Siemens Aktiengesellschaft

Anton Angermaier

Manfred Wier

Klaus Bayerle

Thomas Vogt

Michael Henn

Maximilian Engl

Stefan Krebs

Hartmut Pfleger

Stefan Schneider

Wolfgang Reupke

A method for adapting mechanical tolerances when performing time measurements on rotating shafts includes assigning each two cylinders to a respective mechanical segment on a crankshaft sensor wheel, and obtaining two adaptation values for the same mechanical segment in order to correct segment times. If a difference between these two adaptation values is greater than a predefined threshold value, the adaptation increment is rejected as invalid. As a result, disruptive oscillations, such as may occur when a crankshaft with a two-mass flywheel is used, can be gated out during the adaptation of the measured time values.

Method for adapting mechanical tolerances when performing time

During the warm-up phase of a catalytic converter, the fuel-oxygen ratio in the exhaust gas upstream of the catalytic converter is regulated in dependence on the temperature of the catalytic converter. The amount of fuel is measured on the basis of an injection time into the internal combustion engine. The injection time is calculated from a basic injection time weighted with a weighting factor. The weighting factor depends on the secondary air mass which is delivered to the exhaust gas duct and on a predetermined set value for the fuel-oxygen ratio of the exhaust gas (.DELTA.value) upstream of the catalytic converter. The secondary air mass is regulated in dependence on an engine air intake.

Process for controlling a fuel-oxygen ratio in exhaust gas upstream of a

Nonconcentricity or lack of smoothness values are proportional to the change in angular speed of the crankshaft. Deviation values that are proportional to the cyclical combustion fluctuations are ascertained, after the nonconcentricity values of successive combustion cycles are averaged, by comparison of the current nonconcentricity value with the associated mean value. Then the deviation quantity is compared with an individual-cylinder-specific limit value, and cyclical combustion fluctuations are deduced if the deviation quantity exceeds a limit value.

Method for detecting cyclical combustion fluctuations in an internal

A method for detecting combustion misfires in an internal combustion engine is based on the speed of rotation of the crankshaft. An unsteady running value is derived from measured cylinder segment times and subsequent correction of mechanical teeth defects. A disturbance caused by torsional oscillations of the crankshaft is taken into account by a cylinder-selective disturbance variable compensation dependent on load and speed of rotation.

Method for detecting combustion misfires in an internal combustion engine

A method for avoiding misdetection in a diagnosis of a tank venting system for a motor vehicle includes deriving a statement about a fill level of a fuel tank by evaluating a signal of a pressure sensor in the tank venting system. To that end, prior to the diagnosis of the tank venting system, the pressure fluctuations are detected and compared with a threshold value. If the pressure fluctuations exceed the threshold value, then a conclusion is drawn that the fuel tank is full, and the diagnosis is not enabled.

Method for avoiding misdetection in a diagnosis of a tank venting system

A secondary air pump communicates through an air duct with an exhaust gas line of an internal combustion engine. A catalytic converter for cleaning exhaust gas is connected in the exhaust gas line. The secondary air mass pumped by the secondary air pump is measured with an air flow rate meter. A control unit compares the measured secondary air mass with the desired secondary air mass set by the control unit. If the measured secondary air mass differs from the set secondary air mass by more than a specified amount, then the control unit has detected a malfunction.

Method of monitoring a secondary air pump

An adaptation method for correcting tolerances of a transducer wheel includes determining a correction factor for each individual tooth or each segment of the transducer wheel by measuring angular speed while taking into account both production tolerances and variations from one manufactured part to another of its kind as well as noncentral support of the transducer wheel on the shaft. The correction factor also compensates for a mass moment caused by a piston and a connecting rod. In an adaptation algorithm, a periodic disturbance by a gas moment caused by varying cylinder pressures and a moment fed back from the road are taken into account.

Adaptation method for correcting tolerances of a transducer wheel

A method for detecting oscillations of a crankshaft of an internal combustion engine includes determining if an engine is within a predetermined rpm range. An amplitude of a crankshaft vibration is ascertained if the engine is within the predetermined rpm range. A determination is made as to whether or not the amplitude is greater than a limit value. A frequency of the crankshaft vibration is ascertained if the amplitude is greater than the limit value. A determination is made as to whether or not the frequency is within a predetermined frequency range. An oscillation of the crankshaft is ascertained and a process for detecting combustion misfires by evaluating fluctuations in the crankshaft speed is suppressed for a predeterminable period of time, if the frequency is within the predetermined frequency range.

Method for detecting crankshaft oscillations

In a method of identifying stroke positions and for synchronizing sequential fuel or ignition distribution to cylinders of a four-stroke internal combustion engine with an even number of cylinders, as a function of signals of a crankshaft sensor, pistons of two cylinders each having the same position and direction of motion always form one group. Fuel injection and ignition is jointly carried out for each group from engine starting until a predetermined engine operating state is reached. Either fuel injection or ignition of a predetermined cylinder is omitted for at least one engine stroke, once the predetermined engine operating state is reached. If combustion does not occur within two engine cycles, beginning with the engine stroke in which the fuel injection or the ignition is omitted for the first time, the predetermined cylinder and otherwise the other cylinder of the same group is synchronized. A switch over to sequential fuel injection or ignition is carried out once synchronization has been carried out.

Method of identifying the stroke positions in an internal combustion

A method for detecting bad stretches of road includes ascertaining a tripping variable representing acceleration of at least one wheel of a vehicle. A bad stretch of road is detected if the amount of the tripping variable exceeds a predeterminable limit value. The tripping variable is dependent on at least two segment times that the wheel needs to pass through associated angle segments.

Method for detecting stretches of bad road

A method for detecting combustion misfires in internal combustion engines includes calculating a non-concentricity value from fluctuations in angular speed of a crankshaft, and dropping the non-concentricity value below a negative non-concentricity limit value if a combustion misfire is present. If the non-concentricity value drops below the non-concentricity limit value, a value for a stretch of bad road is calculated from successively calculated non-concentricity values, and the value for a stretch of bad road is dropped below or made of equal magnitude to a positive limit value for a stretch of bad road, if a stretch of bad road is present. The previously indicated combustion misfire is not confirmed if the value for a stretch of bad road drops below or is of equal magnitude to the limit value for a stretch of bad road. However, the previously indicated combustion misfire is confirmed if the value for a stretch of bad road exceeds the limit value for a stretch of bad road.

Method for combustion misfire detection with bad road detection

A method for recognizing stretches of rough or bad road includes recognizing tank pressure values at successive evaluation instants. A change in tank pressure is ascertained from successive tank pressure values. A stretch of rough or bad road is recognized if the change exceeds a limit value.

Method for recognizing stretches of rough road with the aid of a tank

A method for detecting combustion misfires includes calculating engine roughness values from fluctuations in crankshaft rpm, comparing the values with threshold values, and forming cylinder groups having an increased likelihood of misfiring. During a period of observation, each engine roughness value calculated for each cylinder is separately compared with a first threshold value and with a second threshold value being reduced in comparison with the first threshold value, a first counting sum associated with the cylinder is formed if the first threshold value is exceeded, and a second counting sum associated with the cylinder is formed if the second threshold value is exceeded. After the period of observation has elapsed, if the total sums of all of the first or second counting sums exceed a predeterminable total sum limit value, group sums are formed for each cylinder group from the second counting sums, and a conclusion is drawn as to the occurrence of a multi-cylinder misfire in the group having the higher group sum if the second counting sums of the individual cylinders in a group are approximately of equal magnitude, and conversely, if the second counting sums of the various cylinders are different, a conclusion is drawn as to a single-cylinder combustion misfire for the cylinder having the highest first counting sum, if the total sum of the first counting sums exceeds a predeterminable total sum limit value.

Method for detecting combustion misfires in a plurality of cylinders

A method is provided for recognizing erratic combustion in a multicylinder internal combustion engine by using a time measuring device to measure successive time periods which a crankshaft needs to rotate through predetermined angles during operating strokes of successive cylinders. The method includes determining a static component by using a calculating device to subtract a time period of the next cylinder in an ignition order from the time period of a cylinder to be examined. The static component is multiplied with a standardizing factor by using the calculating device. A dynamic component is determined by using the calculating device to subtract a time period of a next cylinder in the ignition order from a time period of a preceding cylinder in the ignition order, and a dynamic component is negated. A change component for a lack of smoothness value is formed, the lack of smoothness value is multiplied with a weighting factor to form a weighted value, and the weighted value is set equal to zero if the weighted value is negative. A sliding average is formed from the weighted value in a sliding averaging process. A lack of smoothness value is determined from addition of the static component, the dynamic component, and the sliding average. A combustion misfire is recognized if the smoothness value falls below a given limit value.

Method for recognizing erratic combustion

A method for monitoring a report of misfires in an internal combustion engine through at least two different submethods includes forming one subgroup from at least two submethods. A weighting graph containing weighting values dependent on operating parameters of a vehicle is assigned to each submethod, and the values are a measure of reliability of a report of the submethod. A weighting value is read out of the associated weighting graph upon each report in a submethod. The weighting values of the submethods of one subgroup are added to make a reference value. The reference value is compared with a limit value, and a misfire report is confirmed if the reference value is greater than the limit value.

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Landshut, Germany

Anton Angermaier