DE2140964A1 - FUEL INJECTION SYSTEM FOR MIXED COMPRESSING, EXTERNAL IGNITION ENGINE WITH CONTINUOUS INJECTION INTO THE INDUCTION MANIFOLD - Google Patents

Description

R. 445

Kh / Lm 11 »8.1971

Attachment to
Patent and
Utility models!

ROBERT BOSCH GMBH, 7 Stuttgart 1

Fuel injection system age for mixture-compressing, externally ignited internal combustion engine with continuous injection

into the suction pipe

The invention relates to a fuel injection system for mixture earned end, spark-ignition internal combustion engines, with continuous injection into the intake manifold _s in which the through-flowing quantity of air is moved over a working member against a restoring force of an I-lessorgan and an arbitrarily operable throttle valve arranged one behind the other and Kits organ according while the moving part of a valve arranged in the fuel line for the metering of an amount of fuel proportional to the air flow is adjusted.

2 -

309809/0384

" ² " 2U0964

"Robert Bosch GmbH 'Kh / Lm R. 445

Stuttgart

by virtue of hydraulic fluid, which is continuously and under Constant pressure conveyed through a pressure line is applied to the working element via a throttle.

In a known fuel injection system of this type (see German Offenlegungsschrift 1 960 144), the amount of fuel is metered as proportionally as possible to the amount of air flowing through the intake manifold, the ratio between the metered amount of fuel and the amount of air being able to be changed by changing the restoring force of the measuring element as a function of engine parameters. In this fuel injection system, air or measuring element vibrations at full load in the range of low speeds can lead to an increase in the mean value of the position of the control slide and thus to an undesirable higher fuel metering. Therefore, "proposed in another fuel injection system of this type (see -dteutfche Patent Application P 20 62 0? 8.4), a" at dsßr above-described system extends as a damping acting throttle between the control pressure circuit and the Bruck space into which the control slide as a return member of the Hess organ * To be replaced by a Di ⁸ OSSeI that is dependent on the flow direction, which avoids the undesired, excessive fuel metering. Both the valve, which changes the restoring force of the measuring element when the engine is at operating temperature for λ correction as a function of engine parameters, and the flow-direction-dependent throttle mean construction costs. *

The invention is based on the object of a fuel injection system to develop in which the metered amount of fuel is as proportional as possible to that through the intake manifold flowing 'air quantity isb and on a λ-correction by an additional valve depending on the engine parameters and a flow-direction-dependent throttle can be dispensed with.

309809/0384 _ ₃ _

Robert Bosch GmbH R ₀ 4Λ5 Kh / Lm

Stuttgart · ·. ·

This object is achieved according to the invention in that the Measuring element in an intake manifold from section "is movable, the individual for adjustment to the map of the internal combustion engine has frustoconical sections.

An advantageous embodiment of the invention is such that the intake pipe section for idling the internal combustion engine has a section with a cone angle between 30 ° and 70 °, for the lower partial load area of the internal combustion engine a section whose cone angle is about 10 to 20% larger than that of the section for idling, a transition section for the transition between the lower partial load area and the full load area and for the full load area of the internal combustion engine has a section with a cone angle that is approximately the cone angle of the Corresponds to idle section.

An embodiment "of the invention is shown in the drawing and is described in more detail below.

Show it:

Pig, 1 the entire fuel injection system, Fig. 2 is a diagram showing the fuel injection amount as a function of the speed.

In the fuel injection system shown in FIG the combustion air flows in the direction of the arrow into an intake manifold 1, in whose intake manifold section 3 a measuring element 2 is arranged is, and further through a connecting hose'4- and a suction pipe section 5 rait an arbitrarily actuatable Throttle valve 6 to one or more cylinders (not shown) of an internal combustion engine. The measuring organ 2 is one plate arranged transversely to the direction of flow, which is ixi Depending on the air pressure flowing through the intake manifold

numge moved. 3 09809/0 38 4

Robert Bosch GmbH R. 445 Kh / Lm

Stuttgart

The measuring element 2 directly controls a metering and quantity divider valve 7 · A lever connected to it is used to transmit the adjustment movement of the measuring element 2. 8, the, is mounted as friction-free as possible around a pivot point 9 and in its pivoting movement with a nose 10 as Control slide designed movable valve part 11 of the metering valve 7 is actuated. The end face facing away from the nose 10 12 of the control spool. 11 is acted upon by hydraulic fluid, which acts as a restoring force for the measuring element 2 serves.

The fuel is supplied by an electric motor 14 driven fuel pump 15 »which sucks in fuel from a container 16 and via a line 17 the Metering valve 7 supplies. A line 18 branches off from the line 17, into which a pressure relief valve 19 is connected is.

The fuel passes from the line 17 into a channel in the housing of the flow divider valve 7. The channel 22 leads to an annular groove 23 of the control slide 11 and further via various branches to chambers 24, so that one side of a membrane 25 is acted upon by this fuel pressure. Depending on the position of the control slide 11, the annular groove 23 covers more or fewer control slots 26 which each lead through channels 27 to a chamber 28 which is separated from the chamber A by the membrane 25. From the chamber 28, the fuel passes through channels 29 to the individual injection valves, not shown, which are arranged in the vicinity of the engine cylinders in the intake manifold. The membrane 25 serves as a movable part of a flat seat valve,

- 5 - ■ 309809/0384

140964

Robert Bosch GmbH H. 44-5 Kh / Lm

Stuttgart

by the spring 30 when the fuel injection system is not working is kept open. The diaphragm cans formed each from a chamber 24 and 28 cause that independently of the overlap existing between the annular groove 23 and the control slots 26, that is, independent of the overlap to the injection valve In the flowing fuel quantity, the pressure gradient at the metering valve 23, 26 remains largely constant. In order to it is guaranteed that the adjustment path of the control slide 11 and the metered amount of fuel are proportional to

The suction pipe section 3 has individual frustoconical sections 61, 62, 63? 64 with different taper angles or diameters. During the pivoting movement of the lever 8, the measuring element 2 is moved in the suction pipe section 3 in such a way that the ring cross-section changing between the plate 2 and the inner circumference of each frustoconical section is proportional to the adjustment path of the measuring element 2. If this prerequisite is given, there is a linear dependence of the adjusting movement of the measuring element 2 and the displacement movement of the control slide 11 for each frustoconical section, so that the amount of air flowing around the intake manifold is always measured in a proportional amount of fuel.

The pressure fluid acting as a constant restoring force on the control slide 11 is fuel ³ . For this purpose, a line 33 branches off from the line 17 and opens into the pressure chamber 34 into which the control slide 11 protrudes with its end face 12 facing away from the pivot lever 8. A throttle 35, which separates the supply circuit 17 of the metering valve 7 from the control pressure circuit 33, is arranged in the line 53.

6 - 2U0964

praises Bosch GmbH 'R. 445 Kh / Lm

Stuttgart

The pressurization of the pressure chamber 54 takes place via a Choke 57- This choke is used to limit the overshoot of the measuring element 2 when accelerating and to limit the effect of suction surges of the internal combustion engine as Attenuation required.

In the position of the measuring element shown in FIG. 1 the measuring element 2 is in the rest position in a cylindrical section 60. On the cylindrical section 60, the section 61 closes in the flow direction with a cone angle between 30 ° and 70 ° on, in which the measuring element 2 works in the idle position. The section 61 merges into a section 62 for the lower partial load area, which is followed by a transition section 63 connects to a section 64 for full load, which is approximately has the same cone angle as the idle section 61.

The fuel injection system works as follows:

When the internal combustion engine is running, 4kirch is the Electric motor 14 driven fuel pump 15 fuel from the fuel it retains 16 sucked in and fed to the metering valve 7 via line 17. At the same time sucks the internal combustion engine via the suction pipe 1 to air, through which the measuring element 2 a certain deflection from its Rest position 'experiences. In accordance with the deflection of the measuring element 2, the control slide is also controlled via the lever 8 shifted, which thereby has a larger cross-section of the control slots 26 releases.

In Fig. 2, the solid lines a characterize the map of the internal combustion engine to be adapted., Where Q is the

- 7 -309809/0384

Robert Bosch GmbH R ₀ 445 Kh / Lm

Stuttgart

injected fuel quantity per work cycle and η the speed represent the internal combustion engine. If you put the ■ suction pipe section 3, in which the measuring element 2 moves, as The cone with a constant cone angle occurs when using the known throttle 57 at full load in the area lower speeds an increase in the middle position of the control slide 11 and thus · an undesirable Fuel enrichment according to the dashed lines b. This phenomenon is due to the fact that when accelerating and during the intake stroke of the internal combustion engine due to the greater air speed im Saugrohr.der control slide 11 is accelerated more strongly by the measuring element 2 than in the backward direction the pressure in the pressure chamber 34, wherein in the first case a significantly higher pressure builds up in the pressure chamber 34 than 'the acting in the backward direction on the control slide Pressure. According to the invention, therefore, the suction pipe section designed in such a way that the dash-dotted Characteristic curves c would result. The influence of the pulsating flow in the suction pipe on the measuring element 2 then results in an excessive speed in the range of low speeds Fuel metering together with metering accordingly the line c results in a line d marked by crosses, which is approximately the ideal map of the Internal combustion engine corresponds. In the area of the speed of sound, in the area of the suction pipe section 3? i.e. below the. horizontal line e, which corresponds to a certain amount of air, no more pulsation occurs.

According to the invention, the suction pipe section 3 is exposed individual truncated cone-shaped sections with different Conical vortex together * In the rest position, this takes

309809/038 4 ⁸ "

- 8- 2H0964

Robert Bosch GmbH R. 445 Kh / Lm

Measuring element 2 has a position in the cylindrical section 60, to which a section 6/1 joins in the flow direction a relatively acute cone angle in which the measuring element 2 experiences a relatively large deflection when idling, so that a rich fuel-air mixture is established. A section 62 adjoins section 61 with a relatively wide cone angle in which the measuring element 2 is located in the lower partial load area. This Section 62 ensures a poor fuel-air mixture in the emission test area. The section 62 for lower partial load is through a transition section 63 with the section 64 connected, which has approximately the same cone angle as the Le erlauf, from section 61.

In the embodiment of the suction pipe section according to the invention 3 can therefore rely on a control of the restoring force on the measuring element as a function of engine parameters for λ correction and a flow-direction-dependent throttle to pressure chamber 57 can be dispensed with.

3 0 9809/0384

Claims (4)

Robert Bosch GMBH . H. 445 Kh / Lm Stuttgart Expectations p. yInject fuel! age for mixture-compressing, third-party ^^^ ignited internal combustion engines with continuous injection into the intake manifold, in which a measuring element and an arbitrarily actuated throttle valve are one behind the other are arranged and the measuring element according to the amount of air flowing through a working element "against a Restoring force is moved and thereby the movable part of a valve arranged in the fuel line for the metering of an amount of fuel proportional to the amount of air is adjusted, with hydraulic fluid as the restoring force serves, which continuously and under constant pressure through a pressure line conveyed the working member acted upon via a throttle, characterized in that the measuring element (2) is in a suction pipe section. (3) is movable, the individual frustoconical sections for adjustment to the engine map (61, 62, 63, 64) has. 2. Fuel injection system according to claim 1, characterized in that the intake pipe section (3) for idling the internal combustion engine has a section (61) with a cone angle between 39 ° ^ d-? 0 ° . - 10 309809/0384 Robert Bosch GmbH H. 44J? Stuttgart Injecting 3. Fuel !, age according to claim 1, characterized in that the suction pipe (3) for dae lower part-load range of the internal combustion engine has a portion (62), whose cone angle is large by about 10 to 20% than that of the portion (61) for idling. 4. Fuel injection system according to claim 1, characterized in that that the suction pipe section (3) for the transfer . gear between the lower partial load area (62) and the full load area (64) has a transition section (63). 5 · fuel injection system according to claim 1 ,. characterized, that the suction pipe section (3) for the full load area the internal combustion engine has a section (64) with a cone angle which is approximately the cone angle of section (61) corresponds to idling 309809/0384 Empty soap