Abstract: A method is disclosed for controlling a variable valve timing mechanism of an internal combustion engine having a plurality of cylinders, wherein, at a first operating point of the internal combustion engine, the fuel quantity which is fed in in each case is reduced successively for each cylinder until a predetermined unsmooth-running limiting value is reached. The variable valve timing mechanism is controlled with consideration of the cylinder-individual values for the fuel-quantity reduction at the first operating point.

Abstract: A method is disclosed for checking a valve on an exhaust gas turbocharger of an internal combustion engine, wherein an exhaust gas flow exits the internal combustion engine, a first portion of said flow flowing through a turbine of the exhaust gas turbocharger into an exhaust gas system and a second portion flowing through the valve into the exhaust gas system, wherein said method includes the steps of varying a fuel-to-air ratio in a fresh gas supplied to the internal combustion engine, determining a residual oxygen content in the exhaust gas system, and determining that the valve is defective if a variation of the residual oxygen content occurs in a manner different than a predetermined manner of the variation of the fuel-to-air ratio in the fresh gas. A device for checking the valve can be integrated into an integrated engine control unit of the internal combustion engine.

Abstract: A method is provided for checking the functional capacity of a liquid-cooled exhaust manifold of an internal combustion engine, having an exhaust line connected to the exhaust manifold, in the course of which an exhaust gas sensor having an electrical heater is arranged. During the operation of the internal combustion engine, the electrical resistance of the exhaust gas sensor is determined, on the basis of which the current value of the exhaust gas temperature is evaluated, and compared to a target value of the exhaust gas temperature, which is expected at this point in the operation of the internal combustion engine. Depending on the result of the comparison, the functional capacity of the liquid-cooling of the exhaust manifold is estimated.

Abstract: An internal combustion engine has a plurality of cylinders with fuel-metering injection valves, and an exhaust gas probe that generates a measurement signal characteristic of the air/fuel ratio in the respective cylinder. A correction signal for fuel mass to be metered is determined using a lambda controller as a function of the exhaust gas probe measurement signal. When at least one predefined condition is met within a predefined operating range of the engine, a cylinder-specific diagnosis relating to the emissions of pollutants is performed on the basis of unsmooth running, wherein the cylinder-specific diagnosis is actively performed only in a respective detection phase that is applied to a neutral value by a modified proportional discrete level of the correction signal and is performed with a modified integral parameter of the lambda controller that is reduced as compared with an integral parameter in a normal operating mode of the lambda controller.

Abstract: A method for controlling a variable valve train of an internal combustion engine including multiple cylinders is disclosed. At a first operating point of the engine, an intake air amount is determined and cylinder-individual values for a fuel amount reduction are determined by successively reducing the respectively supplied fuel amount for each cylinder until a characteristic representing uneven running of the engine has reached a predetermined uneven running threshold value. A ratio of a change in the intake valve lift to the resulting change in the intake air amount is determined for the first operating point. Cylinder-individual deviations of the intake valve lift from a reference value are determined based on the ratio, the intake air amount at the first operating point, and the associated value for the fuel amount reduction. The variable valve train is then controlled on the basis of the cylinder-individual deviations of the intake valve lift.

Abstract: A method is disclosed for controlling a variable valve timing mechanism of an internal combustion engine having a plurality of cylinders, wherein, at a first operating point of the internal combustion engine, the fuel quantity which is fed in in each case is reduced successively for each cylinder until a predetermined unsmooth-running limiting value is reached. The variable valve timing mechanism is controlled with consideration of the cylinder-individual values for the fuel-quantity reduction at the first operating point.

Abstract: A method for the functional testing of a pressure switch of a tank vent device for an internal combustion engine of a motor vehicle, enables the testing of the pressure switch even while the crankshaft is rotating. The pressure switch is located in a low pressure position if the pressure in the tank vent device is lower than a pressure threshold, and is otherwise in a high pressure position. In a rotating operating state of the crankshaft in which the pressure in an intake pipe exceeds the pressure threshold, a tank vent valve being disposed in a connecting line between a fuel vapor reservoir and the intake pipe is actuated such that the tank vent device and the intake pipe are pneumatically connected to each other. The pressure switch is assessed as defective if it is in the low pressure position after actuation of the tank vent valve.

Abstract: A method is disclosed for checking a valve on an exhaust gas turbocharger of an internal combustion engine, wherein an exhaust gas flow exits the internal combustion engine, a first portion of said flow flowing through a turbine of the exhaust gas turbocharger into an exhaust gas system and a second portion flowing through the valve into the exhaust gas system, wherein said method includes the steps of varying a fuel-to-air ratio in a fresh gas supplied to the internal combustion engine, determining a residual oxygen content in the exhaust gas system, and determining that the valve is defective if a variation of the residual oxygen content occurs in a manner different than a predetermined manner of the variation of the fuel-to-air ratio in the fresh gas. A device for checking the valve can be integrated into an integrated engine control unit of the internal combustion engine.

Abstract: In a control method suitable for an internal combustion engine (1) of a motor vehicle with an automatic engine cut-off and starting system (33) by which the internal combustion engine (1) can be cut off and started independently from the driver of the motor vehicle, the starting of the internal combustion engine (1) is detected and a variable determined, which represents a measure for the work performed by the internal combustion engine (1) since it has been started. The cut-off of the internal combustion engine (1) is controlled by the automatic engine cut-off and starting system (33) according to the variable.

Abstract: A method for monitoring a coolant temperature sensor of a motor vehicle is provided, wherein an actual value (TCOist=TCOSt) of a coolant temperature (TCO) is determined by a coolant temperature sensor when an internal combustion engine of the motor vehicle is started (t=tSt), and the coolant temperature sensor is diagnosed as a functional coolant temperature sensor if the actual value (TCOist) of the coolant temperature (TCO) drops briefly (tmin0) when the internal combustion engine is started (t=tSt). A controller, e.g., an engine controller, for performing such method is also provided.

Abstract: A first camshaft misalignment value is determined from a measurement variable allocated to an engine air flow path. A second misalignment value is determined from a first operating variable outside of the air flow path. A trouble-free operation is identified when both values are smaller than a predefined first threshold. Misalignment is confirmed when one of both values is greater than the first and a difference between both values is smaller than a predefined second threshold. An air flow path fault is identified when the first value is greater and the second value is smaller than the first threshold and when the difference between both values is greater than the second threshold. A fault outside of the air flow path is identified, when the second value is greater and the first value is smaller than the first threshold and when the difference is greater than the second threshold.

Abstract: A method is provided for checking the functional capacity of a liquid-cooled exhaust manifold of an internal combustion engine, having an exhaust line connected to the exhaust manifold, in the course of which an exhaust gas sensor having an electrical heater is arranged. During the operation of the internal combustion engine, the electrical resistance of the exhaust gas sensor is determined, on the basis of which the current value of the exhaust gas temperature is evaluated, and compared to a target value of the exhaust gas temperature, which is expected at this point in the operation of the internal combustion engine. Depending on the result of the comparison, the functional capacity of the liquid-cooling of the exhaust manifold is estimated.

Abstract: An internal combustion engine has a fuel delivering device with a high-pressure pump which conveys fuel into a fuel reservoir, and a volume flow control valve that is assigned to the high-pressure pump. A control difference (FUP_DIF) is determined from a difference between a predefined fuel pressure (FUP_SP) and a detected fuel pressure (FUP_AV). The control difference (FUP_DIF) is fed to a controller that encompasses at least one integral portion (I_CTRL). A corrective value (COR) for an error value of a fuel flow rate is determined in accordance with the integral portion (I_CTRL) of the controller if a sum of the integral portion (I_CTRL) exceeds a given threshold value during a predefined mode of operation of the internal combustion engine. In addition, an actuating signal (PWM) for the volume flow control valve is generated according to a controller value (FUEL_MASS_FB_CTRL) and the corrective value (COR).

Abstract: A method for monitoring a coolant temperature sensor of a motor vehicle is provided, wherein an actual value (TCOist=TCOSt) of a coolant temperature (TCO) is determined by a coolant temperature sensor when an internal combustion engine of the motor vehicle is started (t=tSt), and the coolant temperature sensor is diagnosed as a functional coolant temperature sensor if the actual value (TCOist) of the coolant temperature (TCO) drops briefly (tmin0) when the internal combustion engine is started (t=tSt). A controller, e.g., an engine controller, for performing such method is also provided.

Abstract: In a method for monitoring a coolant temperature sensor and/or a cylinder head temperature sensor of a motor vehicle, during a start (t=tSt) of an internal combustion engine of the motor vehicle an actual value (TCOist=TCOSt) of a coolant temperature (TCO) is determined by a coolant temperature sensor, and an actual value (TCYLHist=TCYLHSt) of the cylinder head temperature (TCYLH) is determined by a cylinder head temperature sensor, wherein the coolant temperature sensor and/or the cylinder head temperature sensor are diagnosed as functional sensors when the actual values (TCOist, TCYLHist) of the coolant temperature (TCO) and the cylinder heat temperature (TCYLH) deviate in the same direction upward in relation to an outside temperature (TAM) and/or an intake air temperature (TIA). By a control device, particularly a motor control device, a method can be and is carried out accordingly.

Abstract: In order to diagnose a coolant pump (11) which is provided for the purpose of circulating a coolant in a closed cooling circuit of an internal combustion engine (10) and which can be activated and deactivated independently of the operating state of the internal combustion engine (10), both a value representing the coolant temperature (TCO) of the internal combustion engine (10) and a value representing the cylinder head temperature (TZK) of the internal combustion engine (10) are determined at a predefined time instant (t2) after a cold start of the internal combustion engine (10) has been detected and the values are subsequently compared with each other. The coolant pump (11) is rated in terms of its operational integrity as a function of the result of the comparison. This enables a faulty coolant pump to be detected at a very early stage after a cold start of the internal combustion engine.

Abstract: A method and a device operate an internal combustion engine having a plurality of cylinders with which are associated respective injection valves for metering fuel, and having an exhaust gas probe which is arranged in an exhaust gas tract and the measurement signal of which is characteristic of the air/fuel ratio in the respective cylinder, and having a crankshaft angle sensor the measurement signal of which is representative of a crankshaft angle of the crankshaft. Within a predefined operating range of the internal combustion engine, and when at least one predefined condition is fulfilled, a rough-running based cylinder-individual diagnosis (CYBL-HOM) with regard to harmful emissions is carried out before activation of a cylinder-individual lambda control (CILC) is enabled.

Abstract: An internal combustion engine (30) with a supercharger device (50, 52) for increasing the charging pressure in an air inlet system (33) has a number of cylinders (32). Each cylinder (32) has at least one exhaust valve (36) which is connected to the exhaust system (40) and at least one inlet valve (34), which is connected to the air inlet system (33). Scavenging is carried out with a valve overlap between the inlet valve (34) and the exhaust valve (36). For controlling the operation of the internal combustion engine the system monitors whether the scavenging was successful.

Abstract: The tank venting device has a fuel vapor reservoir connected to a fuel tank to deliver escaping fuel vapors to the fuel vapor reservoir, and is connected to the internal combustion engine in such a manner that during a tank venting operation the fuel vapors contained in the fuel vapor reservoir are delivered as regeneration gas. To check the operability of the venting device the fuel concentration in the regeneration gas is ascertained at a minimum of two different points in time during the venting operation. The fuel concentration values in the regeneration gas are compared with respective reference values representing the regeneration gas fuel concentration in the situation in which no additional fuel vapors are delivered during the venting operation. The assessment of the venting device operability is carried out by comparison of the values ascertained for the fuel concentration in the regeneration gas with the reference values.

Abstract: In order to diagnose a coolant pump (11) which is provided for the purpose of circulating a coolant in a closed cooling circuit of an internal combustion engine (10) and which can be activated and deactivated independently of the operating state of the internal combustion engine (10), both a value representing the coolant temperature (TCO) of the internal combustion engine (10) and a value representing the cylinder head temperature (TZK) of the internal combustion engine (10) are determined at a predefined time instant (t2) after a cold start of the internal combustion engine (10) has been detected and the values are subsequently compared with each other. The coolant pump (11) is rated in terms of its operational integrity as a function of the result of the comparison. This enables a faulty coolant pump to be detected at a very early stage after a cold start of the internal combustion engine.