US3154152A - Apparatus for fuel injection - Google Patents

Description

Oct. 27, 1964 A. BLANCHARD 3,154,152

APPARATUS FOR FUEL INJECTION Filed July 10, 1962 2 Sheets-Sheet 1 FIG 1 INVENTOR ANDREBLANCHARD 3M and ATTORNEY Oct. 27, 1964 A. BLANCHARD 3,154,152

APPARATUS FOR FUEL INJECTION Filed July 10, 1962 2 Sheets-Sheet z ATTORNEY United States Patent 3,154,152 APPARATUS FOR FUEL INJECTION Andr Blanchard, 34 Rue Casteja, Bordeaux, Gironde, France Filed July 10, 1962, Ser. No. 208,793 4 Claims. (Cl. 12332) The present invention relates to a method of supplying internal combustion engines with liquid fuel and also to devices for the practical application of this method.

The method essentially consists in introducing the liquid fuel in the chamber reserved for combustion (usually a cylinder) during the time alloted for the supply, under low pressure and through a plurality of nozzles causing the fuel to flow into the combustion chamber laminarly in a plurality of wiredrawn streams. Also, the method includes simultaneously subjecting said fuel in said combustion chamber to the action of an electric field, either electrostatic or electromagnetic, the effect of this action being to cause said liquid to vaporize at a short distance from the outlet of the liquid fuel into the combustion chamber.

It is recalled that a physical effect is employed at the outlet as previously claimed in the French Patent No. 1,117,341 filed by the applicant on January 7, 1955, and the corresponding United States Patent No. 2,826,513, Canadian Patent No. 699,287 and the British Patent No. 793,958. The present application is a continuation-inpart of applicants co-pending application Serial No. 818,387, filed June 5, 1959, and entitled Method and Devices for the Supply of Liquid Fuel to Internal Combustion Engines, now abandoned.

The device for the practical application of this method consists essentially in at least one insulated conveyor nozzle which receives the liquid fuel under such a pressure that the flow of the liquid fuel at the orifice outlets of the nozzle is Wiredrawn; in means for producing an electric field in the combustion chamber, these means being characterized in that one electrode is placed in the interior of the insulated nozzle into which the liquid fuel is conveyed, this electrode being separated from the orifice outlets of the nozzle by means of a column of liquid fuel, while the other electrode is the piston itself or the combustion chamber itself which is grounded, the first of these electrodes being supplied with a high voltage current. Means are provided to enable the flow of fuel through the nozzle to be regulated in accordance with the heat of the engine in such manner as to produce the required number of fuel injections per unit of time.

Further features of the invention will become apparent from the description which follows below with reference to a number of forms of embodiment, which are given by way of example and not in any sense by way of implied limitation.

FIG. 1 shows in diagrammatic form the supply elements of a cylinder;

FIG. 2 shows the injection device in greater detail;

FIG. 3 is a fragmentary, enlarged perspective of the control valve;

FIG. 4 is a detailed view, seen from the end, of an injection nozzle with ten orifices;

FIG. 5 is a longitudinal axial cross-section of one of these orifices;

FIG. 6 is a diagram on a larger scale of the constantlevel supply chamber.

In FIG. 1, it may be seen that a source 1 is followed by an electronic sawtooth voltage generator 2 which increases the voltage and conveys it at a suitable frequency BJMJEZ Patented Oct. 27, 1964 to a contact-breaker 3 keyed on to the camshaft of the engine to be supplied. This contact-breaker distributes the voltage in appropriate sequence to the various cylinders in such manner as to produce successive injections of liquid fuel into the cylinders, said fuel being conveyed from the constant level tank through the piping systems 25. Contact-breaker 3 is illustrated as prepared for use with four cylinders. The ignition device, which is not characterized by any special feature is illustrated in FIG. 1.

FIG. 1 shows the device which permits the creation of a pulsatory voltage of 10 kv. in an engine developing very high power with a consumption of 36 liters per hour and a rotation speed of 6000 r.p.m. Since the injections take place at the rate of one for every two revolutions there are therefore 3000 injections per minute. A very simple calculation shows that each injection has a volume of 1.2 cu. mm. The pulsatory frequency to be adopted will therefore be substantially higher than fifty pulses per second.

By way of example, the voltage of the source 1 (for example 12 v.) is obtained from a battery. This is rendered in sawtooth form by generator 2, then applied to contactbreaker 3. The contact-breaker 3 is keyed on to the camshaft of the engine so as to cut off the high-voltage supply at the bottom dead-center point of admission. In FIG. 1 piston 13 of the cylinder 4 is shown nearly in its top deadcenter position.

On the previous stroke, the exhaust valve 14 was opened under the action of the camshaft 15 so as to allow the gases to escape, and then reclosed: when the piston 13 begins to move down, the injection operation takes place (admission stroke). For this purpose, the inlet valve 16, which is controlled in the usual manner by the camshaft 17, is opened, thus putting the combustion chamber in communication with the open air through the conduit 18' which supplies all the charging air. The combustion chamber is thus substantially at atmospheric pressure, less the reduction in pressure caused by the downward stroke of piston 13.

injection of fuel through injection 26 takes place simultaneously with the injection of air through valve 16. It is to be noted that at the end of the injection, at lowermost position of the piston 13 the air inlet-valve 16 will be closed and consequently tubes 13 and 18 which end on the upstream side of this valve will also be closed. However, during the injection stroke, the interior of the cylinder is put into communication with atmospheric pressure through the intermediary of tubes 18 and 18 thus tending to reduce to an appreciable degree the vacuum due to the downward stroke of the piston (which would be liable to modify the flow and therefore the force of the jet). Tube 18 provides pressure equilibrium between tank 19 and the interior of the cylinder before closing of valve 16. Thus, tube 18 nullifies or cancels any disturbances to which the nozzle is exposed in the combustion chamber.

The liquid fuel tank is located at 21. As in the case of normal types of engines, the liquid fuel is sucked out by a pump 22 and is delivered into the auxiliary tank 23 which is movable vertically, and the operation of which will be described below. This tank 23 is provided with an overflow tube and is coupled to the constant level chamber 19 by means of a flexible sleeve 23 (see also FIG. 6).

A conduit 25 starts from the constant level chamber 19 and conveys the fuel to the injector which is given the general reference 26. The horizontal portion of this conduit which terminates as the injector will be insulated over a fairly considerable length l (l) on the upstream side of the injector 26. Indeed, as the liquid fed to the injector is brought to about 10,000 volts, it is necessary to insulate the pipe 25 conveying this liquid over a sufi'icient length l (l) in order that the liquid column of length l (I) be suflicient for providing an ohmic resistance which prevents too high a voltage drop at the end corresponding to the spray orifices opening into the cylinders of the engine.

A description now follows below with reference to the injector 26 proper (FIG. 2).

The supply of fuel conveyed from the constant level chamber is controlled by the valve 26 which is inserted in the conduit 25. This cylindrical valve of insulating material is mounted so as to be capable of rotating in a nylon block 29 and is driven by the camshaft, as ordinary inlet valve, the purpose being to open and close the inlet duct exactly at the required moment. It is provided with a recess 28 (FIG. 3) and is arranged to be displaceable vertically in addition to being rotatable so as to open selectively recess 28. Thus, in the course of the inlet stroke, the rotational movement of valve 27 permits the arrival of the fuel through the conduit 25. The quantity of fuel so admitted depends upon the axial position of valve 27, orifice 28 being configured to permit the greatest quantity of fuel to be admitted while valve 27 is in its lowest position as indicated in FIG. 2.

The nylon block 29 is inserted on a block of quartz 31 which contains the injection orifices and which is flared externally at the approach to the cylinder so as to avoid any short-circuit between the outlets of the orifices and the metallic wall of the cylinder 4.

The high voltage supply, which is brought in through the connection 32 and is derived from the contact-breaker 3, emerges in the insulating portion of the tube 25 at A, at a distance from the injection nozzles which is suflicient to avoid the risk of incurring short-circuits between the electrode constituted by this extremity of the connection 32 and the other electrode formed by the cylinder 4.

The inlet conduit 25 does not open directly into the cylinder, but is flared out at 33 in such manner as to supply a series of nozzles which are shown in end-view FIG. 4 and in longitudinal cross-section in FIG. 5. Each nozzle comprises (FIG. a metallic tube 34 supported entirely within insulating material and terminating at the orifice proper 35 (FIG. 4). It can be seen (FIG. 4) that the orifices are arranged in a symmetrical group with respect to the horizontal center line e-f. It has been found that the diameter of tube 34 should be slightly larger in gasoline-powered than in kerosene-powered engines. Metallic tube 34 carries the carburent which is at high potential and insulated from the ground, since tube 34 is itself supported entirely within insulating material. Since tube 34 is itself non-insulative, it maintains the high potential in the carburent. If tube 34 were insulating, there would not be a sharp potential variation between the carburent and the charging air.

The manner in which the engine can be made to accelerate by causing the level of liquid fuel to vary by means of the accelerator will now be explained with reference to FIGS. 1 and 6. FIG. 1 shows a simple device controlled by the accelerator and designed to vary the height of tank 23. In the vicinity of the constant level chamber 19 and coupled to chamber 19 by means of a flexible tube 24, is located an auxiliary tank 23 mounted in such manner as to rise or fall under the action of the accelerator pedal, by means of a suitable mechanism. This auxiliary tank 23 receives the fuel conveyed by pump 2 through pipe 41. This tank is furthermore, rigidly fixed to an overflow pipe 42 which returns the excess fuel to the main tank 21.

It can be seen in FIG. 6 that fuel passes into auxiliary tank 23 by first passing through a perforated surface 43, the holes of which are so designed as to avoid the effects of eddies and air bubbles in case of excessive movement of tank 21 which would otherwise create troublesome air bubbles and undesirable effects on the flow of fuel.

The overflow tube 42 is provided at its upper portion with a check-valve 45 controlled by a light spring. This check-valve closes as soon as suction takes place in the cylinders, in order that the vacuum should not be transmitted to fuel tank 21.

The overall operation of the device is as follows:

As the flow of fuel reaches the cylinders of the engine, a sawtooth pulse of high voltage is applied so as to burst or vaporize the fuel. The flow of fuel is adjusted so as to issue from nozzles 35 laminarly or in wiredrawn streams. The voltage creates an intense electric field between the electrode 32 and the conductive grounded portions of the cylinders, and said voltage being applied at the correct instant, the fuel jets burst. This phenomenon which is now well known, has been described in the applicants US. Patent No. 2,826,513.

The flow of fuel through valve 27 and then into the combustion chamber is synchronized with the application of the electric field within the chamber. This synchronization is possible because of the low pressure existing in fuel line 25, on both sides of valve 27. This low pressure is permitted, since an electric field, instead of high pressure, is used to vaporize the fuel. In conventional diesel fuel injection systems the high pressure used for vaporization results in a constant dribbling of fuel into the chamber with attendant noxious and wasteful effects. Air is admitted through valve 16 which is sized to admit ten to twelve times the amount of air as fuel is admitted through valve 27. This air is injected both prior to and during vaporization, cam 17 being designed to obtain this result.

I claim:

1. A device for feeding the combustion chamber of an internal combustion engine with fuel, comprising at least one electrically insulated nozzle opening into said combustion chamber, said nozzle including a plurality of fuel introduction orifices communicant with said chamber and an outwardly flared chamber within said nozzle and in front of said orifices, means for supplying said nozzle with liquid fuel, and electric field generating means for creating such an electric field within said chamber as to cause vaporization of said fuel in the vicinity of said nozzle, consisting of an electrode accommodated within the insulated nozzle and ending short of the outlet of said nozzle at a distance sufficient to avoid short circuit between said electrode and said combustion chamber and means for applying voltage to said electrode; and said combustion chamber including grounded portions.

2. Device as claimed in claim 1, wherein the said means for supplying liquid fuel comprise a constant level fuel tank communicating with the nozzle, an auxiliary tank movable upwards and downwards relatively to the constant-level tank, a flexible tube interconnecting said tanks, an accelerator control member connected to said auxiliary tank for adjusting the position thereof, and a fuel pump discharging into said auxiliary tank.

3. Device as claimed in claim 2, wherein the auxiliary tank comprises an overflow pipe movable bodily with said auxiliary tank, and a check valve in said pipe for preventing back-flow suction therethrough.

4. A device for feeding the combustion chamber of an internal combustion engine with fuel comprising:

(A) at least one electrically insulated nozzle opening into said combustion chamber, said nozzle including a plurality of metal-lined fuel introduction orifices communicant with said chamber and an outwardly flared chamber in front of said orifices,

(B) means for supplying said nozzle with liquid fuel including a rotary valve driven in rotation by the engine cam shaft so as to admit fuel in the injection stroke of said combustion chamber, said valve being further capable of displacement axially so as to increase or decrease the amount of fuel injected,

5 6 (C) electric field generating means for creating such References Cited by the Examiner an electric field within said chamber as to cause UNITED STATES PATENTS vaporization of said fuel in the vicinity of said nozzle,

said electric field generating means consisting of an 20931339 9/37 PiPPig 123-32 electrode accommodated Within the insulated nozzle 5 2,331,912 10/43 Holthouse 123 32 and ending short of said chamber and said orifices of 21436090 2/48 BQdmB 123 32 2,578,145 12/51 Miller 123-32 said nozzle at a distance sufficient to avoid short circuit between said electrode and a grounded portion of said combustion chamber and means for applying voltage current to said electrode. 10

RICHARD B. WILKINSON, Primary Examiner.

Claims (1)

1. A DEVICE FOR FEEDING THE COMBUSTION CHAMBER OF AN INTERNAL COMBUSTION ENGINE WITH FUEL, COMPRISING AT LEAST ONE ELECTRICALLY INSULATED NOZZLE OPENING INTO SAID COMBUSTION CHAMBER, SAID NOZZLE INCLUDING A PLURALITY OF FUEL INTRODUCTION ORIFICES COMMUNICANT WITH SAID CHAMBER AND AN OUTWARDLY FLARED CHAMBER WITHIN SAID NOZZLE AND IN FRONT OF SAID ORIFICES, MEANS FOR SUPPLYING SAID NOZZLE WITH LIQUID FUEL, AND ELECTRIC FIELD GENERATING MEANS FOR CREATING SUCH AN ELECTRIC FIELD WITHIN SAID CHAMBER AS TO CAUSE VAPORIZATION OF SAID FUEL IN THE VICINITY OF SAID NOZZLE, CONSISTING OF AN ELECTRODE ACCOMMODATED WITHIN THE INSULATED NOZZLE AND ENDING SHORT OF THE OUTLET OF SAID NOZZLE AT A DISTANCE SUFFICIENT TO AVOID SHORT CIRCUIT BETWEEN SAID ELECTRODE AND SAID COMBUSTION CHAMBER AND MEANS FOR APPLYING VOLTAGE TO SAID ELECTRODE; AND SAID COMBUSTION CHAMBER INCLUDING GROUNDED PORTIONS.

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