Injector Carburetor

Abstract

This application relates to low profile injection carburetors in which the proportioning of the injected fuel to the demands of the motor is effected by providing an arrangement for returning some of the pulsed fuel to the fuel storage tank, the amount returned being decreased as motor demands increase, said control being effected by a valve, the loading of which changes in response to an operating condition of the motor.

Description

The present invention relates to injection carburetors and more particularly to an improved injection carburetor of low profile yet characterized by high efficiency over a wide range of operating conditions.

Prior art injection carburetors involve a nozzle in the throat of a carburetor which has a valve in it which is spring biased to a closed position. Fuel is fed to this nozzle in pulses and the valve in the nozzle opens in response to the fuel pressure to inject fuel in the throat. As the engine runs faster and more air passes through the throat, it is common to reduce the pressure on the nozzle valve so that more fuel is injected as more air flows through the throat.

This prior art arrangement suffers from the serious disadvantage of presenting a high profile despite the fact that in the designing of modern cars manufacturers seek a hood as low as possible for driver visibility reaons. In practically all cars the carburetor, with the associated air cleaner system, is the highest of the various pieces of equipment under the hood.

An additional disadvantage of prior art injection carburetors is that known arrangements for adjusting the loading on the injection nozzle valve complicate the construction in the throat of the carburetor and the delicate adjusting equipment so exposed to the air and fuel has been found to wear and deteriorate rapidly.

It is an object of the present invention to overcome the foregoing difficulties and to provide an injection type carburetor of low profile in which the control of the fuel in response to changes in engine requirements is effected by means which are convenient, reliable and easy to build.

Other objects and advantages of this invention will be apparent upon consideration of the following detailed description of several embodiments thereof in conjunction with the annexed drawings wherein:

FIG. 1 is a diagrammatical illustration of a typical prior art injection type carburetor over which the present invention constitutes an improvement.

FIG. 2 is a schematic view partly in section of one form of injection carburetor constructed in accordance with the principles of the present invention.

FIG. 3 is a view in vertical section of another type of carburetor constructed in accordance with the teachings of the present invention; and

FIG. 4 is a view in vertical section of still another form of carburetor constructed in accordance with the teachings of the present invention.

In order to emphasize the advantages of the present invention over the prior art the construction of FIG. 1 will be briefly described.

From the gasoline tank 1 a gasoline pump 2 pumps gasoline through the lines 3, 4 to a so-called pulse generator 5, from which a return line 6 leads back to the gasoline tank 1. When the gasoline is led to the pulse generator and within same, vapor bubbles form and the disadvantages of this are removed by the circulation pump pumping a relatively great quantity of gasoline so that the vapor bubbles formed are returned to the gasoline tank. The pulse generator 5 passes gasoline on through the conduit 7 to the injection nozzle 8 of the carburetor. This transport of gas takes place under strong and distinct pressure pulses, which cause the valve body 9 to vibrate. These vibrations, which produce a high-grade atomization of the gas, can be adjusted by means of the coil spring 10, in which the valve body is suspended; and, in this way, a flow of gasoline is obtained from the injection nozzle, which is proportional to the tension in the coil spring 10. This spring is connected to an adjusting disc 11 which is movable in the longitudinal direction of the spring. The position of disc 11 in the carburetor body 12 is controlled by the air being sucked in by the engine. The carburetor body is connected to the intake manifold of the engine by means of its lower flange.

FIG. 2 relates to a first embodiment of the invention and, where applicable, the same reference numerals have been used as before with respect to FIG. 1. The supply of circulating gasoline to the pulse generator takes place also in this case as described above. The gasoline, which in the pulse generator has been given strong pressure pulses, is led to a channel 13. From this channel a conduit 14 leads to an injection nozzle 15 placed in the carburetor body 16. In the aperture of the injection nozzle there is a valve body 17, which is pressed against the aperture of the nozzle by a tensile spring 18, the other end of which is attached to an adjusting screw 19, by means of which the tension of the tensile spring can be adjusted to suitable strength. When the valve body 17 is actuated by the pressure pulses of the flowing gas, vibrations are obtained and a following atomization of the gasoline streaming through the aperture of the nozzle in substantially the same was as described above. The quantity of the injected gas must of course always be in a certain desired relation to the quantity of air being sucked in at the same time. In the present case, adjustment of the quantity of gasoline is carried out by the quantity of gas, with which each pressure pulse from the pulse generator is supplied to injection nozzle, is adjusted to the right level by a separate device. On the drawing, FIG. 2, this device has been drawn directly in connection with and on top of the pulse generator, which, however, does not mean that this device may not be placed at another location and connected to the pulse generator by means of a conduit in suitable manner.

The adjusting means consists of a housing 20, containing a valve body 21, biased to a closed position by a compression spring 22, whose other end butts against a rod 23. At the roof of the housing 20 there is a lead-through 24 to a diaphragm housing 25. The rod 23 makes a contact with a diaphragm 26, on the opposite side of which there are an equalizer spring 27 and an adjusting screw 28. The diaphragm divides the diaphragm housing so that lower and upper chambers 29, 30 are formed, which communicate with the interior of the carburetor body through the conduits 31, 32 respectively. The conduits 31 and 32 connect to the carburetor immediately under and over respectively a constriction 33 disposed in the throat of the carburetor body.

The adjusting device functions in the following way. The pulse generator 5 supplies gasoline to the channel 13, from which the gasoline can be led through the conduit 14 to the injection nozzle in the carburetor and by pressing itself by the valve 21 into the housing 20, from which it is led back to the gasoline tank through the return pipe 34. The pulse generator delivers for each pulse stroke practically the same quantity of gasoline to the channel 13. The quantity of gasoline passing by the valve 21 and being led back to the gasoline tank will be proportional to the tension of the spring 22, which will thus result in that the remaining quantity of gasoline passing the conduit 14 to be injected into the carburetor also becomes a function of the tension in the spring 22.

When the air sucked in by the engine flows through the carburetor, a pressure difference will arise at its passage by the constriction 33. This pressure difference is a definite function of the passing quantity of air, and when said pressure difference through the conduits 31, 32 via the diaphragm 26 and the rod 23 are caused to actuate the tension in said spring 22, the quantity of gasoline injected into the carburetor will be a definite function of the quantity of air passing at the same time through the carburetor. Increased percolation of air through the suction channel will give a higher pressure in the conduit 32 than in the conduit 31 and in this way the diaphragm 26 will be displaced downwards and increases the spring tension 22 resulting in increased fuel pressure in the conduit 14. By a suitable dimensioning and design of the details included in the adjusting device it is easy to achieve such an adjustment that the quantity of gasoline injected into the carburetor is in desired relation to the quantity of air simultaneously streaming through the carburetor.

The carburetor shown in FIG. 2 of the drawing is presented in a very schematic form. Thus, the injection nozzle in the drawing has received unproportionally great dimensions on account of it being necessary to show the details included therein. In practice the injection nozzle with relative details does not require any greater vertical space than what is required by merely the valve body 9 with relative bracket 9a in the design of an injection carburetor shown in FIG. 1. It appears from this comparison what an essential advantage is gained by the considerably lower headroom or profile obtained with the invention.

In a carburetor according to the description all details for the adjusting function -- in contrast to types so far known -- can be totally enclosed. In this way, the wear is reduced to the least possible level and reliable function is secured. In the carburetor body itself there are no wholly or partly unprotected movable parts.

Another advantage obtained with a carburetor according to the invention is illustrated in an embodiment shown in the enclosed drawing, FIG. 3. This carburetor can, in a simple manner be provided with a great number of injection nozzles, which up to now has not been feasible due to the necessity for direct connection to the adjusting means which heretofore could not be done without using very complicated and expensive constructions. The advantage of being able to distribute the injected gasoline among a great number of injection nozzles is that a higher degree of atomization and better distribution are achieved by injection of smaller quantities of gasoline through a nozzle with a small valve than when greater quantities of gasoline are injected through a nozzle which must therefore have greater dimension and a corresponding bigger valve. Another advantage is achieved by the fact that when injection takes place through a great number of injection nozzles, the possibilities of obtaining a homogeneous mixture of the atomized gasoline particles with the passing air increases.

The carburetor shown in the drawing, FIG. 3, is drawn in its life-size (full scale) to show in how high a degree a carburetor according to the invention can be made with low building height. By the building height of a carburetor the measure between the flange of the carburetor against the intake manifold and the shoulder or flange of the carburetor, where the air cleaner is mounted, is meant. In the present case -- the carburetor is dimensioned for an engine having a cylinder volume of about 7 liters -- this measure is about 35mm. For the sake of comparison it should be mentioned that for an ordinary carburetor (Rochester Quadrojet) of the same engine the corresponding measure is about 85mm.

The carburetor as it has been illustrated in the drawing, FIG. 3, consists of a carburetor housing 41, which by means of the flange in its lower portion can be connected to the intake manifold of the engine. The throttle 42 is, as usual, connected to the gas pedal of the car. An annular and hollow flange 43 is adapted in the carburetor body and the cavity 44 is connected to a conduit 45. The flange 43 has a number of inwardly directed nozzle apertures 46, each provided with a valve body 47, which is pressed against the aperture by means of a spring 48, which tension is adjustable by means of an adjusting screw 49. Immediately before and after the annular flange 43 conduits 50, 51 are connected and these lead to the adjusting device parts 20 - 30, inclusive, as described above in conjunction with FIG. 2. Between the flange 52 of the carburetor body and the cover 53 an air cleaner 54 is placed.

When air streams through the carburetor as indicated by arrows in the drawing, the annular flange 43 will be such a constriction that a pressure difference will arise, where the conduits 50, 51 are connected on both sides of the flange. In a way as described above with reference to the adjusting means shown in FIG. 2, a suitably adapted quantity of gasoline will be supplied through the conduit 45 to the cavity 44 in the annular flange. Thus, in this cavity a pulsating pressure will arise, which actuates the valve bodies 47. In a way as described above these will vibrate and the gasoline is injected into the carburetor in a high-grade atomized form. By means of the adjusting screws 49 the quantity of gasoline injected through the nozzles can be individually adjusted in such a way that it will be possible to achieve a very high degree of homogeneity in the fuel/air mixture. The mixing possibilities are additionally simplified by the injection of gasoline taking place just where the stream of air is subject to a heavy turbulence on account of the constricted passage.

The adjusting device parts 20 - 30, inclusive, can also be adapted to be actuated by the motor speed, and this can for instance be arranged by disposing an electromagnet directly connected to the electric generator of the car engine near to the diaphragm 26, which, in this case, is made from magnetic material.

It is realized that at the embodiment according to for instance FIG. 2 the spring 18 in the injection nozzle with the related valve 17 and spring 22 with the related valve 21 as well as diaphragm 26 and equalizer spring 27 must be set depending on each other to certain definite conditions in order to achieve the desired adjusting function.

The embodiment according to FIG. 4 makes this setting easily accessible. The adjusting device is directly built together with the carburetor in such a way that also a roof is obtained over the air cleaner at the upper part of the carburetor. In this way the previously mentioned advantage of a low building height is maintained.

The carburetor consists of a carburetor base 61 containing a throttle 62 connected to the gas pedal of the car in usual manner, constriction 63 containing injection nozzles 64 with pertinent springs 65 and adjusting screws 66. The annular cavity 67 has an inlet 68 and an outlet 69 leading into an adjusting housing 70 with a valve body 71, which is pressed against a channel 72 communicating with said outlet 69 by means of a plate or leaf spring 73 attached to a rotatable shaft 74. On this shaft outside the adjusting housing 70 there is a lever 75. By means of the rods 76 a diaphragm housing 77 is attached to the carburetor. A diaphragm 78 splits the diaphragm housing into an upper and lower chamber 79, 80, of which the upper one communicates by means of a conduit 81 with an aperture 81a immediately under said constriction. The diaphragm 78, whose position and movements are equalized by the springs 82, 83 has a rod 84 movably attached to the lever 85, which is rotatably mounted at a rigid point 86, and has at its other end a stop 87, on which a sliding edge 88 on the lever 85 bears.

The carburetor functions as follows. Gasoline is supplied with pulsating pressure through the inlet 68, and with reference to the previous description, FIG. 2 it is easily realized how injection takes place and that the adjustment of the injected gas quantity becomes a function of the tension of the plate spring 73 and also of the position of the lever 75. When the air quantity streaming through the carburetor increases at opening of the throttle 62, the diaphragm 78 is raised on account of the reduced pressure in the chamber 79. By means of the rod 84 the motion is transferred via the lever 85 and the stop 87 to the lever 75, which will then turn the shaft 74 anticlockwise. In this way the tension in the plate spring 73 will increase, which in its turn causes that the injection of gasoline into the caruburetor increases. Now it is easy to realize that it is possible in a simple way to calibrate each change of the quantity of gasoline being injected into the carburetor at movements of the stop 87 caused by changes in air quantities by designing the sliding surface 88 on the lever 75 in such a curve as for each position of the stop 87 -- i.e. each air quantity sucked in -- gives the desired position of the lever 75 -- i.e. desired injected quantity of gas. The advantages of this arrangement are obvious. As each expert knows well, theoretical calculations of flow conditions at constrictions of the type described in the present construction always mean several uncertain factors. This makes of course a predetermination of the included adjusting means, springs etc. very difficult. According to the device here described afteradjustments become possible in a much simpler way by adjustment of the sliding surface 88 of the lever 75. Adjustments of this carburetor for different types of engines that may require different relations in the air/fuel ratio will be simple to carry out as well.

Claims

What is claimed is:

1. In an injection carburetion system including a carburetor having a throat on the air intake side thereof, a fuel reservoir, and a fuel pulsing device connected to the carburetor and fuel reservoir to transfer fuel from said reservoir to said carburetor, the improvement that comprises a plurality of injector nozzles arranged in an annular path around said throat, an annular channel around said throat for supplying said nozzles with fuel from said reservoir through said pulsating device, a conduit connecting said annular channel with said pulsing device, a valve by which a portion of the fuel output of said pulsing device is returned to said reservoir, said valve being connected to said annular channel, a spring biasing said valve to a closed position, a rotatable shaft attached to said spring to pivot said spring, a first lever attached to said shaft and having a curved edge, a second lever having a stop on one end thereof which bears against said edge of said first lever, the other end of said second lever being pivotally fixed to the carburetor base, a diaphragm housing positioned on the carburetor, a diaphragm splitting the diaphragm housing into an upper and lower chamber of which the upper one communicates with the carburetor throat immediately below the annular channel and a rod attached at one end to the diaphragm and at the other end to a point intermediate the ends of said second lever, said diaphragm being responsive to a variable of motor performance for modifying the magnitude of the bias imposed by said spring.