Robert Boschgmbh

Bernd Bodig

Werner Jundt

Gerd Hohne

Peter Werner

Gerhard Sohner

Herman Roozenbeek

Helmut Roth

Helmut Schmied

Hartmut Michel

Bernd W Kalkhof

Klaus Hueser

Richard Schleupen

Peter Jurgen Schmidt

Lothar Gademann

Hermann Kull

Bert Wurst

Heinz Decker

Adolf R Fritz

Karl Seeger

Walter Ruf

Georg Pfaff

Achim Herzog

Gunther Schmidt

Hans Linstedt

Gert Strelow

Gotz Bundschuh

A circuit for neutralizing very fast current fluctuations in a power consumer circuit, such as an integrated circuit having a pair of input or output conductors includes a bipolar transistor 17 whose collector is connected via a parallel connection of a semiconductor diode and a resistor to one of the conductors. The emitter of the transistor is grounded and the base is connected to the other conductor. Another parallel connection of a diode and a resistor is connected between the two conductors to bias the transistor to a preset current when a standard current of a constant magnitude flows through the consumer circuit. If current surges or breaks occur in the standard current, the preset current flowing through the collector resistor undergoes corresponding changes and a compensating current is very fast loaded to the conductors through the capacitance of the barrier layer of the p-n junction of the collector diode to neutralize the changes of the standard current.

Circuit for compensating very fast current fluctuations

The voltage developed by a primary winding of an ignition coil is supplied to a voltage divider for furnishing an analog signal of reduced amplitude for evaluation on an analog basis, which reduced amplitude analog signal is averaged by a capacitor connected between the voltage divider tap and ground. The capacitor eliminates the undesired effect of voltage spikes, but is not large enough to interfere with the measurement of voltages exceeding the ignition-initiating primary winding voltage value. The same reduced primary winding voltage is supplied through an input resistor to one input of a differential amplifier connected to operate as a switch having hysteresis and having a reference voltage applied to it such that the output will be the provision of a steady voltage having a duration corresponding to the spark discharge duration, for subsequent digital evaluation. The tap of the voltage divider that provides the analog output voltage for the system is subjected to a clamping action provided by another voltage divider of low ohm value connected across a 5-volt source and having its tap connected to the tap of the first mentioned voltage divider by a diode, so that primary winding voltages above the spark-initiating voltage will be measured on a reduced scale, while the differential amplifier and other integrated circuits are prevented from having overvoltages applied to them. The circuit is therefore suited for economical manufacture in so-called hybrid technology.

Circuit apparatus for measuring the primary voltage of an ignition coil

An integrated anode power stage using one or more Darlington transistors combinations is constituted for currents exceeding 5 amperes and voltages exceeding 200 volts. On a common semiconductor substrate there are provided, in addition to the Darlington circuit or circuits a large number of peripheral components, both active and passive, such as are required for protection, regulation and turning on or off of the final stage for operating an ignition coil in a motor vehicle. By providing these components in basins of the same conductivity type as the base of the power transistor a unit is provided that is economical to make as well as compact and reliable.

Integrated circuit Darlington transistor power stage incorporating

An operational amplifier is used as a threshold switch and an inductive generator that provides a wave used for timing operation of the threshold switch also feeds a circuit that produces a reference current corresponding to the average absolute magnitude of the generator voltage, which, in turn, is fed to at least one current mirror, the output of which is used to shift the operating threshold of the operational amplifier. A second current mirror is used in alternation with the first for half-waves of the generator voltage which are of opposite polarity and a positive feedback connection around the operational amplifier provides a switching characteristic having an appropriate amount of hysteresis so that the inherent timing shift is compensated on switching in response to both positive-going and negative-going portions of the generator output wave.

Speed-dependent signal generator

A capacitor which is charged by recurring square waves of a normally functioning microprocessor discharges at a steady rate, so that if the square waves do not continue, an operational amplifier will switch over and produce a reset pulse for the microprocessor. Repeated transitions of one polarity of the square wave recharge the capacitor during a short interval terminated by a second operational amplifier when the capacitor reaches a fixed level of charge. This second amplifier, which has feedback coupling, also initiates the timing discharge of the capacitor. A diode network at its output prevents charging the capacitor in the static state. This arrangement makes it unnecessary to provide another capacitor for quickly recharging the capacitor to prevent its discharge from switching over the first-mentioned operational amplifier.

Monitoring circuit for resetting malfunctioning electronic components,

A timing wave generator 26 provides the same input to two threshold switches that switch on at approximately the same time but have different switching hysteresis. The switch with the smaller hysteresis can affect ignition timing only through a delay circuit while the other can do so directly. If the engine stalls the delay circuit will assure that the primary current is shut off in a short time. In normal operation the large hysteresis of one of the threshold switches is in control and provides insensitivity to disturbance, but during startup the characteristics of the delay circuit can provide the appropriate ignition timing.

Ignition system for an internal combustion engine

Oscillations which would normally occur when the current in the primary winding of an ignition coil is limited to a predetermined value prior to ignition are suppressed by use of a feedback resistor. Specifically, the basic circuit consists of the primary winding of the ignition coil connected in series with a Darlington transistor configuration which, in turn, is connected in series with a measuring resistor, at a common point. The input of the current control system is connected to the common point through an additional resistor, while the output of the control circuit is connected to the input base of the Darlington configuration. Oscillations which might otherwise occur are suppressed by the use of a feedback resistor connected between the input and output lines of the control circuit.

Circuit for decreasing oscillatoins in the primary winding of an

A switching transistor (7, 9) is serially connected with the primary (5) of an ignition coil; current flow therethrough is controlled from an a-c signal generator (16) with respect to an ON threshold level (Ue) to store electromagnetic energy, and an OFF threshold level (Ua) to generate a spark; a variable conductivity circuit (26) controlled from a sensing resistor (8) modifies the response level of the threshold switch (13) with respect to the null or cross-over level of the applied signal. To prevent excessive current flow under idle-speed conditions, in accordance with the invention, the ON threshold level, at least, of the switch is shifted by introducing an auxiliary bias voltage derived from an auxiliary capacitor (36) and connected (37, 38) by the signal source through a diode (38) which prevents application of an auxiliary bias voltage to the threshold switch (13) under extremely low, e.g. starting conditions, permits application of the additional bias voltage providing for shift of the ON response level (Ue) under idling conditions, but again loses control as the speed continues to increase, and control by the variable conductivity circuit takes over.

Low-speed compensated ignition system for an internal combustion engine

The AC signal generator furnishing the basic control signal for ignition timing is a Hall generator the flux through which is gradually increased while the crankshaft of the engine rotates through a predetermined angle of rotation. The Hall generator is part of a magnetic circuit which also includes an air gap. The change in flux is accomplished by rotating a tapered magnetically conductive member through the air gap. The output of the Hall generator is applied through a linear amplifier to a threshold circuit whose output controls an electronic interrupter switch connected in series with the ignition coil.

Flux control system for a hall generator in an ignition system of an

In order to increase the closure angle of an interrupter switch connected in series with the primary winding of an ignition coil with increasing engine speeds, a capacitor is connected to the input of a trigger circuit whose output controls this closure angle. The capacitor is charged through a diode while the trigger circuit is switched out. The voltage across the capacitor shifts the threshold of the trigger circuit in a direction increasing the time that the interrupter switch is conductive. The charge on the capacitor is controlled by a signal generator which furnishes an output signal having an amplitude increasing with increasing engine speeds. The closure angle of the interrupter switch therefore also varies as a function of engine speed.

Apparatus for maintaining constant ignition energy with increasing

In order to prevent ignition power losses at low engine speeds and further to provide for the use of ignition control signals of both unipolar and bipolar nature, the invention provides that a Schmitt trigger which generates the principal ignition control signal is actuated by the transducer. The switching thresholds of this Schmitt trigger are changeable by a secondary threshold recognition circuit which can shift at least the negative threshold of the principal threshold circuit to more positive values. The invention also includes a delay circuit which prevents the return of the shifted threshold to more negative values. Still further included is a third threshold circuit which is engaged only at some higher engine speed.

Apparatus for generating engine speed-dependent ignition control signals

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

When the current through the primary winding of an ignition coil of an ignition system in an internal combustion engine has increased to a predetermined value, base current for a power transistor connected in series with the coil is shunted away, causing a rise in voltage across the primary winding. When the voltage rise across the primary winding has reached a maximum allowable value less than the value required to cause the generation of a spark, the transistor is switched back to the fully conductive state. This cycle is repeated during the time the transistor would normally be conductive and terminates at the ignition time, that is at the time the transistor is blocked by the ignition timing circuit of the internal combustion engine to create the spark.

System for decreasing the power consumption in the output transistor of

In a known ignition system, the emitter-collector circuit of the ignition transistor is connected in series with the primary winding of the ignition coil and with a precision resistor. When the voltage across the latter exceeds a predetermined value, an auxiliary transistor is switched to a conductive state. The emitter-collector circuit of the auxiliary transistor is connected to the base of the ignition transistor and, when conductive, prevents further increases of current through the primary winding of the ignition coil. To protect this circuit, a series circuit including two Zener diodes is connected between the base and collector of the ignition transistor. Further, a voltage divider is connected in parallel with the emitter-collector circuit of the ignition transistor and an additional resistor is connected between the base and the emitter thereof. When overvoltages across the primary winding cause breakdown of the Zener diodes, the current through the Zener diodes is blocked from the emitter-collector circuit of the auxiliary transistor either by a diode or by a blocking transistor having an emitter-collector circuit connected in parallel with the base-emitter circuit of the auxiliary transistor. The blocking transistor is maintained in the conductive state blocking the auxiliary transistor throughout the application time of an externally applied blocking signal which is adapted to maintain the ignition transistor in the blocked state.

Ignition system with overvoltage and excess current protection

A transistor switch connected in series with the primary winding of the ignition coil permits and blocks current flow through the coil when in a conductive and non-conductive state respectively. Normally, the switch is 'on' and 'off' respectively in the presence and absence of an ignition current pulse furnished in synchronism with the rotation of the crankshaft of the engine. For increasing speeds, the time the switch is 'on' prior to the ignition time is increased by switching it to the conductive state when the charge on a control capacitor reaches a predetermined charge. The charge on the control capacitor is changed in a first direction following receipt of each ignition signal. The rate of change of charge depends upon the resistance of the emitter-collector circuit of a first control transistor. The latter is, in turn, determined by the charge on an integrator capacitor which varies with changes in engine speed. When the charge on the control capacitor reaches a predetermined charge, the output transistor switch to the conductive state allowing current flow in the ignition coil.

Growing community of inventors

Leinfelden, Germany

Bernd Bodig