DE2106501A1 - Carburettor with variable Ventun cross-section - Google Patents

Description

PATENT LAWYERS 2106501. Dipi.-chem. Dr. D. Thomsen Dipi.-ing. H. Tiedtke
Dipl.-Chem. Q. BUhHnQ Dipi.-Ing. R. ΚίΠΠΘ MUNICH 15
KAISER-LUDWIQ-PLATZ I
TEL. 0811/530211
530212
CABLES: THOPATENT
TELEX: TO FOLLOW Dipi.-ing. W. Weinkauff FRANKFURT (MAIN) 50
FUCHSHOHL 71
TEL. M11 / 51 «M.

Answer requested to: <

Please reply toi

8000 Munich 15 February 11, 197]

Nissan Motor Company, Limited Yokohama City, Japan

Carburetor with variable
Venturi cross section

The invention relates to a carburetor ir.it variable Venturi cross section for motor vehicle internal combustion engines.

In a known carburetor with a variable Venturi cross-section, the throttle valve is essentially closed when idling or under internal load, so that no suction or only slight suction occurs on the Venturi section. In this state, the suction piston is moved in the direction of the fuel nozzle in order to reduce the vrirksarce cross-sectional area between the fuel nozzle and a nozzle needle. As a result, a significant amount of fuel from the fuel nozzle can enter the suction line of the hashim, dpi ¹ that of the

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109B35 / 1100

The air-fuel odor to be fed to the machine becomes macer and the performance yield is impaired.

The object of the invention is to eliminate this eighth].

The invention proposes a solution to this problem Carburetor for a motor vehicle Frennkraftmaschine before that a throttle valve, a venturi section located downstream of the throttle valve, a constriction and a flow regulating device for the continuous reduction of the effective cross-sectional area on the venturi section when the throttle valve closes having, wherein the flow regulating device has a Responsive fluctuations in the negative pressure downstream of the venturi section Suction piston to vary the confusing cross-section has surface on the venturi section, a stronab of the venturi section located and leading to a suction line of the machine and a 5ne via the narrowing in the Fuel nozzle opening into the venturi section, the .Togl'olben and the constriction on their opposite hands are formed to form an enlarged space therebetween, so that liquid fuel from the fuel nozzle over the Venturi section is sucked into the Genischkanal when the suction piston see the constriction when the machine is idling approaching.

The invention is illustrated schematically in the following Drawings explained in more detail.

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FiC. 1 is a partial sectional view of an invention Vercasers n \ it variable venturi cross section;

Fig. 2 is a view showing the piston of the Verc? This is illustrated by Petrachtun £ in the direction of the arrow Λ in PiL '· 1.

The carburetor according to the invention with a variable venturi cross section is generally designated 10. The Vercaser 10 has, as usual, an open to the open air duct 12, a Ger, ischkanal I ¹ J, the upstream pit the air duct '12 and strouab to a suction line (not £; ezei £ t) of the ^T achine is connected! , a throttle valve IG, which controls the flow of the air-fuel to be supplied to the machine via the pleasure channel 1H, and a venturi section 13, which has a flow control device 20 and a control unit; or pressures 22. A fuel ^{nozzle 2 1} 'is supplied by a feed channel 26 for liquid fuel and opens at the bridge 22 to feed liquid fuel via the venturi section IE into the injection channel IF. The fuel feed channel 26 is connected via a channel 28 to a (not shown) tchvimmerkaniiuer. The flow regulating device 20 has a housing 30 and a movable suction piston 32 of known construction. From the front end 32a of the Sgkolbens.32 · £ ehts a nozzle needle 3 ¹ I, which over the fuel nozzle? Λ in * ^: &. the fuel feed channel 2 (> is inserted. The nozzle needle 3 * 1 is in Richtunt on its tip yerjCnct, to the in the Venturi

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Section 18 Fuel to be admitted is continuously increasing change when the suction piston 32 and, accordingly, the nozzle needle 34 depending on fluctuations in the negative pressure in the Suction line move towards or away from bridge 22. whereby the effective cross-sectional area into which the liquid fuel is drawn from the nozzle 24 is varied.

In the idling operating state, the throttle valve 1 € is essentially closed, so that atmospheric pressure is established upstream of the throttle valve 16 and the suction piston approaches the bridge 22. In this state, the actual cross-sectional area at the venturi section 18 is such that? "A significant amount of liquid fuel can go from the fuel nozzle 24 to the intake line of the engine. This tendency is particularly increased when the suction piston 32 moves very close to the bridge 22 or is even in contact with it The air-fuel unit to be supplied to the machine is extremely lean, the I * aschino cannot work satisfactorily.

In order to eliminate this difficulty, you ßchlögt ^T "r ~ findunj before to provide between the front end 32n dos Gogkolbenn 32 and the bridge 22 is an enlarged space 36 o: * ner stronger admission of intake air through the venturi 18 into the mixing passage Ik allowed As a result, the liquid fuel can enter the venturi section 18 in an amount which is sufficient to obtain a mixture with an adequate mixture ratio, even if the flow rate 32 is up to the point

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- C _

has been moved to the constriction 22. Such an enlarged space 36 can be limited in any arbitrary manner. In the example shown, the enlarged space 36 is through delimits the bridge 22 and a recess 36a in the front end of the piston. If necessary, the recess in the bridge 22 be trained.

If the engine is idling, the throttle valve 16 is essentially closed, so that atmospheric pressure is established upstream of the throttle valve 16 and the suction piston 32 approaches the bridge 22 as a result. A sufficient amount of air flows through the enlarged space 36, as a result of which the liquid fuel is sucked out of the fuel nozzle and through the venturi section 18 into the mixture channel IM. The liquid fuel flowing through the venturi section 18 is mixed with the air passing through to form an air-fuel mixture with an optimal air-fuel ratio, which is then supplied to the engine ^{via the mixture channel I 1 I.}

Invention3ger: Yes, the machine can therefore malfunction be excluded by the fact that an enlarged space 36 is provided, the air flow through the venturi section 18 is ensured, even if the suction piston 32 is in the immediate IJc ^ he of the narrowing 22 is located.

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Claims (3)

Claims 1. Carburetor for a motor vehicle engine, characterized by a throttle valve (16), a downstream of the throttle valve seated Venturi section (18) with a constriction (22) and a Druehflußregulieinrichtung (20) for ^ as continuous regulation of the effective cross-sectional area at the Venturi section when closing of the throttle valve, the flow regulating device having a suction piston (32) which responds to fluctuations in the negative pressure downstream of the venturi section and for varying the effective cross-sectional areas at the venturi section, through a mixture duct (14) located downstream of the venturi section and leading to a suction line in the machine, through a mixture duct (14) in the venturi section through the throat opening into the fuel nozzle (24), wherein the Sogkolben and the constriction at their opposite ^T Ondwänden to form an enlarged space (3C) are formed between them, so that liquid fuel from the fuel nozzle by the V Enturiabschnitt is sucked into the mixture channel when the suction piston approaches the constriction during the idling operating state of the fascine. 2. Carburetor according to claim 1, characterized in that the enlarged space (36) by a recess in the front end of the suction piston (32) is formed. 3. Carburetor according to claim 1, dnc'urch fekennzeiehnot, that the enlarged fluff by a recess in c'or Verenfunr; is formed. 109835/1100