A method for operating an exhaust gas post-treatment system of a diesel engine and associated exhaust gas post-treatment system are described. The system has two NOx sensors upstream and downstream of an SCR catalytic converter. The NOx sensor downstream of the SCR catalytic converter is used to divide the NOx information measured by the sensor upstream of the SCR catalytic converter into an NOx value and an NH.sub.3 value. Using this simple method, the SCR catalyst control and diagnosis can be carried out precisely and robustly.

A particulate matter detecting apparatus (S) comprises a sensor body (S1) which has a sensor device (1) which is retained in a housing (H) secured to an exhaust pipe (101) of an internal combustion engine (ENG) and detects particulate matter contained in exhaust gas, a sensor temperature determining unit (2) which works to determine a temperature of the sensor device, and a mounted condition diagnosis unit (3) which diagnoses a mounted condition where the sensor body is mounted in the exhaust pipe. The mounted condition diagnosis unit includes a diagnosis threshold setting unit (31) and a mount error determining unit (32). The diagnosis threshold setting unit determines a diagnosis threshold (Tth), as used in a diagnosis of the mounted condition, as a function of an operating condition of the internal combustion engine to have a temperature value lower than a temperature of the sensor device when the sensor body is normally mounted in the exhaust pipe. When a sensor temperature (T), as determined by the sensor temperature determining unit, is lower than the diagnosis threshold, the mount error determining unit determines that an error in the mounted condition is occurring.

A method of treating exhaust gas in an exhaust passage using a selective catalytic reduction system is provided. The system comprises a hydrolysis catalyst in the passage upstream of a SCR catalyst, and a diesel exhaust fluid (DEF) dosing unit for injecting DEF onto the hydrolysis catalyst at a variable DEF dosing rate. The method comprises the steps of predicting an initial DEF dosing rate for converting all nitrogen oxide (NOx) contained in the exhaust gas, and estimating an amount of ammonia stored on the SCR catalyst. The method further comprises the steps of measuring a NOx conversion rate for the system, and adjusting the initial DEF dosing rate based upon the ammonia storage estimate and the measured NOx conversion rate to produce a first adjusted DEF dosing rate. An amount of ammonia-equivalent stored on the hydrolysis catalyst is then estimated, and the first adjusted DEF dosing rate is adjusted based upon the ammonia-equivalent storage estimate to produce a second adjusted DEF dosing rate. DEF is then injected at the second adjusted DEF dosing rate.

A method for controlling a return valve of an exhaust system and to an exhaust system with a control unit which is configured to carry out the method. The method is based on the object of avoiding an overpressure in the line system for urea solution as a result of a reduction in the injection rate. The method includes the steps of determining whether one or more of the following states are present during the operation of the exhaust system: a) an injection rate per unit of time of urea solution of the dosing valve is less than or equal to a predefined injection limit, b) a pressure measured by the pressure sensor in the line system overshoots a predefined first upper pressure limit (P2). The return valve is opened for a first predefined opening duration (Δt1) if states a) and b) are present and at least one of the states has already been present for at least a predefined period of time (Δta). The return valve is closed after the first predefined opening duration (Δt1) has elapsed.

The invention concerns a method for monitoring an SCR catalytic converter in an exhaust line of an internal combustion engine, into which a reducing agent solution for the reduction of nitrogen oxides is dosed, wherein the SCR catalytic converter is diagnosed as defective if a measured variable is below a corresponding threshold and wherein the diagnosis of the SCR catalytic converter occurs when enabling criteria are met, wherein the enabling criteria are selected depending on a BPU model and a WPA model such that when the SCR catalytic converter (3) conforms to the BPU model, ammonia slip occurs through this SCR catalytic converter (3), and when the SCR catalytic converter corresponds to the WPA model, no ammonia slip occurs through this SCR catalytic converter.

A method and control device for monitoring the function of a particulate filter in an exhaust gas duct of an internal combustion engine. A soot emission in the exhaust gas duct downstream from the particulate filter is determined with a particle sensor, an expected soot emission after a limit particulate filter at the location of the particle sensor is simulated and a comparison value is ascertained. A good particulate filter is found if the measured soot emission is less than the comparison value of the simulated soot emission. A defective particulate filter is found if the measured soot emission is higher than the comparison value of the simulated soot emission. The simulated soot emission is determined as being a simulated soot particle concentration at the installation site of the particle sensor such that a basic soot concentration in a soot concentration model is corrected at least with an oxygen correction.

Various methods and arrangements for improving fuel economy and noise, vibration, and harshness (NVH) in a skip fire controlled engine are described. An engine controller dynamically selects a gas spring type for a skipped firing opportunity. Determination of the skip/fire pattern and gas spring type may be made on a firing opportunity by firing opportunity basis.

An aftertreatment system comprises a SCR system, a reductant injector operatively coupled to the SCR system, and a reductant insertion assembly operatively coupled to the reductant injector. The reductant insertion assembly comprises a pump configured to pump the reductant through the reductant injector. A controller is operatively coupled to the reductant insertion assembly and configured to receive predetermined calibration values of the pump corresponding to delivery of a reductant by the pump through a calibration injector. The controller determines a desired flow rate value of the reductant into the SCR system. The controller determines an insertion time of the reductant injector for delivering the reductant through the reductant injector based on the desired flow rate value, a pump operating parameter value of the pump and the predetermined calibration values, and activates the reductant injector for the insertion time.

Methods of and apparatus for monitoring the health of a fuel oxygen conversion unit for a vehicle or a vehicle engine are provided. For example, a method comprises providing a distribution of sensed values obtained from a plurality of sensors distributed along an axial length of a gas oxygen reduction unit of the fuel oxygen conversion unit and determining the health of the fuel oxygen conversion unit from the distribution. As another example, a fuel oxygen conversion unit defines a circulation gas flowpath from a fuel gas separator to a contactor and comprises a gas oxygen reduction unit positioned in the circulation gas flowpath for reducing an oxygen content of a flow of stripping gas through the circulation gas flowpath. A plurality of sensors are distributed along an axial length of the gas oxygen reduction unit.

A method of generating vehicle control data includes: storing, with a storage device, relationship prescription data; operating, with an execution device, an operable portion of an internal combustion engine; acquiring, with the execution device, a detection value from a sensor that detects the state of the vehicle; calculating, with the execution device, a reward; and updating, with the execution device, the relationship prescription data using update mapping determined in advance, the update mapping using the state of the vehicle based on the detection value, an operation amount used to operate the operable portion, and the reward corresponding to the operation as arguments, and returning the relationship prescription data which have been updated such that an expected profit for the reward calculated when the operable portion is operated in accordance with the relationship prescription data increases.