GB1568666A - Creation of Inventions and Patents with Artificial Intelligence

GB1568666A – Carburettor and method for regulating the fuel/air mixture fed to an internal kcombustion engine
– Google Patents

GB1568666A – Carburettor and method for regulating the fuel/air mixture fed to an internal kcombustion engine
– Google Patents
Carburettor and method for regulating the fuel/air mixture fed to an internal kcombustion engine

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Publication number
GB1568666A

GB1568666A
GB48020/76A
GB4802076A
GB1568666A
GB 1568666 A
GB1568666 A
GB 1568666A
GB 48020/76 A
GB48020/76 A
GB 48020/76A
GB 4802076 A
GB4802076 A
GB 4802076A
GB 1568666 A
GB1568666 A
GB 1568666A
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GB
United Kingdom
Prior art keywords
fuel
carburettor
pipe
pressure
chamber
Prior art date
1975-11-21
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.)

Expired

Application number
GB48020/76A
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.)

Robert Bosch GmbH

Original Assignee
Robert Bosch GmbH
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.)
1975-11-21
Filing date
1976-11-18
Publication date
1980-06-04

1976-11-18
Application filed by Robert Bosch GmbH
filed
Critical
Robert Bosch GmbH

1980-06-04
Publication of GB1568666A
publication
Critical
patent/GB1568666A/en

Status
Expired
legal-status
Critical
Current

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Classifications

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

F02M7/12—Other installations, with moving parts, for influencing fuel/air ratio, e.g. having valves

F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING

F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS

F02D—CONTROLLING COMBUSTION ENGINES

F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for

F02D35/0015—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for using exhaust gas sensors

F02D35/0046—Controlling fuel supply

F02D35/0053—Controlling fuel supply by means of a carburettor

F02D35/0069—Controlling the fuel flow only

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

F02M3/00—Idling devices for carburettors

F02M3/08—Other details of idling devices

F02M3/09—Valves responsive to engine conditions, e.g. manifold vacuum

Description

PATENT SPECIFICATION
( 21) Application No 48020/76 ( 22) Filed 18 Nov 1976 ( 31) Convention Application No 2552207 ( 32) Filed 21 Nov 1975 in ( 33) Fed Rep of Germany (DE) ( 44) Complete Specification published 4 June 1980 ( 51) TNT CL ‘ F 02 M 17/38 F 02 D 35/00 F 02 M 7/00 ( 52) Index at acceptance F 1 H 101 102 103 107 124 201 211 215 219 BX ( 11) ( 19) l 568666 ( 54) CARBURETTOR AND METHOD FOR REGULATING THE FUEL/AIR MIXTURE FED TO AN INTERNAL COMBUSTION ENGINE ( 71) We, ROBERT BOSCH GMBH, a German company of Postfach 50, 7 Stuttgart 1, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which, it is to be performed, to be particularly described in and by the
following statement:
This invention relates to a carburettor and method for regulating the flow of air/ fuel mixture to an internal combustion engine by varying a cross-section which affects the fuel metering of the carburettor in relation to the operational characteristic of the internal combustion engine.
In a conventional carburettor, one or more by-pass cross-sections are arranged in parallel to the main fuel nozzle of the carburettor, which can be opened or closed by a solenoid valve Opening takes place at a fixed frequency with opening periods which vary in dependency on the operating parameters of the internal combustion engine Another well known device is one where the fuel metering point is supplied with fuel at different pressure levels by electronically operated valves Float chambers having variable filling levels constitute the fuel supply source This device has the disadvantage that the metered quantity of fuel is subject to pulsating changes.
Integration of the metered quantity fluctuations, resulting from the constantly changing regulating variables, in order substantially to avoid the fluctuations is not possible with this device, since there are only marginal differences in pressure to provide a regulating operation, which means that a change in quantity can only take place at a relatively slow rate.
Furthermore, carburettors are known with which the air pressure in the float chamber of the carburettor is controlled in dependence on operating parameters, in which the air space in the float chamber is alternately connected to a higher and lower pressure Pressure in the form of pressure upstream of the butterfly valve in the induction pipe of the carburettor and at the narrowest cross-section of the venturi of the carburettor is used This arrangement has the disadvanatge that the available pressure is subject to pulsations and that the level of pressure or the available pressure differential is dependent upon the operating conditions of the internal combustion engine at the time Further, air represents a compressible medium, which can easily be induced to fluctuate in quantity and thus have an unwanted influence on control so that additional measures have to be taken to prevent the fluctuation or to compensate for it.
It is the task of the invention to provide a carburettor and method with which a reliable control of the composition of the fuel/air mixture in an internal combustion engine, can be achieved with simple means whilst avoiding the disadvantages described above, whereby a regulation having a good integral characteristic and being readily adjustable to respond to the respective conditions is possible.
The present invention seeks to fulfil this task in providing that a cross-section can be varied by a throttle device operated by the fuel The use of fuel as an adjusting medium has the advantage that a stable operation of the correcting elements can be achieved with little interference or fluctuation By interpolation of these elements, a good integrating regulating relationship of the quantity of fuel fed to the internal combustion engine is achieved.
There is provided by the present invention a carburettor for regulating the fuel/ air mixture fed to an internal combustion engine, the carburettor having a venturi in the induction pipe thereof, a passage for supplying fuel or air to the induction pipe, and means for varying the cross-section of the passage or of the induction pipe dependent on a parameter characterising the operational behaviour of the internal combustion engine; wherein a variable throttle device is employed as the means to vary said cross-section, the throttle device being ar1,568,666 ranged to be operated by the fuel received by the carburettor in dependence on the operating behaviour of the engine.
In an embodiment of the invention, the variable throttle device has a resiliently biased displaceable element defining with the passage a pressure chamber subject in use to the fuel pressure prevailing at the outlet of the float chamber of the carburettor via a connection between that outlet and the chamber; the chamber being arranged to be fully or partially closed off by a valving device from the float chamber outlet and connected to a further source of fuel pressure acting to displace said element to reduce the cross-section of the passage in dependence on the value of the operation parameters of the internal combustion engine.
The pressure in the supply pipe of a fuel supply pump may serve as the further source of fuel pressure A stable and quick adjustment of a throttle device can be achieved in this way with a sufficiently large pressure differential and an integral control relationship which are themselves independent of the particular operational conditions of the internal combustion engine Since this control influences a cross-sectional area of the carburettor which has a direct effect on the quantity of fuel fed in, the control influence is multiplicative A further advantage is that when making available the various fuel pressures, no additional expenditure is, as a rule, necessary, which makes this particular device particularly simple.
A nozzle needle valve may be used as the throttle device, with which the crosssection of the feed passages of the main and/or idling fuel jets and the cross-section of the feed passage of the by-pass fuel jet to the main fuel jet or the cross-section of the fuel passages of the idling air and/or idling air correction jets can be adjusted.
In another embodiment of this invention, a spring loaded choke flap valve in the induction pipe upstream of the venturi crosssection of the carburettor serves as the throttle device.
The present invention will now be described with reference to the accompanying drawings in which:
Fig 1 is a diagram of a first embodiment of the present invention, Figs 2 to 5 respectively are diagrams of alternative switching devices that may be used in the embodiment of Fig 1, Figs 6 to 8 respectively are diagrams of three further embodiments of the invention.
In Fig 1 a carburettor is shown constructed in the conventional way, the induction pipe 1 connected to an internal combustion engine (not shown); the carburettor being shown on the upright, i e operating, position A butterfly valve or throttle flap 2 is arranged in the pipe 1 in the usual way and upstream of the flap 2 the pipe decreases in diameter in the shape of a venturi 3 Fuel is fed into the carburettor through a fuel 70 pump 7 which draws the fuel from a reservoir through a pipe 6 A feed pipe 8 of the fuel pump leads in to a float chamber 10 containing a float 11, the needle valve 12 of which controls the feed pipe entrance 13 75 into the float chamber to ensure a constant fuel filling level in the float chamber.
From the outlet of the float chamber at the deepest part thereof a fuel pipe 16 is then taken off which merges with an acend 80 ing feed pipe 18 connected in the usual way to the induction pipe 1 upstream of the venturi 3, by an air correcting jet 20 A fuel supply pipe 21, supplying fuel to the venturi, is also fitted in the pipe 18 in the 85 usual way, of which an exit portion 22 extends into the narrowest cross-section of the venturi 3.
A pipe 24 also branches off from the fuel pipe 16 and from the uppermost part 90 of the pipe 24 above the fuel level, a connecting pipe 26 fitted with the idling air jet leads to a pressure regulator pipe 27 for the float chamber, which connects the air space of the float chamber to the induction 95 pipe upstream of the venturi 3 A branch 29 of pipe 24 leads downward and merges downstream of the throttle flap 2, through a bore 30 into the induction pipe The idling regulating screw 31 controls the aper 100 ture of the bore 30 Transition bores 32 branch off from pipe 29 in the area of the induction pipe directly upstream of the closed position of the flap.
An idling fuel jet 34 in the pipe 24, and 105 the main fuel jet 35 located in the fuel pipe 16 between the float chamber and pipe 24, meter the flow of fuel As so far described, the carburettor is conventional The embodiment of the present invention illustrated 110 in Fig 1 however, provides a throttle device 37 in the main fuel jet 35 and a throttle device 38 in the idling fuel jet 34 These throttle devices each consist of a needle valve 39 extending into the opening of the 115 respective jets The needle valves 39 of the two throttles are each led into a bore 41, respectively at the tip of the needles and have a plate 43, acting as an adjusting element, at their opposite, rear, end fitted 120 with a gasket 44 around the circumference of the plate The gasket slides within a respective one of bores 46, 47, lying co-axially of the jet opening, and separates the bore into a pressure chamber 48, 49 respectively 125 and an operating chamber 50, 51 respectively In each operating chamber 50, 51 there is arranged a spring 52, co-axial to the needle valve 39, which is supported between plate 43 and the front face of the 130 bore forming the operating chamber to bias the needle valve to move so as to enlarge the epening of the jet The operating chambers 50, 51 are each connected to the 2 outlet of the float chamber through respective bores 54 and 53 so that there is a float chamber pressure in the operating chams bers.
The pressure chambers 48 and 49 are 0 connected to one another by a pipe 56 A lppe 57 also leads from the pressure chamber 49 to the float chamber outlet 14 A valving device 58 is fitted in this pipe which will be more fully described in connection Id with Pigs 2 to S A pressure supply pipe 60, branching of from the supply line 8 also leads to the switching device.
The valving device shown in Fig 2 consists of a three-port, two-way valve 62 which is operated by an electromagnet 63.
The electromagnet 63 is connected to a regulating device 64 through a pipe 65; the regulating device receiving its controlled arameter through a lead 66 of a probe 67 which is a conveptional exhaust measuring robe such as an oxygen measuring probe.
be measuring probe is arranged in the usual manner in a section 68 of the exhaust system of the internal combustion engine, so and there determines in the usual way the eomposition of exhausts, e g with reference $o oxygen content As soon as there is an excess of oxygen, or as soon as a certain predetermined value is either reached or ex3 ceeded, the probe emits a threshold valuevoltage signal to the regulating device 64, which converts this into a corresponding regulating value for the valving device.
According to the construction of the regulating device, the three-port, two-way valve, is either timed with an opening ratio as to the two ways of the valve dependent on the appropriate regulation variable of an oxygen measuring probe, or according to this variable, is operated by analog signal.
Regulating devices of this type are known nd need not he more fully described here.
Regulation is not only limited to the use of an oxygen measuring probe signal as described above under Fig 2 Other parameters may also be used in the same way for control purposes which distinguish the operational behaviour of the internal combustion engine, e g such as the smoothness of the internal combustion engine This is achieved in a conventional model by determining with a measuring recorder the distribution of pressure in the combustion area, which is taken as a measure of smoothness of the engine In the same way, changes in the moment of torque of the drive shaft of the internal combustion engine or variations of revolutions may be used as a signal It has further been proposed to influence the fuel/air mixture regulation by measurin& flow of ions in the exhaust gases from the internal combustion engine by use of a suitable probe Other methods for determining the composition of exhaust such for example as measuring temperature 70 could also be applied here.
The embodiment of the invention according to Fig 1 in conjunction with Fig 2 operates as follows:
The quantity of air inducted in through 75 throttle flap 2, determined by the number of revolutions of the engine itself determines the pressure in the venturi 3, which draws a flow of fuel from the fuel exit portions 22 of pipe 21 Additional air can 80 be introduced in the usual way by the air correcting jet 20 and through the pipe 21 and the exit portion thereof No further elucidation need be given on this known form of operation Likewise, air is drawn 85 into the by-pass through the idling air jet 25 when the throttle flap 2 is shut whilst the internal combustion engine is operating and simultaneously fuel is drawn through the idling fuel jet 34 The fuel/air mixture, 90 fed to the internal combustion engine in the way described, is determined after adjustment of the idling regulating screw The maximum quantity of fuel which can be introduced at idling or full load is deter 95 mined by the cross-sectional area of the jet aperture of the idling fuel jet 34 or by the main fuel jet 35 Depending on the size of this cross-section e g in the case of the main fuel jet, the flow of fuel is throttled 10 to a greater or lesser degree so that at comparable pressure ratios at the venturi 3, a larger or smaller quantity of fuel can be introduced into the suction pipe 1 It is therefore possible, through the throttle de 105 vices 37 and 38 provided, to have a varied nozzle-cross-section together with a varied fuel metering quantity at the same operational ratios (revolutions and position of throttle flap) 110 As long as the pressure chambers 48 and 49 are connected by the valving device through the connecting pipe 57 to the outlet of the float chamber, plate 43 will be subject to an equally high pressure on both 115 sides Because of this, spring 52 causes the needle valve 39 to move away from the appropriate jet so that its opening remains unthrottled If, on the other hand, the pressure chambers 48 and 49 were connec 120 ted through the valve 62 to the pipe 60, there occurs in these pressure chambers an increase in the pressure, i e by the pressure of the fuel pump, which induces the needle valve 39 to move in the direction of the 125 jets until an equilibrium is achieved between the force of the spring and the force deriving from the hydraulic pressures, at plate 43.
By intermediate adjustment whereby the 130 1,568,666 1,568,666 valve 62 is correspondingly displaced, there is obtained in the pressure chambers 48 and 49, according to the regulating variables or the operational behaviour of the internal combustion engine, a determined intermediate pressure The same can be achieved when the three-port, two-way valve is time controlled, in the sense of a constant alternation of the pressure chambers 48 and 49 connection, on the one hand, with the float chamber and on the other hand, with the pipe 60 The appropriate opening times are, according to the operational behaviour of the internal combustion engine, postponed by the regulating device 64 according to the regulating signal to maintain the pressure source having the higher or the lower level of pressure for a longer time as determined by the signal.
In order to obtain a constant operating pressure in the pipe 60, a pressure limit valve 69 can be fitted in the by-pass leading to the fuel supply pump 7.
Thus, in the present device there are two constant pressures to produce the required intermediate pressure in pressure chambers 48 and 49, resulting in a very accurate and reliable regulation of the cross-sections of the main fuel jet 35 and idling fuel jet 34.
In order to obtain good further integration behaviour, a throttle 70 can be fitted in the pressure supply pipe 60 and a throttle 71 can be fitted in the connection pipe 57 between the valving device 58 and the float chamber outlet 14 The cross-sections of these throttles which, for example, can be replaced by correspondingly small dimensioned connection pipes, are set according to the volumes available in the pressure chambers 48 and 49, as well as according to the initial pressures.
Fig 3 is another form of the valving device 58 In this example, there is in the pipe 60, a two-port, one-way valve 73, and a two-port, one-way valve 74 is fitted in the connecting pipe 57 between its convergence with the pipe 60 and the exit of the float chamber 14 Both valves are operated by electromagnets 75 and 76, which are connected through leads 77 and 78 to the regulating device 64 The valves can be controlled in phase opposition by the regulating device 64, with an opening ratio per unit of time, which alters in accordance with the control value of the appropriate operational parameters used.
This can be termed as a keying ratio or relative duration of connection.
Fig 4 illustrates an alternative to the valving device of Fig 2 In the example of Fig 4 an electromagnetic switch valve is provided in the pipe 60 where connection pipe 57 branches from it This is accordingly timed by a regulating device 64 and is again controlled by a keying ratio.
Fig 5 depicts a valving device with only one valve 81 fitted in the pressure supply pipe 60 This valve is likewise operated by an electro-magnet 82 of a regulating device 64 In the connection pipe 57 be 70 tween its convergence with the pressure pipe 60 and the float chamber outlet, a throttle 84 is also fitted to throttle the flow from valve 81, whose dimensions conform to those special ratios Valve 81 can be 75 operated both in the timed mode and by analog signal mode as described above by a regulating device which is appropriately designed.
The embodiment according to Fig 6 is 80 principally constructed in the same way as the embodiment of Fig 1 and as a result only the changed detail is described The throttle devices 37 and 38 are not fitted in the main and idling fuel jets, but are ar 85 ranged at the air correcting jet 20 and the idling air jet 25 The throttle devices, which are constructed in substantially the same way, are also arranged co-axially with the jet bore axis, and each consists of one 90 needle valve 39 with a plate 43 which on the one side is loaded by the pressure spring 52 and on the other side is subject to the hydraulic pressure leading to the pressure chambers 48 and 49 through the valving de 95 vice 58, the connecting pipe 57 and the pipe 56 The operating chambers 50 and 51 are connected to the float chamber by pipe 53 and pipe 54.
Similar to the altering of the fuel meter 100 ing jets of a carburettor, it is also possible, by altering the cross-section of the idling air jet or the air correcting jet, to alter the metered quantity of fuel for the same operating conditions (revolutions and throttle 105 flap adjustment) This is carried out in the same way as shown in Fig 1 Through the relative control of the valving device 58 by a regulating device, a pressure is induced in the pressure chambers 49 and 48 corres 110 ponding to the operational procedure of the internal combustion engine A fixed adjustment of the needle valve 39, or a fixed cross-section of the appropriate jets corresponds to this pressure Naturally regu 115 lation can only be carried out on one of the jets-the idling air jet or the air correcting jet, depending on the size of the internal combustion engine of which they form a part, or depending on special requirements 120 The same can also be said of the embodiment according to Fig 1 whereby the influence of the jet cross-section may either be through the main fuel jet or the idling fuel jet alone Here, it would also be logi 125 cal to carry out adjustment only on the main fuel jet for internal combustion engines with small output.
Engagement in the idling jet section for relatively large engines could be significant, 130 1,568,666 especially in the case of independent idling, that is to say the fuel for the idling system is extracted directly from the float chamber, or between the float chamber and main r” jet, but not behind the main jet.
Instead of the embodiment of the adjustment mechanism of the throttle needle in the shape of a plate having a gasket, other versions such as for example piston, roller membranes or simple membranes may be used as means of adjustment.
F Pig 7 illustrates a further version of the invention where by the by-pass cross-section to the main fuel jet is regulated As in the 4 $ previous embodiments, reference is made to a conventional carburettor with a venturi 103 situated in an induction pipe 101 and a throttle flap 102 lying downstream therefor.
The carburettor fuel supply is by a fuel pump 107 which draws in fuel from a fuel container 105 through pipe 106, which is then conveyed to a float chamber 110 through a supply pipe 108 In the by-pass to the fuel supply there is located a pressure limit valve 169, which brings about the connection between supply pipe 108 and pipe 106 when a certain pressure has been exceeded.
The entry of the supply line 108 into the float chamber 110 is controlled by a needle valve 112 of a float determining the level of fuel in the float chamber From the base of the float chamber there branches off c fuel pipe 116 leading to an ascending feed pipe 118 The pipe 118 merges with the induction pipe 101 upstream of the venturi 103 through an air correcting jet 120 A pipe 121 is fitted in the feed pipe 118 which during induction causes the fuel to be mixed with air, the mixture being fed to the venturi through an exit pipe 122 at the narrowest cross-section of the venturi 103 The main fuel jet 135 is also arranged in fuel pipe 116, the former determining the appropriate flow of fuel for the various operational parameters of the internal combustion engine.
To this point the carburettor described also corresponds to a conventional car$ O burettor, as with Figs 1 and 6 For the purposes of simplification, the idling system which is of no further interest, has been omitted from the drawing.
Differing from the conventional constructi Qn of a carburettor, a further fuel pipe 86 branches off and passes into an exit pipe X 7 extending into the venturi The exit pipe is situated immediately downstream of the exit pipe, 122, and slightly beneath the fuel level, which is regulated by float 111.
An additional by-pass jet 88 is fitted in the fuel pipe $ 6 which branches off from the fuel pipe 116, upstream of the main fuel jet 135 A needle valve 139 having a plate 143 at its rear end for adjustment purposes controls the cross-section of this jet In a similar version to the throttle devices 37 and 38, the needle valve 139 is arranged co-axially to the bores of the by-pass fuel jet 88 in this particular throttle layout 90 70 A closely fitting ring gasket 144 is fitted around plate 143 and slides in a cylindrical area, which thus becomes separated into a pressure chamber 148 and an operating chamber 150 The needle valve 139 which 75 is close fitting, extends through a bore 141.
The pressure chamber 148 on the plate side 143 facing the point of the needle valve is connected to the outlet 114 of the float chamber by a pipe 157 via valving de 80 vice 58 In the operating chamber 150 opposite, there is a pressure spring 152 whose purpose is to move the plate 143 together with the needle valve, thus bring ing about a reduction in the area of the jet 85 cross-section.
The operating area is also connected to the outlet 114 of the float chamber by pipe 153 so that the hydraulic pressures on the plate 143 can become equalised-in so far 90 as the connecting pipe 157 remains open and the needle valve 139 can be kept in position, closing the jet bore under the influence of the pressure spring 152.
On failure of pressure in chamber 148, 95 no fuel can be expelled through pipe 87 although it lies below the normal fuel level in the float chamber.
As in the previous embodiments depicted above, the valving device 58 is fitted in the 100 connection pipe 157 which can be designed as in the embodiments of Figs 2 to 5 A pressure pipe 160 also branches off from the supply lead 108 to the connecting pipe 157 Pressure from the float chamber or 105 the feed pressure or discharge pressure of the fuel supply pump can now be fed alternately to the pressure chamber 148 through the valving device 58 and, depending upon the operational behaviour of the internal 110 combustion engine, a mixed pressure can be introduced which lies between those limiting pressures In order to improve the integration behaviour, a throttle 170 is fitted in the pressure pipe 160 as well as a 115 throttle 171 in the connecting pipe 157 between float chamber and valving device 58.
Operation of the device is largely similar to those embodiments described above Fuel, dependent on the flow of air, is fed through 120 the pipe 87 in addition to the quantity of fuel fed through the fuel exit pipe 122 which, too, is dependent on the flow of fuel/ air, in the same way.
However, this quantity of fuel may be 125 varied by altering the by-pass fuel nozzle cross-section according to the behaviour of the internal combustion engine Because the exit of the pipe 87 lies beneath the fuel level of the float chamber, this guarantees 13 i _ ated by the fuel received by the carburettor in dependence on the oprating behaviour of the engine.

Claims (1)

2 A carburettor according to Claim 1,
wherein the variable throttle device has a 70 resiliently biased displaceable element defining a pressure chamber subject in use to the fuel pressure prevailing at the outlet of the float chamber of the carburettor via a connection between that outlet and the 75 chamber; the chamber being arranged to be fully or partially closed off by a valving device from the float chamber outlet and connected to a further source of fuel pressure acting to displace said element to reduce the 80 cross-section of the passage, in dependence on the value of the operation parameters of the internal combustion engine.
3 A carburettor according to Claim 2, wherein the further pressure source is con 85 stituted by the fuel supply pump of the engine; the carburettor comprising a pipe to connect said chamber to the pump.
4 A carburettor according to Claim 3, wherein said pipe joins with said connec 90 tion between the float chamber outlet and said chamber and the valving device comprises either a three-port, two-way valve installed in said connection at the junction with said pipe or two two-port, one-way 95 valves installed respectively in said connection and said pipe.
A carburettor according to Claim 3, wherein the valving device consists of a switch-over valve at the junction of said 100 pipe and said connection.
6 A carburettor according to Claim 3, wherein the valving device consists of a valve in said pipe, and a fixed throttle fitted in said connection between the float cham 105 ber and the adjacent end of said pipe.
7 A carburettor according to any of the preceding claims, wherein a resiliently biased needle valve serves as the throttle device, and said passage is the main fuel or 110 another fuel passage of the carburettor.
8 A carburettor according to Claim 5, wherein the throttle device is provided in duplicate with one being installed in the main fuel passage and the other device in 115 said other fuel passage of the carburettor.
9 A carburettor according to Claim 7 or 8, wherein the resiliently biased needle valve is installed to control the cross-section of the feed passage of a by-pass fuel 120 jet of the main fuel jet.
A carburettor according to Claim 9, wherein a fuel pipe leads from the by-pass fuel jet into the venturi directly downstream of a fuel pipe controlled by the main 125 fuel jet and below the level the fuel assumes in the use of the carburettor, in the float chamber thereof.
11 A carburettor according to Claim 7, wherein the resiliently biased needle valve 130 the efficiency of altering the cross-section E of the by-pass fuel jet 88 by means of regu i lation for the entire area of flow When the internal combustion engine is not operating, or when the regulating device breaks down, the by-pass fuel jet 88 is in its closed j position, caused by the pressure spring 152 operating the needle valve 139 This may naturally also occur in certain extreme operation areas of the internal combustion engine.
Fig 8 shows a further possibility of controlling a cross-section, the alteration of which can have multiple effects on the feedin of fuel Leaving out the no longer relevant carburettor parts, a choke valve flap 92 is fitted upstream of the venturi 203 of the carburettor in section pipe 201, which turns around shaft 93 when the lever 94 connected to this shaft is operated A piston rod 95 of an adjustable piston 97 in a hydraulic cylinder 96, is pivoted to the lever 94 A piston 97 separates the hydraulic cylinder into an operational chamber 98 and a pressure chamber 99 which, as in the previously described examples, can be connected to the float chamber by a pipe 257 and/or to the feed pump outlet valving device 58 The piston 97 is spring loaded in the operational chamber 98 to such an extent that the choke valve flap 92 is moved into the opening direction when there is no fuel pressure in the pressure chamber 99.
The operational chamber 98 is also, as in the examples shown in Figs 1, 6 and 7, connected to the float chamber through pipe 253 This device operates in the same way as the other examples above According to the valving device controlled by the regulating mechanism, a mixed pressure between the pressure of the fuel pump and the float chamber pressure is switched-in in pressure chamber 99 Subjected to this mixed pressure, the piston is pushed against the force of spring 100 and the induction pipe becomes more or less closed by the throttle flap As a result of the increased suction caused thereby, an increased quantity of fuel is fed to venturi 203.
WHAT WE CLAIM IS: 1 A carburettor for regulating the fuel/air mixture fed to an internal combustion engine, the carburettor having a venturi in the induction pipe thereof, a passage for supplying fuel or air to the induction pipe, and means for varying the cross-section of the passage or of the induction pipe dependent on a parameter characterising the operational behaviour of the internal combustion engine; wherein a variable throttle device is employed as the means to vary said cross-section, the throttle device being arranged to be opera 1,568,666 7 1,568,666 7 is installed to control the cross-section of the feed passage of an idling air jet or an idling air correction jet.
12 A carburettor according to Claim 9, wherein the throttle device is provided in duplicate with one being installed in the respective passages of the idling air jet and the idling air correction jet.
13 A carburettor according to Claim 9, 10, 11 or 12, wherein the throttle device comprises a displaceable element resiliently biased to urge the needle valve from the closed position.
14 A carburettor according to any of the preceding Claims 1 to 6, wherein in the case where it is the cross-section of the induction pipe which is varied by said means, the throttle device comprises a resiliently biased choke valve flap located in the induction pipe.
A carburettor according to Claim 2 and any preceding Claims 3 to 14 as dependent on Claim 2, wherein the valving device consists of electrically operated valves, 2 $ which are timed by a control mechanism having a keying ratio or relative duration of operation corresponding to the control value of an operating parameter of the internal combustion engine, and which can be operated to assume any position between open and closed.
16 A carburettor according to Claim 2 and any of the preceding Claims 3 to 14 as dependent on Claim 2, wherein the valving device consists of electromagnetically operated valves whose cross-section may be continuously adjusted by a regulating device according to the extent of variation of an operational parameter of the internal combustion engine.
17 A carburettor according to Claim 3 or any of preceding Claims 4 to 16 as dependent on Claim 3, wherein fixed throttles are fitted in the pressure pipe and in the connecting pipe between the switching device and float chamber of the carburettor.
18 A carburettor according to any of the preceding claims, wherein a parameter employed to characterise engine operation is the exhaust gas composition, and a probe is provided to measure that parameter.
19 A carburettor according to Claim 18, wherein said probe measures ion flow in the exhaust gases of the engine.
A carburettor according to any of preceding Claims 1 to 18, wherein a parameter employed to characterise engine operation is the smoothness of the engine, and a sensor is provided to measure that parameter.
21 A carburettor substantially as hereinbefore described with reference to Fig 1 of the accompanying drawings.
22 A carburettor substantially as hereinbefore described with reference to Fig 1 and any one of Figs 2 to 5 of the accompanying drawings.
23 A carburettor substantially as hereinbefore described with reference to Fig 6 or Fig 7 or to Fig 8 of the accompanying drawings.
24 A method for regulating the fuel/ air mixture fed to an internal combustion engine using a carburettor having a venturi in the induction pipe thereof, a passage for supplying fuel to the induction pipe and means for varying the cross-section of the passage dependent on the operational characteristics of the engine, the method comprising varying the cross-section of the passage with a variable throttle device operated by the fuel supply to the carburettor in dependence on the operating parameters of the engine.
A method according to Claim 25 substantially as hereinbefore described.
26 A method for regulating the fuel/ air mixture fed to an internal combustion engine, substantially as hereinbefore described with reference to the accompanying drawings.
Agents for the Applicants:
W P THOMPSON & CO, Chartered Patent Agents, Coopers Building, Church Street, Liverpool L 1 3 AB.
Printed for Her Majesty’s Stationery Office by Burgess & Son (Abingdon), Ltd -1980 Published at The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY from which copies may be obtained.
1,568,666

GB48020/76A
1975-11-21
1976-11-18
Carburettor and method for regulating the fuel/air mixture fed to an internal kcombustion engine

Expired

GB1568666A
(en)

Applications Claiming Priority (1)

Application Number
Priority Date
Filing Date
Title

DE19752552207

DE2552207A1
(en)

1975-11-21
1975-11-21

DEVICE FOR CONTROLLING THE FUEL-AIR MIXTURE IN A COMBUSTION ENGINE

Publications (1)

Publication Number
Publication Date

GB1568666A
true

GB1568666A
(en)

1980-06-04

Family
ID=5962270
Family Applications (1)

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Title
Priority Date
Filing Date

GB48020/76A
Expired

GB1568666A
(en)

1975-11-21
1976-11-18
Carburettor and method for regulating the fuel/air mixture fed to an internal kcombustion engine

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US
(1)

US4100897A
(en)

JP
(1)

JPS5264544A
(en)

BR
(1)

BR7607714A
(en)

DE
(1)

DE2552207A1
(en)

FR
(1)

FR2332435A1
(en)

GB
(1)

GB1568666A
(en)

IT
(1)

IT1123067B
(en)

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* Cited by examiner, † Cited by third party

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Title

ITRE20110060A1
(en)

2011-08-02
2013-02-03
Emak Spa

“CARBURETION CONTROL SYSTEM”

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* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

US1982049A
(en)

1931-03-20
1934-11-27
Leibing Automotive Devices Inc
Fuel control apparatus

DE712708C
(en)

1939-03-14
1941-10-23
Versuchsanstalt Fuer Luftfahrt

Device for controlling the fuel inlet valve in carburetors

US2584911A
(en)

1947-03-17
1952-02-05
George M Holley
Pressure carburetor

US2617397A
(en)

1947-10-17
1952-11-11
Bendix Aviat Corp
Fuel metering device

US2610044A
(en)

1948-12-18
1952-09-09
Bendix Aviat Corp
Carburetor

US3768259A
(en)

1971-07-06
1973-10-30
Universal Oil Prod Co
Control for an engine system

JPS5118023B2
(en)

1972-04-14
1976-06-07

DE2242345C3
(en)

1972-08-29
1980-03-13
Robert Bosch Gmbh, 7000 Stuttgart

Constant pressure carburetor for internal combustion engines

IT995212B
(en)

1972-08-29
1975-11-10
Bosch Gmbh Robert

FUEL DOSING SYSTEM FOR INTERNAL COMBUSTION ENGINES

DE2321721C2
(en)

1973-04-28
1982-12-16
Robert Bosch Gmbh, 7000 Stuttgart

Device for reducing harmful components of exhaust gas emissions from internal combustion engines

JPS5053722A
(en)

1973-09-12
1975-05-13

FR2284044A1
(en)

1974-09-04
1976-04-02
Laprade Bernard
Constant vacuum carburettor – has needle controlled by vacuum modulated in response to exhaust gas composition

JPS5821097B2
(en)

1974-12-24
1983-04-27
日産自動車株式会社

Ninen Kikanno Idol Antei Souchi

1975

1975-11-21
DE
DE19752552207
patent/DE2552207A1/en
not_active
Withdrawn

1976

1976-11-02
US
US05/737,978
patent/US4100897A/en
not_active
Expired – Lifetime

1976-11-16
FR
FR7634497A
patent/FR2332435A1/en
active
Granted

1976-11-18
IT
IT29499/76A
patent/IT1123067B/en
active

1976-11-18
BR
BR7607714A
patent/BR7607714A/en
unknown

1976-11-18
GB
GB48020/76A
patent/GB1568666A/en
not_active
Expired

1976-11-22
JP
JP51140630A
patent/JPS5264544A/en
active
Pending

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Publication number
Publication date

FR2332435A1
(en)

1977-06-17

BR7607714A
(en)

1977-10-04

IT1123067B
(en)

1986-04-30

JPS5264544A
(en)

1977-05-28

FR2332435B1
(en)

1982-12-10

US4100897A
(en)

1978-07-18

DE2552207A1
(en)

1977-06-08

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