Abstract: Methods and systems are provided for determining an amount of alcohol in fuel injected into an engine based on outputs from an exhaust gas sensor. In one example, a method includes estimating a first fuel alcohol content based on an air-fuel ratio estimated with the exhaust oxygen sensor and estimating a second fuel alcohol content based on a change in sensor output during modulating a reference voltage of the exhaust oxygen sensor between a first and second voltage. The method further includes adjusting engine operation based on a difference between the first and second fuel alcohol contents.

Abstract: Methods and systems are provided for determining an amount of alcohol in fuel injected into an engine based on outputs from an exhaust gas sensor. In one example, a method includes estimating a first fuel alcohol content based on an air-fuel ratio estimated with the exhaust oxygen sensor and estimating a second fuel alcohol content based on a change in sensor output during modulating a reference voltage of the exhaust oxygen sensor between a first and second voltage. The method further includes adjusting engine operation based on a difference between the first and second fuel alcohol contents.

Abstract: Methods are provided for accurately learning part-to-part variability of an intake or exhaust oxygen sensor. A correction factor is learned based on a sensor reading in dry air conditions, the dry air reading learned by applying a higher reference voltage to the sensor. An ethanol transfer function is then adjusted based on the learned correction factor so as to improve the accuracy of combusted fuel ethanol content estimation.

Abstract: Various systems and methods are described for an engine system with an exhaust gas recirculation system. In one example method, a correction for a gas constituent sensor is determined based on output from the gas constituent sensor and output from a pressure sensor over a range of boost pressure. The gas constituent sensor output is adjusted based on the correction, and an amount of exhaust gas recirculation is adjusted based on the adjusted gas constituent sensor output.

Abstract: Methods are provided for accurately learning part-to-part variability of an intake or exhaust oxygen sensor. A correction factor is learned based on a sensor reading in dry air conditions, the dry air reading learned by applying a higher reference voltage to the sensor. An ethanol transfer function is then adjusted based on the learned correction factor so as to improve the accuracy of combusted fuel ethanol content estimation.

Abstract: Various systems and methods are described for an engine system with an exhaust gas recirculation system. In one example method, a correction for a gas constituent sensor is determined based on output from the gas constituent sensor and output from a pressure sensor over a range of boost pressure. The gas constituent sensor output is adjusted based on the correction, and an amount of exhaust gas recirculation is adjusted based on the adjusted gas constituent sensor output.

Abstract: The invention relates to a method for detecting the start of combustion in the combustion chamber of an engine with autoignition. In the method, the profile of the cylinder pressure is measured and the signal which is obtained in this way is transformed using wavelet functions. A sudden rise in the absolute value of the wavelet coefficients which are obtained indicates the start of combustion. The simple and at the same time precise detection of the start of combustion which is possible in this way can be used within the framework of a feedback regulation—by changing engine operating parameters such as, for example, the start of injection of the fuel—to regulate the start of combustion in a desired way.

Abstract: The invention relates to a method for detecting the start of combustion in the combustion chamber of an engine with autoignition. In the method, the profile of the cylinder pressure is measured and the signal which is obtained in this way is transformed using wavelet functions. A sudden rise in the absolute value of the wavelet coefficients which are obtained indicates the start of combustion. The simple and at the same time precise detection of the start of combustion which is possible in this way can be used within the framework of a feedback regulation—by changing engine operating parameters such as, for example, the start of injection of the fuel—to regulate the start of combustion in a desired way.

Abstract: A method for detecting misfire in an internal combustion engine comprising the steps of measuring instantaneous angular velocity of the engine crankshaft during combustion in the combustion chamber of a piston and cylinder assembly, determining if combustion has occurred using crankshaft acceleration data, measuring engine block combustion energy vibrations by means of an accelerometer, determining whether combustion has occurred using the accelerometer data, identifying the cylinder where the acceleration data originates, comparing the results of the crankshaft acceleration information with the accelerometer information to detect whether each set of data detects misfire, decreasing the threshold for detecting a misfire using accelerometer data if a misfire is detected only by the crankshaft acceleration data whereby a reliable misfire signal can be obtained during those instances when the crankshaft acceleration data is unreliable and increasing the threshold for the accelerometer when the crankshaft acceler

Abstract: A control system and method for obtaining combustion stability in an internal combustion engine including an accelerometer mounted on the engine for detecting engine block vibrations and an engine controller for processing an accelerometer output signal indicating engine block vibration intensity to measure cylinder combustion energy, the energy measurement being correlated to other combustion parameters including indicated mean effective pressure (IMEP), the controller developing a control signal that may be used in a closed loop fashion to adjust engine variables including exhaust gas recirculation, air/fuel ratio, and spark advance, thereby adjusting the engine operating characteristics to achieve optimum combustion energy.

Abstract: A method and system to determine the borderline spark timing for a given speed and load of a given cylinder and control spark timing relative to that borderline spark timing to maintain the torque/efficiency of the engine. The system measures combustion related events at several steps from a retarded spark timing to a spark timing signal which is calculated to be beyond the borderline spark timing value. From these measurements, the borderline spark timing signal for a given cylinder at a given speed and load is determined and saved. Borderline spark timing is the spark timing at which audible knock starts to occur.