Abstract: In a method for an emission-optimized transition between a spark-ignition mode of an internal combustion engine and a self-ignition mode of the internal combustion engine, the internal combustion engine is operated in the preparation phase and chronologically before the transition of modes in a spark-ignition mode in at least one cylinder cycle with a rich mixture (?<1) and, subsequently, in the same cylinder cycle with a lean mixture (?<1). After that, the internal combustion engine is operated in the self-ignition mode. In a method for an emission-optimized transition between a self-ignition mode of an internal combustion engine and a spark-ignition mode of the internal combustion engine, in a transition phase of the operation modes and during a last cycle of the self-ignition mode and/or a first cycle of the spark-ignition mode, fuel is post-injected into at least one combustion chamber of the internal combustion engine.

Abstract: For the direct re-entry in the CAI operating mode following a pull fuel cut off phase the CAI specific valve lift is maintained during its pull fuel cut off phase. Upon a request signal for the CAI re-entry after the closing time of the particular cylinder, an advance fuel injection quantity is injected in the combustion chamber and externally ignited and combusted in the following CAI interim compression phase of the exhaust stroke, as a result of which hot exhaust gas is formed in the combustion chamber, fresh air is drawn into the combustion chamber during the following intake stroke, a main fuel injection quantity is injected in a main compression phase during the following compression stroke, and the exhaust gas content brought about from the earlier auxiliary fuel injection, is mixed with the air-fuel mixture newly introduced for the main ignition to form a self-ignitable, homogenous fresh air-exhaust gas-fuel mixture.

Abstract: Systems and methods for determining the gas composition of a gas mixture in a fuel tank of a motor vehicle filled with a compressed natural gas (CNG) mixture are provided. A pressure sensor and a temperature sensor are used to measure a gas pressure and a gas temperature in the fuel tank A processor may execute an algorithm to determine, based at least on the measured gas temperature and the measured gas pressure in the fuel tank, a current vapor pressure of each of at least one component of the CNG mixture in the fuel tank. If the measured gas pressure in the fuel tank falls below a threshold, a corresponding current composition of the CNG mixture in the fuel tank may be determined.

Abstract: For at least one disturbance variable of the cylinder pressure signal, which disturbance variable occurs only during specific limited time spans as the pressure profile of an operating cycle, a filter tuned to the type of disturbance variable is fixed and is assigned to the corresponding disturbance variable time window or windows (8, 9, 10) in the operating cycle. The cylinder pressure signal (2) is then filtered as a function of the crankshaft angle, in that, according to the crankshaft position, a time-tuned and type-tuned filter is applied to a current disturbance variable.

Abstract: In a method for changing the operating mode in an internal combustion engine it is possible to switch between an operating mode with spark ignition of the engine and an operating mode with auto-ignition of the engine. Hereby, a first map is provided in which at least one range is specified in which a suitable auto-ignition of the engine can take place. After the engine start, therefore, it is determined whether the engine has reached an operating point lying within this range of the first map in order then to switch the engine to the operating mode in which auto-ignition can take place reliably.

Abstract: To determine the gas work WK from the areas formed by the cylinder pressure curve over the associated stroke volume V?, a cylinder-pressure-proportional integrator is started integrating the signals of the cylinder pressure sensor in multiple integrator runs depending on a settable integrator capacitance. A lower and an upper threshold value are predefined, whose difference corresponds to the integrator capacitance. Upon reaching one of the threshold values, respective new integrator runs are started, at the beginning and end of which the current crankshaft angle ? (is detected, respectively. For each integrator run, the associated individual work is determined depending on the product of the integrator capacitance and the particular covered stroke volume and the gas work resulting from the cylinder pressure curve is determined by summation of the individual works. The gas work may be used in particular for determining the internal mean pressure of the cylinder.

Abstract: In a method for an emission-optimized transition between a spark-ignition mode of an internal combustion engine and a self-ignition mode of the internal combustion engine, the internal combustion engine is operated in the preparation phase and chronologically before the transition of modes in a spark-ignition mode in at least one cylinder cycle with a rich mixture (?<1) and, subsequently, in the same cylinder cycle with a lean mixture (?<1). After that, the internal combustion engine is operated in the self-ignition mode. In a method for an emission-optimized transition between a self-ignition mode of an internal combustion engine and a spark-ignition mode of the internal combustion engine, in a transition phase of the operation modes and during a last cycle of the self-ignition mode and/or a first cycle of the spark-ignition mode, fuel is post-injected into at least one combustion chamber of the internal combustion engine.

Abstract: The resolution of output signals from at least one measuring sensor on an internal combustion engine can be increased by: the working level range of the sensor is divided into at least two range sections, each section is provided with the same given output level range limited with relation to the working level range, for the output signal from the sensor and the switching from one to the other section is carried out independently by the sensor, when a range boundary between two adjacent sections is reached, exceeded or fallen below, the operating point of the internal combustion engine is determined by an engine management based on at least one parameter, the time curve for the raw sensor signal is predicted from at least one set of performance characteristics for the current operating point and the engine management determines which section is current from the predicted raw sensor signal time curve.

Abstract: In a method and a device for examining a valve lift switching process in a motor vehicle the occurrence or the number of switching errors is reduced. The method has the steps of detecting whether a switching error and/or an external event occurs that may influence the mode of operation of the valve lift switching; blocking the valve lift switching if a switching error and/or an external event has occurred; activating and examining the valve lift switching during at least one uncritical operating condition; releasing the valve lift switching if the valve lift switching does not show any abnormalities during monitoring.

Abstract: The resolution of output signals from at least one measuring sensor on an internal combustion engine can be increased by: the working level range of the sensor is divided into at least two range sections, each section is provided with the same given output level range limited with relation to the working level range, for the output signal from the sensor and the switching from one to the other section is carried out independently by the sensor, when a range boundary between two adjacent sections is reached, exceeded or fallen below, the operating point of the internal combustion engine is determined by an engine management based on at least one parameter, the time curve for the raw sensor signal is predicted from at least one set of performance characteristics for the current operating point and the engine management determines which section is current from the predicted raw sensor signal time curve.

Abstract: For at least one disturbance variable of the cylinder pressure signal, which disturbance variable occurs only during specific limited time spans as the pressure profile of an operating cycle, a filter tuned to the type of disturbance variable is fixed and is assigned to the corresponding disturbance variable time window or windows (8, 9, 10) in the operating cycle. The cylinder pressure signal (2) is then filtered as a function of the crankshaft angle, in that, according to the crankshaft position, a time-tuned and type-tuned filter is applied to a current disturbance variable.

Abstract: To determine the gas work WK from the areas formed by the cylinder pressure curve over the associated stroke volume V?, a cylinder-pressure-proportional integrator is started integrating the signals of the cylinder pressure sensor in multiple integrator runs depending on a settable integrator capacitance. A lower and an upper threshold value are predefined, whose difference corresponds to the integrator capacitance. Upon reaching one of the threshold values, respective new integrator runs are started, at the beginning and end of which the current crankshaft angle ? (is detected, respectively. For each integrator run, the associated individual work is determined depending on the product of the integrator capacitance and the particular covered stroke volume and the gas work resulting from the cylinder pressure curve is determined by summation of the individual works. The gas work may be used in particular for determining the internal mean pressure of the cylinder.

Abstract: For the direct re-entry in the CAI operating mode following a pull fuel cut off phase the CAI specific valve lift is maintained during its pull fuel cut off phase. Upon a request signal for the CAI re-entry after the closing time of the particular cylinder, an advance fuel injection quantity is injected in the combustion chamber and externally ignited and combusted in the following CAI interim compression phase of the exhaust stroke, as a result of which hot exhaust gas is formed in the combustion chamber, fresh air is drawn into the combustion chamber during the following intake stroke, a main fuel injection quantity is injected in a main compression phase during the following compression stroke, and the exhaust gas content brought about from the earlier auxiliary fuel injection, is mixed with the air-fuel mixture newly introduced for the main ignition to form a self-ignitable, homogenous fresh air-exhaust gas-fuel mixture.

Abstract: In a process and device for determining the composition of a gas mixture of the fuel tank of a motor vehicle filled with a CNG gas, the measured values of a pressure sensor and a temperature sensor, which are generally present in conventional fueled motor vehicles, are used to determine the vapor pressure (pd) of at least one of the gases in the gas mixture, in particular ethane, propane and/or butane. If the vapor pressure of one of the components of the CNG gas in the fuel tank falls short, then one relevant, current composition of the gas mixture is determined. This offers the advantage in an internal combustion engine that as much gas can always be injected with the 20 requisite energy value, as is called for by the specified air-fuel ratio (?-value) and the conditions of operation. This achieves optimum combustion with minimal exhaust.

Abstract: According to the invention, prior to or during an intermediate compression around the upper dead center of a piston of an internal combustion engine during a change in charge a predetermined first fuel mixture is metered into the combustion chamber of the respective cylinder. During the intermediate compression, measured values of pressure in the combustion chamber are measured in a predetermined first crankshaft angle window using cylinder pressure sensor. A measurement for a conversion rate of the first fuel mixture is determined based on the detected measured values of the pressure and reference values of the pressure, which characterize the corresponding pressure curve in the combustion chamber when no fuel is metered. A control signal for at least one actuator of the internal combustion engine is determined based on the conversion rate.

Abstract: In a method for changing the operating mode in an internal combustion engine it is possible to switch between an operating mode with spark ignition of the engine and an operating mode with auto-ignition of the engine. Hereby, a first map is provided in which at least one range is specified in which a suitable auto-ignition of the engine can take place. After the engine start, therefore, it is determined whether the engine has reached an operating point lying within this range of the first map in order then to switch the engine to the operating mode in which auto-ignition can take place reliably.

Abstract: The isentropic exponent (?) and the constant (k) in the equation p·V?=k for processes before and after fuel combustion in the cylinder are determined on the basis of the signals from a cylinder pressure sensor and from a crankshaft sensor. Cylinder pressures (p) before and after fuel combustion can be determined through the equation with the corresponding isentropic exponents (?) and corresponding constants. During fuel combustion, cylinder pressure (p) is sensed by the cylinder pressure sensor. The ratio between the fuel mass burned in the cylinder of the internal combustion engine and the fuel mass (MBR) supplied to the cylinder is determined on the basis of the above-mentioned variables. The process has the advantage of reducing the computation outlay necessary to determine the ratio between the fuel mass burned in the cylinder of the internal combustion engine and the fuel mass (MBR) supplied to the cylinder.

Abstract: The invention relates to a system and method for use in a homogeneous charge compression ignition (HCCI) combustion engine that is preferably equipped with an exhaust gas recirculation device. This system and method enable an improved adjustment of the temperature level inside the combustion chamber. In addition to adjusting the temperature by using the exhaust gas recirculation device, an influencing of the temperature, which is independent thereof, ensues based on the compression of the induced fresh air by the exhaust gas turbocharger. An increase in temperature is maintained even after the compressed air is expanded on a throttle valve, and this increase in temperature can, in the end, be used for influencing the energy content inside the combustion chamber.

Abstract: In one aspect, a method for controlling an internal combustion engine using valve lift switchover is provided. Within the scope of this method, a switchover intake manifold model for the switchover-relevant pressure range for valve lift switchover is applied in addition to the use of a basic intake manifold model. This ensures a valve lift switchover with approximately constant torque of the internal combustion engine.

Abstract: This invention describes a method for optimizing a valve-lift changeover on spark-ignition engines with lambda control. On the basis of the evaluation of an acceleration characteristic and a lambda characteristic during the valve-lift changeover, it is determined whether cylinder charging errors and/or torque errors that require correction are present in the spark-ignition engine.