Abstract: The invention relates to a final ignition stage of a transistorized ignition system (1) having a Darlington transistor (DT), in the collector-emitter circuit of which the primary coil current (I.sub.SP) of an ignition coil (ZS) flows and which is controlled via a base line (2). According to the invention, there is a regulating transistor (T.sub.1) arranged between the base line (2) to the base of the Darlington transistor (DT) and earth, said regulating transistor being driven in correspondence with the size of the primary coil current (I.sub.SP) and for purposes of current limitation partially conducting away to earth the base current flowing into the Darlington transistor (DT). Thus, a simple, cost-effective circuit for limiting the primary coil current and thus the stored ignition power is obtained.

Abstract: A protective case (13) for a vehicle ignition system covers both the ignition coil (5), an electronic control device (6), and the terminals (11) and connecting conductors (12) therebetween. The preferred material is plastic, with an electromagnetically conducting coating for screening against incoming and outing electromagnetic noise. Thus, protection is provided against mechanical, chemical, and electromagnetic environmental influences. The case is dimensioned to snap over and seal respective edges of the electronic control device (6), the ignition coil (5) and its core (8), the electrical terminals (11), and the interconnecting conductors (12). The case is bifurcated along an access slit (16) which is secured in a normally closed position by knob (15) which press-fits into a mating hole on the other side of the slit. Two sides of the case have curved ridges or dimples which provide flexibility to hinge the case open for insertion of the ignition coil (5) and electronic control device (6).

Abstract: To permit continued operation of a vehicle in spite of malfunction of an electronic ignition computer system, or any other electronic control module in an automotive vehicle, a transducer (10) provides an output to a trigger stage which has its output connected a digitally operating microprocessor (17) and to a bypass or transfer switch (21). The output from the microprocessor is connected to an analog and operating output stage (19, 20) to be controlled by the digital system of the microprocessor (17). Upon sensing of low operating voltage (U) as determined, for example, by a threshold switch (22), or of starting condition the switch (21) is closed, bypassing or interrupting connection to the microprocessor, and directly connecting signals from the transducer output stage to the input of the ignition circuit to permit operation under emergency conditions.

Abstract: A safety device is included in a circuit comprising a power source and a user device. The power source has one terminal connected to ground, as does the user device, with the safety device connected in a conducting path leading to the ground in the user device. In the event of an incorrect polarity connection between the power source and user device, a current path through the safety device and to ground is established.

Abstract: An overvoltage protection circuit is galvanically, directly connected across at least part of the secondary winding in the ignition system of an internal combustion engine. The input portion of the overvoltage protection circuit is a voltage divider preferably constituted by RC elements. The voltage at the tap of the voltage divider is applied to a Schmitt trigger. When the voltage across the secondary winding becomes excessively high, the Schmitt trigger output pulse triggers a monostable multivibrator whose output pulse in turn increases the conductivity of a transistor switch located in series with the primary. The increase in primary current tends to oppose further increases in primary and secondary voltages. Alternatively, the output from the multivibrator could be used to shorten the time of current flow in the primary winding in subsequent ignition time intervals or to completely block any subsequent ignition process.

Abstract: Adapter plugs are proposed for electronic circuits in motor vehicles which normally receive plug-in units. The adapter plug is interposed between the circuits and the plug-in units and contains circuits which improve the operation of such units. Specifically, in ignition control circuits, the circuitry in the adapter plug can contain a thyristor which is normally blocked, but which shunts energy from the ignition capacitor when the ignition switch is open while the interrupter switch is closed. This prevents the generation of undesired sparks.

Abstract: When the engine accelerates, the angle over which the ignition switch is closed prior to initiating the spark is automatically increased. Acceleration of the engine is detected by a comparator which compares the value of a speed-dependent signal in sequential cycles and initiate closure of the ignition switch if a predetermined difference is exceeded between the so-compared signals at a predetermined time in the cycle. Under static or decelerating conditions, the speed-dependent signal is compared, in each cycle, to the output of an integrator circuit. The integrator circuit integrates in a first direction at a first rate up to the above-mentioned predetermined time in the cycle and in the opposite direction at a second predetermined rate for the remainder of the cycle. The average value of the integrator output signal corresponds to the engine speed. When the so-compared signals are equal, the second comparator furnishes an output signal which closes the ignition switch.

Abstract: To permit use of shaft position transducers which provide needle pulses at predetermined angular positions of the crankshaft of an engine, such as Wiegand-type, and still enable generation of a counted dwell time even under transient conditions, or under low-speed conditions, the output from the Wiegand transducer is connected to a logic circuit which, under normal operating conditions, by use of a counter counts a predetermined time interval after opening of a switch in series with the ignition coil to determine the dwell period or initiation of current flow for a subsequent ignition event by resetting the counter with a reverse polarity subsequent pulse, thereby passing, upon reset, a predetermined count state which, similar to the normal counting of the count state, initiates closing of the switch.

Abstract: The voltage across a capacitor is changed in a first direction while the current in the primary winding of the ignition coil increases to a predetermined value less than the value required for ignition and is thereafter changed in a second direction until ignition takes place. The voltage across the capacitor is applied to the inverting input of a difference amplifier constituting a threshold stage controlling the initiation and termination of current flow through the ignition coil. The two changes are symmetrical when the engine speed remains constant. The residual voltage across the capacitor at the end of the second change is maintained until the start of the next subsequent first change, so that the time at which the threshold stage switches in, that is the time at which primary current starts to flow in the ignition coil changes as a function of the residual voltage in the capacitor.

Abstract: Changes in the magnetic field around a Wiegand wire created by a magnetic rotor coupled to a shaft of the engine induce a signal in a sensing coil. The signal is applied to an input switch which forms part of a control circuit. The output of the control circuit is connected to an interrupter switch connected in series with an ignition coil such that a spark is created at the secondary of the ignition coil when the interrupter switch opens. The control circuit maintains the interrupter switch in the nonconductive state for a predetermined percentage of the ignition cycle at low engine speeds and for a lesser percentage at high engine speeds so that enough energy can build in the ignition coil prior to the next interruption at the higher speeds.

Abstract: An inductive transducer having an electromagnetic inductive pickup coil in flux linking relationship to a rotary electromagnetic armature provides spaced output pulses to control current flow, and subsequent interruption of current through an ignition coil; to automatically increase the time during which current can flow through the coil, and change ignition timing, an impedance load circuit is connected to the inductive transducer through a control switch, so that the output characteristic of the inductive transducer is changed when the control switch is operated; the control switch may be speed dependent, or automatically speed dependent by the inclusion of a Zener diode which becomes conductive when the output voltage from the transducer rises, for example as speed of the engine, and hence of the transducer increases.

Abstract: To operate an ignition control transistor, connected into the primary ignition coil under minimum saturation condition regardless of voltage level of the supply voltage, delivered, for example, from the battery of an automotive vehicle, at least one timing circuit is connected to the voltage supply to have a timing interval which varies as a function of supply voltage, the timing interval controlling the duration of current flow through the transistor as a function of supply voltage so that the transistor will be conductive for the required time to store magnetic energy in the coil, though not for an excessively long period of time regardless of the level of supply voltage within the limits normally experienced in automotive ignition systems.

Abstract: A monitoring resistor in series with the spark coil primary winding and the electronic interruptor switch provides a signal to an integrator for shifting the control thresholds of a threshold switch that controls the interruptor away from their quiescent values that are nearer the zero crossover of the timing voltage wave provided by an engine driven timing signal generator. The integrator output voltage remains constant during the time the interruptor switch is open. While current flows through the interruptor circuit, the integrator increases the control voltage until the primary winding current reaches a predetermined level and then decreases the control voltage until the timing wave recloses the interruptor.

Abstract: A transistorized ignition system is protected against interruption of power supply by, for example, turn-off of the main or ignition switch while the transistor is in conductive condition so that, upon sudden interruption, an ignition event could be triggered at a time unsuitable for the remainder of the engine. A turn-off protection circuit is provided which includes a coupling resistor connected to the junction of the primary of the ignition coil and the main ignition current supply transistor thereto. The coupling resistor is connected in a circuit which holds the main current supply transistor in conductive condition, supplied from the energy stored in the ignition coil even after the main, ignition switch has been opened. A closed circuit for current flow due to this stored energy is provided within the overall ignition circuit.

Abstract: To provide for gradual turn-off of an ignition coil current control transistor, a control capacitor which provides turn-off current has its charge state changed gradually by means of an auxiliary transistor so connected to the capacitor that the conduction of the emitter-collector path of the auxiliary transistor is gradually changed, the main switching transistor being connected to and controlled by the auxiliary transistor and likewise changing gradually from conductive to blocking state in dependence on the gradual change in conduction of the emitter-collector path of the auxiliary transistor to prevent rapid turn-off of the main switching transistor and hence an undesired pulse at the secondary of the ignition coil which may induce continued operation of the internal combustion engine even though the ignition has been turned off.

Abstract: To provide a first accurately timed ignition impulse for any one ignition event, and then, selectively, one or more ignition pulses, in accordance with sensed or existing operating parameters of the engine, a first ignition pulse is generated, accurately, in accordance with timing as determined by an ignition timing stage; a frequency generator is selectively enabled upon the presence or absence of operating parameters at certain values to provide sequential ignition pulses after the first, accurately timed ignition pulse has been provided.

Abstract: Current flow to the ignition coil during low-speed operation of the engine, is controlled by an auxiliary control switch which is connected in shunt with the primary of the ignition coil. Serially connected with the primary is a main control switch which is controlled to close until current through the primary has reached a certain value, at which time the main switch opens and the shunt auxiliary switch is closed to permit continued inductive current flow through the coil and thus store ignition energy, the cycle repeating to maintain current flow through the primary at a level to store sufficient energy for the ignition spark which, at the ignition instant, effects opening of the shunt circuit by opening the auxiliary switch while also opening the circuit to the primary, thus providing a high-voltage pulse which provides for sparking of the spark plug.

Abstract: To prevent a spurious inductive spark when the master ignition switch of the vehicle is opened with the breaker terminals closed, so that current stored in the ignition coil might cause a spurious inductive voltage pulse, a protective circuit branch is connected in parallel across the primary of the ignition coil and includes an auxiliary semiconductor short-circuiting switch, preferably a thyristor, the conduction of which is controlled to close by an auxiliary control circuit which senses opening of the master ignition switch and permits application of a portion of the inductive current flow to the gate of the thyristor to render it conductive, thus short-circuiting the primary of the ignition coil and preventing an inductive voltage kick which might cause a spurious spark.

Abstract: To prevent generation of a spurious spark at the spark plug if the distributor braker control assembly should have commanded an ignition control transistor to be conductive and when the ignition switch is disconnected under those conditions, thus cutting off power to the ignition control transistor rendering it non-conductive and causing spurious voltage pulses which results in a spark at the ignition, a control path is provided connected to a control transistor for the actual ignition transistor and connected in circuit with the current flow due to the energy stored in the ignition coil to control the emitter-collector path of the ignition switching transistor to continue to remain conductive for a short period of time to drain off the stored energy in the coil, although the main ignition switch has been opened.

Abstract: To improve the operation of semiconductor control ignition systems under widely varying supply voltage conditions, a voltage divider having a division tap point is connected in parallel to the main switching part of the switching transistor of the ignition system, and a voltage breakdown element, typically a Zener diode is connected from the tap point to the control electrodes of the semiconductor switch to provide an additional control voltage thereto if the voltage at the tap point exceeds a value leading to breakdown of the breakdown device (Zener diode); the main control circuit for the main ignition transistor may be conventional.