US2721100A

US2721100A - High frequency injector valve

Info

Publication number: US2721100A
Application number: US255958A
Authority: US
Inventors: Jr Albert G Bodine
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-11-13
Filing date: 1951-11-13
Publication date: 1955-10-18
Anticipated expiration: 1972-10-18

Description

Oct. 18, 1955 A. G. BODINE, JR 2,721,100

HIGH FREQUENCY INJECTOR VALVE Filed Nov. 13, 1951 IG. 1. F FIG. 2. 4o ,4z

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United States Patent HIGH FREQUENKIY INJECTQR VALVE Albert G. Bodine, In, Van Nuys, Calif. Application November 13, 1951, Serial No. 255,958

15 Claims. (Cl. 299-25) This invention relates generally to fuel injectors for internal combustion engines, and more particularly to a vibrating fuel injector valve and control system therefor by which improved engine operation and control are obtained.

In the maintenance of certain fuel injector valves, such as some of those used for diesel engines, it has sometimes been noted, particularly with low speed engines, that the nozzle valve ultimately gives best engine operation if, when first placed on the shop hydraulic tester, it is in a condition to give forth a grunting noise while fuel is being injected therethrough. Apparently, the valve buzzes against the valve seat a number of times during an injection interval, causing the fuel spray to be injected in intermittent bursts, somewhat in the fashion of a string of sausages. This mode of pulsed fuel injection conditions the fuel to in some way improve combustion. Apparently it is not sufficient for explanation to say that the buzzing valve gives greater atomization, as the benefit to combustion is greater than could be attributed to improved atomization and the explanation probably involves the fact that the pulsed fuel injection inherently tends toward dispersion of the charge, and away from charge accumulation.

This buzzing of the valve is due to a dynamic instability arising out of the fact that hydraulic pressure increases as the valve approaches its seat, and the pressure of the valve spring increases as the valve leaves its seat, thus meeting to a slight degree the physical requirements for a self-sustained vibratory system. However, this purely accidental effect is not only quite weak, but results only under a very critical set of conditions. The effect just barely happens, even under the best of conditions, and is always on the verge of stopping. The least malfunc' tion will substantially destroy the effect. The elfect de* scribed involves a cyclic bodily movement of the springloaded valve. The driving force under such conditions must necessarily be quite large, and the system is sensi tive to the condition of the valve seat and adjoining hy draulic spaces. Also, because of this bodily movement, the friction factor is very important. But most important of all is the fact that this vibratory system, involving bodily movement of the valve, is necessarily a very low frequency device, never going above a few hundred cycles per second. This all means that combustion cannot be depended upon to be very materially aided by such a buzzing nozzle, except perhaps in relatively slow speed engines.

The general object of the present invention is the provision of a vibratory fuel injector valve, characterized by positiveness of action, dependability, and capability for high frequency operation, as for example in the range of 20,000 to 40,000 cycles per second.

A further object is the provision of an electrical drive means and control system for such a vibratory valve, timed from the engine and permitting drive of the valve during the injection phase of the cycle at frequencies of the order indicated.

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A still further object is the provision of a vibratory injector valve and control system thereof by which the size and timing of the successive incremental fuel spray clouds or bursts can be easily adjusted and controlled.

The invention provides a control for the burning rate and for the total charge for each cycle, with the control being of a precision nature, commensurate with the small total charge per cycle of an average high speed engine. The injector of the present invention takes over the function of metering and timing, as well as spraying. The injector pump becomes a simple pressure source. A substantial degree of self-pumping can also be accomplished with some forms of the invention by controlling, .in the design of the injector, the acoustic impedance of the hydraulic column behind the valve. In this Way the down stroke of the valve displaces fiuid through the injector nozzle because of back flow resistance back down the injection line.

The invention will be best understood from the following detailed description of one present illustrative embodiment thereof, reference being had to the accompanying drawings, wherein:

Figure 1 is a longitudinal section view of a fuel injector embodying the invention;

Figure 2 is a diagrammatic view of a control system in accordance with the invention for the fuel injector of Figure 1; and

Figure 3 indicates a modification.

With reference first to Figure 1, numeral 10 designates generally a magneto-striction type of valve actuating de vice embodying a central elastic valve rod 11 and a vibratory magneto-strictive armature means, here in the form of a relatively elongated tubular magneto-strictive bar or sleeve 12 surrounding and annularly spaced from rod 11, these

members

11 and 12 being fixedly joined to one another at one end, as indicated at 13. The rod 11 and sleeve 12 are of approximately the same length, and the rod 11 carries at its free end valve element 14 adapted to seat on annular valve seat 15 surrounding injection orifice 16 in screwthreaded nozzle fitting 17. Valve element 14 is usually made of an abrasion resistant material; and also may be of low modulus, so as to prevent bodily bouncing of the valve mechanism. In a typical case, the

members

11 and 12 are typically 2.5" in length, though this figure is given without intention of limiting the invention. Two axially aligned magnetic field coils 18a and 18b surround the

members

11 and 12, and these coils may be embedded in a phenolic molded body 19. The body 19 may incorporate powdered iron particles around the coils to give a flux path outside of the coils.

The phenolic body 19 is mounted between the nozzle fitting 17 and an opposite end fitting 20, the latter being in the nature of a ring having an internally threaded portion 21 adapted to receive the externally threaded coupling part 22 of fitting 23, and it will be understood that the fuel supply line will be coupled to the latter. Fitting 23 has axial bore 24 opening to an enlarged chamber 25 in which is contained biasing spring 26 acting through inverted cup 27 against the juncture of the members 1.1 and 12, and it will be seen that this spring 26 exerts a light biasing force tending to press the valve element 14 against its seat 15. Also, as shown in the drawings, an annular fuel chanel 29 is formed around the magneto-strictive device, completing a fuel conduit from the bore 24 in fitting 23 down to the valve controlled seat 15 and discharge nozzle 16.

The leads to coils 18a and 18b may be brought out in any desired manner, and are here shown as leading to electrical sockets 30a and 301:, respectively, into which may be screwed conventional electric connector plugs, not shown.

The magnetic coils 18a and 1811 are energized by an oscillating current or currents of frequency correspond ing with the resonant frequency of the magnetostriction device. Magneto-striction materials, for example, nickel alloys, when submerged in liquids having an acoustic impedance range including that of hydrocarbon fuel, have a speed of sound of approximately 16,000 feet per second. Speed of sound divided by wave length gives frequency, and the lowest natural resonant frequency in the illustrative embodiment (with

members

11 and 12 approximately 2 /2 inches in length) is in. the range of 20,000 cycles persecond. The oscillating coil energizing currents should accordingly have a corresponding frequency.

A suitable fuel pump, not shown, is to be, understood as incorporated in the fuel'supply line,but this fuel pump does not meter or time the injection and merely maintains pressure at sufficient volume.

Operation of the valve is as follows: The periodic magnetic field produced by the coils 1%: and 18b energized by the oscillating currents (developed as hereinafter described) generates, on each pulse, a momentary shortening stress in the magneto-strictionmember 12. The latter accordingly contracts sli htly in a longitudinal direction, while counterbalancing forces are developed causing the other member or leg 11 to elongate, the junction point remaining stationary. Between shortening stresses, the magneto-striction member 12' elongates, while the member 11 contracts. The two legs 11' and 12 of the device thus alternately lengthen and contract, one leg always lengthening while the other is shortening. While the junction point of the two legs remains stationary, the two ends remote from the junction point move in opposite phase at the resonant frequency of the vibratory system constituted by the

members

11 and 12. The valve element 14 carried by rod 11 moves onto and olf of its valve seat 15 at corresponding frequency, thus opening and closing the valve at relatively high frequency range, typically at approximately 20,000 cycles per second. I of course do not wish to limit myself to a valve operating at 20,000 cycles per second, since benefits of the invention are obtainable, though to different degrees, from a few hundred'cycles per second up to a number of times the 20,000 cyclefrequency here mentioned as being typical.

It should be understood that the small magneto-striction bar 12 and the valve rod 11 do not move bodily (except to find an equilibrium location for the periods of actuation) but simply shorten and lengthen, each in the manner of a quarter Wave length bar fixed at one end and undergoing longitudinal elastic vibration.

The novel type of two-legged magneto-striction device here shown has certain advantages, but I wish it to be understood that a conventional single bar device, with the valve carried directly by the end of the magnetostriction-bar may also be used. Also, the general shape of the magneto-striction armature means can depart considerably from that of a typical bar, i. e., it can-be quite chunky in proportions. The diagrammatic illustration of Figure 2 indicates more particularly the single bar type of device, but it will be understood that the control system of'Figure 2 is usable with either type, and in the ensuing discussion the two-legged type of Figure 1 will be assumed.

Figure-2 shows schematically an illustrative control and driving system for the injector valve of a two-cylinder engine. Two separate oscillators O and 01 are employed, each having a pair of coils 18a and 18b forming the magnetic coil means of a magneto-striction valve device-such as shownin Figure 1. The two oscillators are identical, and a description of one will suffice, it being noted that like reference numerals are employed for corresponding parts. The two coils18a and 18b of each oscillator are included in the plate and grid circuits of a high-muvacuum tube 40. A condenser 41 is connected between the plate and grid leads.

A condenser 42in'the plate circuit has its cathode side grounded, and its plate side connected through

contacts

43 and 44 and a variable resistor 45 with the positive terminal of a source of plate voltage, as indicated. The negative plate voltage terminal is connected through resistor 46 to ground.

Assuming the simple case of a two cylinder engine, there are two pairs of the

contacts

43, 44, and these are arranged to be alternately closed by an engine-driven rotary commutator arm 50. This commutator arm 5%; is driven at half engine speed, and, assuming fuel injection is desired for 30 of crank angle, the arm 50 is made wide enough to close the

contacts

43 and 44 for 15 of rotation of said arm. Preferably, a third contact 51 is used, to be closed with contact 43 after the commutator arm has separated from contact 44 connected to plate voltage. The contacts 51 are grounded, and it will be seen that upon closure of contacts 43 and 51, the condenser 42 is discharged. If the contacts 51 are not used, high resistances 52 can be connected across the condensers to. discharge the condensers after

contacts

43 and 44 are opened;

The operation of the control system of Figure 2 is as follows: Commutator arm 50, upon

first closing contacts

43 and 44, closes the circuit from the plate power source to condenser 42. The charge on this condenser then builds up in a gradualmanner, depending upon the resistance and capacitance parameters of the circuit. The resistance 46-isemployedto assure a gradual build up under all circumstances, while the variable resistor 45 permits a degree of control of voltage build-up time.

The gradual buildup in plate voltage gradually increases the power. of the oscillator, thus gradually increasing the amplitude of vibration of the magnetostriction controlled injector valve, and therefore the rate of fuel injection. Such a magneto-striction device has a resonant frequency, depending upon the length of the legs 11' and 12, and this resonant frequency as determined by the magneto-striction device governs the frequency of oscillation of the vacuum tube oscillator. The frequency of operation of the valve is thus substantially fixed, but as plate power is built up by the gradual chargingrof condenser 42, the amplitude of vibration of the valve element is gradually increased, so that the rate of fuel injection (the quantity of fuel injected on each opening movement of the vibrating valve element) is gradually increased to a maximum.

The described gradual increase in the rate of fuel injection is provided to give time for combustion to be established before a large fuel charge has been permitted-to accumulate in the cylinder. This is especially to be' desired with diesel (auto-ignition) engines, as is known-in the'art;

Following 15 of rotationof the commutator arm 50, the plate energizing circuit is opened atcontact 44-, and contact 43 is thenimmediately closed with contact 50, which connects the positive terminal of condenser 42 to ground-and so discharges saidcondenser. The oscillator is thus abruptly damped, stopping the vibration of the valve, and so avoiding fuel dribble. This is a desirable feature, though not apparently essential in all cases, since a valve of the type described tends to shut off rather quickly when the power is turned off, the voltage across the condenser 42 beingfairly rapidly dissipated, particularly if a leaking resistor such as 52 is shorted thereacross.

Using two of the oscillators for a two cylinder engine, synchronized by. the single commutator arm 50, in the arrangement shown in Figure 2, it will be seen that fuel injection occurs in the two cylinders through 30 intervals, timed one-half commutator revolution apart, or, in other words, one crank shaft revolution apart. The systern-is useful'with either spark ignition or auto-ignition engines. For: spark ignition engines, the commutator can be incorporated in the spark timer-distributor, thus giving a dependable fixed relationship between spark and injection.

The power of the oscillations within the oscillators, and therefore at the rate of fuel injection, is under the control of the variable resistors 45. These, therefore, can be employed to throttle the engine. It will be seen that the variable resistors 45 can influence not only the voltage build-up time on the oscillator, but also the amplitude of the final voltage. Both effects give control over the throttling of the engine. The resistors 45 can obviously be operated independently, so as to control or adjust individual cylinders, or can be linked together for control of the engine as a whole.

It is also possible to throttle the engine by adjusting the fuel pressure. This can be accomplished by use of a variable rate pump, or a variable pressure by-pass relief valve of conventional design used with the pump.

It will be evident that the high frequency operation of the injector valves 14 results in fuel introduction in a series of extremely small increments; the spray stream can be described as pulsed, a large number of pulses or bursts of fuel being injected for each injection period. In other words, pulse frequency is very much higher than injection period frequency, so as to assure that each injected fuel charge will be broken into a very large number of individual bursts. Not only is atomization thus made more complete, but fuel accumulation is prevented, and diesel type combustion of unusually smooth characteristics can thus be accomplished. Apparently, the separated incremental spray clouds can be more smoothly and less explosively burned than when the fuel present is all contained within a single cloud body.

Figure 3 shows a modified embodiment, wherein the oscillator coils are outside of the magneto-striction device, but have coupled thereto a third coil which energizes a coil within the magneto-striction valve. In this instance, the two oscillator coils are indicated at 60 and 61, respectively, and it will be understood that these two coils correspond with the two coils of an engine controlled oscillator system such as shown in Figure 2. Coupled to oscillator coils 6t) and 61 is output coil 63, leading to a coil 64 of a magneto-striction controlled injector valve diagrammatically indicated at 65. The magneto-striction device in this case may be the same as that shown in Figure l, with the exception that it employs but a single energizing coil.

This application is a continuation-in-part of my prior application entitled Sonically Actuated Valve, filed February 27, 1951, Serial No. 212,984, now Patent No. 2,702,559.

It is obvious, of course, that my valve will have uses other than with engines, particularly wherever accurate timing and quantity are desired. Many chemical processes have need of precise valving.

It is to be understood that the drawings and description are for illustrative purposes only, since various changes in design, structure, and arrangement may be made without departing from the spirit and scope of the appended claims.

I claim:

1. An injector valve operable to inject fuel into an engine cylinder including, in combination, a nozzle member with a discharge orifice and a valve seat surrounding said orifice, a vibratory valve element movable onto and off of said seat so as to interrupt the flow of fuel through said valve, a magneto-striction member operatively connected to said valve element to move said valve element off of and onto its seat as said member alternately elongates and contracts, magnetic coil means surrounding said magneto-striction member, and means for energizing said coil means with an oscillating current of frequency which is high as compared with injection period frequency.

2. An injector valve operable to inject fuel into an engine cylinder including, in combination, a nozzle member with a discharge orifice and a valve seat surrounding said orifice, a vibratory valve element movable onto and off of said seat, a magneto-striction member mechanically operatively connected to said valve element to move said valve element off of and onto its seat as said member alternately elongates and contracts, and an oscillator capable of operating at a frequency which is high as compared with injection period frequency including coil means surrounding said magneto-striction member.

3. An injector valve operable to inject fuel into an engine cylinder including, in combination, a nozzle member with a discharge orifice and a valve seat surrounding said orifice, a vibratory valve element movable onto and off of said seat, a magneto-striction member mechanically operatively connected to said valve element to move said valve element off of and onto its seat as said member alternately elongates and contracts, a high frequency vacuum tube oscillator capable of operating at a frequency which is high as compared with injection period frequency including coil means surrounding said magneto-striction bar, and means for varying the power of said oscillator.

4. An injector valve including, in combination, a nozzle member with a discharge orifice and a valve seat surrounding said orifice, a valve element movable onto and off of said seat, a magneto-striction bar operatively connected to said valve element to move said valve element off of and onto its seat as it alternately elongates and contracts, a vacuum tube oscillator including coil means surrounding said magneto-striction bar, and means for effecting a gradual build-up of the plate voltage on the oscillator.

5. An injector valve including, in combination, a nozzle member with a discharge orifice and a valve seat surrounding said orifice, a valve element movable onto and off of said seat, a magneto-striction bar operatively connected to said valve element to move said valve element 011 of and onto its seat as it alternately elongates and contracts, a vacuum tube oscillator including coil means surrounding said magneto-striction bar, and means for effecting a gradual build-up of the plate voltage on the oscillator, and then abruptly dropping said voltage.

6. An injector valve including, in combination, a nozzle member with a discharge orifice and a valve seat surrounding said orifice, a vibratory valve element movable onto and off of said seat, a magneto-striction bar operatively connected to said valve element to move said valve element off of and onto its seat as it alternately elongates and contracts, magnetic coil means surrounding said magneto-striction bar, and a high frequency vacuum tube oscillator arranged to energize said coil means.

7. An injector valve including, in combination, a nozzle member with a discharge orifice and a valve seat surrounding said orifice, a valve element movable onto and off of said seat, a magneto-striction bar operatively connected to said valve element to move said valve element off of and onto its seat as it alternately elongates and contracts, magnetic coil means surrounding said magnetostriction bar, a vacuum tube oscillator arranged to energize said coil means, and means for effecting a gradual build-up of plate voltage on said oscillator.

8. An injector valve including, in combination, a nozzle member with a discharge orifice and a valve seat surrounding said orifice, a valve element movable onto and off of said seat, a magneto-striction bar operatively connected to said valve element to move said valve element off of and onto its seat as it alternately elongates and contracts, magnetic coil means surrounding said magneto-striction bar, a vacuum tube oscillator arranged to energize said coil means, means for effecting a gradual build-up of plate voltage on said oscillator, and means for effecting an abrupt drop of said plate voltage.

9. A fuel injector valve for an internal combustion engine, comprising the combination of: a nozzle member with a discharge orifice and a valve seat surrounding said orifice, a valve element movable onto and off of said seat, a ma gneto-striction bar operatively connected to said valve element to move said element onto and off of its seat as it alternately elongates and contracts, coil means for said bar, avacuum tube oscillator arranged to energize said coil means witha' high frequency current, and engine driven control means for causing said oscillator to energize said coil means during the injection interval of the engine:

10. A magneto-striction driven valve, comprising: a valve nozzle having an orifice and seat therearound, a valve closure element movable onto and off of said seat, an elastic rod connected at one end to said valve closure element, a magneto-striction' bar connected at one end tothe opposite'end of said elastic rod, and coil means surrounding said magneto-striction bar for subjecting the latter to' a magnetic field;

11. A- magneto-striction driven valve, comprising: a valve nozzle having an orifice and seat therearound, a valve closure element movable onto and off of said seat, spring means urging said valve closure element normally toward said seat, an elastic rod connected at one end to said valveclosure element, a magneto-striction bar connected atone end to the opposite end of said elastic rod, and coil means surrounding said magneto-striction bar for subjecting the latter to a magnetic field.

12. A magneto-striction driven valve, comprising. a' valve'nozzle having an orifice and seat therearound, a valve closure element movable onto and off of said seat, an elastic rod connected at one end to said valve closure element, amagneto-striction bar connected at one end to the opposite end of said elastic rod and extending alongside said rod insubstantial parallelism therewith, and coilmeans surrounding said elastic rod and magnetostriction bar for subjectingthelatter to a magnetic field.

13. A magneto-striction driven valve, comprising: a

valve nozzle having anorifice and seat therearound, a

valve closure element movable onto and off of said seat,

springmeans urging said valve closure element normally toward said' seat, an elastic rod connected at one end to said valve closure element, a magneto-striction bar connected at one'end to the opposite end of said elastic rod and extending alongside said rod in substantial parallelism therewith; and coil means surrounding said elastic rod and magne'to-striction' bar for subjecting the latter to a magnetic field;

14. An injector valve including, in combination, a nozzle member with a discharge orifice and valve seat surrounding said orifice; a magneto-s'triction device comprising a magnetic coil means and a vibratory magnetostricti on armature means, and a valve element movable onto and off o'f' said'seat attached to and operable by said vibratory m'agneto-striction armature means.

15; A vibratory fuel injector comprising, a fuel nozzle operableto inject fuel into an engine cylinder, a vibratory valve'elernent coac'ting'with' said nozzle to open and close the same, and a'nelectrically powered high frequency vibrator capable'of' operating at a frequency which is high as compared with injection period frequency operatively connected to" said valve element for positively vibrating saidvalve'eleme'nt' when said'vibrator is energized, whereby to open and" close said fuel nozzle and deliver fuel therefrom in'successive bursts occurring at high frequency.

Refereuce's'Cited-in the file of this patent UNITED STATES PATENTS 1,966,446 Hayes July 17, 1934 2,244,874 Fielder June 10, 1941 2,317,166 Abrams Apr. 20, 1943 2,453,595- Rosenthal Nov. 9, 1948 2,577,853 Kurata- Dec. 11, 1951