Robert Boschgmbh

Gerhard Sohner

Helmut Roth

Werner Jundt

Peter Werner

Bernd Bodig

Gerd Hohne

Herman Roozenbeek

Walter Ruf

Manfred Mezger

Heinz Decker

Karl Seeger

Georg Pfaff

Ulrich Drews

Hartmut G Brammer

Richard Schleupen

Hartmut Michel

Peter Jurgen Schmidt

Ingo Gorille

Bernd W Kalkhof

Ulrich Bentel

Karl-Heinz Adler

Reinhard Leussink

Dieter Neuhaus

Erich Jesse

Bernhard Schmidt

Karl-Heinz Nubel

Hansjorg Manger

Hans Linstedt

Gert Strelow

Gotz Bundschuh

Thomas Jokh

Final ignition stage of a transistorized ignition system

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).

Protective case for combination ignition coil and electronic control

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. The analog portion of the system is a single integrated module, separate from the digitally operating microprocessor (17) for ease of error diagnosis, maintenance and repair. This is particularly important with digitally operating control systems (17) which are subject to malfunction under low voltage conditions or upon occurrence of stray or distrubance signals in the network, for example under starting conditions.

Electronic engine control system with emergency operation mode

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.

Safety device for a conducting path in a load device

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.

Ignition coil with overvoltage protection connected to the secondary

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.

Adapter for improving the operation of electrical circuits in a motor

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. The integrating rates may be varied as a function of operating parameters of the engine.

Ignition system with automatic increase in ignition energy during

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.

Ignition system with improved temperature and voltage compensation

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. Thus, even though the normal counting time has not yet been reached, the reset operation of the counter will trigger closing of the switch and hence sufficient current flow through the ignition coil to store the appropriate electromagnetic energy therein for a reliable spark at the spark plug.

Internal combustion engine ignition system

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.

Ignition system using a Wiegand wire

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.

Electronically self-controlled ignition system for internal combustion

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.

Supply voltage variation compensated ignition system for an internal

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. While the control voltage is being decreased, the coil current is allowed to rise to a limiting value and is then held constant by another circuit controlled by the monitoring resistor that slightly reduces the conductivity of the interruptor switch in its closed condition, but this occurs only while the engine is accelerating to the operating speed range. During this time the switch-on threshold for controlling the interruptor is raised towards the peak of the timing wave, but the switch-off threshold is clamped to its initial value. With further increase in engine speed, the net effect of the integrator operation changes sign and the switch-on threshold is lowered. As soon as the switch-on threshold goes below its initial value, the switch-off threshold is unclamped and is depressed along with the switch-on threshold towards the negative peak of the timing wave by the integrator action. The result is to keep the amount of energy stored in the spark coil at the time of primary circuit interruption constant over a wide range of speed.

Motor ignition system control circuit for maintaining energy storage in

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. Preferably, the system includes a coupling transistor, connected across the power supply, which is blocked when the main transistor is conductive, so that the main transistor is controlled by power supply voltage appearing at the collector of the coupling transistor; the coupling resistor of the turn-off protected circuit then applies the inductive voltage from the coil to the collector terminal of the coupling transistor, and hence simulates continued power supply to the main current supply transistor to continue to hold it conductive and thus prevent abrupt turn-off and initiation of an undesired ignition event.

Turn-off protected ignition system for internal combustion engines

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.

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Remshalden, Germany

Gerhard Sohner