Robert Boschgmbh

Klaus Hirschmann

Eberhard Schnaibel

Lothar Raff

Erich Junginger

Ernst Wild

Frank Blischke

Richard Hotzel

Georg Mallebrein

Klaus Joos

Werner Hess

Lutz Reuschenbach

Erich Schneider

Christoph Woll

Klaus Winkler

Werner Mezger

Nikolaus Benninger

Kersten Wehmeier

Christian Tischer

Joerg Lange

Magnus Labbe

Manfred Hundhausen

Wilfried Tuleweit

Thomas Oelker

Kersen Wehmeier

A method for regulating the fuel/air ratio of a combustion process which is operated alternatingly with excess air and air deficiency, and having at least one catalyst volume in the exhaust gas of the combustion process which stores oxygen when there is excess oxygen in the exhaust gas and gives it off when there is oxygen deficiency, in which method the oxygen charges into the catalyst volume taking place when there is excess air, and the oxygen discharges from the catalyst volume taking place when there is air deficiency determined, and in which the fuel/air ratio is regulated in a first control loop such that the sum of the oxygen charges and oxygen discharges determined in a predefined interval takes on a predetermined value, wherein the combustion process is operated using oxygen excess or oxygen deficiency, respectively, at least until these appear at an oxygen-sensitive Nernst probe downstream from the catalyst volume.

Method and device for regulating the fuel/air ratio of a combustion process

The invention concerns a procedure to determine the oxygen storage capability of an emission control system with an exhaust gas sensor with discrete-level ability disposed in front of the emission control system. If in a period of time before the determination of the oxygen storage capability, the control intervention of the exhaust gas sensor is ascertained, and if this mean value is taken into consideration when calculating the fuel-delivery control phase during the determination of the oxygen storage capability of the emission control system, or if this mean value is used to correct the lambda value used to calculate the amount of oxygen stored, an improved measuring accuracy can be achieved while using a cost effective discrete level sensor. In that during the rich or lean operation of the cycle to determine the oxygen storage capability, the mean value of the control intervention is used for the calculation, pre-control errors are compensated for, as they can arise, for example, through dispersion of the injection valves or errors in the acquisition of cylinder fill. If the mean value is used to correct the lambda value, the amount of oxygen stored can be more accurately determined as a result of the measured air mass. In the procedure according to the invention, a cost effective step discrete-level sensor can be used in front of the emission control system.

Procedure to measure the oxygen storage capability of an emission control system

A method for detecting combustion misfires of an internal combustion engine and a device for carrying out the method, in which an evaluation of a lambda signal made available by at least one broadband lambda sensor is provided. The lambda signal is compared to a lambda signal threshold value. A warning signal is made available in response to the exceeding of a threshold in the direction of lean combustion. The procedure especially makes possible the detection of continual misfires which occur, for example, in response to an error in the air supply to the internal combustion engine and/or because of a lack of fuel. The procedure makes possible the detection of dangerous situations for at least one exhaust gas treatment device that is present, which may be removed by introducing protective measures, error warnings and error memory entries.

Method for detecting misfires of an internal combustion engine and device for carrying out the method

The invention further relates to a method and a model for modeling a discharge phase of a nitrogen oxide (NOx)-storage catalytic converter (') of an internal combustion engine (). The NOx-storage catalytic converter (&#x2032;) is subdivision into an oxygen (O2)-store and a nitrogen oxide (NOx)-store and a reducing agent mass flow (msrg) is determined which charges the O2-store and the NOx-store. To model a discharge phase of the NOx-storage catalytic converter (&#x2032;), the O2-store is modeled via a first integrator for oxygen (O2) and the NOx-store via a second integrator for nitrogen oxide (NOx) and the first integrator and the second integrator are charge proportionally with the reducing agent mass flow (msrg) in accordance with an apportioning factor determined in dependence upon the O2-store content (mo2sp) and the NOx-store content (mnosp) of the NOx-storage catalytic converter (&#x2032;).

Method and model for modeling a discharge phase of a nitrous oxide storage catalytic converter

A method for monitoring a secondary air system in combination with the exhaust-gas system of a motor vehicle is described. The method includes the steps of: providing a probe downstream of the junction of a secondary air line into the exhaust-gas channel; obtaining an air/fuel ratio (&lgr; ) utilizing the probe; obtaining a signal for the intake air flow (mass ); arithmetically determining the secondary air mass (mass ) in dependence upon (a) the ratio of intake air flow to fuel (&lgr; ), which is metered per unit of time; (b) the air/fuel ratio (&lgr; ); and, (c) the signal for the intake air flow (mass ); and, evaluating the operability of the secondary air system in dependence upon the secondary air mass (mass ).

Method for monitoring a secondary air system in associated with the exhaust system of a vehicle

The invention is directed to a method for computing a fuel-metering signal for adjusting a pregiven lambda value for the composition of the air/fuel mixture of an internal combustion engine. In the method, a first signal is formed which represents the air quantity flowing into the engine and a second signal is formed on the basis of the first signal so that a first lambda desired value adjusts when using its second signal as a fuel-metering signal. Various additional second lambda desired values are formed as a function of operating parameters of the engine. A selection is made of those second lambda desired values having the highest priority and the fuel-metering signal is formed by weighting the second signal with the second lambda desired value of the highest priority.

Method for forming a fuel-metering signal for an internal combustion

The invention is directed to a method for controlling the composition of the air/fuel mixture for an internal combustion engine. In the method, the mean value of the control oscillation is influenced via a change of the delay times tv with which a sign reversal of the actuating variable change is delayed. The dead time of the control is determined from the time-dependent performance of the control actuating variable and is considered for the change of the delay times tv.

Lambda control method

A mixture controller for adjusting an output value, which is outputted by a PI two-point controller, to control the air/fuel ratio of a mixture supplied to an internal combustion engine to a pregiven value. The engine produces an exhaust-gas flow during operation and has an oxygen probe mounted in the exhaust-gas flow. The mixture controller continuously detects the signal of the oxygen probe to obtain sequential measurement values of the signal. A check is made as to whether a currently detected measurement value of the signal has crossed over a threshold value in the lean or rich direction compared to the previously detected measurement value of the signal. The output value is changed when a crossover of the signal in the lean direction is present by shifting the output value with a large step via a P-jump in the rich direction and starting an integration of the output value in the rich direction from a previous lean direction. The output value is also changed when a crossover of the signal in the rich direction is present by stopping the integration of the output value in the rich direction and starting an integration in the lean direction after a pregiven delay time has elapsed. The operation of the mixture controller is returned to checking after the output value has changed. A return of the operation of the mixture controller to the checking operation is inhibited until an inhibit time has elapsed.

Mixture controller for an internal combustion engine

The invention is directed to a method for reducing the exhaust-gas emissions of an internal combustion engine which is equipped with a lambda control and a catalytic converter and for which the metering of fuel can be interrupted in dependence upon operating parameters. The method is characterized in that the engine at first is operated with a rich fuel/air mixture during transition from operation without fuel metering to operation with fuel metering. The oxygen deficiency associated therewith compensates the oxygen excess which is stored in the catalytic converter when the metering of fuel is interrupted. An operating state wherein oxygen is loaded therefore occurs quickly after a fuel cutoff. This operating state also defines an optimum at steady state and this is advantageous especially for the conversion of nitrogen oxide.

Method for adjusting the fuel/air mixture for an internal combustion

The invention is directed to a method for determining the particular current value of at least one control parameter for a lambda control of an internal combustion engine which provides a shift to make the fuel mixture lean or a shift to make the fuel mixture rich in dependence upon the operating state of the controlled engine. The method includes the steps of: determining a base value for the control parameter in dependence upon the current value of at least one pregiven operating variable as the current value applies for a control with a minimal discharge of toxic gas during steady-state operation of the engine; and, modifying the base value with a transition variable having a value decaying as a function of time when changes in the operating state of the engine occur. The method of the invention affords the advantage that the control parameter does not have a value which was applied for a minimum discharge of toxic gas for a typical operation sequence at steady-state or transient operation; instead, for steady-state and transient operations, optimized values are available. In this way, a discharge of exhaust gas is obtained which is lower compared to possibilities which have existed up until now.

Method and arrangement for determining a parameter of a lambda controller

Method for correcting the measuring errors of a hot-film air-mass meter

The invention relates to a method for the continuous lambda control of an internal combustion engine 13 having a catalyzer. The method is carried out by generating a control oscillation FS of pregiven amplitude at least in pregiven operating conditions. This method is based on the recognition that with an increase in amplitude of the control oscillation, the conversion window becomes wider insofar as a maximum amplitude is not exceeded. The conversion window is that range of lambda values wherein the conversion exhibits at least a pregiven quality.

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Leonberg, Germany

Klaus Hirschmann