US3295014A - Transistor ignition system having ballast resistor shunt to maintain constant current through the ignition transformer - Google Patents

Transistor ignition system having ballast resistor shunt to maintain constant current through the ignition transformer Download PDF

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Publication number
US3295014A
US3295014A US334755A US33475563A US3295014A US 3295014 A US3295014 A US 3295014A US 334755 A US334755 A US 334755A US 33475563 A US33475563 A US 33475563A US 3295014 A US3295014 A US 3295014A
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United States
Prior art keywords
transistor
voltage
ballast resistor
primary winding
transformer
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
US334755A
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English (en)
Inventor
Michael S Fisher
Frederick S Kamp
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RCA Corp
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RCA Corp
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Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
Priority to US334755A priority Critical patent/US3295014A/en
Priority to GB50379/64A priority patent/GB1048219A/en
Priority to NL6415246A priority patent/NL6415246A/xx
Priority to ES0307688A priority patent/ES307688A1/es
Priority to BE657799A priority patent/BE657799A/xx
Priority to DE19641464020 priority patent/DE1464020B1/de
Application granted granted Critical
Publication of US3295014A publication Critical patent/US3295014A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • F02P3/02—Other installations having inductive energy storage, e.g. arrangements of induction coils
    • F02P3/04—Layout of circuits
    • F02P3/05—Layout of circuits for control of the magnitude of the current in the ignition coil
    • F02P3/051—Opening or closing the primary coil circuit with semiconductor devices

Definitions

  • Another object of the present invention is to provide an improved, transistorized ignition system wherein the time for current to reach a steady state in the ignition transformer is faster than in many prior art ignition systems.
  • Still another object of the present invention is to provide an improved, transistorized ignition system of the type described that is relatively simple in circuitry, easy to manufacture and operate, and yet highly eliicient in use.
  • the improved ignition system of the present invention comprises means for regulating the current to the primary winding of an ignition transformer over a relatively wide range of available voltages.
  • Current from a unidirectional source of voltage is caused to flow to the primary Winding of the ignition transformer through a ballast resistor and the emitter-collector path of a transistor.
  • the base of the transistor is biased so as to cause current to flow to the primary winding when a pair of breaker points in the emitter-base circuit of the transistor is closed.
  • Current regulation means are provided to shunt the ballast resistor automatically with a circuit having an impedance that varies with the voltage of the voltage source, thereby tending to maintain the current through the transistor substantially constant.
  • Improved transistor biasing means are also employed to interrupt current through the transistor faster than in prior art ignition systems and to prevent the transistor from conducting again until the proper time in the cycle.
  • FIG. 1 is a schematic diagram of a transistorized igni- Patented Dec. 27, 1966 tion system in accordance with the present invention.
  • FIG. 2 is a graph of operating current vs. battery voltage to explain the operation of the ignition system illustrated in FIG. 1.
  • a transistorized ignition system 10 of the type wherein the voltage from a unidirectional voltage source, such as a battery 12, supplies the energy for producing a spark across the gap 14 of a spark plug SP.
  • the transistorized ignition system 10 may be of the type used in an automobile wherein the voltage of the battery 12 may be rated at 12 volts, for example.
  • the negative terminal of the battery 12 may be connected to a common connection, such as ground, and the positive terminal of the battery 12 is connected to the emitter of a PNP transistor T1 through an ignition switch 16 and a ballast resistor 18.
  • the collector of the transistor T1 is connected to the common connection through the primary winding 20 of an ignition coil or transformer 22.
  • One end of the secondary Winding 24 of the ignition transformer 22 is connected to the common connection, and the other end is connected to the rotor 26 of a distributor 28.
  • a contact 30 of the distributor 28 is connected to one point 32 of the spark plug SP, another point 34 of the spark plug SP being connected to the common connection. While only one spark plug SP is shown and described herein for the sake of clarity, there is a different one for each contact of the distributor 28.
  • Means are provided to bias the transistor T1 into conduction when breaker points 36 and 38 are closed.
  • the point 38 is connected to the com-mon connection, and the point 35 is connected to the base of the transistor T1 through a resistor 40 and the primary winding 42 of transformer 44.
  • the base of the transistor T1 is connected to the emitter of the transistor T1 through the secondary winding 46 of the transformer 44 and a resistor 48.
  • the primary winding 20 of the transformer 22 is shunted by a capacitor 49.
  • the rotor 26 is mechanically coupled to a rotating cam 35, as indicated by the dashed line 37, to separate (open) the normally closed breaker points 36 and 38 to fire the spark plugs SP at the proper time in the cycle.
  • the ignition system It ⁇ thus far described operates satisfactorily as long as the voltage of the battery 12 is substantially constant.
  • the voltage of the battery 12 is lowered, as by the heavy load caused by starting an automobile engine or by excessively cold weather, sufficient current may not be supplied to the primary winding 20 to cause the spark plugs to be fired.
  • Regulatory means comprising the circuit included within the dashed polygon 50, are provided to maintain the current through the primary winding 20 of the ignition transformer 22 substantially constant over a relatively wide range of battery voltages.
  • a regulatory resistor 52 is connected in shunt, that is, in parallel, with the ballast resistor 13 through the emitter-collector path of a PNP transistor T2.
  • the base of the transistor T2 is connected to the common connection through a biasing resistor 54.
  • the transistor T2 is biased to conduct fully, that is, to saturate, when the battery voltage is at or below a predetermined voltage, say, for example, 8 volts. Under these conditions, the resistance of the current path to that circuit including the emitter-collector path of the transistor T1 and the primary winding 20 of the ignition transformer 22 is relatively low because current can flow through the path provided by the ballast resistor 18, and the path provided by the regulatory resistor 52 and the relatively low impedance of the fully conducting transistor T1, both paths being in parallel with each other.
  • a PNP transistor T3 has its emitter connected to the junction between the ballast resistor 18 and the regulatory resistor 52 and its collector connected to the base of the transistor T2.
  • the base of the switching transistor T3 is connected to the common junction 55 between two serially connected resistors 56 and 58 through a diode 60, the anode of the diode being connected to the base of the transistor T3.
  • the resistors 56 and 58 comprise a voltage divider that is connected in parallel with the ballast resistor 18.
  • the voltage at the base of the transistor T3 is sufiicient to bias the transistor T3 into conduction. This action increases the voltage across the resistor 54 and biases the transistor T2 with a positive-going voltage that increases its impedance. Thus, current through the transistor T2 decreases when the transistor T3 is switched on, and vice versa.
  • a predetermined voltage say 12 volts
  • the transistor T3 is biased fully on, and the transistor T2 is biased fully oil.
  • the impedance of the emitter-collector path of the transistor T2 varies from a minimum at saturation to a substantially infinite value at cut-ofi over a range of voltages across the ballast resistor 18.
  • the operation of the ignition system 10, including its current regulatory circuit 5-0, will now be explained.
  • the battery 12 is used to start an automobile engine (not shown) of which the ignition system is a part.
  • the voltage of the battery 12 due to its internal resistance, drops to, say, 8 volts.
  • the voltage across the resistor 56 is now insufiicient to bias the transistor T3 into conduction, and the transistor T2 conducts fully.
  • Current from the battery 12 now flows to the primary winding 20 of the ignition transformer 22 through the parallel paths provided by the ballast resistor 18 and the regulatory resistor 52, provided the breaker points 36 and 38 are closed, so that the transistor T1 is conductive.
  • the voltage across the ballast resistor 18, that is, the voltage across the voltage divider comprising the resistors 56 and 58 also, is great enough to bias the transistor T3 into conduction.
  • Current through the emitter-collector path of the transistor T3 increases the voltage across the resistor 54 and applies an increased positive-going bias to the base of the transistor T2, increasing the impedance of the transistor T2 and decreasing the current through the regulatory resistor 52.
  • the impedance of the transistor T2 increases so that the current available to the primary winding 20 remains substantially constant.
  • the current that remains substantially constant is the steady-state current, and not the current during the initial rise time of the current.
  • the transistor T3 may be turned fully on, biasing the transistor T2 fully ofi.
  • Current to the primary winding 20 of the ignition transformer 22 now flows only through the ballast resistor 18, the regulatory resistor 52 being disconnected from the circuit by the cut-off transistor T2.
  • the impedance of the emitter-collector path of the transistor T2 is substantially infinite.
  • the change in current through the primary winding 20, that is, through the transistor T1 for different battery voltages of the battery 12 is shown.
  • the current through the transistor T1 increases proportionally with the battery voltage until the latter is about substantially 8.5 volts.
  • current through the transistor T1 is supplied through the ballast resistor 18 and through the regulatory resistor 52, the transistor T2 being fully on, that is, saturated.
  • the current through the transistor T1 is substantially constant, that is, about 8 amps.
  • An example of an ignition system in accordance with the present invention may comprise components with the following values:
  • Transformer 44 a bifilar wound 1:1 transformer With an inductance of about 6 mh./winding.
  • the core is a hlgh frequency response audio material.
  • a transistor having an emitter, a collector and a base
  • an ignition transformer having a primary winding and a secondary winding, a ballast resistor, means connecting said ballast resistor, the emitter to collector path of said transistor and the primary winding of said ignition transformer in series between said output terminals,
  • variable conductivity shunting means connected across said ballast resistor, means to sense the voltage appearing across said ballast resistor, and means to so vary the conductivity of said shunting means in response to the voltage appearing across said ballast resistor as to keep the maximum current flow through said primary winding constant over a predetermined range of variation of said source.
  • variable shunting means comprises the emitter to collector path of a second transistor
  • said voltage sensing means comprises a voltage divider having an intermediate point and being connected across said ballast resistor, and
  • said means to vary the conductivity of said shunting means comprises a connection from said intermediate point to the base of said second transistor.
  • An ignition system comprising, in combination,
  • (k) means connecting said emitter-collector path of said second transistor across said ballast resistor
  • I (1) means connecting said emitter-collector path of said third transistor between said terminals
  • (0) means connecting said base of said second transistor to said emitter-collector path of said third transistor.
  • An ignition system for causing the firing of a spark plug in an internal combustion engine, said ignition system comprising (a) a source of voltage having a pair of output terminals,
  • (h) means connecting said ballast resistor, the emittercollector path of said first transistor, and the primary winding of said first transformer in series in a circuit between said pair of output terminals,
  • (j) means connecting said secondary winding of said second transformer between said emitter and said base of said first transistor
  • (in) means to sense the voltage across said ballast resistor and to feed back signals to said base of said second transistor to vary its impedance in accordance with changes in the voltage across said ballast resistor.
  • an ignition system adapted to be energized from a battery having a pair of output terminals, one of said terminals being connected to a common connection, said ignition system comprising (a) first, second, and third transistors each having an emitter, a collector and a base,
  • (k) means connecting said base of said first transistor through the primary winding of said second transformer and through said breaker points in series to said common connection when said points are touch- (1) means for connecting the secondary winding of said second transformer between the base and emitter of said first transistor,
  • (n) means connecting the emitter-collector path of said third transistor between the other of said output terminals and said base of said second transistor
  • (q) means connecting said base of said third transistor to the voltage divider to bias said third transistor into conduction when the voltage across said ballast resistor is greater than a first predetermined value, said second transistor being biased to cut off when the voltage across said ballast resistor is greater than a second predetermined value.

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  • 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)
US334755A 1963-12-31 1963-12-31 Transistor ignition system having ballast resistor shunt to maintain constant current through the ignition transformer Expired - Lifetime US3295014A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US334755A US3295014A (en) 1963-12-31 1963-12-31 Transistor ignition system having ballast resistor shunt to maintain constant current through the ignition transformer
GB50379/64A GB1048219A (en) 1963-12-31 1964-12-10 Ignition system
NL6415246A NL6415246A (enrdf_load_stackoverflow) 1963-12-31 1964-12-30
ES0307688A ES307688A1 (es) 1963-12-31 1964-12-30 Una disposicion reguladora de corriente para un sistema de ignicion para automoviles.
BE657799A BE657799A (enrdf_load_stackoverflow) 1963-12-31 1964-12-30
DE19641464020 DE1464020B1 (de) 1963-12-31 1964-12-31 Stromregulierungsanordnung einer Zuendschaltung fuer Brennkraftmaschinen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US334755A US3295014A (en) 1963-12-31 1963-12-31 Transistor ignition system having ballast resistor shunt to maintain constant current through the ignition transformer

Publications (1)

Publication Number Publication Date
US3295014A true US3295014A (en) 1966-12-27

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US334755A Expired - Lifetime US3295014A (en) 1963-12-31 1963-12-31 Transistor ignition system having ballast resistor shunt to maintain constant current through the ignition transformer

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US (1) US3295014A (enrdf_load_stackoverflow)
BE (1) BE657799A (enrdf_load_stackoverflow)
DE (1) DE1464020B1 (enrdf_load_stackoverflow)
ES (1) ES307688A1 (enrdf_load_stackoverflow)
GB (1) GB1048219A (enrdf_load_stackoverflow)
NL (1) NL6415246A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2093793A5 (enrdf_load_stackoverflow) * 1970-05-28 1972-01-28 Motorola Inc
US4029991A (en) * 1976-04-14 1977-06-14 General Motors Corporation Instrument panel illumination dimming control
US4036199A (en) * 1975-03-18 1977-07-19 Ducellier & Cie Device for protecting an ignition device for motor vehicles
US4327310A (en) * 1979-02-20 1982-04-27 Joerg Manfred Spark circuit

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2984766A (en) * 1959-12-30 1961-05-16 Ford Motor Co Ignition system
US3019782A (en) * 1958-07-01 1962-02-06 Motorola Inc Ignition system
US3136939A (en) * 1960-02-09 1964-06-09 Holley Carburetor Co Transistorized voltage regulator
US3150285A (en) * 1962-01-31 1964-09-22 Ford Motor Co Transistorized ignition system with a bistable electromagnetic switch
US3152296A (en) * 1959-11-30 1964-10-06 Bell Telephone Labor Inc Regulated power conversion system
US3174094A (en) * 1962-02-01 1965-03-16 Hughes Aircraft Co High efficiency power supply utilizing a negative resistance device
US3219876A (en) * 1961-09-21 1965-11-23 Gen Motors Corp Ignition system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3019782A (en) * 1958-07-01 1962-02-06 Motorola Inc Ignition system
US3152296A (en) * 1959-11-30 1964-10-06 Bell Telephone Labor Inc Regulated power conversion system
US2984766A (en) * 1959-12-30 1961-05-16 Ford Motor Co Ignition system
US3136939A (en) * 1960-02-09 1964-06-09 Holley Carburetor Co Transistorized voltage regulator
US3219876A (en) * 1961-09-21 1965-11-23 Gen Motors Corp Ignition system
US3150285A (en) * 1962-01-31 1964-09-22 Ford Motor Co Transistorized ignition system with a bistable electromagnetic switch
US3174094A (en) * 1962-02-01 1965-03-16 Hughes Aircraft Co High efficiency power supply utilizing a negative resistance device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2093793A5 (enrdf_load_stackoverflow) * 1970-05-28 1972-01-28 Motorola Inc
US4036199A (en) * 1975-03-18 1977-07-19 Ducellier & Cie Device for protecting an ignition device for motor vehicles
US4029991A (en) * 1976-04-14 1977-06-14 General Motors Corporation Instrument panel illumination dimming control
US4327310A (en) * 1979-02-20 1982-04-27 Joerg Manfred Spark circuit

Also Published As

Publication number Publication date
BE657799A (enrdf_load_stackoverflow) 1965-04-16
DE1464020B1 (de) 1970-06-04
NL6415246A (enrdf_load_stackoverflow) 1965-07-02
GB1048219A (en) 1966-11-16
ES307688A1 (es) 1965-07-01

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