Abstract: Methods and apparatus are disclosed for efficient factor analysis of a large population of data records, using factors that are categorical variables. Computation is balanced between extracting key factors by training a machine learning classifier on a reduced sample of data records, for computational efficiency, and scoring the categorical values of the key factors on the entire population, for accuracy of results. A joint factor is constructed by combining all proposed root factors, and the sample is generated by stratified sampling on the joint factor. The key factors are selected from candidate factors which can be combinations of the root factors. Original variables of a dataset, whether categorical or not, can be binned to obtain new categorical factors. Variations and user interfaces are also disclosed.

Abstract: An exhaust-gas purification system and method controls an internal combustion engine having at least one cylinder-piston unit operating in a overrun (drag) mode in which piston motion is induced by motion of an output shaft of a drive output unit associated with the internal combustion engine. A control device controls, for each of cylinder-piston unit, an intake fluid, an exhaust valve and fuel injection to heat an exhaust emission control device by deactivating fuel injection, passing the substantially fuel-free intake fluid into the cylinder, compressing and thereby heating the fluid in the cylinder, and passing the heated outlet fluid to the exhaust emission control device. The control device may control the amount of heating based on measurement and/or use of a temperature model of the exhaust emission control device.

Abstract: A method is provided for operating an internal combustion engine in a motor vehicle, The internal combustion engine has at least one cylinder with a combustion chamber, a water injection unit with a tank and at least one injection nozzle for directly or indirectly injecting water into the combustion chamber, an exhaust gas system with at least one exhaust gas catalytic converter and a particulate filter device which has a particulate filter for filtering particles out of an exhaust gas flow guided in the exhaust gas system. A control unit is provide for a state monitoring process and for controlling the combustion in the cylinder.

Abstract: A method is provided for operating an internal combustion engine in a motor vehicle, The internal combustion engine has at least one cylinder with a combustion chamber, a water injection unit with a tank and at least one injection nozzle for directly or indirectly injecting water into the combustion chamber, an exhaust gas system with at least one exhaust gas catalytic converter and a particulate filter device which has a particulate filter for filtering particles out of an exhaust gas flow guided in the exhaust gas system. A control unit is provide for a state monitoring process and for controlling the combustion in the cylinder.

Abstract: An exhaust-gas purification system and method controls an internal combustion engine having at least one cylinder-piston unit operating in a overrun (drag) mode in which piston motion is induced by motion of an output shaft of a drive output unit associated with the internal combustion engine. A control device controls, for each of cylinder-piston unit, an intake fluid, an exhaust valve and fuel injection to heat an exhaust emission control device by deactivating fuel injection, passing the substantially fuel-free intake fluid into the cylinder, compressing and thereby heating the fluid in the cylinder, and passing the heated outlet fluid to the exhaust emission control device. The control device may control the amount of heating based on measurement and/or use of a temperature model of the exhaust emission control device.