DE2516949A1 - CARBURETTORS FOR COMBUSTION MACHINERY - Google Patents

Description

Deutsche Vergaser GmbH & Co KG, Neuss, Leuschstr. 1 2516949

Carburettors for internal combustion engines

The invention relates to a carburetor for internal combustion engines
with a mixing chamber located in the carburetor housing, which is delimited downstream by an arbitrarily actuatable mixture throttle and upstream by an air throttle that controls the intake air cross-section and is actuated by the pressure prevailing in the mixing chamber, a RypsPluftkanal opening into the mixing chamber, into which the fuel supply opens, with a Air throttle connected via a linkage, the cross-section of a
Fuel nozzle controlling nozzle needle.

With 'such carburetors a good atomization of the fuel by changing the intake air cross-section according to the air flow rate.

From DT-PS 1 ^ 76261 it is known, in addition to the air funnel
a bypass air duct that can be closed by means of a slide
to be provided, which opens out inclined in the narrowest cross section of the air funnel. There is also calibration in the bypass air duct
the fuel leak. This arrangement has the disadvantage that
in the transition and partial load range the bypass, which is practically a pre-atomizer , ± n range of low flow velocity «and and therefore no satisfactory geaisch is formed.

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In order to improve the mixture preparation even further at idle and part load, it is possible to use the in the intake manifold fortified cone to be heated by exhaust gas.

A favorable, i.e. slowly responding, opening characteristic To achieve in the transition area from idle to full load, the cone is designed as a paraboloid of revolution. A precise one Adjustment in this area is made possible by the fact that the tube is movable by means of a rack and pinion drive i;

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

The carburetor housing 10 is euf the intake manifold 1? attached. His Venturi-shaped mixing chamber. 1 * »is downstream through an arbitrary actuatable mixture throttle 16 limited, which consists of a

(17 coaxially and by a rack and pinion drive) longitudinally displaceable to the mixing chamber l * f arranged drilling 18 and a cone 20 arranged in the suction pipe 12 consists. Upstream of the mixing chamber through a coaxial and Ik langsverschieblich transitioning to the l in the mixing chamber ¹ 'air funnels 22 arranged tubular air throttle 2k and an air inlet cone 26 is limited. The air inlet cone 26 is part of the end piece 28 of the carburetor cover 3 °. Between the carburetor housing 10 and the carburetor cover 30, a circular membrane 32 is clamped, which connects the tubular air throttle 2h and encloses the

6098U / 0164

The invention is based on the object of creating an arrangement in the case of a carburetor of the type mentioned at the beginning, which also A perfect mixture formation is guaranteed in the partial load range.

This object is achieved in that the Bypass air duct is arranged centrally within the air funnel and has the fuel outlet in its lower end, designed as a pre-atomizer, and in the narrowest part Area of a second pre-atomizer opens and that the

Air throttle tubular coaxial and slowly displaceable to the

air ' Bypass channel and to the mixing chamber upstream of the pre-atomizer is arranged and that the arbitrarily actuatable mixture throttle from a coaxial and slowly displaceable to the mixing chamber downstream of the pre-atomizer pipe and a cone that cooperates with this and is rigidly attached in the suction pipe.

In order to get an exact metering of the fuel quantity without air leakage achieve, it is provided that the metering cross section of the fuel nozzle below the fuel level d * r float chamber lies. For the even supply of the fuel quantity so dimensioned, it is expedient that the fuel outlet is via a Ring channel centered ia bypass air channel aiindct.

6098U / 0164

CJOPY

Mixing chamber] Λ negative pressure extracted via a channel J> h acts against a compression spring JiS. A bypass air duct 38 is arranged centrally in the connecting piece 8, which is designed in its lower end as a venturi-shaped pre- atomizer hO and in its narrowest cross section the fuel outlet h? having. The fuel is fed to the fuel outlet h? Via an annular channel kh and a bridge h6 located in the air funnel 22. fed.

The Hinpkanal hh is fed via the bore h? I from the fuel nozzle 52 located in the float chamber $ G , the passage cross-section of which is controlled by a nozzle needle ^ h, which is connected to the air throttle 2 ^ in via a fork-shaped linkage 5 & and the bolts 5 <P Connect. The pre-atomizer * tC lies with its mouth cross-section in the area of the narrowest cross-section of a second pre-atomizer 60, which is held in the bridge i + 6 and in turn lies with its termination cross-section in the narrowest cross-section of the mixing chamber I ^.

The function of the carburetor is as follows. When idling, the air valve ? .H is completely closed and the air required to form the mixture flows through the bypass air duct 38. At the fuel outlet * »2, the fuel required for the formation of idle odor is produced in the pre-decomposer kO.

■ suctioned off tight spaces with high air speed and passes through

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the wide pre-atomizer 60 and the Miechkamffler lh through the idle ring gap 62 remaining between the pipe 18 and the cone 20 into the suction pipe 12.

Is the ear 1? Raised via the rack drive 17, the negative pressure in the mixing chamber stiffens and v / ircts via the channel J> h in this way on the licmbran J ?,

that this dip force of the compression spring 3 ^ overcomes and moves the air throttle 2h. This is the Hf uptlufteinlaP into the air funnel 22 according to the movement of the air throttle? 6 h gradually released in Zusammenwirkunp with the air inlet cone?. Kit of the movement of the air throttle h , the cross-section of the passage of the fuel nozzle 32 is controlled via the linkage 56 by means of the nozzle needle Jh , so that with increasing air throughput at the fuel outlet hz , more fuel is also available. The air flows according to the arrows drawn through the air funnel 22% and part of the air through the second pre-atomizer 6C, which increases the pressure gradient of the first pre-atomizer ΊΟ, since the second pre-atomizer 60 opens into the narrowest cross-section of the mixing chamber lh . The mixture hits the cone 20 _t vertically, which can be heated, and is directed into a suction pipe 12. The transition from the partial load area to the full load area takes place steplessly, no additional systems are used, like a separate "idle ays tea" can be omitted. This is possible because

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Claims (1)

Claims l) Afer gas for internal combustion engines with a carburetor housing located mixing chamber, which is delimited downstream by an arbitrarily actuatable Geniech throttle and upstream by an air throttle that controls the intake air cross-section and is actuated by the pressure prevailing in the mixing chamber, an Eypaßluftkanal opening into the mixing chamber, into which the fuel supply opens, with an air throttle via a rod-connected nozzle needle controlling the cross section of a fuel nozzle, characterized in that the bypass air duct (38) is arranged centrally within the air funnel (? 2) and the fuel exits (* ♦? ) and opens in the narrowest area of a second pre-atomizer (6c) and that the air throttle (P ¹ O tubular, coaxial and longitudinally displaceable to the bypass air duct (3?) and to the mixing chamber (I ¹ O) is arranged upstream of the pre-atomizer (60) and that the mixture throttle (l6), which can be actuated voluntarily, consists of a coaxial and longitudinal displacement Usually to the mixing chamber (I ¹ O downstream, of the pre-atomizer (60) arranged drill (18) and a cone (PO) which cooperates with this and is rigidly fixed in the suction pipe (1?). 8U / 0164 that the fuel leakage is in the range of high flow velocity in all load conditions. A starting system can also be provided, but is not essential to the invention. The coaxial arrangement of the tubular chokes 1 ?,? * » has the advantage that the negative pressure or the air flow runs parallel to it, so that no forces are transverse to the direction of movement of the respective throttle body can have an effect. By designing the cone 18 as a paraboloid of revolution there is also the advantage that a desired opening characteristic is set IMRt. Through the pipe 18 and heated cone 20 existing GemiBChdroesel 16 results der'Vorteil that at idle and part load, the mixture covers a longer distance on the cone 20 and is therefore more heated becomes than at full load, vo a large part of the mixture does not come into contact with the cone at all. 60 98AA / 016A ?) Carburetor according to claim 1, characterized in that the metering cross section of the fuel nozzle (5?) Is below the fuel level of the float chamber (50). J.) Carburetor according to claim 1, characterized in that the fuel supply opens centrally in the bypass air duct (JP.) Via an annular duct (Ά). h) Carburetor according to claim 1, characterized in that the cone (? C) fastened in the suction pipe (l?) is heated by exhaust gas. 5) carburetor according to claims 1 and 'f, characterized in that that the cone (? 0) is a paraboloid of revolution. 6) Carburetor according to claim 1, characterized in that the Tube (l8) can be moved by means of a rack and pinion drive (17). 6098U / 0164