EP0400211A1 - Dispositif de formation de mélange d'air et de carburant pour moteurs à combustion interne - Google Patents

Dispositif de formation de mélange d'air et de carburant pour moteurs à combustion interne Download PDF

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Publication number
EP0400211A1
EP0400211A1 EP89118678A EP89118678A EP0400211A1 EP 0400211 A1 EP0400211 A1 EP 0400211A1 EP 89118678 A EP89118678 A EP 89118678A EP 89118678 A EP89118678 A EP 89118678A EP 0400211 A1 EP0400211 A1 EP 0400211A1
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EP
European Patent Office
Prior art keywords
fuel
nozzle
line
section
fuel delivery
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP89118678A
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German (de)
English (en)
Inventor
Martin Prof. Dr. Feldinger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mannesmann VDO AG
Original Assignee
Mannesmann VDO AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mannesmann VDO AG filed Critical Mannesmann VDO AG
Publication of EP0400211A1 publication Critical patent/EP0400211A1/fr
Withdrawn legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M7/00—Carburettors with means for influencing, e.g. enriching or keeping constant, fuel/air ratio of charge under varying conditions
    • F02M7/06—Means for enriching charge on sudden air throttle opening, i.e. at acceleration, e.g. storage means in passage way system
    • F02M7/08—Means for enriching charge on sudden air throttle opening, i.e. at acceleration, e.g. storage means in passage way system using pumps
    • F02M7/093—Means for enriching charge on sudden air throttle opening, i.e. at acceleration, e.g. storage means in passage way system using pumps changing output according to intake vacuum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M9/00—Carburettors having air or fuel-air mixture passage throttling valves other than of butterfly type; Carburettors having fuel-air mixing chambers of variable shape or position
    • F02M9/12—Carburettors having air or fuel-air mixture passage throttling valves other than of butterfly type; Carburettors having fuel-air mixing chambers of variable shape or position having other specific means for controlling the passage, or for varying cross-sectional area, of fuel-air mixing chambers
    • F02M9/127—Axially movable throttle valves concentric with the axis of the mixture passage
    • F02M9/133—Axially movable throttle valves concentric with the axis of the mixture passage the throttle valves having mushroom-shaped bodies

Definitions

  • the invention relates to a fuel-air mixture formation device for internal combustion engines, with a nozzle body which, together with a throttle body movable therein, forms a nozzle which opens into an intake manifold of the internal combustion engine, and with a fuel quantity control device with a fuel delivery line which opens into the nozzle.
  • the mixture composition (lambda value) must be kept within narrow limits in order to achieve low-pollutant operation, regardless of the particular operating point of the engine. This is the only way to comply with the legally prescribed permissible limit values for the pollutants in the exhaust gas of the engine. Especially when operating the engine with exhaust gas catalysts, the "lambda window" for optimal conversion of the mixture composition may fluctuate very little by an optimal lambda value.
  • the air pressure in the intake manifold changes. This will when the pressure in the intake manifold is reduced, the force accumulated on the intake manifold wall evaporates in the form of a fuel film and the fuel-air mixture is enriched after the mixture formation device, that is to say the lambda value is reduced, - If the pressure in the intake manifold increases, deposit fuel on the intake manifold and thus lean the mixture entering the engine, i.e. the lambda value increases.
  • the fuel-air mixture supplied to the engine deviates to a greater or lesser extent from the lambda value required for the optimal conversion.
  • the change in the intake manifold pressure takes place when the engine changes load, in particular by changing the position of the throttle body controlling the mixture quantity, for example a throttle valve, a throttle cone, etc.
  • the fuel-air mixture that arises in the mixture formation process arranged centrally on the intake manifold deviates only slightly from the ideal composition even without regulation. Due to the variable intake manifold wetting, especially in the case of rapid load changes, a mixture deviating from the ideal mixture is supplied to the engine and the exhaust gas quality is thus deteriorated. The faster the intake manifold pressure changes when the engine is subjected to load changes, the less it is possible to regulate these deviations from the ideal lambda value to the lambda value required for optimal conversion by regulating via the lambda probe.
  • the fuel quantity control device has a metering unit which is connected to a fuel delivery line connected to the fuel tank and the fuel delivery line which opens into the nozzle, and comprises a metering member for controlling the fuel flow rate which can be moved independently of the engine load and which is coupled to the throttle body in a movement-locking manner.
  • the nozzle-side fuel delivery line is connected to the intake manifold via a branch line and the branch line is separated into a fuel delivery line side line section and an intake pipe side line section by a compensating element movable therein, such that an increase in the intake manifold pressure leads to a movement of the compensating element reducing the volume of the fuel delivery line side line section and a reduction in the intake manifold pressure leads to an opposite movement of the compensating element.
  • the correction of the mixture composition when the pressure in the intake manifold changes - regardless of whether this change is caused by a movement of the accelerator pedal and / or the vehicle resistance - is controlled by the pressure in the intake manifold. This also ensures that the additionally supplied or withdrawn fuel mass also takes place in accordance with the rate of change of the intake manifold pressure, that is to say deviations from the optimal mixture composition not only from the size of the change in load but also as a function of the speed of the change in load.
  • the additional supply or withdrawal of the fuel mass as a function of the change in the intake manifold pressure occurs due to the movement of the compensating element, which seals the line section on the fuel delivery line side from the line section on the intake pipe side.
  • the compensating element itself can be designed in different ways, for example as an elastic membrane, which is advantageously spring-loaded in the direction of a movement reducing the volume of the fuel delivery line-side line section, or as a piston displaceable in the branch line, which is advantageously in the direction of a volume of the fuel delivery line-side line section reducing movement is spring-loaded.
  • a throttle is integrated into the line section on the fuel delivery line side, which is intended to prevent the control from being abruptly effected via the compensating element.
  • the throttle advantageously has different flow values in the two flow directions.
  • the passage cross section of the throttle in the flow direction to the compensating element initially tapers and then abruptly expanded so that the additional fuel is slowly supplied when the intake manifold pressure rises, but is rapidly withdrawn when the intake manifold pressure decreases.
  • the function of the compensating element can be combined with a further compensating element which is directly assigned to the metering unit.
  • the metering unit is connected via an opening which is sealed by means of the further movable compensating element to a compensating rum which is connected via a further branch line to the nozzle-side fuel delivery line or the line section on the fuel delivery line, and the metering element and the further compensation element are connected to one another in a movement-locking manner, such that that a movement of the metering element in the direction of an enlarged fuel passage cross section leads to a movement of the further compensation element that reduces the compensation space and a movement of the metering element in the direction of a reduced fuel passage cross section leads to a movement of the further compensation element that increases the compensation space.
  • the metering element arranged in the metering unit accordingly moves in the sense of a fuel reduction and with the metering element also the further compensating element, the fuel between the metering element and throttle body via the additional branch line acting as a bypass line sucks.
  • the further compensating element also promotes fuel via the branch line into the line between metering element and throttle body.
  • both compensation elements thus cause the deviation from that caused by the mixture formation device ideally controlled fuel-air mixture is reduced in the event of a sudden change in load and the control is relieved by the lambda probe.
  • the compensating element acted upon via the intake manifold effects a correction of the mixture composition as a function of the rate of change of the intake manifold pressure, the additional compensating element assigned to the metering unit a change as a function of the speed and the size of the movement of the accelerator pedal.
  • FIG. 1 shows a fuel tank 1, from which fuel is conveyed to a metering unit 6 via a pump 2, through a filter 3 connected downstream, and a system pressure regulator 4, through a fuel delivery line 5, through a fuel delivery line 5. From there, the fuel reaches a first section 7a of a further fuel delivery line 7, which opens into a metering regulator 8.
  • a second section 7b of the fuel delivery line 7 leads from the metering regulator 8 to a convergent-divergent nozzle 9 which is formed by a rotationally symmetrical nozzle body 10 and a rotationally symmetrical throttle body 11 which can be displaced therein.
  • the second section 7b of the fuel delivery line 7 opens in the vicinity of the narrowest cross section 12 into the nozzle 9, which in turn opens into an intake manifold 13 of the internal combustion engine, not shown.
  • the metering unit 6 is divided into two sub-spaces 16 and 17 by an aperture 15 having an opening 14, the sub-space 16 with the fuel tank 1 via the fuel delivery line 5 and the sub-area 17 via the fuel delivery line 7 with the Nozzle 9 is connected.
  • a metering element 18 designed as a cone can be moved in the direction of its axis of rotation perpendicular to the diaphragm plane into and out of the diaphragm opening and thus determines the remaining cross-section of the fuel through the metering unit 6 depending on its position.
  • the metering element 18 is rotationally symmetrical in the region of its tip and its circular base connected to an axis 19 and mounted longitudinally displaceably in two bearings 20 of the metering unit 6.
  • the throttle body 11 is connected to the free end of the axis 19 in a rotationally symmetrical manner with respect to the metering element 18. Because of the movement-locking connection, the movements of the throttle body 11 and the metering element 18 are thus coupled.
  • the axial path of the axis 19 and thus the path of the throttle body 11 and metering element 18 correspond to the accelerator pedal path indicated by the double arrow A.
  • the metering regulator has, inter alia, two fuel spaces 22 and 23 which are sealed off from one another by means of a flexible membrane 21.
  • the fuel chamber 22 is divided by a connecting line 24 into two sub-chambers 22a and 22b, a branch line 25 opening into the sub-chamber 22b is connected behind the system pressure regulator 4 to the fuel delivery line 5, so that part of the fuel delivered by the pump 2 is connected via the branch line 25 is promoted in the fuel chamber 22.
  • a return line 26, which leads to tank 1, is connected to subspace 22a of fuel chamber 22.
  • a fixed throttle 27 is inserted into the return line 26 in the region of the outflow from the subspace 22a.
  • the branch line 25 is led into the partial space 22b and ends at a slight distance from the partial space wall opposite the entry area, which is also designed as a flexible membrane 28.
  • an electromagnet 29 is arranged, which can be controlled via control electronics 30 and, due to the design of the flexible diaphragm 28 responsive to a magnet, the diaphragm 28 more when a control current is applied or less moved away from the adjacent opening of the branch line 25.
  • the input of the fuel chamber 22 is thus provided with a movable throttle and the output of this fuel chamber is provided with a fixed throttle 27.
  • the first section 7a of the fuel delivery line 7 opens into the fuel chamber 23 and, in accordance with the design of the branch line 25, the second section 7b of the fuel delivery line 7 extends into the fuel chamber 23 until just before the flexible membrane 21.
  • a movable throttle is thus likewise formed between this and the facing inflow opening of the second section 7b of the fuel delivery line 7, but the throttling results there due to the movable throttle assigned to the subspace 22b and the different pressures which thus arise in the subspace 22.
  • the current lambda value can be entered into the control electronics, which is determined in a known manner via a lambda probe.
  • FIG. 2 illustrates the relationships between the air mass flow ⁇ a and the fuel mass flow ⁇ B determined in the experiment as a function of the pressure p L in the narrowest cross section of the nozzle 9 for the supercritical and subcritical flow state.
  • the fuel mass flow ⁇ B is reduced via the control electronics 30, into which the pressure p L and furthermore the pressure p o and the temperature T o are entered as an essential parameter.
  • the control variable originating from the control electronics 30 activates the electromagnet 29 which, according to the measure of the control variable, more or less attracts the flexible membrane 28 and thus increases the passage gap between the open end of the branch line 25 and the membrane 28 accordingly. This causes an increase in the fuel pressure in the fuel chamber 22, so that the flexible membrane 21 is moved onto the open end of the second section 7b of the fuel delivery line 7 and thus the gap between the flexible membrane and this section 7b is reduced, with the result that less Fuel can be delivered through the fuel delivery line 7.
  • Figure 3 shows that with a standardized representation ⁇ of the air mass flow ⁇ a and the normalized fuel mass flow ⁇ required for a constant lambda value the scatter band for ⁇ and ⁇ becomes narrow for the entire operating range, that is to say for the pressure in the narrowest cross section of the nozzle, that is to say it is only slightly dependent on the position of the throttle body 11.
  • Deviations due to the scattering range around the ideal lambda value can be compensated for by the lambda probe, which works together with the control electronics 30.
  • FIG. 1 furthermore illustrates the regulation of the fuel quantity according to the invention which is dependent on the pressure in the intake manifold 13 and which takes place simultaneously with the regulation of the fuel quantity by means of the control electronics 30.
  • the section 7a of the fuel delivery line 7 is connected to the curved section of the intake manifold 13 via a branch line 7c, the branch line 7c being sealed by a membrane 35 into a line section 7d on the fuel delivery line side and a line section 7e on the intake pipe side.
  • a compression spring 36 acts on it, in such a way that it prestresses the diaphragm 35 in the direction of a movement which reduces the volume of the line section 7d on the fuel delivery line side.
  • a throttle 37 is integrated in the line section 7d, in such a way that the passage cross section of the throttle 37 in the direction of flow to the diaphragm 35 initially tapers gradually and then abruptly expands.
  • the throttle 37 thus has different coefficients of friction.
  • the diaphragm 35 With an increase in the intake manifold pressure, thus an accumulation of fuel on the walls of the intake manifold 13, the diaphragm 35 is moved in the direction of the spring 36 according to the dashed arrow direction. This reduces the space 38 filled with fuel, as a result of which the fuel mass supplied to the nozzle 9 via the pipeline 7b is increased.
  • the intake manifold pressure is reduced, the flow of fuel through the throttle 37 takes place with a smaller delay due to the design of the throttle 37 than with a correspondingly large increase in the intake manifold pressure.
  • the figure shows that the sub-space 16 is connected via an opening 31 to a compensating chamber 32, a compensating piston 33 connected to the metering element 18 and arranged concentrically to its axis of rotation passes through the opening 31, and the compensating chamber 32 is also connected via a further branch line 34 is connected to the fuel delivery line-side line section 7d.
  • the mixture is emaciated from the mixture formation device by moving the accelerator pedal in the sense of reducing the amount of mixture to a corresponding movement of the metering element 18 and the compensating piston 33 and the throttle body 11 in the direction of the arrows drawn with solid lines, as a result of which, due to the increasing compensation space 32, part of the fuel which is usually conveyed into the fuel delivery line 7b is stored in the compensation space 32 via the branch line 34.
  • the mixture supplied by the mixture formation device is enriched by the throttle body 11 and the metering element 18 with the compensating piston 33 are moved in the opposite direction in accordance with the arrows drawn in broken lines, so that fuel additionally flows into the section 7b of the fuel delivery line 7 via the branch line 34 as a result of the associated reduction in the compensating space 32.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Control Of The Air-Fuel Ratio Of Carburetors (AREA)
EP89118678A 1989-05-31 1989-10-07 Dispositif de formation de mélange d'air et de carburant pour moteurs à combustion interne Withdrawn EP0400211A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3917679 1989-05-31
DE3917679A DE3917679A1 (de) 1989-05-31 1989-05-31 Kraftstoff-luft-gemischbildungsvorrichtung fuer verbrennungsmotoren

Publications (1)

Publication Number Publication Date
EP0400211A1 true EP0400211A1 (fr) 1990-12-05

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Application Number Title Priority Date Filing Date
EP89118678A Withdrawn EP0400211A1 (fr) 1989-05-31 1989-10-07 Dispositif de formation de mélange d'air et de carburant pour moteurs à combustion interne

Country Status (3)

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EP (1) EP0400211A1 (fr)
JP (1) JPH0396647A (fr)
DE (1) DE3917679A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE9318951U1 (de) * 1993-11-30 1994-02-17 Kabisch, Herbert, 51377 Leverkusen Vorrichtung zur Herstellung von Gemischen aus Gasen und Flüssigkeiten, insbesondere von Luft und Brenn- und Kraftstoffen
DE19951751A1 (de) * 1999-10-27 2001-05-03 Bayerische Motoren Werke Ag Kraftstoff-Fördersystem für Kraftfahrzeuge
CN104696114A (zh) * 2015-02-16 2015-06-10 杭州赫日新能源科技有限公司 一种两级控制的文丘里进气混合器

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR672651A (fr) * 1928-07-11 1930-01-06 Zenith Carburateur Soc Du Perfectionnements aux carburateurs
DE807448C (de) * 1939-06-17 1951-06-28 Solex Sarl Schwimmerloser Vergaser fuer Brennkraftmaschinen, insbesondere fuer Flugzeugmotoren
US4087493A (en) * 1975-02-13 1978-05-02 Carbo-Economy, S.A. Apparatus for providing a uniform combustible air-fuel mixture

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR672651A (fr) * 1928-07-11 1930-01-06 Zenith Carburateur Soc Du Perfectionnements aux carburateurs
DE807448C (de) * 1939-06-17 1951-06-28 Solex Sarl Schwimmerloser Vergaser fuer Brennkraftmaschinen, insbesondere fuer Flugzeugmotoren
US4087493A (en) * 1975-02-13 1978-05-02 Carbo-Economy, S.A. Apparatus for providing a uniform combustible air-fuel mixture

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Publication number Publication date
DE3917679A1 (de) 1990-12-06
JPH0396647A (ja) 1991-04-22

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