Abstract: A method for detecting misfires in an internal combustion engine is given wherein: uneven-running values are detected which are a measure for the changes of the crankshaft rpm of the engine with the changes being caused by misfires; the spacing between bands of uneven-running values is computed; a check is made as to whether the computed band spacing is greater than a pregiven threshold spacing and, if this is the case, this data is used as an indication that misfires and not disturbances of the crankshaft rpm are present; in the case that no significant band spacing greater than the threshold spacing is determined and, in addition, uneven-running values drop below a pregiven negative threshold value, this is used as an indication that disturbances of the crankshaft rpm are present and the detection of misfires is interrupted.

Abstract: A process of adapting mechanical tolerances of a transmitter wheel provided with a plurality of approximately equidistant markings which are sensed by a pick-up supplying a pulse train whose time interval is measured and stored, includes connecting a transmitter wheel with a rotating shaft of an internal combustion engine, carrying out a check as to whether or not the internal combustion engine is in thrust operation, and placing a second and following time intervals in relation to a first time interval when the thrust operation is detected.

Abstract: In order to determine the fuel quantity to be fed into an internal combustion engine during each stroke of the engine, the air mass sucked into each cylinder for combustion during each intake stroke is determined based on an intake-pipe pressure. A current air mass is determined using a measured value for the intake-pipe pressure. Subsequently, during a period in which there is no change in an air intake cross-section for each cylinder, the air mass is determined using a projected intake-pipe pressure, and the fuel quantity to be fed to each cylinder during the current and subsequent intake strokes is determined based on the air mass determinations and a wall film model.

Abstract: A misfire detection system for an internal combustion engine is disclosed with the system being used to evaluate wheel rpm fluctuations. This system detects a rough roadway over which the misfire detection is to be inhibited. This detection is made with the aid of wheel rpm signals; that is, signals as they are present for all motor vehicles equipped with anti-locking brake systems and for motor vehicles which utilize the wheel rpm signal for determining road speed. In motor vehicles of this kind, the advantage is provided that the wheel rpm signal has a double use. The advantage is provided that a reliable detection of a rough roadway is possible for all motor vehicles independently of whether wheel rpm signals are used for inhibiting the misfire detection or not.

Abstract: A system for detecting multiple misfires and for allocating misfires to cylinders for detected multiple misfires in a multi-cylinder internal combustion engine is so configured that the rough-running values for the individual cylinders are determined. The system then however forms sum terms with these rough-running values and, in turn, forms sums with these sum terms which sums are compared with threshold values. When at least one sum exceeds the corresponding threshold value, then this shows the presence of multiple misfires. As soon as multiple misfires are detected, the rough-running threshold values for allocating misfires to cylinders are reduced. Advantageously, the rough-running values are so modified in advance that their correction terms are influenced as little as possible by misfires. In this way, misfires can also reliably be allocated to individual cylinders when multiple misfires are present.

Abstract: To measure the irregular running of an internal combustion engine, the following equation, for the running irregularity value (LUW) is applied:LUW=f(T)x.vertline.(T.sub.-- V2-T.sub.-- V1)-(T.sub.-- V3-T.sub.-- V2).vertline.,The values T.sub.-- V1, T.sub.-- V2 and T.sub.-- V3 are combustion time periods, as they are measured at any one time between two fixed segment marks. Different groups of runningirregularity values are formulated, which differ in that combustion time periods are applied in the mentioned equation for different combinations of cylinders. In each group, the running-irregularity values are averaged; and the difference between the minimum and the maximum value of the averaged values is formulated. The difference is evaluated as a variable for the extent of running irregularity.

Abstract: In a method for protecting a catalytic converter from overheating, a conventional misfire recognition method is used to determine whether misfires are occurring in a cylinder. If this is the case, an attempt is made to interrupt the fuel supply to the affected cylinder. If this succeeds, the remaining cylinders are supplied with a lean mixture. If it does not succeed, all the cylinders are operated with a rich mixture. The lean setting of the mixture in the case of interrupted fuel supply to the affected cylinder has the effect that after the combustions in the cylinders, no further fuel reaches the catalytic converter which could combust in the catalytic converter with the oxygen induced by the affected cylinder.

Abstract: The invention is directed to a method for determining misfires in an internal combustion engine of a motor vehicle. The determination is discontinued after a misfire under specific further conditions for a pregiven number of ignition strokes. When the misfire determination is not discontinued, then a check is made as to whether simple measurement value relationships apply which make a misfire very improbable. If such measurement value relationships are present, then the actual complicated misfire determination is discontinued. It is of special significance to count ignition strokes, which are counted in order to determine the relative frequency of misfires, only then when the above-mentioned conditions are all satisfied which determine as to whether a condition is present at all in which a determination of the misfire is purposeful. In this way, the decisive frequency determination is not influenced by the count of the ignition strokes which are not at all relevant to misfires.

Abstract: The electronic counter for counting a periodic clock signal generated at a preset clock frequency (f.sub.o) includes a clock circuit generating the periodic clock signal at the preset clock frequency (f.sub.o); an adjustable frequency divider (4) having an output (8), a first input (5) and a second input (7), the first input of the frequency divider (4) being connected to the clock circuit (6) so as to receive the periodic clock signal and the second input (7) of the frequency divider being connected to receive a cycle speed signal (n), the frequency divider (4) containing means to produce a pulsed output signal at a divider output frequency (c.sub.o); a tracking circuit (T) connected to the output (8) of the frequency divider (4) to receive the pulsed output signal at the divider output frequency (c.sub.

Abstract: In a method for adjusting air and fuel masses for a multi-cylinder internal combustion engine with individual injection for each cylinder, the fuel mass for each injection operation is calculated taking into account the probable intake-pipe pressure during the opening time of the inlet valve. After a change of the accelerator pedal, the throttle flap is only adjusted when the fuel masses decisive for the new throttle-flap position have been calculated and substantially ejected.

Abstract: A method for learning control and precontrol for adjusting the lambda value for the air/fuel mixture to be metered to an internal combustion engine 11 compares a large comparison value with a small comparison value with the large comparison value being formed by averaging of adaptation factors for large precontrol values and the small comparison value being formed by averaging of adaptation factors for small precontrol values. Whenever the large comparison value is smaller than the small comparison value, a global summand is incremented by a correction value, otherwise it is decremented. An apparatus operating according to this method has the advantage that disturbing influences which act additively on the injection time are compensated with great accuracy.

Abstract: An adaptation value memory is used for a learning control method having precontrol for an internal combustion engine and a corresponding apparatus. The adaptation value memory has a predetermined number of support points which are addressable via data records of values of address operating values. A learning operation is initiated if a support point region is left during operation of the internal combustion engine and if steady state operation was present therebefore. The adaptation value of the above-mentioned support point is changed by the learning operation when a control means issues an actuating variable which deviates from a desired actuating variable. The actuating variable deviation is not applied in full strength, instead, it is applied attenuated to change the old adaptation value. This is performed by means of an attenuation means which, as main function groups, has a learning intensity table 26, a counter read memory 27 and a counter difference table 28.

Abstract: A method and a system for adjusting the lambda value of an air/fuel mixture to be supplied to an internal combustion engine wherein a throttle flap is adjusted in each case in such a manner that lean operation is obtained in a lower load range and a stoichiometric operation (lambda=1) is obtained in an upper load range.

Abstract: A known control system for adjusting the lambda value of an internal combustion engine includes a corrective value ROM for transient operation wherein corrective values are stored for correcting the injection times for transient operation. In contrast thereto, the system according to the invention includes a corrective base value ROM 30, an adaptation value RAM 35 and an adaptation unit 34. The values from the corrective base value ROM are not utilized directly for correcting injection times; instead, these values serve as corrective base values which only become adapted corrective values by means of multiplication with adaptation values. The adaptation unit adapts the adaptation values in the adaptation value RAM. For this purpose, the adaptation unit determines the lambda value control deviations during a transient operation.

Abstract: Engine knock sensor signals are amplified, band-pass filtered and rectified and then a sequence of integrated signal peak values are compared with reference signals relating to a typical engine knock signal. If the deviation of the integration values or peak values or their sum over a measurement period differs by less than a predetermined amount from the corresponding reference values, a knock indication is produced. The initial integration or peak value may be given less weight than those that follow. The knock sensor may be an engine block sound sensor, or a combustion chamber light, pressure or iron current sensor. Additional criteria, such as the interval between null transitions or signal maxima or the number of them in a measuring period may be used to inhibit a knock indication in case the main processing should occasionally provide an anomalous knock signal, but this precaution is not sufficiently needed to warrant its inclusion in simplified systems.

Abstract: To modify engine operation and reduce the tendency of the engine to knock or ping, a knocking signal is generated which is representative of knocking intensity and/or frequency of knocking occurrence, and compared with a permissible knocking signal. The result of the comparison is utilized to change an operating parameter of the engine, for example by injecting a fluid, e.g. water, into the engine, changing charge pressure, for example of a turbocharger or the like. The permissible engine knock signal can be modified in accordance with an engine operating parameter, for example at low temperature, or low speed, the permissible knocking limit can be raised since the damaging effect of knocking at low temperature or low speed is less than under different operating conditions.

Abstract: A regulating device is proposed for control variables of an internal combustion engine, in particular for the fuel metering signal and the ignition signal, which has an intervention capability for signals of at least one knocking sensor on the engine via a knocking-signal evaluation circuit; this knocking-signal evaluation circuit includes a frequency recognition circuit and preferably an amplitude recognition circuit, and it detects and evaluates the knocking signal only during specific times or angles relating to the ignition signal. The frequency recognition circuit is realized by means of two counters. The counting range of the first counter marks the value of the upper threshold frequency which can be recognized, while the counting range of the second counter characterizes the frequency band.