Abstract: A vehicle control system for a vehicle may include a controller, a single pedal and a torque control module. The controller may be operably coupled to components and/or sensors of the vehicle to receive information indicative of operational intent of an operator of the vehicle and information indicative of vehicle status. The single pedal may be configured to provide the information indicative of operational intent. The torque control module may be configured to generate both a propulsive torque request and a braking torque request based on the information indicative of the operational intent and the information indicative of vehicle status.

Abstract: A power plant (1) having two engine groups (10, 20) and a main gearbox (MGB) (2), and a rotary wing aircraft (30) having such a power plant (1). Each engine group (10, 20) drives said MGB (2) mechanically to rotate a main outlet shaft (3) and, consequently, a main rotor (31) of said aircraft (30) at a frequency of rotation NR. A first engine group (10) has two main engines (11, 12) and is by a first setpoint NR* for said frequency of rotation NR, while a second engine group (20) has one secondary engine (21) and is regulated by a second setpoint W1* for power from said second engine group (20). The first engine group (10) is also regulated by a third setpoint W2f* for anticipating power such that said first engine group (10) and said second engine group (20) deliver the power needed at said main rotor (31).

Abstract: A dual compressor turbocharger includes two compressors. One compressor supplies fuel pressure, and one compressor supplies air pressure. The dual compressor turbocharger includes a turbine driven by exhaust of an engine and a shaft coupled to the turbine. The first compressor is mounted on the shaft and includes a first inlet coupled to an air supply and a first outlet coupled to an air intake of the engine. The second compressor is mounted on the shaft and includes a second inlet coupled to a fuel supply and a second outlet coupled to a fuel supply rail of the engine.

Abstract: Methods and systems are described for evaluating presence of fuel shifts in an engine. In one example, a method comprises indicating a fuel shift based on a time delay of an exhaust gas sensor during an entry into and an exit out of deceleration fuel shut off (DFSO).

Abstract: Methods and systems are provided for maintaining stoichiometry of an exhaust gas during operation of a fuel injector at a threshold pulse width. In response to operation of a fuel injector at the threshold pulse width and a rich exhaust gas air-fuel ratio, airflow is increased to the intake manifold. Engine actuators may also be adjusted to maintain torque during the increased airflow while operating the fuel injectors at the threshold pulse width.

Abstract: The invention relates to a method for managing the power of a hybrid vehicle selectively driven by an electric motor and a heat engine, the electric motor being supplied with power by a power storage unit capable of being recharged by the heat engine, wherein according to the method the level of charge of the power storage unit is monitored so as to select the mode in which the vehicle is driven by the heat engine or that in which the vehicle is driven by the electric motor, said method including the steps of: determining a travelling profile of the vehicle associated with a path of said vehicle; and determining (36), according to said travelling profile, a threshold level of charged (S2), referred to as authorized threshold, below which the mode in which the vehicle is driven by the heat engine is activated.

Abstract: An emission test system may include at least one controller configured to determine, directly or indirectly, a quantity of diluted exhaust sample in a container at the completion of an emissions test, and to cause additional diluent gas to be added to the container based on the determined quantity.

Abstract: An engine includes: a first part that is provided in a first passage that interconnects an inside of a crankcase and a part of an intake passage at a downstream side of an adjustment part adjusting an intake air amount and changes gas flow in the first passage; and a second part that is provided in a second passage that interconnects the inside of the crankcase and a part of the intake passage located at an upstream side of the adjustment part and changes gas flow in the second passage. If an engine temperature is higher than a given value, and the degree of fuel decreasing correction exceeds a given value, the first part decreases the gas flow rate through the first passage and the second part restricts a flow direction in the second passage to a direction in which gas flows to the crankcase from the intake passage.

Abstract: Methods and systems are provided for detecting hydrocarbon ingestion into an engine based on the simultaneous monitoring of cylinder imbalance and an elevated exhaust exotherm. Crankshaft acceleration data is monitored during steady-state and transient engine conditions while exhaust temperatures are estimated during non-regeneration conditions. Engine speed and load is limited to reduce further hydrocarbon ingestion.

Abstract: A method for automatically controlling a stationary gas engine, where an engine speed control deviation is computed from a set engine speed (nSL) and an actual engine speed (nIST), and a set torque is determined as a correcting variable from the speed control deviation by a speed controller, where a set volume flow is determined as a function of the set torque to establish a mixture throttle angle (DKW1, DKW2) and a gas throttle angle, and where the set volume flow is varied to adjust the gas throttle angle by a correction factor.

Abstract: A method and a system for correcting an engine torque based on a vehicle load may include: determining whether a vehicle load determination condition is satisfied continuously for a predetermined maintaining time, determining an average engine torque for the predetermined maintaining time if the vehicle load determination condition is satisfied continuously, determining whether the average engine torque is larger than a predetermined engine torque, determining a ratio of the average engine torque and the predetermined engine torque if the average engine torque is larger than the predetermined engine torque, determining a correction factor using the ratio of the average engine torque and the predetermined engine torque, and determining the engine torque using the correction factor and a predetermined normal torque filter.

Abstract: A control system for a vehicle includes an error detection module and a remedial control module. The error detection module detects whether an accelerator of the vehicle is stuck is based on vehicle speed, a position of the accelerator, and one of a pressure applied to a brake of the vehicle and a status of a parking brake of the vehicle. The remedial control module, when the accelerator is stuck, at least one of resets the position of the accelerator and decreases torque output of a powertrain system.

Abstract: A fuel injection control for an internal combustion engine includes: estimating a convergence temperature of the exhaust gas catalytic converter; calculating an OTP boost value using the estimated convergence temperature; and estimating the convergence temperature on the assumption that the temperature decrement quantity of the exhaust gas catalytic converter which is caused by the power boosting is zero when both of the OTP boosting execution condition and the power boosting execution condition are met.

Abstract: A sensor control apparatus includes: a gas sensor including an oxygen concentration detection cell having a first solid electrolyte body, a reference electrode and a detection electrode, and a heater; an electric current supply unit that supplies electric current to the oxygen concentration detecting cell; an activation determination unit; a heater control unit that sets a first target temperature equal to or higher than an activation determination temperature when the activation determination unit determines that the temperature of the gas sensor is equal to or higher than the activation determination temperature; an automatic stop detection unit; and a first temperature switching unit that controls electric current supplied to the heater such that the target temperature of the heater is switched to a second target temperature different from a temperature at which blackening is generated in the first solid electrolyte body when an automatic stop is detected.

Abstract: The present invention performs correction appropriately according to errors in the fuel system and air system respectively and corrects both variations in the air-fuel ratio and torque. When the difference between a target air-fuel ratio and a real air-fuel ratio is equal to or below a predetermined value when feedback control based on the air-fuel ratio of an exhaust manifold 10A is in progress, the air-fuel ratio of a cylinder cyl—1 having the largest variation of angular acceleration is corrected to the rich side, for example, by increasing the amount of fuel. Angular acceleration per cylinder is then detected again and when the variation in angular acceleration among cylinders is not eliminated, it is judged that there is an error in the amount of air control of the cylinder having the largest variation and the amount of air, amount of fuel, ignition timing or the like are corrected.

Abstract: A method of controlling an amount of fuel to an engine is disclosed. The method includes determining first and second fuel limits. The first fuel limit is indicative of a higher value than the second fuel limit. The method also includes determining an amount of fuel to be delivered to an engine as a function of at least one engine parameter. The method further includes controlling the amount of fuel to be less than or equal to the first fuel limit in a first set of operating conditions and controlling the amount of fuel to be less than or equal to the second fuel limit in a second set of operating conditions.

Abstract: A control system for an internal combustion engine, which is capable of enhancing the accuracy of fuel control and ignition timing control even when there is a possibility that the reliability of a calculated intake air amount lowers, and enables reduction of manufacturing costs. An ECU of the control system calculates a first estimated intake air amount according to a valve lift, a cam phase, and a compression ratio, calculates a second estimated intake air amount according to the flow rate of air detected by an air flow sensor. The ECU determines a fuel injection amount according to the first estimated intake air amount when an estimated flow rate Gin_vt calculated based on an engine speed, the valve lift, the cam phase, and the compression ratio is within the range of Gin_vt?Gin1, and according to the second estimated intake air amount when Gin2?Gin_vt.

Abstract: In a method of controlling an internal combustion engine wherein an injection begin is calculated depending at least on an actual engine speed and the injection begin is corrected, the injection begin correction is calculated from a deviation of a desired air mass flow from an actual air mass flow.

Abstract: In a fuel injection control method of an engine, an electronic control unit calculates a pressure integrated value for one combustion cycle by detecting a combustion cycle and continuously detecting a suction air pipe pressure and determines that the engine is under an accelerated state such that a pressure difference determined by comparing the pressure integrated value with the pressure integrated value at the preceding combustion cycle becomes equal to or more than a predetermined acceleration determining reference value, thereby increasing a fuel amount. The electronic control unit determines that the engine is under the accelerated state at a particular time when the difference between the pressure integrated value and the atmospheric pressure becomes equal to or less than a reference value and a pressure difference integrated value obtained by integrating each of the pressure differences within an integrating period becomes equal to or more than another reference value.

Abstract: Electronic control apparatus for a vehicle, in particular a heavy goods vehicle, which apparatus includes an electronic control unit (ECU) adapted to control actuation of vehicle brakes. The ECU has a non volatile storage memory for storing braking related control parameters particular to the vehicle and a discretely programmable storage device to carry operating data for one or more auxiliary functions of the vehicle. The ECU is operable to check one or more incoming and outgoing variables and control algorithms against a predefined list such as to safeguard the braking function against error modes.

Abstract: Air-fuel ratio control apparatus for an engine of automobile for controlling an air-fuel ratio to a desired value includes module (33) for computing a purge ratio (Pr) from a purge quantity (QPRG) and an engine operation state, module (35) for computing a purge air concentration (Pn) from the purge ratio (Pr) and an air-fuel ratio feedback correcting coefficient (CFB), module (36) for computing a purge air concentration correcting coefficient (CPRG) from the purge ratio and the purge air concentration, module (39) for computing a fuel injection quantity (Qf) supplied to the engine (6) from the purge air concentration correcting coefficient, and module (37) for detecting an accelerating state of the automobile. The purge air concentration correcting coefficient is reset to an initial value when the purge air concentration correcting coefficient is not greater than a predetermined value (indicating leanness) and when the acceleration is detected.

Abstract: A method and a device for controlling an engine, in which a control module calculates a setpoint torque based on an accelerator position and calculates an air mass and a fuel mass from this setpoint torque. In the process, a setpoint value for lambda (ratio of air mass to fuel mass) is taken into account when the fuel mass is calculated. A monitoring module calculates a monitoring value for the air mass from the fuel mass and compares it to a measured air mass for fault detection.

Abstract: The present invention relates to a method and system for preventing a lean Air/Fuel ratio that may occur when accelerating an engine. An engine is supplied with a base amount of fuel that is adjusted, or compensated, according to one or more compensation variables that are based on an oxygen sensor signal. If the compensation variables are reduced by more than a predetermined amount and the throttle valve open-angle exceeds a predetermined value, then the method and system of the invention prevent a lean Air/Fuel ratio that may occur by initializing the compensation variables for a predetermined period of time, thereby allowing the engine to perform smoothly.

Abstract: When control conditions are satisfied, an A/F value is estimated from an average value of rotation speed Ne and an increasing rotation speed &Dgr;Ne calculated. The estimated A/F value as a base is obtained from the average value of the rotation speed Ne, and a correction value for the estimated A/F value is obtained from the increasing rotation speed &Dgr;Ne. Then, a fuel increment/decrement correction coefficient &ggr; and an air increment/decrement correction coefficient &bgr; are calculated, and used in the control of A/F ratio toward a target A/F value based on a final estimated A/F value.

Abstract: An intake air quantity detected by an air flow meter is corrected based on a change speed of an engine load and on a change speed of an engine rotation speed, and an oxygen quantity stored in a catalytic converter is estimated based on the corrected intake air quantity and an oxygen concentration in the exhaust gas.

Abstract: An engine control system for diminishing driveline vibrations extracts resonant frequency component coincident in frequency with a driveline resonant vibration according to a gear ratio of a transmission of the driveline from a change in charging efficiency with time that is detected on the basis of a signal representative of an amount of intake air, converts the resonant frequency component to a demanded amount of engine torque reduction after having adjusted the resonant frequency component in phase, and causes the demanded amount of engine torque reduction by retarding an ignition timing and/or reducing an amount of fuel injection.

Abstract: The present invention relates to a method and system for preventing a lean Air/Fuel ratio that may occur when accelerating an engine. An engine is supplied with a base amount of fuel that is adjusted, or compensated, according to one or more compensation variables that are based on an oxygen sensor signal. If the compensation variables are reduced by more than a predetermined amount and the throttle valve open-angle exceeds a predetermined value, then the method and system of the invention prevent a lean Air/Fuel ratio that may occur by initializing the compensation variables for a predetermined period of time, thereby allowing the engine to perform smoothly.

Abstract: In an internal combustion engine mounted on a vehicle, the constitution is such that the fuel injection quantity is switched to correspond to the operating state of said engine while being gradually increased when an auxiliary brake is switched from a non-operating state to an operating state, thereby preventing excessive fuel supply due to a time delay in the operation of the auxiliary brake, and improving the exhaust property.

Abstract: An intake air quantity detected by an air flow meter is corrected based on a change speed of an engine load and on a change speed of an engine rotation speed, and an oxygen quantity stored in a catalytic converter is estimated based on the corrected intake air quantity and an oxygen concentration in the exhaust gas.

Abstract: An engine control device provided with a lean NOx catalyst comprises means for estimating a condition of the lean NOx catalyst, means for performing reactivation control of the lean NOx catalyst based on the result, and means for controlling the termination of the reactivation control. The lean NOx catalyst is constantly made usable in a favorable condition.

Abstract: An apparatus and method for controlling fuel injection signals to an engine during a sudden acceleration event. The present apparatus and method includes an electronic controller coupled to the electronically controlled fuel injectors of the engine and operable to recognize a sudden acceleration condition based upon certain sensed conditions associated with the acceleration of the engine. The controller is further operable to increase the pull-in current level and/or the hold-in current level of the fuel injection signals to improve fuel injector performance, fuel consumption, and emissions when a sudden acceleration event is recognized. Shortening the duration of the fuel shots associated with the fuel injection signal helps offset additional electrical power requirements associated with the higher current levels.

Abstract: An engine control device provided with a lean NOx catalyst comprises means for estimating a condition of the lean NOx catalyst, means for performing reactivation control of the lean NOx catalyst based on the result, and means for controlling the termination of the reactivation control. The lean NOx catalyst is constantly made usable in a favorable condition.

Abstract: 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.

Abstract: A fuel injection control apparatus for an internal combustion engine includes an injector control apparatus 120B for controlling a fuel injection amount toward a target fuel injection amount Fm. The injector control apparatus 120B includes an expected engine revolution number calculating means 9 for calculating an expected engine revolution number Nf for a predetermined interval based on the engine revolution number Ne, expected throttle opening degree calculating means 10 for calculating an expected throttle opening degree .theta.f for the predetermined interval based on a throttle opening degree .theta., expected drawn air amount calculating means 11 for calculating an expected drawn air amount Qf for the predetermined interval based on the expected engine revolution number and the expected throttle opening degree, and target fuel injection amount calculating means 12 for calculating a target fuel injection amount Fm.

Abstract: An air-fuel ratio control system for an internal combustion engine includes an air-fuel ratio sensor arranged in the exhaust system of the engine. An ECU estimates the air-fuel ratio of a mixture supplied to each of the cylinders cylinder by cylinder in response to an output from the air-fuel ratio sensor, by using an observer for observing an internal operative state of the exhaust system, based on a model representative of the behavior of the exhaust system, and calculates cylinder-by-cylinder air-fuel ratio control amounts corresponding respectively to the cylinders for carrying out feedback control of the air-fuel ratio of the mixture supplied to each of the cylinders such that the estimated air-fuel ratio of the mixture supplied to each of the cylinders is converged to a desired value.

Abstract: An air-fuel ratio control system for an internal combustion engine includes an ECU which cuts off fuel supply to the engine at deceleration thereof, measures a fuel cut-off period over which the fuel cut-off means cuts off fuel supply to the engine, and enriches the air-fuel ratio of a mixture supplied to the engine to a degree dependent upon the measured fuel cut-off period, at the restart of fuel supply to the engine immediately after termination of cutting-off of fuel supply to the engine.

Abstract: An air/fuel ratio control apparatus for executing auxiliary control of an air/fuel ratio by compensating an injected fuel amount set by a control system for maintaining the air/fuel ratio at a preset value. The air/fuel ratio control apparatus includes a state detecting unit for detecting a plurality of physical values which can be measured at low temperature and which show a state of an engine, an air/fuel ratio estimating unit for receiving a plurality of physical values detected by the state detecting means as input parameters and for estimating the air/fuel ratio using a neural network, and a compensatory fuel amount calculating unit for calculating a compensatory fuel amount for the injected fuel amount from the estimated air/fuel ratio. Here, low temperature refers to a temperature at which an air/fuel sensor cannot operate.

Abstract: In an internal combustion engine equipped with electronically controlled fuel injection valves, there is provided an air-fuel ratio detecting system. The system comprises a wide range type air-fuel ratio sensor disposed in an exhaust pipe of the engine. The sensor issues an output voltage that varies continuously in accordance with an exhaust gas air-fuel ratio possessed by an exhaust gas in the exhaust pipe. The output voltage of the sensor is translated to an air-fuel ratio of air-fuel mixture with reference to a reference table. A variation characteristic of the output voltage of the sensor is decided relative to variation of the air-fuel ratio of air-fuel mixture. A correction data of the translated air-fuel ratio is formed with reference to the variation characteristic. The translated air-fuel ration is corrected with reference to the correction data.

Abstract: An exhaust gas sensor has first and second sensor elements. Exhaust gas surroundings of the first sensor element are catalytically activated, so that an oxygen partial pressure which is in equilibrium will always be measured by the first sensor element, regardless of the conversion capability of a catalytic converter. The exhaust gas surroundings of the second sensor element are separate from the exhaust gas surroundings of the first sensor element, so that the exhaust gas surroundings of the second sensor element are not catalytically active. As a function of the conversion capability of the catalytic converter, the second sensor element measures either an equilibrium oxygen partial pressure or a free oxygen partial pressure, which are of different magnitudes. A malfunction of the catalytic converter is detected by comparing measurement signals of the first and second sensor elements.

Abstract: A feedback control system and method for operating an internal combustion engine to provide the desired air/fuel ratio under all running conditions. The feedback control operates to modify the fuel/air ratio from that achieved by a basic setting that is derived from parameters of engine performance so as to maintain the desired ratio. The feedback control adjusts the air/fuel ratio in two different modes. In a first, normal operation mode, the feedback control adjusts the air/fuel mixture supplied to all cylinders based upon feedback from a sensor connected to a single of the cylinders. In a second operational mode, when the speed of the engine is accelerating, the feedback control determines and adjusts the air/fuel mixture, but makes adjustments to all cylinders except the sensed cylinder independent of the output of the sensor.

Abstract: A hybrid gaseous fueling system having a low pressure supply and a high pressure supply is disclosed. This system provides the advantages of fueling with a low pressure charge during steady state operation and also provides a way to more rapidly smooth engine transients resulting from changes in engine operating characteristics such as speed or load by modulating high pressure fueling of the engine. Furthermore, air/fuel ratio control may be readily integrated into this system. In addition, start-up of the engine is performed using more fuel from the high pressure supply than the low pressure supply up to a predetermined level of engine operation. At that level and beyond, low pressure fueling is greater than high pressure fueling.

Abstract: An Electronic Engine Controller (EEC) which controls operation of an engine employs a switching type oxygen sensor to determine the composition of exhaust gas produced by the engine. The EEC enhances the signal received from the oxygen sensor to generate quantitative information from the qualitative information received from the oxygen sensor. The EEC utilizes the enhanced information from the oxygen sensor to adapt Transient Fuel Control (TFC) parameters. The EEC detects a transient, quantifies the transient in terms of two TFC parameters and adapts the TFC parameter employing fuzzy-logic controls.

Abstract: A fuel metering control system for an internal combustion engine, having a feedback loop. In the system, the quantity of fuel injection (Tim) to be supplied to the engine (plant) is determined outside of the feedback loop. A feedback correction coefficient (KSTR) is calculated using an adaptive controller and a feedback control is carried out by multiplying the quantity of fuel injection by the coefficient in the feedback control region. In view of the situation, once leaving the feedback control region due to, for example, fuel cutoff, but soon returning to the feedback control region shortly, internal variables of the adaptive controller necessary for coefficient calculation are held so as to make it unnecessary to determine the variables and to keep the control continuity and to enhance the controllability. On the other hand, if it takes a longer time to return the region, the variables are set to initial values.

Abstract: A control system is described for metering the fuel in an internal combustion engine. On the basis of the operating state of the internal combustion engine and a mixture correction signal for correcting the deviation of the air/fuel ratio from a desired value, a basic injection quantity signal is generated. A transition compensation signal is also generated while taking into account an adaptive correction factor. The adaptive correction factor is generated by comparing the mixture correction signal with a reference. The transition compensation signal is logically combined with the basic injection quantity signal to form a signal indicative of the quantity of fuel to be injected. In a second exemplary embodiment, the adaptive correction factor is determined by comparing the output signal of an exhaust gas sensor with a reference.

Abstract: A feedback control system for a gaseous fuel supplied internal combustion engine wherein the air-fuel ratio is maintained at a stoichiometric ratio by mixing air with the gaseous fuel supply to the charge former. A manually controlled air bleed is incorporated to permit adjustment for deterioration in the system due to age or carbon deposits or the like. In addition, the feedback control position of the air bleed valve is memorized, and the memorized value is utilized for control under some conditions when feedback control would not be appropriate, such as for cold starting when the sensor is not at its operating temperature or upon the resumption of normal control after a fuel shutoff during decell.

Abstract: A fuzzy logic controller for determining the air/fuel ratio of air and fuel to be delivered to an engine. The fuzzy logic controller has four input signals, two based on an air/fuel ratio feedback measurement, one based on throttle position, and one based on vehicle speed. The controller uses these inputs to obtain an "error" signal and its derivative, which are each converted to fuzzy antecedents for an inferential rule set. Application of the rule set produces at least one fuzzy output, which is defuzzified to produce a desired air/fuel ratio.

Abstract: A fuel injection control system for an engine includes fuel injection valves, each of which injects fuel to one cylinder a plurality of times during each cycle. The system has an arithmetic device for calculating a required fuel injection amount based on driving conditions and a trailing side injection capability of a trailing side injection time point, a determination device for comparing the required fuel injection amount with the trailing side injection capability and determining which is greater, and a fuel injection controller for setting a leading side injection time point and a trailing side injection time point and setting a leading side injection amount and a trailing side injection amount.

Abstract: According to one embodiment of the invention, a purge quantity is controlled in proportion to an air quantity sucked into an internal combustion engine. During normal operation of the engine, a purge air-fuel ratio is calculated according to a purge rate and an air-fuel feedback control quantity. During transient operation of the engine, a target air-fuel ratio feedback control quantity is calculated according to the purge rate and the purge air-fuel ratio. When the difference between the air-fuel ratio feedback control quantity and the target air-fuel ratio feedback control quantity is greater than a predetermined value, the air-fuel ratio feedback control quantity is corrected to the target air-fuel ratio feedback control quantity. An undue fluctuation in air-fuel ratio of a fuel mixture supplied to cylinders occurring upon rapid fluctuation in purge rate can be suppressed.

Abstract: A control device for an internal combustion engine capable of conducting lean burn control, such as exhaust gas emission control, always optimally regardless of a timewise change of the internal combustion engine, variations in engines, and an environmental change. The control device includes a detector for detecting a burn condition of the internal combustion engine, a lean limit air-fuel ratio factor map, a lean burn feedback logic, an oxygen concentration sensor, and a feedback control logic for controlling an air-fuel ratio to a theoretical air-fuel ratio, wherein lean burn is performed at the middle point between the lean limit air-fuel ratio and the theoretical air-fuel ratio.

Abstract: 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.