Siemens Aktiengesellschaft

Siemens Aktiengellschaft

Wojciech Cianciara

Gerhard Fischer

Gerd Rösel

Stefan Krebs

Thomas Haug

Ralph Mader

Ludwig Kettl

Michael St&uuml;rtz

Disclosed is an internal combustion engine comprising at least one cylinder and an exhaust manifold in which a catalytic converter, a first exhaust gas probe, and a second exhaust gas probe are disposed. The first exhaust probe is located upstream from the catalytic converter while the second exhaust gas probe is arranged downstream therefrom. A lambda Controller is provided which is configured so as to determine a lambda correction factor in accordance with a first test signal that is assigned to the first exhaust gas probe. A trim controller is provided to which a setpoint value and an actual value of a second test signal allocated to the second exhaust gas probe are fed as a control difference. The trim controller is configured so as to determine a proportionate corrective factor. A control signal unit is embodied so as to determine a control signal for apportioning fuel into the cylinder in accordance with the lambda correction factor and additionally determine the control signal for apportioning fuel into the cylinder according to the proportionate corrective factor in a diagnostic mode of a component associated with the exhaust manifold.

Device for the operation of an internal combustion engine

After the start of an internal combustion engine, a check is made to see whether a positive change in a measurement signal is established. A positive change is established if the measurement signal lies below a predetermined threshold value when the internal combustion engine is started. A fault entry is made if, within a predetermined time period, the positive change in the measurement signal, expressed as the difference between the measurement signal when the internal combustion engine is started and a present value of the measurement signal when the time period has elapsed, does not reach an expected value.

Method for checking analog sensors

The total ignition angle ZW(z) of each cylinder z is composed of cylinder-selective values basic ignition angle GZ(z) &lcub;determined by engine speed n and load L&rcub;, knock adjustment angle KNK(z), in addition to a first adaptation value AD,(z) and a second adaptation value AD,common to all cylinders. AD,(z) is increased when KNK(z) is greater than a threshold DEC and is reduced when KNK(z) is lower than a threshold INC. The second adaptation value AD,is formed as a function of the average value {overscore (AD,+L )} of the adaptation values of all cylinders.

Method for the cylinder-selective knock control of an internal combustion engine

A process for monitoring the functioning of an exhaust gas sensor disposed in a mixture-regulating circuit of an internal combustion engine includes outputting either a rich voltage representing a rich mixture composition or a lean voltage representing a lean mixture composition as a function of a composition of a mixture to be supplied to the engine, and using a behavior of the voltages during engine operation as a criterion for evaluating the functioning of the exhaust gas sensor. The temperature of an exhaust gas sensor is ascertained and compared with a temperature threshold value. If the temperature threshold value is exceeded, monitoring is performed to determine if that status is maintained for a predetermined period of time or number of cycles. A value occurring for a rich voltage or a lean voltage is detected and compared with a diagnostic value if the conditions are met. It is concluded that the exhaust gas sensor is superannuated, if the diagnostic threshold is not attained.

Diagnostic process for an exhaust gas sensor

A method for distinguishing sources of error in a mixture formation or mixture regulating system of an internal combustion engine having an exhaust system with a lambda regulator and a heated lambda sensor is disclosed. A value of a sensor voltage is continuously measured. The value of the sensor voltage is compared with a lower diagnostic limit value and an upper diagnostic limit value. A lambda regulator value of the lambda regulator is varied in an enriching direction to a maximum lambda regulation limit if the lower diagnostic limit value fails to be attained, and the lambda regulator value is varied in a leaning down direction to a minimum lambda regulation limit if the upper diagnostic limit value is exceeded. The heating output of the sensor heater is raised after a time period has elapsed during which there is no departure from the maximum lambda regulation limit, and the heating output of the sensor heater is lowered after a time period has elapsed during which there is no departure from the minimum lambda regulation limit. A conclusion is drawn that there is a permanently lean mixture formation error if the lower diagnostic limit value for permanently lean mixtures is exceeded again, and a conclusion is drawn that there is a permanently rich mixture formation error if the upper diagnostic limit value fails to be attained again. Otherwise a sensor error is detected.

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Probstberg, Germany

Wojciech Cianciara