Robert Boschgmbh

Gunter Grather

Friedrich Rabus

Josef Wahl

Richard Schleupen

Bert Wurst

Karl-Heinz Adler

Ewald Stuible

A speed discriminator circuit furnishes an upper speed range signal if the engine speed is above a preselected speed. When the engine speed is above the preselected speed, the electronic switch controlling the current flow through the primary winding of the ignition coil is switched to the conductive state at a time when a control signal which varies as a function of actual engine speed becomes less than a speed varying reference signal. The switch is opened, thereby creating the first spark, either when the control signal, which is an AC signal, passes through zero or when the current in the primary winding of the coil has reached a predetermined value indicating that sufficient energy for ignition has been stored in the ignition coil. When the speed is less than the preselected speed the electronic switch is closed when the AC control signal passes through zero and is reopened when the current through the primary winding of the ignition coil is indicative of sufficient stored energy for ignition. A circuit for creating a series of additional sparks following the first spark is also disclosed.

Speed-dependent ignition timing system for internal combustion engines

To combine the advantage of a capacitor discharge ignition system, in which the spark intensity is essentially independent of engine speed even at high speeds of the engine, and the extended spark discharge of electromagnetic coil storage ignition by interrupting current through an ignition coil, an ignition event control circuit--for example a breaker contact, optical or electromagnetic transducer or the like--controls a discharge circuit through a capacitor which, after having been charged, suddenly and abruptly discharges through the ignition coil to generate an ignition event. Triggering of the ignition event also initiates repetitive energization of the ignition coil, under control of a frequency generator, which is then connected to the ignition coil to repetitively cause current flow, and abrupt interruption thereof, so that the spark duration, initiated for discharge of the capacitor, is extended. To provide for sufficient ignition energy upon starting, the starting switch can be connected to override the charge circuit to the capacitor so that current flow through the ignition coil, alone, stores sufficient electromagnetic energy for generation of the spark; the slight delay incurred thereby, and the longer current flow time to store sufficient electromagnetic energy is acceptable for operation of the engine under starting conditions.

Extended spark capacitor discharge ignition system

To accurately determine the dwell time as well as the ignition instant in a digitally controlled ignition system to provide essentially constant ignition energy to a spark plug, and permit ready adjustment and matching of a basic system to various types of internal combustion engines, a counter is controlled to count up at a rate depending on speed of the engine starting from a predetermined angular position of the crankshaft of the engine with respect to a piston, then count down at a second rate, which may be fixed; a fixed number is introduced into the counter which changes the count state during either the first or the second count cycle, or upon transition of counting from the first to the second count cycle, the determination of the number being readily changed by specific connection of output terminals from the counter to a decoding stage, thus avoiding the necessity of reconnecting the internal wiring of a group of gates to match the system to any given engine.

Ignition system for internal combustion engines, particularly of the

A frequency generator is enabled when an ignition event is to occur, to provide a sequence of current pulses to an ignition coil, so that multiple sparks will be commanded for any one single ignition event. To compensate for changes in operating parameters, particularly low-voltage condition of supply current, the frequency generator is controllable to change the pulse width, or the frequency thereof. To simply compensate for voltage variations, the frequency generator is a voltage controlled oscillator (VCO), controlled by the electrical supply network, typically the battery of a vehicle.

Multiple spark ignition system for an internal combustion engine

Sequentially generated charge pulses are applied to the spark gap through a diode which prevents back-flow of energy applied to the spark gap, the capacity of the ignition cable, or a capacitor, and of the spark gap causing a build-up of charge accumulation as a result of the sequentially applied charges, until the gap breaks down; the breakdown voltage, therefore, will be determined by the conditions of the gap. The pulses are generated at a pulse repetition rate which is high with respect to the rate of generation of spark impulses through a circuit in which the respective capacities and winding ratios and inductances of the ignition coil and the cabling are controlled so that the pauses between sequentially generated spark pulses and the timing of the spark pulses can be matched to the system parameters.

High-voltage ignition system to generate a spark for an internal

To provide sufficient current flow to the ignition coil in an ignition system of an automotive-type internal combustion engine under high-speed conditions, without excessive current flow under other speed conditions, a memory is provided which is loaded in the time interval between successive signals in advance of the ignition instant, separated by a time which decreases as the speed of the engine increases, the memory accumulating a stored value which is representative of the time duration. The memory is cleared or unloaded under controlled conditions in the interval between the occurrence of the second signal and the next subsequent first signal at controlled rates, one rate occurring during a timing interval established by a timing circuit, the timing interval of which depends on an operating parameter of the ignition system, for example supply voltage, and at a second rate after the timing interval, the unloaded or cleared time of the memory controlling current flow through the ignition coil for the next subsequent ignition pulse or ignition cycle to thereby maintain a minimum time of current flow through the ignition coil without extending the current flow if the time interval between successive signals becomes longer as a consequence of intermediate or low-speed operation of the engine.

Ignition system with essentially constant ignition coil energy supply

To generate a plurality of spark pulses for a multi-spark breakdown for each ignition event for ignition of a combustible mixture in an internal combustion engine, while providing for positive generation of the first spark at a predetermined time instant, a time delay circuit is connected to control a frequency generator for generation of a plurality of spark pulses, the first spark pulse, however, being controlled through a differentiating network, for example an R/C network, for positive generation of the first pulse.

Multi-spark ignition system for internal combustion engines

A signal generator, such as a breaker contact, an electronic ignition control system, or the like, provides signals when an ignition event is to occur, to control the operation of a controlled switch, connected in circuit with a spark coil, to open the circuit and induce a pulse for application to a spark plug. To provide a sequence of pulses to the spark plug for any one ignition event, a pulse generator is enabled when an ignition event is commanded. To ensure generation of at least one pulse, even under abnormal conditions which inhibit proper operation of the pulse generator, a timing circuit is connected to the ignition circuit, controlled by the signal generator commanding the ignition event and opening the circuit to the controlled switch to ensure generation of at least one spark pulse; the timing circuit has a longer time constant than the frequency generator under normal operation and thereby provides its command pulse to the controlled switch only upon failure of operation of the frequency generator under normal conditions.

Ignition system for internal combustion engine

To prevent application of excessive spark energy in an ignition system designed for proper firing voltages even under low-battery voltage conditions, upon rise of the battery voltage to normal or excessive values, a voltage sensing circuit, including a threshold stage, is connected to the secondary of the ignition coil to sense the secondary voltage, the threshold stage providing an output when the voltage is exceeded and blocking continued supply of power to the ignition coil of the system to thereby limit the ignition voltage.

Voltage limited ignition system, particularly for an internal combustion

To provide a sharp voltage pulse to break down the spark gap of a spark plug, an ignition coil is constructed to have two secondary winding portions, one providing a high-voltage output and the other providing high energy level or current output. The high current output portion is connected through a diode to charge a capacitor which is further connected through an additional blocking diode to the spark gap, to which also the high voltage portion is connected, so that the spark gap will be supplied by a circuit common to both winding portions of the ignition coil, the high voltage pulse breaking down the spark gap and the high energy pulse, of lower voltage, however, providing spark energy for an extended period of time after initial breakdown of the gap. Preferably, the system is transistor-controlled, with the ignition instant being determined by a digital counter counting forward and reversely under control of a rotation-pulse transducer coupled to the crankshaft of the engine.

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Pinache, Germany

Gunter Grather