US3673999A - Electrical apparatus for initiating combustion in free piston engines - Google Patents

Electrical apparatus for initiating combustion in free piston engines Download PDF

Info

Publication number
US3673999A
US3673999A US66215A US3673999DA US3673999A US 3673999 A US3673999 A US 3673999A US 66215 A US66215 A US 66215A US 3673999D A US3673999D A US 3673999DA US 3673999 A US3673999 A US 3673999A
Authority
US
United States
Prior art keywords
electrical
piston
voltage
power
combustion
Prior art date
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 - Lifetime
Application number
US66215A
Other languages
English (en)
Inventor
James G Lacy
John V Byrne
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.)
Tectonics Companies Inc
Original Assignee
Individual
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.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US3673999A publication Critical patent/US3673999A/en
Anticipated expiration legal-status Critical
Assigned to TECTONICS COMPANIES, INC., A CORP. OF MN reassignment TECTONICS COMPANIES, INC., A CORP. OF MN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: COMPRESSOR PARTNERS LTD., HILLIARD-LYONS PATENT MANAGEMENT, INC., A CORP. OF KY, HLPM NETHERLANDS BV, A DUTCH CORP.
Assigned to TECTONICS COMPANIES reassignment TECTONICS COMPANIES ASSIGNMENT OF ASSIGNORS INTEREST. SEE DOCUMENT FOR DETAILS Assignors: BRAUN, ANTON T.
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B71/00—Free-piston engines; Engines without rotary main shaft
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B71/00—Free-piston engines; Engines without rotary main shaft
    • F02B71/02—Starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P15/00—Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 and combined with layout of ignition circuits
    • F02P15/001—Ignition installations adapted to specific engine types
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P15/00—Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 and combined with layout of ignition circuits
    • F02P15/001—Ignition installations adapted to specific engine types
    • F02P15/005—Layout of ignition circuits for rotary- or oscillating piston engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P3/00—Other installations
    • F02P3/06—Other installations having capacitive energy storage
    • F02P3/08—Layout of circuits
    • F02P3/0876—Layout of circuits the storage capacitor being charged by means of an energy converter (DC-DC converter) or of an intermediate storage inductance
    • F02P3/0884—Closing the discharge circuit of the storage capacitor with semiconductor devices

Definitions

  • This electrical signal from the velocity probe is applied to a Schmitt trigger through a suitable electrical connection such as a voltage divider network or preferably a resistor-capacitor and diode network, and the Schmitt trigger provides an electrical timing signal to conventional means for initiating successive combustion power strokes within the engine.
  • a suitable electrical connection such as a voltage divider network or preferably a resistor-capacitor and diode network
  • the Schmitt trigger provides an electrical timing signal to conventional means for initiating successive combustion power strokes within the engine.
  • combustion is initiated for each power stroke at a point in time related to the velocity of the power piston, and thus to the time at which the power piston reverses direction, without the necessity of regard to the physical position, i.e., linear location, of the power piston along its path of movement within the power cylinder.
  • the Schmitt trigger is set in one condition when the piston velocity increases to a predetermined level as the piston accelerates during the first part of its movement toward a firing position Then, as the piston slows down while approaching its reversal for the start of the power stroke, the decrease in piston velocity to a predetermined level sets the Schmitt trigger in another condition to cause a spark igniting another combustion initiating action. Additional electrical circuitry is included which may be used to aid in starting free piston engines.
  • This combustion causing apparatus has the advantage that, in the event of a misfire, the engine will only lose power for a few strokes and then regain full power. The engine will regain full power in a few strokes, even if there is insufficient energy, immediately after the misfire, to fully return the power piston to its desired normal operating inner dead point or top-deadcenter position in the power cylinder, because: immediately before the power piston stops and begins to reverse direction, whatever its linear position in the power cylinder may be, combustion will be initiated; this combustion of gases, although less efficient as compared to the correct operating point of the engine, will supply sufficient energy to the power piston to return it to a point closer to a desired inner dead point than achieved during the last stroke; and in a succession of these inefficient power strokes the desired inner dead point of the power piston will again be attained.
  • a misfire will not cause the engine to stop and necessitate a restarting.
  • a preferred embodiment of apparatus includes means for sensing the instantaneous velocity of a power piston within the free piston engine.
  • the velocity sensing means includes a magnetic sensing coil attached to the housing of the free piston engine and a magnet connected to move with the power piston.
  • the voltage output of the magnetic sensing coil is proportional to the velocity of the power piston and thus an electrical signal output from the sensing means is proportional to the power piston velocity.
  • the electrical signal output from the sensing means is applied to a Schmitt trigger circuit through a voltage divider network or a resistor-capacitor and diode network, and the Schmitt trigger circuit provides the properly timed signal to initiate combustion.
  • the voltage signal output from the sensing means first exceeds the preset threshold of the Schmitt trigger circuit and that circuit provides a first signal output which prepares the remaining circuitry for an ignition initiating signal.
  • that circuit provides a second signal output which is used to trigger a silicon controlled rectifier of a conventional capacitive discharge ignition arrangement and initiate combustion.
  • FIG. 1 shows a diagrammatic view of a free piston engine and the electrical combustion initiating apparatus of the present invention with a velocity probe operated by the free piston engine providing the electrical signal used to initiate combustion;
  • FIG. la shows an enlarged view of the velocity probe of FIG. 1;
  • FIGS. 3 through 6 show electrical waveforms at various points in the electrical circuit of FIG. 2;
  • FIG. 7 shows a schematic representation of an additional electrical circuit which may be used in conjunction with the electrical circuitry of FIG. 2 to aid in starting a free piston engine;
  • FIG. 8 shows a diagrammatic representation of a switch shown schematically within FIG. 7;
  • FIGS. 9 through 12 show waveforms at various points in the electrical circuit of FIG. 2 when used in conjunction with the electrical circuit of FIG. 7;
  • FIG. 13 shows a schematic representation of additional electrical circuitry which may be used in conjunction with the electrical circuitry of FIGS. 2 and 7 to further aid in starting a free piston engine;
  • FIG. 14 is a circuit diagram similar to the signal generating and input portion of FIG. 2, but utilizing a preferred resistorcapacitor and diode network with the velocity-responsive transducer to provide an input signal for the Schmitt trigger circuit;
  • FIG. I5 is a graph showing the relationship of the desired ignition time to the velocity of the power piston and the mean value of the voltage across the condenser of FIG. 14, during operation of the engine;
  • FIG. 16 is a graph showing how the voltage across such condenser varies as the engine starts up from rest.
  • a free piston engine generally designated as 13 is shown having a power piston 14 and compressor piston 19 inter-connected by shaft 21 to form a commonly moveable power means.
  • Power piston 14 is reciprocally moveable within a power cylinder 23 formed within a housing 25 of free piston engine 13 to alternately expand and compress gases within a combustion chamber 27 defined within power cylinder 23.
  • a permanent magnet generally designated is connected to shaft 21 to move with power piston 14.
  • a magnet member generally designated as is fixed with respect to the housing of free piston engine 13 in the embodiment shown.
  • Magnetic member 20 is formed of a coil of highly conductive wire wound on magnetic material having a relatively high permeability and a relatively low hysteresis and provides an electrical signal output across terminals and 32 from that coil.
  • Magnet 15 and member 20 together form a movement-related parameter sensing means used with the electronic circuitry of the present invention and yield a signal related to the instantaneous velocity of a power piston of a free piston engine, as will be explained hereinafter.
  • the movement-related parameter which is sensed for generating a signal for the circuitry of the present invention may also be the acceleration of a free piston or the velocity or acceleration of some other moving mass within the engine, a pressure created by a free piston within the engine, a fluid flow produced by the movement of a piston within the engine, the voltage output of a generator run by the free piston engine, or another parameter which is related to the movement of a free piston or other mass within the engine.
  • a movement related parameter is defined to be a parameter which gives an indication of the movement of a free piston or other mass within the engine moving with the free piston, as distinguished from the specific linear position of the piston or other mass.
  • a movement-related parameter is to be contrasted with a displacement parameter which directly indicates the position or linear displacement of a free piston along its path of movement. Examples of such displacement parameters are the displacements or positions of parts mechanically linked to a moving piston within a free piston engine and the specific displacement or instantaneous position of a cam follower riding on a cam surface fixed to a moving piston within the free piston engine.
  • a variable resistor 34 is connected between terminal 30 and ajunction point 36.
  • a resistor 38 is connected between junction point 36 and terminal 32, which also functions as the circuit common or ground.
  • Variable resistor 34 and resistor 38 form the two parts of a conventional voltage divider network with the voltage output from the voltage divider appearing at junction point 36 which is directly connected to a further junction point 37.
  • a first diode 40 has its anode connected to junction point 37 and its cathode connected to a power input terminal 42 which is arranged to connect to a source of positive voltage.
  • a second diode 44 has its cathode connected to junction point 37 andits anode connected to the circuit common which includes terminal 32.
  • a collector 76 of transistor 72 is connected to power input means 42 through a collector resistor 78, and a base 80 of transistor 72 is connected to collector 52 of transistor 50 through a resistor 82.
  • a diode 84 has its anode connected to the collector 76 of transistor 72 and its cathode connected to the base 86 of a transistor generally designated 88.
  • Transistor 88 has an emitter 90 connected to the circuit common and a collector 92 connected to power input means 42 through a collector resistor 94.
  • a capacitor 96 interconnects the collector 92 of transistor 88 and a junction point 98.
  • a diode 100 has its cathode connected tojunction point 98 and its anode connected to the circuit common to prevent the voltage atjunction point 98 from decreasing below the voltage of the circuit common.
  • a pair of input terminals 102 and 104 are also shown in FIG. 2. Terminals 102 and 104 are arranged to connect a conventional 12 to 400 volt DC to DC converter 106 to a source of power, not shown, such as 12 volt battery.
  • Converter 106 includes a positive output terminal 108 and a negative output terminal 110.
  • a silicon controlled rectifier or thyristor 112 has an anode connected to output terminal 108 and a cathode connected to output terminal 110. The gate or trigger of the silicon controlled rectifier 112 is connected to junction point 98.
  • a capacitor 114 has one end connected to output terminal 108 and a second end connected to one end 116 of the primary 118 of a conventional pulse-high frequency ingition transformer generally designated 120 of the type used with capacitor discharge ignitions.
  • the magnet 15 is attached to move with the power piston of the free piston engine, and thus magnet continually reciprocates with the ower piston.
  • Member is attached to the housing of the free piston engine adjacent the reciprocating magnet 15 such that the arms 22, 24 of member 20 are aligned with poles 16, 17 of magnet 15, respectively, as the magnet 15 reciprocates under the member 20.
  • a magnetic circuit is thus completed from pole 17, through arm 24, through portion 26, through arm 22, and to pole 16 as the arms 22, 24 overlay the poles 16, 17.
  • the exact spacing of member 20 and magnet 15 depends upon the voltage output desired from coil however, a greater spacing allows for variation in magnetic pole strength of magnet 15 from unit to unit without significantly affecting output.
  • the flux traversing member 20 passes through coil 28 so as to conventionally induce a voltage across terminals and 32 attached to the wire ends of coil 28.
  • the rate of change of flux linking coil 28 is arranged to be proportional to the rate of change of overlay between the poles l6.and l7 and the arms 22 and 24, the voltage induced in coil 28 is directly proportional to the velocity of magnet 15 with respect to coil 28.
  • This voltage induced in coil 28 is represented in ,FIG. 3. Before the arms 22, 24 overlay the poles 16, 17, no voltage is induced in coil 28.
  • the induced voltage represented in FIG. 3 is applied to the electrical circuitry of FIG. 2.
  • the voltage is first reduced by the effect of voltage divider resistors 34 and 38 such that a fixed proportion of the voltage represented in FIG. 3 appears at junction points 36 and 37.
  • the exact proportion of the voltage applied to the voltage divider network through terminals 30 and 32 that will appear at junction point 16 depends on the relative magnitudes of the resistors 34 and 38. In fact, by varying resistor 34, the precise timing of the initiation of ignition may be somewhat controlled, as will be hereinafter explained.
  • the voltage between the collector 52 and the emitter 56 of transistor 50 begins to decrease rapidly towards a collectoremitter saturation voltage of approximately 0.8 volts for a silicon transistor.
  • Transistor 72 of Schmitt trigger 83 is normally conducting; however, when transistor 50 begins conducting, the base current for transistor 72 is shunted through transistor 50 and to the circuit common. Since the base bias for transistor 72 is shunted through transistor 50, transistor 72 conducts less current. Since transistor 72 conducts less current, the current through emitter resistor 58 decreases and the voltage across resistor 58 decreases. A decrease in voltage across resistor 58 lowers the voltage at emitter 56 of transistor 50 and thus increases the voltage across the base-emitter of transistor 50 which causes transistor 50 to become more conducting. The circuit then regenerates in the conventional fashion of a Schmitt trigger until transistor 50 is fully conducting.
  • transistor 50 When transistor 50 is fully conducting, the collector-emitter saturation voltage of transistor 50 is approximately equal to the necessary base-emitter voltage of transistor 72; thus there is insufficient voltage remaining across base resistor 82 to provide base current to transistor 72, and transistor 72 is rendered non-conducting.
  • Transistor 88 is normally non-conducting since any base current which may be supplied to transistor 88 through resistor 78 is shunted through the normally conducting transistor 72. However, when transistor 72 is rendered nonconducting at T1 and the voltage at collector 76 of transistor 72 begins to rise towards the voltage appearing at power input terminal 42, transistor 88 is rendered conducting and the voltage at collector 92 of transistor 88 drops from the voltage at power input terminal 42 to approximately the voltage at the circuit common. At T-2 when transistor 72 is again rendered conducting, transistor 88 is rendered non-conducting, and the voltage at collector 92 again rises towards the voltage at power input 42. Thus, transistor 88 has the effect of inverting the voltage pulse appearing at collector 76 of transistor 72, as shown in FIG. 5.
  • capacitor 96 is in series with resistor 94 and the internal gate-to-common impedance of silicon controlled rectifier 112, capacitor 96 is charged to approximately the voltage at power input terminal 42.
  • the voltage across it cannot change instantaneously, as is well-known in the electrical arts, and the voltage at junction point 98 attempts to decrease below the voltage of the circuit common. See FIG. 6.
  • diode 100 prevents junction point 98 from decreasing in voltage below the voltage value of the circuit common, at T-l capacitor 96 rapidly discharges through the now conducting transistor 88 and the forward impedance of diode 100.
  • the capacitor is arranged to be fully discharged.
  • capacitor 96 cannot instantaneously change voltage and the positive going step is applied to junction point 98, as shown in FIG. 6.
  • This positive going step renders diode 100 non-conducting because of its polarity and provides the trigger current necessary to render silicon controlled rectifier 112 conducting.
  • capacitor 114 and the primary 118 of ignition transformer 120 are connected in series with each other, and there is a rapid oscillatory build-up of current in ignition transformer 120, as in conventional ignition circuits. This rapid increase in current is then applied to the spark plug of the free piston engine by secondary 124 of ignition transformer 120 in a conventional manner.
  • variable resistor 34 of the voltage divider network comprising resistor 34 and resistor 38 varies the exact timing of the initiation of combustion by varying the point at which transistor 50 changes back from a conducting state to its normally non-conducting state. More particularly, if resistor 34 is decreased in value, a larger proportion of the voltage applied across terminals 30 and 32 will appear across resistor 38 and hence be applied to the input of Schmitt trigger 83. This larger proportion of voltage will delay the point in time at which the voltage applied to the base 48 of transistor 50 will again decrease sufficiently to cause transistor 50 to become non-conducting by the regeneration of Schmitt trigger 83. Thus, decreasing the value of variable resistor 34 will delay the initiation of combustion.
  • variable resistor 34 Conversely, increasing the value of resistor 34 will cause a decreased proportion of the voltage applied terminals 30 and 32 to appear across resistor 38, and this decreased voltage will cause transistor 50 to return to its normally nonconducting state at an earlier point in time.
  • decreasing the value of variable resistor 34 has the effect of initiating combustion at an earlier point in time.
  • the timing can be varied so that combustion is triggered at a desired time interval before the point of reversal or time of zero velocity of the power piston. This triggering point occurs when the electrical signal, which is proportional to the velocity of the power piston in this embodiment, has decreased by a predetermined percentage below its peak value (T-l in FIG. 3), for example to the value shown at T-2 in FIG. 3.
  • the output voltage provided by coil 28 is very likely to be insufficient to operate Schmitt trigger 83 even if applied directly to base 48 of transistor 50.
  • the power piston is continually increasing in maximum speed towards the maximum speed which exists during the normal running condition.
  • the output provided from coil 28 is also reduced in maximum amplitude. It has been found that the peak value of voltage during these initial strokes, as divided by resistor 34 and resistor 38, is very likely to be less than the voltage required to operate Schmitt trigger 83 when applied through the voltage divider network, and thus Schmitt trigger 83 may not operate during these first few strokes.
  • FIG. 7 To overcome the problem of the near zero first stroke output of coil 28, the circuitry of FIG. 7 may be used.
  • a resistor of a large value is shown connected between power input terminal 42 and ajunction point 132.
  • a capacitor 134 is connected between junction point 132 and the circuit common. The combination of resistor 130 and capacitor 134 are chosen to provide an extremely long time constant, on the order of one-tenth to 1 second.
  • a switch 136 is connected between junction point 132 and input terminal 70.
  • a base resistor 66 is connected between input terminal 70 and a base 68 of a transistor 60. Transistor 60 is connected in electrical parallel with transistor 50 of FIG.
  • a resistor 139 also has one end connected to input 70 and has its other end connected to the circuit common. Resistor 139 is chosen to be of a low value in comparison to resistor 130.
  • FIG. 8 The diagrammatic representation of FIG. 8 indicates the manner in which switch 136 is closed.
  • Switch 136 is in a form of a commonly available reed switch having a glass enclosure 140 and magnetically actuatable contacts 142 and 144.
  • a magnet 146 different from magnet 15 of FIG. 1, is also mounted to reciprocate with the power piston of the free piston engine sufficiently close to switch 136 to magnetically actuatable contacts 142 and 144 during a portion of the stroke of the power piston of the free piston engine.
  • a vane 145 composed of magnetic type material, is shown between magnet I46 and switch 136.
  • vane 145 may be pneumatically interposed between magnet 146 and switch 136 to prevent magnet 146 from closing the contacts 142, 144 of switch 136. Vane 145 is not necessary, however, since the value of resistor 139 is chosen to be small by comparison to the value of resistor 130 and since the time constant of resistor 130 and capacitor 134 are chosen to be in excess of 0.1 second while the normal stroke time of the free piston engine is in the order of 0.001 second. There is thus insufficient time during a stroke for voltage to build up across capacitor 134 and capacitor 134 is discharged each cycle through resistor 139. Thus after the initial stroke of the engine, transistor 60 is not rendered conducting. Vane 145 may be useful, however, in prolonging the life of switch 136.
  • FIG. 13 illustrates additional electrical circuitry which may be used with the circuitry of FIGS. 7 and 8 to further aid in starting the free piston engine to overcome the problem of the reduced amplitude signals from coil 28 during the first few cycles of operation.
  • a pair of control input terminals 150 and 152 are shown.
  • a resistor 154 is connected between control input terminal 150 and junction point 156.
  • a capacitor 158 is connected between junction point 156 and input terminal 152 which is in turn connected to the circuit common.
  • Junction point 156 is further connected to a base 160 of a transistor 162.
  • a collector 164 of transistor 162 is connected to a junction point 36 of FIG. 2 through a resistor 166.
  • Terminals 150 and 152 are arranged to be connected to an electrical voltage generated by the engine such that the electrical voltage is present in full amplitude only after the engine has reached proper operating speed.
  • transistor 162 is non-conducting during starting and resistor 38 alone forms one leg or part of the voltage divider network consisting of resistor 34 and resistor 38 in FIG. 2.
  • a first voltage division ratio is thus provided. After the first few cycles of operation are complete and the voltage provided by coil 28 has reached its proper amplitude, a lesser voltage division ratio may be used. At this point, the electrical voltage generated by the engine has also reached a proper level to render transistor 162 conducting.
  • resistor l66 is placed in electrical parallel with resistor 38 and the value of the resistance of that leg of the voltage divider network is reduced to thus provide the desired lesser voltage division ratio.
  • the voltage division ratio may be decreased for normal operation of the engine.
  • the switching function of transistor 162 may as well be accomplished by a mechanical switch.
  • a mechanical switch may be caused to operate from a damped butterfly valve positioned in the exhaust of the free piston engine such that when exhaust indicates the engine is operational, the butterfly valve is caused to open by the passage of the exhaust gases, and the switching function of transistor 162 would be mechanically accomplished.
  • FIGS. 14 through 16 show details of construction and operation of a preferred resistor-capacitor (RC) and diode network for replacing the voltage divider network illustrated at the left portion of FIG. 2 and described above.
  • the coil 28 in which electrical signals proportional to instantaneous velocity of the power piston are generated, is connected at one end 32 to the ground or common circuit through parallel paths, one of which includes a condenser 170, and the other of which includes a fixed resistor 171 in series with a variable resistor 172.
  • the other terminal 30 of the velocity sensing coil 28 is connected through a diode 173 to the input 37 of the Schmitt trigger circuit, which is shown in dotted outline at 83.
  • diodes 40 and 44 are connected between the positive voltage input source 42 and the junction 37 at the input to the Schmitt trigger circuit, and between the junction 37 and the ground or common circuit, respectively.
  • Diodes 40 and 44 provide essentially the same functions previously described in connection with FIG. 2.
  • the diode 44 prevents the application to input terminal 37 of undesired transient signals which might otherwise be generated in the RC part of the network.
  • FIG. illustrates the relationships of piston velocity and voltage at various points.
  • curve 174 illustrates the instantaneous velocity of the piston starting at point A corresponding to the outer reversal or dead point at which the piston velocity is zero just as the piston reverses to start its compression stroke.
  • the piston velocity then reaches a maximum at point B relatively rapidly during normal operation, as return energy is supplied to the piston in known manner.
  • the piston velocity decreases from its peak value at B and ultimately reaches zero at point C on the graph, corresponding to the inner reversal point at the end of the compression stroke and the beginning ofthe power stroke.
  • the piston velocity then increases rapidly in the other direction during the power stroke, reaching a maximum at point D and then again reaching zero at the outer reversal or dead point of the piston, shown at E on the graph.
  • the mean value of the voltage on condenser has an absolute value illustrated by line 176 in FIG. 15 and by its distance 178 from the horizontal axis of the graph.
  • the actual voltage signal across coil 28 will have a value which varies in essentially the same fashion as curve 174, since it is proportional at all times to the instantaneous piston velocity.
  • the Schmitt trigger circuit will be set in one condition as previously described.
  • FIG. 16 shows how the mean value of the voltage (shown at 184) across condenser 170 gradually increases in a negative biasing direction as the engine 'starts from rest (at the left of the graph) and reaches normal operation (at the right of the graph).
  • the actual instantaneous voltage across condenser 170 will vary as shown by curve 186, depending on the time constant of the R-C circuit.
  • the mean value of the voltage across con denser 170 is zero.
  • the firing point shown at F in FIG. 15 will accordingly be later, in relation to the reversal point of the piston, i.e. farther from the peak velocity point B of the piston and closer to reversal point C than the normal firing point desired during operation.
  • the mean value of the voltage on condenser 170 will increase in a negative sense as shown in FIG. 16.
  • the spark is progressively advanced.
  • the spark should occur in some cases when the piston velocity has dropped only about l0 percent from the peak velocity which is developed (see point B in FIG. 15) during its compression stroke, i.e. substantially ahead of the point at which the piston velocity drops to zero at the time of reversal of the piston movement as the piston starts its power stroke (see point C in FIG. 15).
  • To obtain such an early signal from the circuit of FIG. 2 would require a relatively high division ratio in the voltage divider network of that circuit and could provide an undesirably low voltage input to the Schmitt trigger circuit. Thus the voltage might be too low to cause a spark.
  • the velocity signal amplitude at coil 28 falls.
  • the time constant of the R-C part of the network in FIG. 14 so that it is equal to or shorter than the mechanical time constant of the engine, the negative bias of the Schmitt input signal resulting from the mean voltage level across condenser 170 will be immediately reduced or removed.
  • the reduced signal from coil 28 will be sufficient to insure that the signal applied from point 37 to the Schmitt trigger is still sufficient to produce a spark in an effective time relationship to the moment of reversal at the end of the next compression stroke after the misfire.
  • condenser 170 has a value of 12 microfareds, while resistor 171 has a value of 2,200 ohms in series with a potentiometer 172 having a maximum resistance of 10,000 ohms.
  • the operation of the Schmitt trigger circuit in connection with the input network of FIG. 14 is essentially similar to the operation of that circuit as previously described in FIG. 2.
  • any voltage level responsive trigger means with hysteresis is intended.
  • a differential amplifier may be used with threshold reference signal applied to one input and the voltage from junction point 37 of FIG. 2 applied to the other input.
  • the Schmitt trigger circuitry has an inherent advantage over a differential amplifier in that, as is well-known to those skilled in the electrical arts, a Schmitt trigger may be designed with hysteresis.
  • this noise pulse would again cause the output of the differential amplifier to change states. Since the noise pulse is usually of short duration, the output from the differential amplifier would immediately revert to its alternate state. Thus, a train of pulses could issue from differential amplifier due to noise on the incoming waveform where the hysteresis of a Schmitt trigger would eliminate this effect of the noise.
  • the present invention provides improved electrical means for controlling the time at which combustion is initiated during the power piston movement of a free piston engine, by developing an electrical signal having a desired reversal-time-related characteristic, i.e. a desired time relationship to the moment in time when the power piston reaches its reversal point at the end of a compression stroke, even though that reversal point may occur at different physical positions or linear displacements of the piston along its path of movement in the engine.
  • a movable piston assembly including a power piston which is freely reciprocable in said cylinder along a path of movement between desired normal inner and outer piston reversal points and in which a power stroke in one direction toward the outer reversal point immediately follows a compression stroke in the opposite direction toward the inner reversal point, and combustion-causing means for initiating combustion in the cylinder to move the power piston in one direction for each successive power stroke
  • electrical sensing means including two relatively movable electrical members operable upon relative movement thereof to produce an electrical sensing signal dependent in magnitude upon the speed of such relative movement, one of which electrical members is operatively connected to the piston, and which members are electrically coupled to each other in a relatively constant manner over a substantial portion, including the final portion, of the movement of the piston during a compression stroke so that an electrical sensing signal is produced by said sensing means determined by the instantaneous value of a movement-related power piston characteristic which has a predeterminable relationship to the moment when the power piston
  • the free piston engine apparatus of claim 1 having electrical network means connecting the sensing means to the input means of the electric control circuit means, the sensing means having a coil in which the electrical sensing signal is generated, said network means including an R-C section having a resistor and a capacitor connected in parallel with each other and in series with the sensing means coil and also including a diode, the input means of the electric control circuit means having two input terminals, and said network means having means connecting the R-C section, sensing means coil and diode in series with each other across said input terminals.
  • the sensing means includes first and second relatively movable parts, one of which is connected to move with the piston assembly
  • the electric control signal generating means comprising voltage level responsive trigger means for providing a first output control signal when the voltage level of the electrical sensing signal applied to the input means is below a threshold amplitude and providing a second output control signal when the voltage level of the electrical sensing signal applied to the input means is above the threshold amplitude
  • said electric control signal generating means providing said predetermined output signal at the output means in response to one of said output control signals from the trigger means
  • said means for causing combustion including control input means for initiating operation of the combustion causing means when said predetennined output signal is applied to the control input means, and the output means ofthe electric control circuit means being connected to the control input means of the combustion causing means.
  • the voltage level responsive trigger means comprises a Schmitt trigger having output means, the signal from the sensing means causing a pulse output from the Schmitt trigger output means.
  • the free piston engine apparatus of claim 4 having voltage dividing means connecting the sensing means to the input means of the electric control circuit means, the voltage dividing means comprising: first resistive means; second resistive means; means for connecting the sensing means, the first resistive means and the second resistive means in electrical series; voltage divider output means connected across the second resistive means; and means for connecting the voltage divider output means to the input means of the electric control circuit means and thereby to the Schmitt trigger.
  • the free piston engine apparatus of claim further including an inverting pulse amplifier having an input means and an output means; means for connecting the input means of the inverting amplifier to the output means of the Schmitt trigger; capacitive means for connecting the output means of the inverting amplifier to the electric control circuit output means and thereby to the control input of the combustion initiating means; and diode means having one end connected to the control input of the combustion initiating means and having the other end connected to provide a unidirectional electrical current path to a common point in the electrical circuitry.
  • the free piston engine apparatus ofclaim 5 also including means for aiding in the starting of the free piston engine, comprising in combination: controlled switch means; further resistive means; and connection means for connecting the further resistive means and controlled switch means in electrical series and for connecting the series connection of the further resistive means and the controlled switch means in electrical parallel with the second resistive means for lowering the voltage division ratio of the voltage dividing means when the switch means is closed; the controlled switch means being arranged to be closed upon the normal operation of the free piston engine.
  • the free piston engine apparatus of claim 3 having voltage dividing means connecting the sensing means to the input means of the electric control circuit means, the voltage dividing means comprising: first resistive means; second resistive means; means for connecting the sensing means, the first re sistive means and the second resistive means in electrical series; voltage divider output means connected across the second resistive means; and means for connecting the voltage divider output means to the input means ofthe electric control circuit means and thereby to the trigger means.
  • the free piston engine apparatus of claim 8, also including means for aiding in the starting of the free piston engine, comprising in combination: controlled switch means; further resistive means; and connection means for connecting the further resistive means and controlled switch means in electrical series and for connecting the series connection of the further resistive means and the controlled switch means in electrical parallel with the second resistive means for lowering the voltage division ratio of the voltage dividing means when the switch means is closed; the controlled switch means being arranged to be closed upon the normal operation of the free piston engine.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
  • Portable Nailing Machines And Staplers (AREA)
US66215A 1970-08-24 1970-08-24 Electrical apparatus for initiating combustion in free piston engines Expired - Lifetime US3673999A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US6621570A 1970-08-24 1970-08-24

Publications (1)

Publication Number Publication Date
US3673999A true US3673999A (en) 1972-07-04

Family

ID=22068038

Family Applications (1)

Application Number Title Priority Date Filing Date
US66215A Expired - Lifetime US3673999A (en) 1970-08-24 1970-08-24 Electrical apparatus for initiating combustion in free piston engines

Country Status (13)

Country Link
US (1) US3673999A (fr)
AU (1) AU461892B2 (fr)
BE (1) BE771550R (fr)
BR (1) BR7105493D0 (fr)
CA (1) CA930791A (fr)
CH (1) CH529922A (fr)
CS (1) CS164891B2 (fr)
ES (1) ES394470A2 (fr)
FR (1) FR2102376B2 (fr)
GB (1) GB1357957A (fr)
NL (1) NL7111552A (fr)
SE (1) SE384904B (fr)
ZA (1) ZA714718B (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3943897A (en) * 1974-10-02 1976-03-16 Frank Kenneth Luteran Ignition system for rotary piston engine
US5287827A (en) * 1991-09-17 1994-02-22 Tectonics Companies, Inc. Free piston engine control system
US5678522A (en) * 1996-07-12 1997-10-21 Han; William Free piston internal combustion engine
CN101782038B (zh) * 2009-12-07 2011-08-24 重庆邮电大学 摩托车点火器用脉冲分离电路
US20160032820A1 (en) * 2013-04-16 2016-02-04 Regents Of The University Of Minnesota Systems and methods for transient control of a free-piston engine
US20160134173A1 (en) * 2014-11-07 2016-05-12 David Deak, SR. Reciprocating magnet electrical generator
US20190089225A1 (en) * 2017-09-20 2019-03-21 Etagen, Inc. Dc-dc converter in a non-steady system
US11251007B2 (en) 2017-10-30 2022-02-15 Wepower Technologies Llc Magnetic momentum transfer generator
US11652432B2 (en) 2017-09-20 2023-05-16 Mainspring Energy, Inc. Auto-braking for an electromagnetic machine
USRE49840E1 (en) 2012-04-06 2024-02-13 Wepower Technologies Llc Electrical generator with rotational gaussian surface magnet and stationary coil
US11973391B2 (en) 2019-11-21 2024-04-30 Wepower Technologies Llc Tangentially actuated magnetic momentum transfer generator
US12062965B2 (en) 2019-07-20 2024-08-13 Wepower Technologies Llc Offset triggered cantilever actuated generator

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2219671B (en) * 1988-04-26 1993-01-13 Joseph Frank Kos Computer controlled optimized hybrid engine

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3316448A (en) * 1965-10-15 1967-04-25 Eltra Corp Contactless ignition system
US3331986A (en) * 1964-11-16 1967-07-18 Eltra Corp Contactless ignition system
US3375812A (en) * 1964-12-10 1968-04-02 Mitsubishi Electric Corp Ignition device for internal combustion engine
US3390668A (en) * 1966-04-13 1968-07-02 Motorola Inc Electronic ignition system
US3446197A (en) * 1965-10-22 1969-05-27 Battelle Development Corp Ignition system for free-piston engine
US3496921A (en) * 1968-08-01 1970-02-24 Ford Motor Co Capacitive storage ignition system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3331986A (en) * 1964-11-16 1967-07-18 Eltra Corp Contactless ignition system
US3375812A (en) * 1964-12-10 1968-04-02 Mitsubishi Electric Corp Ignition device for internal combustion engine
US3316448A (en) * 1965-10-15 1967-04-25 Eltra Corp Contactless ignition system
US3446197A (en) * 1965-10-22 1969-05-27 Battelle Development Corp Ignition system for free-piston engine
US3390668A (en) * 1966-04-13 1968-07-02 Motorola Inc Electronic ignition system
US3496921A (en) * 1968-08-01 1970-02-24 Ford Motor Co Capacitive storage ignition system

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3943897A (en) * 1974-10-02 1976-03-16 Frank Kenneth Luteran Ignition system for rotary piston engine
US5287827A (en) * 1991-09-17 1994-02-22 Tectonics Companies, Inc. Free piston engine control system
US5678522A (en) * 1996-07-12 1997-10-21 Han; William Free piston internal combustion engine
CN101782038B (zh) * 2009-12-07 2011-08-24 重庆邮电大学 摩托车点火器用脉冲分离电路
USRE49840E1 (en) 2012-04-06 2024-02-13 Wepower Technologies Llc Electrical generator with rotational gaussian surface magnet and stationary coil
US20160032820A1 (en) * 2013-04-16 2016-02-04 Regents Of The University Of Minnesota Systems and methods for transient control of a free-piston engine
US10202897B2 (en) * 2013-04-16 2019-02-12 Regents Of The University Of Minnesota Systems and methods for transient control of a free-piston engine
US20160134173A1 (en) * 2014-11-07 2016-05-12 David Deak, SR. Reciprocating magnet electrical generator
US9673683B2 (en) * 2014-11-07 2017-06-06 David Deak, SR. Reciprocating magnet electrical generator
US20190089225A1 (en) * 2017-09-20 2019-03-21 Etagen, Inc. Dc-dc converter in a non-steady system
US10916991B2 (en) 2017-09-20 2021-02-09 Mainspring Energy, Inc. DC-DC converter in a non-steady system
US11652432B2 (en) 2017-09-20 2023-05-16 Mainspring Energy, Inc. Auto-braking for an electromagnetic machine
US10554099B2 (en) * 2017-09-20 2020-02-04 Etagen, Inc. DC-DC converter in a non-steady system
US11251007B2 (en) 2017-10-30 2022-02-15 Wepower Technologies Llc Magnetic momentum transfer generator
US11915898B2 (en) 2017-10-30 2024-02-27 Wepower Technologies Llc Magnetic momentum transfer generator
US12062965B2 (en) 2019-07-20 2024-08-13 Wepower Technologies Llc Offset triggered cantilever actuated generator
US11973391B2 (en) 2019-11-21 2024-04-30 Wepower Technologies Llc Tangentially actuated magnetic momentum transfer generator

Also Published As

Publication number Publication date
FR2102376A2 (fr) 1972-04-07
CS164891B2 (en) 1975-11-28
CA930791A (en) 1973-07-24
AU3259371A (en) 1973-02-22
BR7105493D0 (pt) 1973-06-07
ZA714718B (en) 1973-02-28
CH529922A (de) 1972-10-31
DE2142208A1 (de) 1972-03-02
ES394470A2 (es) 1976-11-16
SE384904B (sv) 1976-05-24
AU461892B2 (en) 1975-06-12
NL7111552A (fr) 1972-02-28
GB1357957A (en) 1974-06-26
BE771550R (fr) 1971-12-31
DE2142208B2 (de) 1975-10-23
FR2102376B2 (fr) 1973-06-29

Similar Documents

Publication Publication Date Title
US3673999A (en) Electrical apparatus for initiating combustion in free piston engines
US3338221A (en) Electrical control device
US3272187A (en) Fuel injection systems for internal combustion engines
US3742918A (en) Electronically controlled fuel-supply system for compression-ignition engine
US3750631A (en) Fuel injection system controlled by the amount of air drawn in during the suction stroke
US3851635A (en) Electronically controlled fuel-supply system for compression-ignition engine
US3631843A (en) Fluid addition system for internal combustion engines
US3628510A (en) Fuel supply system for an internal combustion engine providing timed cranking enrichment
US3584929A (en) Spark duration for capacitor discharge ignition systems
US3051152A (en) Fuel control arrangement
US3665901A (en) System controlling the speedy energization of electromagnets, chiefly those controlling the opening of electromagnetic injectors in internal combustion engines
US3407795A (en) Ignition system for internal combustion engines
US3616784A (en) Fuel supply system for an internal combustion engine providing time and voltage compensated cranking enrichment
US3198282A (en) Internal combustion type seismic wave generator
US3855973A (en) Synchronizing means for sequential fuel injection
US3426740A (en) Distributor
US3669086A (en) Solid state ignition system
US3587552A (en) Automatic advance electronic ignition device for internal combustion engines
US3934570A (en) Ferroresonant capacitor discharge ignition system
US3620196A (en) Arrangement for applying fuel injection corrections as a function of speed, in internal combustion engines
US3842811A (en) Electric fuel injection control system for internal combustion engines
GB1567041A (en) Fuel injection system
EP0316539A2 (fr) Injecteur de carburant avec un système de contrôle électronique
US2982276A (en) Pulse generating system for electronic fuel injection control devices and the like
US3822678A (en) High speed fuel injection system

Legal Events

Date Code Title Description
PA Patent available for licence or sale
AS Assignment

Owner name: TECTONICS COMPANIES

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BRAUN, ANTON T.;REEL/FRAME:005443/0685

Effective date: 19900504

Owner name: TECTONICS COMPANIES, INC., A CORP. OF MN, MINNESOT

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:HILLIARD-LYONS PATENT MANAGEMENT, INC., A CORP. OF KY;HLPM NETHERLANDS BV, A DUTCH CORP.;COMPRESSOR PARTNERS LTD.;REEL/FRAME:005443/0701

Effective date: 19900509