Detonation responsive means for controlling internal-combustion engines

Sept. 17, 1946. p. j. costa 2,407,652

DETONATION RESPONSIVE MEANS FOR CONTROLLING

INTERNAL-COMBUSTION ENGINES

Original Filed June 6, 1942 2 Sheets-Sheet 1

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INVENTOR

PHILIP J. COSTA

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Sept. 17, 1946., p. j. costa

DETONATION RESPONSIVE MEANS FOR CONTROLLING

INTERNAL-COMBUSTION ENGINES

Original Filed June 6, 1942 2 Sheets-Sheet 2

2,407,652

FIG. 4

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INVENTOR

PHILIP J. COSTA

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Patented Sept. 17, 1946

2,407,652

UNITED STATES PATENT OFFICE

2,407,652

DETONATION RESPONSIVE MEANS FOR CONTROLLING INTERNAL-COMBUSTION ENGINES

Philip J. Costa, Franklin Square, N. Y., assignor to Sperry Gyroscope Company, Inc., Brooklyn, N. Y., a corporation of New York

Continuation of application Serial No. 446,070, June 6, 1942. This application February 28, 1944, Serial No. 524,170

Claims. (&lt; ? ¹

This invention relates to detonation responsive means for controlling an internal combustion engine. More particularly the invention is concerned with a' detonation responsive system which includes a device for transmitting cyclic 5 movements of variable duration to known instrumentalities for controlling the operation of an internal combustion engine. While the improved system is useful in the elimination of the occurrence of detonation in the cylinders of any it internal combustion engine, it is particularly adapted to be employed with aircraft engines in which the relatively thin cylinder walls are subject to severe damage or complete destruction under such conditions. This application is a con- ] ί tinuation of my copending application S. N. 446,070, filed June 6,1942.

The principal object of the present invention is to provide an automatically operative system by which the time interval between recurrences of 21 detonating or “knocking” engine conditions is effectively and controllably delayed.

One of the important features of the invention resides in the provision of a combined manual . and automatic system for controlling the ratio i of the fuel to air mixture being utilized by the internal combustion engine.

Another feature of the invention is provided in the combination of elements included in the system which cooperate to obtain the desired result ³and consist of an internal combustion engine, a means for controlling the working conditions of the engine such as the carburetor or ignition timing control device, a detonation pick-up transmitter or means for detecting detonation in 3 the cylinders of the engine and the means or device included in the system which is operable in response to the detonation detecting means.

Other objects, features and structural details of the invention will be apparent from the fol- ⁴lowing description when read in connection with the accompanying drawings, wherein;

Fig. 1 is a schematic view and wiring diagram in which the preferred form of the invention is ₄illustrated.

Fig. 2 is a detail view showing the system employed to control the engine by means of an ignition timing device.

Fig. 3 is a further detail view showing the sys- 5 tem employed to control the engine by means of an additional or auxiliary fuel supply valve.

Fig. 4 is an enlarged vertical section showing in detail· the internal construction of the rocker type of control unit included in the improved 5

01.123—119) detonation responsive system illustrated in Fig. 1, and

Fig. 5 is an elevation view of the control· unit illustrated in Fig. 4 showing the fixed type of control unit employed in Figs. 2 and 3.

With reference particularly to Fig. 1, the detonation responsive system is shown to include an internal combustion engine of the radial cylinder type employed in aircraft which is outlined schej matically and indicated at 10. The carburetor and the air intake tube for the same are designated at 11 and 12, respectively. These parts being of conventional construction are also shown schematically. The means for controlling 5 the working conditions of the engine may cooperate to regulate any portion of the engine operable to suppress detonation, typically as outlined in Van Dijck Patent 2,220,558. The regulator is herein illustrated, by way of example, as 9 the usual fuel mixture control on carburetor ί I having the usual throttle arm ί 3 which may control a throttle valve (not shown) of the butterfly type. This valve provides a means of controlling engine speed or power output by regulating the 5 air-flow to the cylinders. The throttle control determines the speed at which the crank shaft of the engine is revolved, and by a direct linkage (not shown) to the arm the same is posi. tioned manually in a desired manner by the pilot 0 of the craft. A fuel mixture valve (not shown) which controls the flow of fuel through the main metering system of the carburetor and into the air-flow of tube 12 is also directly controlled by the pilot by way of pivotal arm 14, connecting 5 links⁵15 and 15', and adjustable lever 16 located in the cockpit of the craft.

On most high-powered engines the mixture of fuel to air supplied the engine is regulated by limiting the amount of fuel vaporized in the air 0 intake tube 12. By a suitable detent and stop construction usually provided within the carburetor, the arm 14 may be positioned in any one of four operating positions, shown at the dial indications in the cockpit of the craft, with ref5 erence to the settable lever 16, as “full rich,” “auto-rich,” “auto-lean” and “idle cut-off/’ by manual manipulation of the pilot. Provisions of this nature may or may not be incorporated in the improved detonation responsive control 0 system. Such an arrangement, having proven satisfactory, is provided for in the instant case by a relatively fixed holding piece 17 having four notches in the under-surface of the same and a spring urged detent 18 that engages the notches.

Detent 18 is situated on a vertical arm 19 which'

2,407,652 extends from the casing of the control device or unit 28 which itself, in this instance, is mounted to rock about a fixed pivot point 21, Link 15 is pivotally connected to the end of the rod of a piston element contained within the unit 20, and hereinafter more particularly described. Also, link 15' is pivotally connected to the casing of the unit 20 so that the unit is included as an integral portion of the linkage system by which the valve positioning arm 14 is controlled. Arm 14 may be termed the gas to air mixture control in this embodiment of the invention.

With respect to the various positions in which the linkage system may be manually set by the pliot, it may be considered that when the craft takes off the throttle of the carburetor is fully open and the mixture control is set at “full rich” position until the craft is at a safe height above surrounding obstacles. If the craft is still climbing, the pilot can then set lever IS to the “autorich” position which moves arm 14 to open the valve slightly. The valve, in turn, permits less fuel to be vaporized in the,air tube 12, thus decreasing the richness of thefuel to. air mixture entering the cylinders-. Throttle arm 13 is moved independently of the lever IS and is adjusted as desired by the pilot. When the craft reaches a desired altitude and is traveling under normal straight flight conditions, the engine may be adjusted to obtain maximum economy of operation by setting the mixture lever to the “auto-lean” position. As the economy of operation of the prime mover is increased, the frequency c-f occurrence of detonation in the cylinders of the same also increases so that due to engine failures and the inability to determine a safe operating point above that providing most economical operation, the pilots have been warned by engine and carburetor manufacturers against the danger in using- the “auto-lean” position. With the present system, the mixture control lever can be safely set in the “auto-lean” position and an indicator observed to ascertain the frequency of occurrence of detonation in the engine. If such occurrences appear too frequently or are heavier in nature than desired, the position of the relative fixed holding piece 17 may be changed slightly by a suitable adjustment and the mixture arm reset to slightly enrich the ratio, of fuel to air being supplied the engine to maintain detonation below a predetermined maximum level of . severity. In this manner, the prime mover may be controlled to, obtain the greatest operating economy consistent with engine safety, When in the “idle, cut-off” position the mixture valve, by special internal design, actually closes again to richen up the. mixture, even though the lever is put into a different position.

Further, with reference to Fig. 1, each, of the cylinders of the internal combustion engine is provided with a means for detecting detonation, one of such detonation pick-up transmitters being indicated at 22. This transmitter which is illustrated schematically in the drawing may be of the type particularly described in U. S. Letters Patent No. 2,275,675, issued March 10, 1942, to C. S. Draper et al. The output of the transmitter may be fed to a suitable amplifier indicated schematically at 23 by way of leads 24. The amplifier is energized from a suitable source of electrical energy (not shown) and the output of the same may be employed to illuminate a neon tube indicator 25 situated in the cockpit of the craft, the circuit leads for this purpose being shown at 26, A separate circuit-closing relay 27 of con4 ventional construction may also be energized by the output of the amplifier 23 by way of leads 28. The automatic detonation control unit 20 is included in the circuit completed by the relay 27, in this instance, the circuit ’ being energized by a suitable source of energy such as battery 29. If desired, the control unit 20, hereinafter more particularly described could be actuated directly by the output of the schematically shown detonation pick-up transmitter 22 thereby obviating the use of the relay 27 and the independent circuit which the same closes upon occurrence of detonation in any of the cylinders of the prime mover. As shown in Fig. 1, the single flexible cable 30 includes separate leads for completing the circuit containing the relay 27, source 29 and control device or unit 20. It will be understood from the foregoing description that operation of the system is effected by the detonation pick-up transmitter 22 which transforms the high frequency vibrations in the cylinder in which detonation is occurring. into. electrical impulses. These impulses are amplified in the instant case by means, of amplifier 23 and the output of the amplifier is utilized to both effect illumination of the indicator 2 5, and close the relay 27 controlled circuit, which includes the, in this instance, pivotally mounted control unit 20. By suitably controlling the sensitivity of the amplifier 23, the pick-up transmitter may be rendered as. sensitive as desired. Both the control unit and indicator of the system are preferably rendered, operable upon that approach of detonating conditions in the cylinders of the engine known as incipient det-, onation, characterized by several occurrences per minute and not apparently harmful to engines, even for prolonged periods.

With particular reference to Figs. 4 and 5, the illustrated control unit or device. 20 is shown in the form of a cylinder element having a casing 31 and end walls 32 and 33. In Fig. 4, the cylinder element is divided into two fluid containing compartments 3.4. and 35 by a fixed central wall 36 and a solenoid or coil 37 having a side defining plate 3,8. The solenoid 37 is included in the relay controlled circuit whose cable 30 is fixed to the casing 3! by a suitable connection. A piston member for the cylinder element is indicated at 40., the same defining one wall of the compartment 35. This piston performs the function of an actuating member for the control unit to automatically position the instrumentalities employed in controlling the working conditions of operation of the internal combustion engine. In the rocker type, control unit in Fig, 4, such controlling movement, is imparted to lever 15 by way of the piston, rod 41 for piston 48. A spring 42 or other suitable means is effective to restore the piston actuating member to. a normal or initial position against, stops 43 situated on the face of fixed dividing wall 36. In the form of the control unit shown in Fig. 5, the casing 31 is suitably mounted in a fixed position on a bracket piece: 46.

In both of the types of control units 20 shown in the drawings, the solenoid 37 provides a part of the electromagnetic means employed for effecting unidirectional movement of the fluid to the piston member wall defining compartment. 35 to cause movement of the piston actuating member. It will be understood that this result occurs in response to energization of the solenoid when the relay controlled circuit is closed by the detection of detonation at the. pick-up. transmitter. A hollow electromagnetic core piece 48 of cylindrical form cooperates with the solenoid

2,407,652 and is mounted for axial movement within a cylindrical wall defining element 49 whose longitudinal axis is arranged in coaxial relation to the central axis of the solenoid. The core piece 48 has a valve-controlled passageway 50 therein, the valve being represented in the form of a ball 51 which is normally pressed against its seat by a spring 52 situated within the hollow core 48. The electromagnetic plunger or core ¢3 is positioned within the cylindrical wall defining element 49 by means of a spacing spring 53, which the plunger 48 compresses when it moves through influence of the energized solenoid, and an opposing spring 53'. The extent of axial movement permitted the core, is defined by a stop, as. indicated, at 54, situated at the end of a hub piece on the central wall 36.

• A valve-controlled passageway is included in the structural provisions shown in the drawing for connecting the interior of the fluid: containing chamber defined by the cylindrical wall 49 and the chamber 35. In this instance, this construction is provided by valve plate 55, valve ball 56 and the open ended, screw-threaded plug 57. A spring 58 normally holds the valve ball 56 against its seat in the valve plate 55. Compartments 35 and 34 are connected by a passageway 59 situated in the wall of the casing 31. An adjustable valve element 60 is located in a position in the casing 3 ί to restrict the flow of fluid passing from compartment 35 to compartment 34. In addition to passageway 59, a further passageway is provided in the wall of ’ the casing 31, as: indicated at 61, the same connecting the area 34' of the cylindrical casing to the rear of the piston member 40 to· compartment 34. There is no valve situated in passageway 6 i so in effect the connected compartments 34 and 34' form a single compartment. The end of the passageway 61 in the wall of the cylinder element 31 adjacent compartment 34' is of sufficient longitudinal dimensions, the same being formed of greater length than the thickness of the piston member 40, to provide an operative position limit for the movement of the piston member within the cylinder element. This position is indicated by the dotted line position of the piston member 40 in Fig. 4, in which the passageway 61 is shown as directly connecting both compartments 35 and 34. The entire cylinder element 31 is preferably filled with a fluid such as oil and a pressure responsive means such as bellows unit 62 is provided for the structure, the same compressing upon expansion of the fluid due to temperature changes and expanding upon shrinkage in the volume of fluid when the temperature condition affecting the device causes such to occur.

In operation, the energized solenoid 37 of this unit effects movement of the magnetic core 48 to the left, as viewed in Fig. 4, against the action of spring 53. A portion of the fluid within the chamber defined by the cylinder wall 49 and the interior Of the hollow core 48 is consequently forced past the valve ball 56 into the compartment 35. Valve ball 56 permits unidirectional movement of the fluid into the compartment 35 only, such movement resulting in displacement of the piston member 40 and consequent suppression of detonation, e. g. by movement of the mixture control arm of the carburetor. This, in turn, causes enrichment of the fuel mixture supplied the engine by the carburetor to automatically change the operating conditions of the engine so that detonation is overcome. The solenoid 37 is energized by the detonation pick-up transmitter 22 for each; of the cylinders of the engine and generally causes a number of pulsating movements of the core 48, each movement effecting, displacement of the piston member over 5 a predetermined‘minor portion of the full operating range of the piston. When the : solenoid is no longer energized, the return movement of the control device occurs under influence of the spring 42, the fluid being forced to return to the 10 compartment 34, under normal circumstances, by way of passageway 59 which contains the adjustable valve 60, operating as an escapement to delay the return movement. On each return movement of the core 48, fluid from the compart15 ment 34 is admitted to the chamber defined by the cylindrical wall member 49 and the interior of the hollow core 48 by way of the unidirectionally acting valve controlled by spring-loaded ball 5i. The adjustable valve 60 provides a means 20 for regulating the duration of the return movement affected by the control unit which functions as a cyclic actuating means having initiating and returning movements. In the combined manual and automatic control system illustrated 25 in Fig. 1, the automatic mixture control· unit functions when necessary upon : occurrence of detonation in the cylinders of the engine at either manual position 2 or 3, it being presumed that no detonation will occur at either of the: 3₀ other manual settings for the system. When operative, the device functions to enrich the fuel to air mixture supplied the engine until detonation ceases, after which it slowly restores the system to the original conditions of operation 35 at which the same was manually set by the pilot.

It is apparent that by setting valve 60, as desired, the duration of the restorative portion of the cyclic actuating means may be extended to approximately control cyclic recurrence of detona40 tion in the engine at such spaced intervals as to provide safe operation of the craft at the “auto-lean” mixture setting. Incipient detonation of the order of several occurrences per minute may be maintained steadily when the return 45 movement Of the piston requires somewhat over 10 seconds. Normal operation of the automatic control system thus is indicated by several flashes per minute on the signal device or indicator 25. Rapidly recurring flashes definitely : indicate 50 trouble in the automatic control, and warn the operator to shift the manual control lever i 6 as an emergency measure in a direction to suppress detonation, e. g. by enriching the fuel mixture. It will be apparent that while the manual control ₅₅ lever always is operable to enrich the fuel mixture and eliminate detonation, its effectiveness in the reverse direction is limited by the effect on engine operation, since the automatic control becomes operative when detonation conditions ₆₀ arise to preclude manually setting the engine regulator beyond a position corresponding to a maximum allowable detonation severity.

The fixed type of control unit, as shown in Figs. 2 and 5, is mounted on a bracket 46 situated in 65 fixed position with respect to the body of the engine. In the instance shown in Fig.. 2, the unit is employed to initially retard the timed occurrence of ignition in the operation of the internal combustion engine. In this fully automatic arγθ rangement, a pair of linked magnetos of conventional construction illustrated schematically at 63 are controlled from the unit 20 by the connecting link arm 64. The cyclic movement transmitting device or unit 20 operates in the manner 75 previously described in response to the means for

2,407,652 detecting detonation in the cylinders of the engine.

In Fig. 3, a further modification of the invention is shown in which a fixed type of control unit 20 is operative to control the mixture valve for the carburetor by which the ratio of preheated and cold air admitted thereto is regulated in a desired manner. In this instance, the carburetor includes a conventional air temperature controlling valve (not shown) which is automatically regulated by a unit 20 through means of the pivotally mounted arm 05 and link 66. This form of utilization of the control device is slower in response in overcoming detonation but is equally effective.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.