DE2347828A1 - FUEL INJECTION SYSTEM - Google Patents

Description

R. ¹⁷³⁸
August 27, 1973 Kh / Kb

Attachment to

Patent and

Utility model registration

ROBERT BOSCH GMBH, 7 Stuttgart 1

Fuel injection system

The invention relates to a fuel injection system for mixture-compressing, externally ignited internal combustion engines with continuous injection into the intake manifold, in which a measuring element and an arbitrarily actuatable throttle valve are arranged one behind the other and. the measuring element is moved via a working element against a restoring force * in accordance with the amount of air flowing through it, and thereby adjusting 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

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Restoring force pressure fluid is used, which is continuously and under constant, but arbitrarily changeable Pressure conveyed through a pressure line, the working link acted upon, with a disk serving as the measuring element, which fastened transversely to the direction of flow at one end of a stationary and almost friction-free mounted pivot lever is and proportional to the amount of air flowing through the intake manifold in a corresponding flow direction The funnel-shaped widening section of the suction pipe emerges.

Fuel injection systems of this type have the purpose of automatically creating a favorable fuel-air mixture for all operating conditions of the internal combustion engine, in order to enable complete combustion of the fuel and thereby the formation of toxic exhaust gases with the highest possible performance of the internal combustion engine or the lowest possible fuel consumption avoid or at least greatly reduce it. The power fabric me _r length must therefore the requirements of each operating condition of the internal combustion engine can be precisely metered correspondingly very.

In known fuel injection systems of this type, the amount of air flowing through the intake manifold is detected by a measuring element, the amount of fuel is metered proportionally to this amount of air and injected directly into the intake manifold through injection valves in the vicinity of the engine cylinder. The proportionality between the amount of air and the amount of fuel can be changed as a function of engine parameters such as speed, load and temperature. In such fuel injection systems relatively high pressures, which can make the system inoperative arise in Saugrohrrückschlägen, for example by chipping of sleeves or plugs or by damage '. '· ■ -3-

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of the measuring element or of stops.

The invention is based on the object of a fuel injection system to develop the known type, in which the effect of intake manifold setbacks is dampened.

This object is achieved according to the invention in that for damping suction tube setbacks, the measuring element counteracts the force of a spring with flat characteristics over its Zero position can penetrate beyond and from an elastic. Stop is catchable.

An advantageous embodiment of the invention is such that the elastic stop on one with the suction pipe firmly connected steel bracket is arranged.

Another advantageous embodiment of the invention consists in that the spring has a flat characteristic the measuring element holds the fuel injection system in its zero position out of operation and as a spring with flat Characteristic a leaf spring is used.

According to a further advantageous embodiment of the invention, the conical part of the suction tube and the measuring element are in the Arranged air filter housing.

An embodiment of the invention is shown in simplified form in the drawing and is described in more detail below. Show it:

1 shows a fuel injection system. FIG. 2 shows a section along the line II-II in FIG.

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In Pig. 1 flows the drawn in by the internal combustion engine Combustion air through an air filter, not shown, into an air filter housing 1 and in the direction of the arrow on one pendulum suspended measuring element 2 past through a funnel-shaped section 3 via a suction pipe section 4 with an arbitrarily actuatable throttle valve 5 to one or more cylinders (not shown) of an internal combustion engine. The measuring element 2 is transversely to the flow direction and in its central area on a pivot lever 6 shown attached plate, wherein the pivot lever 6 is pivotable about a pivot point 7 in a plane. That Measuring element moves in the funnel-shaped section 3 according to a certain law, which is approximately a represents linear puncture of the amount of air flowing through the suction tube, with a constant one acting on the measuring element 2 Restoring force and a constant air pressure prevailing in front of the measuring element, including that between the measuring element and the pressure prevailing in the throttle valve 5 remains almost constant.

The measuring element 2 acts via the pivot lever 6 and a Roll 8 directly on a control slide 9 of a metering and flow divider valve 10.

The fuel is supplied via a fuel pump 13 which, driven by an electric motor 14, sucks in the fuel from a fuel tank 15 and feeds it to the metering and quantity divider valve 10 via a line 16. A return line 17 branches off from the line 16, into which a pressure relief valve 18 is connected . The lever 6 remote from the pivotal end side of the spool 9 is applied via a line 16 from the end of branch pipe 19 through the under constant pressure fuel, which thus serves as a restoring force on the measuring element. 2

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During the pivoting movement of the lever 6 in the direction of flow of the intake air, the measuring element 2 is in the funnel-shaped Section 3 of the suction tube moves so that the ring cross-section changing between the measuring element and the funnel-shaped section is proportional to the displacement of the measuring element. If this requirement is met, there is a linear one Dependence of the adjusting movement of the measuring element 2 and the. Shifting movement of the control slide 9 »so that the A proportional amount of fuel is always metered into the air volume flowing through the intake manifold. The assigned The amount of fuel comes from the metering and flow divider valve 10 via channels 20 to the individual injection valves, not shown, which are located in the vicinity of the Engine cylinders are arranged in the intake manifold.

The end of the pivot lever 6 facing away from the pivot point 7 is designed as a stop 22 on the side facing away from the measuring element 2, against which a spring 23 with a flat characteristic rests. As shown in FIG. 2, the spring 23 can be designed as a leaf spring which, when the fuel injection system is not in operation, holds the measuring element in its zero position. The zero position of the spring 23 is determined by a hook 24, at one end of which the spring 23 can rest and the other end of which is connected to a bracket 25. The bracket 25 is designed as a steel bracket and is firmly connected to the conical section 3 of the suction tube by screws 26. The bracket 25 carries in its central area an elastic stop 27 'which can consist of rubber, for example, and is arranged in such a way that the stop 22 of the pivot lever comes into contact with the elastic stop 27 due to its zero position when it passes through the measuring organ .

The embodiment of the fuel injection system according to the invention offers the advantage that in case of intake manifold backlashes .

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Measuring element can penetrate beyond its zero point in the conical section of the measuring element, as a result of which the annular gap between measuring element and conical section expands again and thus a pressure relief can take place. The spring 23 must have characteristics that run as flat as possible in order to enable rapid penetration and to achieve a rapid pressure reduction in the intake manifold. The inertial forces based on the movement of the measuring element when diving through must be absorbed by the elastic stop 27 after a sufficiently large annular gap has enabled the pressure to be reduced. The elastic stop 27 should be designed in such a way that it converts as much energy as possible into heat in order to avoid an excessive rebound stroke of the measuring element 2. So that the steel bracket 25 for the elastic stop 27 can be kept small despite the still high forces, it is designed so that the highest possible tensile component and therefore small bending forces arise. The return of the measuring element to its zero position is carried out by the spring 23, which thereby comes to rest against the hook 2k .

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Claims (5)

Λ 7 3 B Expectations f1.jFuel injection system for mixture-compressing, spark-ignited internal combustion engines with continuous injection into the intake manifold, in which a measuring element and an arbitrarily actuatable throttle valve are arranged one behind the other and the measuring element is moved according to the amount of air flowing through a working member against a restoring force and the moving part of a Fuel line arranged valve for the metering of an amount of fuel proportional to the amount of air is adjusted and serves as a restoring force pressure fluid, which is continuously and under constant, but arbitrarily changeable pressure conveyed through a pressure line applied to the working member, with a disk serving as a measuring element, which is transverse to the direction of flow on the one end of a stationary manner and virtually without friction mounted pivot lever is fixed and proportional to the amount of air flowing through the suction tube in a corresponding direction of flow in a funnel för Mig widening section of the suction tube dips, characterized in that to dampen suction tube setbacks, the measuring organ (2) can penetrate against the force of a spring (23) with flat characteristics beyond its zero position and from an elastic one Stop (27) can be intercepted . . « 509815/0083 -8- ' ^{7 3 8} 2. Fuel injection system according to claim 1, characterized in that that the elastic stop (27) is arranged on a steel bracket (25) firmly connected to the suction pipe is. 3. Fuel injection system according to claim 1, characterized in that that the spring (23) with flat characteristics, the measuring element (2) out of operation of the fuel injection system holds in its zero position. Ij. Fuel injection system according to claim 3 »characterized in that that a leaf spring is used as the spring (23) with a flat characteristic. 5. Fuel injection system according to claim 1, characterized in that that the conical part (3) of the suction tube and the measuring element (2) are arranged in the air filter housing (1). 509815/0083