cylinder space S1 located fuel is via the passages el, c2, the leg b2 (in this case in the uppermost position) and leg b6, opening d, passage f5 and outlet g5. This operating state is shown in FIG. Similarly, after the next 60 ° rotation, another fluid or fuel flow path is established opened, causing movement of the piston 52 in the opposite direction and a measured Amount of fuel is discharged at the outlet g4 next in the order, and so on.

Which are located on the inner or bottom surface of the recess 47a ' in the carrier 47 and on the circumferential valve disk 48 supporting the smaller diameter spring 58 (Fig. 2) urges the Valve disks 48 and 49 to rest on the end face of the metering cylinder block 50 which is provided with passages. At least the valve disc 49 is made of a material with which a good Can achieve sealing and which has a suitably long service life. In practice, both can Valve disks 48 and 49 can be made of carbon, and the cylinder block 50 can be made of steel.

From the above description it is clear that the Distance between the upper and lower stops 54 and 55, the stroke length of the piston 52 and thus the length of each stroke The amount of fuel delivered is determined. The position of the lower stop 55 can be changed with the regulating device 29.

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This control device 29 is used to scan the parameter absolute air pressure in a part of the air inlet duct, ie in the chamber 34, the air temperature in this chamber and other temperature parameters specified in more detail below. The regulating device has a pressure cell 71 which can be enlarged and reduced in the axial direction and is evacuated in the interior and is composed of a flexible, corrugated side wall and rigid end plates 73 and 74. The face plate 73 is fixedly attached to a sleeve-shaped part 75 of a cam 16 which has a substantially frustoconical shape, the frustoconical surface being arranged eccentrically to an axis 77 about which the cam is rotatable. For this purpose, the cam is received on a hollow spindle 78 which is internally connected to the outside air at an inlet 79.

The other face plate 74 is in the axial and circumferential directions firmly received on a sleeve 83, which is the output member of an adding device designated in its entirety by 84 whose task is to add a number of parameters, namely those from a probe 85 sensed air temperature in chamber 34 and that sensed by a sensor 86 and one in one annular chamber 87 arranged device supplied temperature.

It is clear that due to the design of the cam 76, the position of the lower stop 55 both in the axial Adjustment and rotation of the cam via a tappet 97, which rests on the cam with a roller 98, can be changed is, wherein axial adjustment of the cam fluctuations and rotation of the pressure sensed by the pressure cell Cam occurs during rotational movement, either from temperature sensor 85 or from temperature sensor 86 or both is generated together.

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A spring 71a arranged in the interior of the pressure cell, which counteracts a spring 78a arranged in the hollow spindle 78, endeavors to enlarge the pressurized can. The size of the ratio between the axial displacement of the Cam and the absolute pressure must be adhered to with high accuracy. Since the side wall 72 of the pressurized can something is elastic and the spring 71a is not easily exchanged or readjusted after it has been inserted into the pressure cell can be, the effective spring force, which results from the combination of the spring 71a with the spring 78a, through appropriate choice of the spring 78a can be determined.

The acceleration piston 81 is urged to the left by a spring 92, but in the event of a sudden pressure increase in the Chamber 34 can be moved to the right. This results in a physical shift of the pressure cell to the right. this occurs when the throttle valve is suddenly opened and the mixture is reduced by lowering the stop 55 and increasing it the stroke length of the piston 52 is briefly enriched. The piston goes due to leakage flow on the piston and through the sealed bearing, whose sealant is not completely impermeable is, gradually back to its initial position shown in FIG.

The temperature sensors 85 and 86 can be designed as wax capsules as they are commonly found in engine cooling systems for controlling fluid or coolant flow. Each sensor has a chamber which can be enlarged in the axial direction and which contains a substance, for example a wax, which is selected to be a vapor pressure change undergoes at a predetermined temperature or within a narrow temperature range, whereby a significant Expansion or enlargement of the capsule is caused in the axial direction. Connection parts of the sensors 85 and 86 are supported in the sleeve 83 or in a housing 95, while the end faces forming the output members on the The ends of the adding device.

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The adding device 84 has the task of performing the algebraic addition of the output variables of the sensors 85 and 86. It comprises two axially interlocking sleeves 88 and 89, each of which is two diametrically opposed Has slots which extend over a quarter of the sleeve circumference and two protruding in the axial direction leave partially cylindrical webs 88a and 89a. The webs of a sleeve engage in the axially displaceable Slots in the other sleeve, so that the two sleeves are displaceable in the axial direction relative to one another, themselves but take each other along when turning.

A helical slot 90 is formed in the sleeve 88, which is axially adjustable by the temperature sensor 85, in which engages a pin 91 fastened to the output sleeve 83 and protruding radially inward therefrom.

The two sleeves 88 and 89 are urged away from one another by a helical compression spring 92 so that each is in contact is held on the output member of the associated temperature sensor 85 and 86, respectively.

The sleeve 89 also has a helical slot 93 into which a radially inwardly protruding pin 94 engages.

In the schematic representation of the Pig. 4 it can be seen that the temperature sensor 85 moves axially in this way of the sleeve 88 which is held against rotation by the sleeve 89 and the pin 94, the helical Slot 90 is supported on pin 91 and thereby, as indicated by arrow 83a, rotation of output sleeve 83 generated clockwise (Fig. 4).

Enlargement of the temperature sensor 86 produces axial movement of the sleeve 89, which because the slot 93 is on the pin is supported, also, as indicated by an arrow 83b,

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rotates clockwise and the sleeves 88 and 83 in the same Direction of rotation drives.

Such rotation is transmitted via the pressure cell 71 to the cam 76 and thereby the position of the lower stop 55 changed and the stroke length of the piston 52 adjusted.

The temperature parameter sensed by sensor 86 may be the temperature of the coolant for the engine. In this case it may be appropriate to guide the coolant through the cavity 87. If necessary, the cavity 87 having Chamber can be omitted and a housing 95a accommodating the temperature sensor 86 can be provided with ribs on the outside in order to measure the temperature or Absorb heat from the engine compartment of the vehicle (Fig. 5).

If necessary, the temperature parameter can be taken from burning fuel components in the engine exhaust gases and the sensor 86 can either be fed directly by placing the sensor in the combustion chamber in which this combustion takes place, can protrude, or transmitted as a heat signal by electrical means.

It is possible to design the sensor 86 so that it senses more than one temperature parameter.

In order to prevent the cold engine from stalling while idling, on the hollow spindle 78 and on the cam 76 in the axial direction extending slots 78b or 76a may be formed which overlap or overlap one another, as soon as the pressure cell and the cam assume an angular position that with respect to the temperature sensor 86 a corresponds to the cold state, whereby air can flow into the chamber 34. As soon as the temperature sensor 86 as a result of temperature parameter sampled by him an operating temperature reached, the slots move by rotation

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out of their mutual coverage and the additional amount of air can therefore no longer pass through the interior of the hollow spindle 78 and enter the slots. Such an additional The amount of air increases the absolute pressure in the chamber without opening the throttle valve and therefore causes axial adjustment of the cam to the right and shifting the stop 55 downwards.

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Claims (8)

EXPECTATIONS Fuel injection device for an internal combustion engine, with a fuel pump connected to one or more fuel injection nozzles or connectable outlet supplies a flow of fuel, with one operational between the fuel pump and the Outlet interposed metering device for dispensing which can be driven over time by the crankshaft or another rotating output member of the engine a metered amount of fuel to the outlet during every working cycle of the motor, and with a sensing device for controlling the metering device and for scanning of parameters with a view to achieving a for a range of engine loads and a range of external operating conditions appropriate air-fuel ratio are selected, characterized in that that the sensor device has sensors (85, 86), each of which provides a mechanical output variable and on a drive member (88 or 89) of an adding device (84) is connected, the output member (83) of which is the metering device (51,52) controls. 2. Fuel injection device according to claim 1, characterized in that the sensor (85, 86) Are temperature sensors, one of which (85) is arranged at a point at which it records the intake air temperature, and the other (86) the temperature in the engine compartment containing cooling water or other selected temperature parameters scans. 409831/0402 - t - 44 369 3. Fuel injection device according to claim 1 or 2, characterized in that the adding device (84) comprises elements (88, 89) which are axially adjustable relative to one another and which are fixed against rotation about an axis (77) are coupled to one another and of which one element (89) is connected to a housing part (33b) via a device (93, 94) is connected, which causes a corresponding rotation upon axial adjustment of the element (89), and the other Element (88) is connected to the metering device (51,52) via a device (90,91 »83) which, when axially adjusted of the element (88) causes a corresponding rotation, the sensors (85, 86) with the elements (88, 89) the adding device (84) are connected in order to adjust them axially. 4. Fuel injection device according to claim 3, characterized in that the elements (88,89) of the adding device (84) are sleeves each having axially extending slots into which each in the axial direction extending webs (88a, 89a) engage. 5. Fuel injection device according to claim 3 or 4, characterized in that the devices (83,90,91,93,94) for generating corresponding rotation axial adjustment of each of the elements (88, 89) of the adding device (84) a helical slot (90 or 93) and a pin (91 and 94, respectively). 6. Fuel injection device according to one of claims 1 to 5, wherein the sensing device is a having evacuated pressurized can, characterized in that that the output member (83) of the adding device (84) is connected to the pressure cell (71) to move the Adjusting device (55) of the metering device (51,52) to be transmitted via the pressure cell (71). / 3 409831/0402 44 369 7. Fuel injection device according to claim 6, in the case of the enlargement of the pressure cell as a function of decrease of the air pressure sensed by the pressure cell is supported by a spring device, characterized in that the spring device has an outside the pressure cell (71) arranged spring (78a). 8. Fuel injection device according to claim 7 »characterized in that the spring device a spring (71a) arranged inside the pressure cell (71) which counteracts the spring (78a) arranged outside and is stronger than this. 409831/0402