Robert Boschgmbh

Karl Seeger

Werner Jundt

Manfred Mezger

Uwe Kiencke

Gerhard Sohner

Herman Roozenbeek

Ulrich Drews

Georg Haubner

Bernd Bodig

Jurgen Wesemeyer

Bert Wurst

Werner Meier

Heinz Decker

Georg Pfaff

Walter Ruf

Gunther Schmidt

Bernhard Schmidt

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 countdown counter (14) counts out a speed dependent number to determine the start of the dwell period when a comparison number (Z17) is reached which is adjusted dynamically by a regulation counter (17). The countdown counter's contents are reduced by a value dependent upon acceleration when acceleration is present in order to improve the dynamic correction. In the case of strong accelerations these dynamic corrections are insufficient and when such a strong acceleration occurs the regulation counter content is set to a high value to assure a succession of strong ignition sparks. The high value of acceleration necessary for this precaution may be determined by comparing the difference of successive engine speed counts with a predetermined value or it may be determined by the failure of the current in the ignition coil primary to reach some predetermined value. After the generation of strong sparks is thus assured, the comparison count value provided by the regulation counter gradually returns to normal by the operation of the provisions for normal accommodation to dynamic conditions.

Dwell period control for engine ignition

A dwell angle control has three counting devices for detecting acceleration. In a first UP/DOWN counter (17), the count in one direction takes place throughout the time the current in the primary circuit of an ignition coil (25) exceeds a current threshold value (I1). The count in the other direction is constant with respect to time. The counts on the first counter are taken over into a second UP/DOWN counter (11) in response to the input signal, the counting direction also being determined by the input signals. When the count in the second counter (11) reaches an adjustable trigger threshold value, the closure time is initiated, the actual ignition time being fixed by an edge of a sensed signal, or the edge of the signal from an ignition computer. The adjustable trigger threshold value is advantageously determined by a third UP/DOWN counter (12) which is set to a fixed value (X) by an edge of the sensed signal and whose counting direction is also determined by the sensed signals. A very good dynamic response is achieved by the detection of acceleration by three counters during different time periods. It is advantageous to switch from a decrease in closure angle to an increase in closure angle at an adjustable speed by switching the adjustable trigger threshold value to a very small value and switching the counter (11) to a continuous DOWN count. This allows a matching to variable ON/OFF ratios of the sensed signal.

Dwell angle control for internal combustion engine ignition system

An ingition system for internal combustion engines has dwell angle control apparatus for controlling the switching times of an electronic switch (21) in the primary circuit of an ignition coil (22) in dependence on the signals of a rotating sensor (10) or an ignition computer (11). Specifically, speed dependent counting values are periodically generated in a counting apparatus (13) each being counted down in a further counting apparatus (14) controlled by an edge of the sensed signal or a computed signal. Upon reaching a presettable triggering counting value, the electronic switch (21) is closed (start of dwell period). This triggering value is set by periodic up and down counting processes in a control counter (17) the upwards counting being constant with respect to time and the count-down process being determined by the length of time of current flow above a settable current value through the ignition coil (23). This allows the counting process of the speed dependent counting value to be triggered and the electronic switch to be opened (ignition time) by a single sensed signal edge per cycle.

Ignition system for internal combustion engines

Clock pulses are counted to provide a count indicative of speed in a counter that is reset with every revolution of a reference mark. The difference between successive counts is multiplied by a fractional factor, which is not necessarily the same for acceleration and deceleration, then added algebraically to the current count value. The acceleration-corrected speed value is then multiplied by a parameter-dependent digital value obtained from a summing circuit to which various engine condition parameters are supplied and the output of the last-mentioned multiplier is supplied to a comparator to which the current count of clock pulses beginning with the reference mark passage is compared. When the comparator finds the match, spark ignition takes place. Another counter counts the clock pulses following each reference mark for sequencing multiplexers that enable some components to serve in more than one operation, in effect controlling the flow of digital values around various loops in the circuit.

In an internal combustion engine in which the fuel supply is interrupted during no-load operation to save gas the ignition timing is retarded following resumption of the fuel supply to cause the resumed torque to be applied slowly. A sequence of ignition timing signals following the activation of the gas pedal is delayed by sequentially smaller and smaller amounts until the normal ignition timing is resumed.

System to decrease operating jolts in a vehicle by controlling fuel and

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

A switch connected in series with the ignition coil is 'on' and 'off,' respectively, in the presence and absence of a pulse furnished by a pulse generator operating in synchronism with the crankshaft of the engine. If the pulse width of the pulses is too small for the current in the ignition coil to reach the minimum value required for ignition, the closing time of the series switch is advanced, while if the pulse width is too long, causing excess heat dissipation in the coil, the closing time of the switch is retarded. To accomplish this, a first digital counter counts downwards for a predetermined time and upwards for a time period in which the current in the ignition coil exceeds a predetermined current. Upon interruption of the current in the coil, the then-present value in the first digital counter is transferred to a second digital counter. The second counter then counts down at a predetermined rate until a predetermined count is reached. At this time, the series switch is switched to the conductive state.

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Markgroningen, Germany

Karl Seeger