DE7232180U - Internal combustion engine with air flow meter - Google Patents

Description

Κ.1058

11.8.1972 Lr / Kb

Attachment to

Patent and

Utility model registration

ROBERT BOSCH GMBH, 7 Stuttgart 1

Internal combustion engine with air flow meter

The invention relates to an internal combustion engine with a throttle valve used to change the amount of intake air and with an air flow meter arranged in the intake pipe, which is preferably a baffle plate that can be adjusted against the force of a spring - Has in particular in the form of a swiveling storage flap. their pivot axis at the edge of the suction cross-section runs.

Internal combustion engines with electronically controlled gasoline injection work can advantageously be equipped with an air flow meter of the type described above, the one depending on the respective mean time

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723218011.10.73

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Robert Bosch GmbH Rt

Stuttgart _{Lr / Kb}

value of the amount of intake air changeable electrical variable, for example an electrical current or an electrical Voltage supplies that in an electrical control unit in electrical opening impulses with one of this control variable dependent pulse duration are implemented. These pulses then determine the opening time of electromagnetic injection valves. When operating internal combustion engines, the speed of the internal combustion engine is generally dependent SAstop devices required, which are used to control auxiliary devices, such as the control an exhaust gas recirculation to change the ignition timing, for speed-dependent full load enrichment, etc.

The invention is based on the object of a speed-dependent switch that can be used for these purposes create that is as simple as possible in its structure and requires little effort.

To solve this problem, internal combustion engines of the type described at the beginning are provided with the air flow meter an electrical switch is connected, which is operated at a presettable amount of air. Appropriate the switch can be equipped with a baffle plate serving as an air flow meter, which is preferably a pivotable one Flap is designed to be mechanically coupled so that the switch at a presettable deflection of the Baffle plate is actuated. It has been shown that for throttle valve opening angles which are greater than 65 °, the amount of air determined by the air flow meter can be assigned to a specific speed. It is therefore possible to use the speed-dependent switch to adjust to the desired limit speed that he is at an air volume belonging to this limit speed from Air flow meter is operated,

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Appropriate refinements and developments of the invention emerge from those described below and in FIG Embodiments shown in the drawing.

Show it:

Pig. I an air flow meter equipped with a damper in its axial longitudinal section and a mechanically actuatable one assigned to the air flow meter Switch and

Fig. 2 shows an electrical air volume that can be preset appealing switch.

The air flow meter according to FIG. 1 belongs to an internal combustion engine, not shown, which operates with intake manifold injection, the intake manifold of which is indicated at 10. In the intake pipe there is a throttle valve 11, which can be pivoted from the idle position shown with the aid of a lever 12 and a Bowden cable 13 as well as with the aid of an accelerator pedal (not shown) and then the ^{intake air flow, indicated by an arrow I 1} I, has a larger passage cross-section as the opening angle increases in the intake pipe 10 releases.

The air flow meter used to measure the intake air volume contains a baffle flap 15, which extends around a shaft 16 running on the edge of the rectangular suction cross-section against the Restoring force of a spiral spring, not shown, with increasing The amount of air is swiveled more clockwise will. A tap 17 is connected to the baffle valve shaft 16, which, together with an annular sector-shaped resistance track 18 a potentiometer forms the at one end of the Minus pole and at its other end, the plus pole one electrical power source can be connected. The one between the tap 17 and one of the potentiometer ends of the flap

Robert Bosch GmbH R ₀

Stuttgart Lr / Kb

15 set partial voltage is in an electronic control device, not shown, for generating electrical opening pulses for injection valve, also not shown an injection system used to operate the internal combustion engine are used, the training of which is not particularly important here. ;

According to the invention, this air flow meter is assembled with a speed-dependent switch which in detail consists of two contact tracks 21 and 22 and a sliding contact 23. The sliding contact is connected to the damper shaft 16 and can be rotated with respect to it and then determined on this so that its two contact fingers 24 and 25 only connect the two contact tracks 21 and 22 with one another when the damper 15 is at an angle ψ has set, which corresponds to the desired limit speed of the internal combustion engine when the throttle valve 11 is open more than 65 °. A barrier 30 ensures that the switching means can be effective only at throttle angles greater than 65 ^{the 0th} When closing the switch formed from the two contact tracks 21 and 22 and the contact fingers 2 ^ and 25 and the sliding contact 23, for example, a device for exhaust gas recirculation, for ignition adjustment, for full load enrichment or the like can be operated.

In the exemplary embodiment according to FIG. 2, an electrical switching stage works together with the air flow meter, of which only its storage flap shaft is indicated at 16 sm. This is connected to the tap 17 of the potentiometer resistor 18 and contains a mechanically or electrically operable blocking element 30 and a threshold switch 31 which can be designed as a Schmitt trigger in a known manner. The barrier 30 ensures that the trigger 31 ψ only one 65 ⁰ lying throttle valve opening angle 11 can come into effect. The threshold switch

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Stuttgart Lr / Kb

31 is set so that it responds to a certain value of the air volume-dependent voltage U _T tapped at the potentiometer resistor 18 and then changes its switching state. If the threshold value switch 31 is designed as a Schmitt trigger, it offers the possibility of changing its threshold value as a function of temperature with the aid of an NTC resistor 33 and thus taking into account the respective operating temperature of the internal combustion engine.

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723218811W.7S

Claims (4)

Ir / lm E. 1058 Kobert Bosch GmbH, Stuttgart July 25, 1973 • Claims 1. Internal combustion engine with a to change the amount of intake air serving throttle valve and with an air flow meter arranged in or on the intake manifold, which is preferably has a baffle plate adjustable against spring force, in particular in the form of a pivotable baffle flap, whose The pivot axis at the edge of the suction cross-section runs transversely to the suction direction, characterized in that one of the Air flow meter actuatable switch is provided, which in the event of a presettable deflection of the baffle plate (15) changes its switching state. 2. Internal combustion engine according to claim 1, characterized in that the baffle plate (15) is in operative connection with a mechanically actuatable switch (21 to 25), the switching contacts (21, 22) of which are closed or respectively ^{at a presettable deflection ((} / ^{;) of the baffle plate} . be opened. 723218011.10.73 3. Internal combustion engine according to claim 2, characterized in that the switch at least one to the axis of rotation of the baffle plate (15) concentric contact track (21, 22) and a slider running on this (25, 24, 25) belongs to the the baffle plate is coupled. 4. Internal combustion engine according to claim 1 with an air flow meter comprising a damper and an electrical one Threshold switch connected to the tap of an adjustable potentiometer connected to a constant voltage is connected, characterized in that the tap (17) of the potentiometer (18) with the shaft (16) of the Storage flap (15) is coupled. 72321801 Lto.73