An engine system including a fuel system control arrangement includes an internal combustion engine including an exhaust line, one or more cylinders, and one or more fuel injectors corresponding to the one or more cylinders, means for determining fresh air mass flow into an intake to the engine, a nitrogen oxide (NOx) sensor in the exhaust line, and a controller configured to determine oxygen (O2) in exhaust gas based on a signal from the NOx sensor and to calculate a current fuel injection quantity based on the O2 in the exhaust gas and determined fresh air mass flow into the intake, to compare the current fuel injection quantity to a theoretical fuel injection quantity under current operating conditions, and to adjust an amount of fuel injection from the one or more fuel injectors when the current fuel injection quantity differs from the theoretical fuel injection quantity to make the current fuel injection quantity closer to the theoretical fuel injection quantity.

The exhaust purification device of an internal combustion engine comprises a catalyst 20 arranged in an exhaust passage and able to store oxygen; and an air-fuel ratio control device configured to control an air-fuel ratio of inflowing exhaust gas flowing into the catalyst. The air-fuel ratio control device is configured to perform a distribution forming control controlling the air-fuel ratio of the inflowing exhaust gas so that in the catalyst, a first region with an oxygen storage amount of equal to or greater than a predetermined value and a second region with an oxygen storage amount of less than the predetermined value are alternately formed along an axial direction of the catalyst. The total number of the first region and the second region formed by the distribution forming control is equal to or greater than three.

The invention provides a system for ventilation of a crankcase (217) of an internal combustion engine, the system comprising—an air inlet guide (203, 212) adapted to guide air to at least one cylinder (220) of the engine,—a closed circuit conduit (209) for guiding crankcase gas from the crankcase (217) to the air inlet guide (203, 212),—wherein the system comprises gas detection means (2181, 2182, 2183) positioned in the air inlet guide (203, 212), for detecting crankcase gas in the air inlet guide.

Method for diagnosing at least one exhaust gas sensor (22;24;26) of an internal combustion engine (10) disposed in an exhaust duct (21), where ambient air (12) is actively introduced into the exhaust duct (21) by means of a device (27), when an operating state is present in which the internal combustion engine (10) does not produce an exhaust gas mass flow, and the diagnosis of the at least one exhaust gas sensor (22;24;26) disposed in the exhaust duct (21) is subsequently carried out.

A method for improving accuracy of correction of fuel quantity at the time when a recirculation valve (RCV) is opened, may include a step of correcting injection amount of fuel based on consideration factors when the RCV is operated to be opened. The consideration factors include property values of a flow path of the RCV, the flow path being mounted to an intake pipe to connect between a front end of a compressor close to the atmosphere and a rear end of the compressor adjacent to combustion chambers, a first calculation value obtained by calculating amount of air to be introduced into the combustion chambers after circulating from the flow path of the RCV to the intake pipe, and a second calculation value obtained by calculating amount of hydrocarbon to be introduced into the flow path of the RCV by purging evaporative gas.

A method for diagnosing a plurality of lambda sensors which are arranged upstream of an exhaust gas catalytic converter in a plurality of exhaust gas banks of a multi-flow exhaust gas system of an internal combustion engine. An opposite lambda offset of the lambda sensors is identified (54) when a difference (ΔT) between a measured exhaust gas temperature (T.sub.measure) and a modeled exhaust gas temperature (T.sub.mod) downstream of the exhaust gas catalytic converter overshoots a threshold value (S).

A method for operating a drive device having a drive unit producing exhaust gas and an exhaust gas posttreatment device designed as a vehicle catalytic converter for posttreatment of the exhaust gas. A first measured value describing the residual oxygen content in the exhaust gas is measured by a first lambda sensor arranged upstream of the exhaust gas posttreatment device and a second measured value describing the residual oxygen content in the exhaust gas is measured by a second lambda sensor arranged downstream of the exhaust gas posttreatment device. The combustion air ratio of a fuel-air mixture used to operate the drive unit is set during an at least temporarily performed normal operating mode on the basis of the first measured value, the second measured value, and a threshold value for the second measured value.

Methods, systems and devices for evaluating incoming air to an engine, industrial controller including engine controls, valves and solenoids, for concentrations of explosive or combustible gases or vapors, and actuating process control including but not limited to shutting down an engine or other industrial process to control an outcome including the prevention of an overspeed condition when pre-set or calculated elevated gas or vapor concentrations are detected. In some embodiments industrial control including engine shutdown may be achieved conventionally via an electronic kill signal, a shutdown of the fuel injector, carburetor or fuel pump, and in emergency conditions by the shutoff of incoming air to an air intake, turbocharger, or other air delivery systems. Decisions based on explosive gas or vapor concentrations and species and the use of networking to allow additional systems to take action before explosive gases or vapors reach said other valve-sensor devices can provide additional safety.

Systems and methods for controlling a gasoline urea selective catalytic reductant catalyst are described. In one example, an observer is provided that corrects an estimate of an amount of NH.sub.3 that is stored in a SCR. The amount of NH.sub.3 that is stored in the SCR is a basis for generating additional NH.sub.3 or ceasing generation of NH.sub.3.

A method and a device for regulating the pressure of the combustion gas and/or exhaust gas of a machine, in particular an internal combustion engine. The combustion gas is supplied to the machine via a supply line and is discharged via an exhaust gas line, and the supply line and/or the exhaust gas line has a regulating device, the regulating device delimiting a pressure-regulated section of the supply line and/or the exhaust gas line, and wherein the pressure in each pressure-regulated section is measured at more than one point.