Abstract: An exhaust gas recirculation passage connects an exhaust passage with an intake passage. A cooling device is mounted to the exhaust gas recirculation passage for cooling exhaust gas in the exhaust gas recirculation passage. An EGR valve adjusts a flow passage area of the exhaust gas recirculation passage. An exhaust gas quantity (EGR quantity) in the exhaust gas recirculation passage is feedback-controlled by manipulating an opening degree of the EGR valve based on a measurement value of an airflow meter. Existence or nonexistence of an abnormality in the cooling device is diagnosed based on whether a measurement value of the opening degree of the EGR valve contains a component corresponding to compensation for reduction of the EGR quantity due to degradation of cooling performance of the cooling device.

Abstract: An air-fuel ratio sensor monitor is provided which is designed to monitor reactive characteristics or response rates of an air-fuel ratio sensor when an air-fuel ratio of a mixture to an internal combustion engine is changing to a rich side and to a lean side. The monitored response rates are used in determining whether the sensor is failing or not, in determining the air-fuel ratio of the mixture accurately, or in air-fuel ratio control of the engine.

Abstract: An electronic control apparatus includes a control circuit and has a power supply holding function whereby when a power switch-off command is received by the apparatus, the supplying of power to the control circuit is continued until it has completed specific processing, during a power supply holding interval. The duration of each such interval is measured and stored in non-volatile memory, and subsequently used for detecting any power supply holding function abnormality, and for ensuring that the specific processing is actually performed, and distinguishing between an abnormality causing premature switch-off and an abnormality causing failure to terminate the supplying of power.

Abstract: A main CPU transmits data used in determination of whether or not a target throttle opening degree calculation logic and an estimated target throttle opening degree calculation logic are normal (a target degree and an estimated target degree of throttle opening, and a dummy estimated target degree of throttle opening and an expected value) to a sub-CPU. The sub-CPU compares the data pieces in each of the pairs so as to calculate monitor data for monitoring whether or not the determination result in the main CPU is correct. In this manner, it is possible to enhance reliability of the routine for determining whether or not the respective logics are normal.

Abstract: A method of evaluating a contribution of a cylinder to an engine includes measuring a first revolutions per minute of the engine during an enabled state; determining a dwell period of the cylinder; applying a direct current voltage signal into a negative terminal of an ignition coil of the engine during the dwell period to disable the cylinder and create a disabled state; and measuring a second revolutions per minute of the engine during the disabled state. A system for evaluating a contribution of a cylinder to an engine includes a first measure module, a determine module, an apply module, and a second measure module. The first measure module measures a first revolutions per minute of the engine during an enabled state. The determine module determines a dwell period of the cylinder. The apply module applies a direct current voltage signal into a negative terminal of an ignition coil of the engine during the dwell period to disable the cylinder and create a disabled state.

Abstract: To identify a failed manifold pressure sensor in a control apparatus having two manifold pressure detection systems as a. A calculating unit calculates a difference between the manifold pressure detected by two sensors. A first comparing unit outputs an abnormal signal when the difference is larger than a threshold value. A calculating unit calculates a difference between the manifold pressure and the atmospheric pressure. A difference calculating unit calculates a difference between the manifold pressure and the atmospheric pressure. When the abnormal signal is outputted from the first comparing unit while an engine is stopped, a second comparing unit compares the differences in response thereto. Depending on which one of the differences is larger, it is determined which one of the manifold pressure sensors is abnormal.

Abstract: A method and system are provided for processing multiple sensor output signals of different ranges/sensitivities so as to provide a seamless transition when switching between the different ranges. More specifically, a determination is made as to whether a selected sensor output range is of a sensitivity higher than a predetermined sensitivity. If the sensitivity is higher, the value of a higher sensitivity sensor output is converted to a value corresponding to the predetermined sensitivity range. An error value is then determined between the converted sensor output value and a sensor output corresponding to a range having the predetermined sensitivity. The sensor output is then modified based on the error value when the control process switches from the selected sensor output to the sensor output corresponding to the predetermined sensitivity. This insures that no glitches will occur in a controller output at the time of switchover.

Abstract: The present invention discloses a method for preventing a control program written in a first engine control unit (ECU) from running in a second ECU, comprising obtaining an ID number from the first ECU; encrypting the ID number; writing the encrypted ID number into a flash memory of the first ECU; encrypting the ID number again and writing the encrypted ID number into an EEPROM of the first ECU; and requiring the control program to match the encrypted ID number placed in the flash memory and the EEPROM before running the program, and if the match fails, terminating the control program from running further.

Abstract: A method of identifying target outputs, such as emissions levels, for a dynamic system, such as an engine. The engine is run at numerous combinations of input parameters, such as actual settings. At each combination of input parameters, the system is driven to a “quasi-steady” state, rather than waiting for it to reach a steady state. Response data collected at this quasi-steady state is used as the basis for identifying the target outputs and the associated inputs.

Abstract: A process which wirelessly detects spark activity and by using software and a microcontroller to process the data share the information with other devices or information networks

Abstract: A method of resetting an active emissions system error indicator associated with a vehicle. The method comprises performing at least a first requesting step, where the requesting step is performed indirectly by using a record mode function until said active e emissions system error indicator resets in response to the requesting step. In one embodiment an additional step comprises the additional step of performing at least a second requesting step for a second type of information, the second requesting step performed either manually or by the record mode function. In a particular embodiment of the invention, an electronic tool, such as a bi-directional scan tool, is used to perform the firsgt and second requesting steps.

Abstract: An apparatus, system, and method are disclosed for providing system feedback from combined input values in a sensor-based control system wherein the reliability of a sensor response is questionable under defined conditions. The apparatus, in one embodiment, is configured to determine an output value. The apparatus may include an input module for receiving input from a sensor configured to provide a sensor response, an estimated expected response value, and a control module for determining an output value based on input from the sensor response and from the expected response value. To determine an output value, the sensor response and the expected response value may be weighted according to a predicted reliability of the sensor response or the model. The system may be embodied in an exhaust gas after-treatment system.

Abstract: A method for monitoring a vehicle exhaust system may include (1) measuring exhaust-gas temperature at an outlet side of an exhaust pipe section which is intended to accommodate a component with a purifying activity, (2) measuring exhaust-gas temperature at an inlet side of the exhaust pipe section, and (3) comparing a time curve of the outlet-side temperature with a time curve of the inlet-side temperature, wherein the comparison comprises determining a time derivative of the outlet-side temperature or of the inlet-side temperature. Alternatively, the method may include (1) measuring exhaust-gas temperature at an outlet side of an exhaust pipe section which is intended to accommodate a component with a purifying activity, (2) determining a calculated value for the exhaust-gas temperature at the outlet side based on at least one of the heat-storing and fluid-dynamic action of the component, and (3) comparing a time curve of the measured outlet-side temperature with a time curve of the calculated value.

Abstract: An engine start control device which in a time period from the start of a starting operation by a starter for starting an engine to the start of the engine, reads out substitute values used at the time of starting the engine, instead of reading out backup data used for normal operation control of the engine, and after starting of the engine, reads out the backup data instead of the substitute values.

Abstract: Disclosed herein is a controller and method useful for transferring control of a process control device between first and second control modes. The controller includes first and second servo control modules that generate first and second drive signals based on feedback information from first and second sensors for control of the process control device in accordance with first and second control modes, respectively. The controller also includes a feedback control transfer module that transfers control of the operation of the process control device from the first control mode to the second control mode based on the feedback information from the first sensor. In certain embodiments, such control transfer involves a control routine that initially generates the second drive signal based on the first drive signal to effectuate a smooth, bumpless transfer between the control modes.

Abstract: The invention relates to a method of estimating a nitrogen oxide mass stored in a catalytic nitrogen oxide trapping device (1) which comprises a catalytic phase and which is traversed by the exhaust gases (2) from the internal combustion engine (3) of a motor vehicle (4) comprising an electronic control unit (5). The inventive method consists in: discretising the geometry of the catalytic trapping device (1) into several (n) perfectly-stirred, successive individual reactors (6, 7); and combining a thermal model, which can be used to calculate the temperature variation of the catalytic phase of the catalytic trapping device (1) during the traversing movement of the exhaust gases, and an absorption model, which can be used at any moment to calculate the nitrogen oxide mass stored in the catalytic trapping device (1) on the basis of the characteristics of said device (1), the temperatures from the thermal model for each individual reactor and the exhaust gas mass flow from the engine (3).

Abstract: A method of diagnosing an operating condition of a short runner valve in an intake manifold of an internal combustion engine using an exhaust sensor in an exhaust manifold of the internal combustion engine. The short runner valve is commanded to an open position for a test period, it is resolved whether the test period has elapsed, and it is determined whether a sensed exhaust gas parameter has exceeded a threshold during the test period. A pass signal is issued if the sensed exhaust gas parameter has exceeded the threshold within the test period. Otherwise, a fail signal is issued if the sensed exhaust gas parameter has not exceeded the threshold within the test period.

Abstract: An electronic control unit for a vehicle-mounted engine system has a computer and a single program memory. The program memory stores a plurality of functionally finely classified programs, which includes programs to be used in common between a normal engine control mode and a fuel evaporation leak diagnosis mode. The plurality of programs is associated, as a reference table, with the plurality of different control modes by separating programs required for the respective control modes. The computer sequentially executes only programs associated with the designated control mode, when any of the control modes is designated.

Abstract: An in-cylinder pressure sensor outputs a signal corresponding to a change rate of an internal cylinder pressure of an engine. The output signal of the in-cylinder pressure sensor is filtered so that frequency components lower than frequencies that substantially compose an internal cylinder pressure required for controlling the engine are cut. The filtered output signal is integrated to determine the internal cylinder pressure. Thus, an internal cylinder pressure having no drift can be determined.

Abstract: An alternator and starter tester system is provided that includes a protective hood or cover, a controller connecting an LCD touch-screen, an alternator main harness connector, a starter harness self-test connector, a barcode connector, USB host and USB function connectors, an Ethernet connector, and a compact flash connector. A multiplexer is also provided to reduce the number of connectors required for various alternators that have the same type of connections but have signals on different pins.

Abstract: It is an object of the present invention to provide an engine control apparatus for detecting a voltage abnormality caused in a power supply thereof at low cost. An engine control apparatus for controlling an engine, includes: power supply voltage detecting unit for detecting a power supply voltage of a battery mounted on a vehicle as a power supply, which supplies the engine control apparatus with power; backup power supply voltage detecting unit for detecting a backup power supply voltage of a backup power supply, which supplies the engine control apparatus with power from the battery via a different path; voltage difference calculating unit for calculating a voltage difference between the power supply voltage and the backup power supply voltage; and power supply voltage abnormality determining unit for determining that there is an abnormality in the power supply voltage when the voltage difference is not within a predetermined range.

Abstract: A method for regulating an internal combustion engine where engine measurement and engine adjustment values is provided, and adaptation values modify the engine parameters, comprising measuring a first engine measurement parameter representative of a first physical engine parameter, measuring a second engine measurement parameter representative of a second physical engine parameter, calculating a first estimation parameter via a first engine parameter, calculating a second estimation parameter via a second engine parameter, determining a first operating mode of the engine regulation method, the first operating mode determined by generating a first adaptation value based on the first engine parameter, generating a second adaptation value based on the second measurement parameter, and comparing the percent difference of the first and second adaptation values to a neutral value of the respective engine parameter, and determining a second operating mode of the engine regulation method.

Abstract: A fail-safe mechanism of an air induction control apparatus for automotive engines is provided which is designed to hold a throttle valve at a middle position when a valve actuator has failed to move the throttle valve. The fail-safe mechanism includes a middle position hold stopper, an opener lever connected to the throttle shaft, and a first and a second coil spring. The first coil spring works to exert a first spring pressure on the opener member in a first rotational direction in which the throttle valve is rotated from a fully opened position to the middle position. The first coil spring is urged at an end thereof into constant engagement with the middle position hold stopper to hold the opener member from rotating in a second rotational direction opposite the first rotational direction. The second coil spring has a first and a second end between which the opener member extends. The first end abuts against the middle position hold stopper.

Abstract: To identify a failed atmospheric pressure sensor in a control apparatus having two atmospheric pressure detecting systems as a failsafe. A first comparing unit outputs an abnormal signal when a difference between atmospheric pressures detected by two sensors is larger than a threshold value. An atmospheric pressure estimating unit estimates the atmospheric pressure from an engine revolution, a throttle opening, and a manifold pressure. The difference calculating unit calculates a difference between the detected atmospheric pressure and the estimated atmospheric pressure. The difference calculating unit calculates a difference between the detected atmospheric pressure and the estimated atmospheric pressure. When an abnormal signal is outputted from the first comparing unit, a second comparing unit compares the differences in response thereto. The failed atmospheric pressure sensor is identified according to which one of the differences is larger.

Abstract: An exhaust gas recirculation control device in a diesel engine, capable of suppressing NOx and smoke discharged. A first temperature sensor (11) is provided at a portion more on the upstream side than a portion where a suction air path (3) joins an exhaust gas recirculation path (4), and a second temperature sensor (12) is provided on the downstream side. Further, an engine load detection sensor (6) and an engine speed detection sensor (7) are arranged. The exhaust gas recirculation control device also has memory means where the temperature of suction air before it is mixed with an exhaust gas and a temperature value at a second temperature sensor installation position are previously memorized, the temperature value corresponding to an appropriate exhaust gas recirculation amount that is uniquely defined by an engine load and an engine speed. Further, judging means is provided.

Abstract: When ENG frames created in an ENG transceiver unit and ECT frames subjected to gateway processing in an ECT gateway processor are transmitted around the same time, a transmission mediating unit alternately transmits each of the ENG frames and the ECT frames. Therefore, as compared with a case where one type of frames are preferentially transmitted, transmission of both types of frames can be started at the earliest timing.

Abstract: In an apparatus, an abnormality determining circuit determines whether a crank signal is abnormal, and a switching circuit switches an input signal to an edge interval measuring circuit from the crank signal to a cam signal when it is determined that the crank signal is abnormal. The edge interval measuring circuit measures an edge interval of temporally adjacent same-directed edges of the cam signal. A count-value control circuit identifies angular positions of a crankshaft based on the cam signal to initialize a count value of a count unit based on the identified angular positions of the crankshaft. The count-value control unit circuit changes an integral number based on a predetermined waveform pattern of the cam signal to shift the count value of the count unit as in the case of the crank signal inputting to the edge interval measuring circuit.

Abstract: When any one of a plurality of variable valve characteristic mechanisms which vary different operating characteristics of an intake valve is failed, a limit which is capable of satisfying predetermined conditions for a change in opening timing of the intake valve at the time when the other operating characteristic is varied by the normally operating variable valve characteristic mechanism, is set and the operating characteristics of the intake valve are controlled while limiting the intake valve opening timing by the limit, by the normally operating variable valve characteristic mechanism.

Abstract: Evaluation of a diagnosis function for diagnosing a transient response of a variable valve mechanism for an engine valve is executed in a manner such that a desired value on the variable valve mechanism is calculated based on testing signals of a rotating speed and a water temperature, that a controlled variable signal for testing indicating a state in which the transient response of the variable valve mechanism is delayed, is generated, and that the diagnostic function for the transient response is evaluated based on whether or not the delay of the transient response is diagnosed on the basis of a correlation between the desired value and a controlled variable signal.

Abstract: The invention relates to an internal combustion engine comprising a crankshaft, a camshaft and an adjusting device, which is used to adjust the phase position of the camshaft in relation to the crankshaft. The phase position is determined in accordance with a detected crankshaft angle and a recorded camshaft angle. A filter coefficient of a filter is determined in accordance with the amplitude of an oscillation of the phase position and the modification of said phase position. A filtered phase position of the determined phase position is calculated using the filter.

Abstract: A method for diagnosing errors in an intake system of an internal combustion engine having a variable intake manifold geometry is provided. According to the method, an air mass flow oscillation in the intake manifold is detected at an engine rotational speed that is present, the detected air mass flow oscillation is subjected to signal analysis to determine a characteristic actual oscillation variable which is compared to a setpoint oscillation variable associated with the engine rotational speed that is present.

Abstract: A control system of an internal combustion engine provided with a throttle valve passage air flow calculation equation by which the throttle valve passage air flow mt is expressed as a function of the downstream side intake pipe pressure at the downstream side of the throttle valve and a cylinder intake air flow calculation equation by which the cylinder intake air flow mc is expressed as a function of the downstream side intake pipe pressure, where said downstream side intake pipe pressure Pm and cylinder intake air flow mc when the throttle valve passage air flow mt found from said throttle valve passage air flow calculation equation and the cylinder intake air flow mc found from said cylinder intake air flow calculation equation match are calculated as the downstream side intake pipe pressure Pmta and cylinder intake air flow mcta at the time of steady operation under the operating conditions at that time is provided.

Abstract: In a method for determination of a change in volumetric efficiency for an internal combustion engine, a reference volumetric efficiency is determined in advance. A first actual volumetric efficiency value which corresponds to a sensor error, is then determined at a first measurement point in a first rotational speed range in which a change in the flow losses in an intake tract has only a minor effect on the volumetric efficiency. A second actual volumetric efficiency value is determined at a second measurement point in a second rotational speed range that is greater than the first rotational speed range. The second actual volumetric efficiency value is corrected by means of the first actual volumetric efficiency value, and the change in volumetric efficiency is determined from the reference volumetric efficiency and the corrected second actual volumetric efficiency.

Abstract: An engine control circuit includes a battery voltage detector, a signal supervisor, and a processor that operates in a normal mode and a power-down mode. The battery voltage detector senses the output voltage of a battery that supplies current to the engine, and asserts a detection signal when the voltage is below a predetermined value. The signal supervisor measures the length of time for which the detection signal remains asserted. The processor switches from the normal mode to the power-down mode when the measured length of time reaches a predetermined value. This scheme avoids loss of engine control when the battery voltage drops briefly and then recovers.

Abstract: An engine control system including an engine controller, a plurality of sensors coupled to the engine controller, and a neural network operating in the engine controller, and where upon failure of at least one of the plurality sensors, the neural network generates a representative value of the failed sensor.

Abstract: A method, a control unit, and a computer program for detecting a defective intake-manifold pressure sensor and/or a defective ambient-pressure sensor in an internal combustion engine having a variable valve timing are provided. The desired detection is carried out exclusively on the basis of a direct evaluation of the pressure upstream from the throttle valve and the pressure in the intake manifold. This method eliminates the need for deriving load signals from these pressures, at least for the determination as to whether at least one of the pressure sensors is defective.

Abstract: A method for optimizing characteristics maps for the control of an internal combustion engine in which a model of the internal combustion engine is first formed by measurements on the internal combustion engine. In the process, a dependency of output variables of the internal combustion engine on the characteristics maps is illustrated. In the optimization, the dependency of the output variables of the internal combustion engine on the characteristics maps and the smoothing of the characteristics maps are optimized simultaneously.

Abstract: In a method for controlling a switching flap (10) arranged in an intake pipe connected with an internal-combustion engine the switching flap (10) is rotated with the aid of a switching-flap shaft (12) connected with an electromotor (18). With the aid of a position-detecting device (22,26;24,26) an end position of the switching flap (10) is detected. Subsequently, a rotation force is continued to be applied to the shaft (12) to hold the switching flap (10) in the end position. For detecting a breakage of the switching-flap shaft (12), an error message is generated when the switching-flap shaft (12) continues to rotate beyond the end position.

Abstract: A control apparatus for an internal combustion engine includes a crankshaft, a camshaft for actuating an intake valve of the engine, a crank position sensor that outputs a crank signal every time the crankshaft rotates 10° of crank angle, an electric motor that is coupled to the camshaft, and an engine control computer that, based on the crank signal, controls the engine every time the crankshaft rotates 30° of crank angle. The motor includes a rotor and three rotation sensors. Each sensor outputs a signal corresponding to induced voltage generated by rotation of the rotor. The computer controls the rotating motor based on the signals from the rotation sensors. When the crank position sensor malfunctions, the computer controls the engine every time the crankshaft rotates 30° of crank angle based not on the crank signal but on a rotation pulse train generated based on the signals from the rotation sensors.

Abstract: An engine diagnostic system is provided that enables a service technician to evaluate engine cylinder contribution to output power. The service technician couples one or more signal leads to the vehicle's battery, alternator, or accessory receptacle (e.g., cigarette lighter receptacle) to provide an alternator output signal to a signal analyzer. The signal analyzer processes the alternator output signal to generate an engine signature, which represents engine cylinder contribution to engine output power.

Abstract: A method for detecting a malfunction in a manifold absolute pressure sensor used in an internal combustion engine. The method includes obtaining a plurality of samples from the manifold absolute pressure sensor. A plurality of samples is obtained from a mass airflow sensor for measuring air flow to the engine. A plurality of inferred manifold absolute pressures is estimated from the plurality of samples obtained from the mass airflow sensor. A linear functional relationship is determined between manifold absolute pressure and inferred absolute pressure from the obtained samples of the manifold pressure sensor and the estimated inferred manifold absolute pressures, such functional relationship having an offset term and a slope. A comparison is made between the determined offset term and the determined slope with a predetermined offset threshold and a predetermined slope threshold level, respectively.

Abstract: A method for improving engine position sensing of an internal combustion engine is described. According to one aspect of the description, the determination of engine position may be improved by correcting rotational position of the internal combustion engine at a number of engine locations.

Abstract: A control apparatus for an internal combustion engine can detect a tubing disconnection failure of an intake pressure sensor thereby to make it possible to give a warning to a user and to take appropriate measures to cope with such a failure situation. A control unit controls the engine based on a throttle opening, an intake pressure measured by an intake pressure sensor, and a rotational speed and a crank angle of the engine. The intake pressure sensor is connected to the intake system through tubing. The control unit includes a failure diagnosis section that detects an abnormality of the intake pressure sensor. The failure diagnosis section detects an open circuit or a short circuit of a signal line between the intake pressure sensor and the control unit based on a change in the intake pressure, and also detects a disconnection failure of the tubing of the intake pressure sensor.

Abstract: A switching device for detecting a voltage interruption at a control unit in a motor vehicle, with a nonvolatile memory for storage of calibration data for an actuator that can be adjusted by the control unit and a drive unit. The control unit is supplied with an internal voltage through a voltage regulator and a bistable multivibrator is connected ahead of the voltage regulator in the external voltage supply of the control unit, and, whereby a microcomputer is connected with the multivibrator and is integrated in the control unit.

Abstract: A signal modifying device, user interface, and method of modifying a signal. The signal modifying device includes a processor, a first input coupled to the processor and an output coupled to the processor. Instructions are stored within the processor that, when executed by the processor, cause the processor to provide a signal incident at the output that corresponds to a signal incident at the input.

Abstract: A combustion state detecting apparatus is provided for an engine having internal pressure sensor for detecting an internal pressure of a combustion chamber of the engine and crank angle detector for detecting a crank angle of the engine. The apparatus calculates a volume of the combustion chamber based on the crank angle detected by the crank angle detector and estimator for estimating a motoring pressure of the engine in accordance with a calculation equation using the calculated volume. The apparatus adjusts either of the pressure detected by the internal pressure sensor and the pressure estimated by the estimator during a compression stroke of the engine to minimize the error between the detected pressure and the estimated pressure. The apparatus determines a combustion state during a combustion stroke of the engine based on a relation between the pressure adjusted and the other pressure.

Abstract: Systems and methods for controlling an engine using feedback from one or more sensors are disclosed. An illustrative control system for controlling a diesel engine may include one or more post-combustion sensors adapted to directly sense at least one constituent of exhaust gasses emitted from the exhaust manifold of the engine, and a state observer for estimating the internal state of the diesel engine based on feedback signals received from the post-combustion sensors and from subsequent use of the estimated state in a controller that sends the actuator setpoints. The post-combustion sensors can be configured to directly measure emissions such as oxides of nitrogen (NOx) and/or particulate matter (PM) within the exhaust stream, and provide such information to a state observer that, in turn, updates an internal dynamical state based on these measurements.

Abstract: Calculation models (22, 24) for an in-cylinder air charge amount determine an estimated intake air pressure (Pe) based on an intake air flow rate (Ms), and then determine an air charge amount (Mc) from the estimated intake air pressure (Pe). A correction execution module (26) corrects, while a vehicle is traveling, the calculation model based on the relationship between the estimated intake air pressure (Pe) and a measured intake air pressure (Ps).

Abstract: An apparatus for measuring a piston temperature can simultaneously measure a temperature of a plurality of pistons by utilizing a Bluetooth unit and occurrence of noise is prevented.

Abstract: Defective actuators in an internal combustion engine with at least one cylinder are detected. A mean value, in particular the arithmetic mean value, determines a measurement variable of all the actuators of a given type present on the cylinders. The measurement variable depends on at least one parameter. In a further step, a deviation is formed which is independent of the parameter. This ensures that the deviation across the entire parameter range remains constant. In a further step, the limit values, in particular the upper and lower limit values, are formed, the limit values being dependent on the deviation and on the mean value formed above. If an individual value of the measurement variable exceeds one of the two limit values, the method according to the invention detects this actuator as faulty and/or defective.