An exhaust aftertreatment system includes a catalyst, an exhaust conduit system, a first sensor, a second sensor, a reductant pump, a dosing module, and a reductant delivery system controller. The exhaust conduit system is coupled to the catalyst. The first sensor is coupled to the exhaust conduit system upstream of the catalyst and configured to obtain a current first measurement upstream of the catalyst. The second sensor is coupled to the exhaust conduit system downstream of the catalyst and configured to obtain a current second measurement downstream of the catalyst. The reductant pump is configured to draw reductant from a reductant source. The dosing module is fluidly coupled to the reductant pump and configured to selectively provide the reductant from the reductant pump into the exhaust conduit system upstream of the catalyst. The reductant delivery system controller is communicable with the first sensor, the second sensor, the reductant pump, and the dosing module.

An outboard motor that controls combustion in an engine according to a purification rate by a catalyst and is capable of performing efficient engine combustion. The outboard motor includes a catalyst provided in an exhaust manifold of an engine and a second catalyst provided in an exhaust pipe, an air-fuel ratio sensor and an O2 sensor, which are located on an upstream side and a downstream side of the catalyst, respectively, and a controller for controlling combustion in the engine. The controller calculates an exhaust gas purification rate based on a value detected by the air-fuel ratio sensor or the O2 sensor and controls the combustion in the engine so as to make the exhaust gas purification rate appropriate.

A method for controlling an exhaust aftertreatment system for vehicles includes: determining, by a controller, whether or not a designated regeneration operation is finished; accumulating, by the controller, a first amount of NO.sub.x emission measured by a rear end NO.sub.x sensor of an selective catalytic reduction (SCR) apparatus and a second amount of NO.sub.x emission calculated by an NO.sub.x emission amount model respectively for a first reference period of time immediately after the regeneration operation is finished; determining, by the controller, whether or not a difference between an accumulated value of the first amount of NO.sub.x emission and an accumulated value of the second amount of NO.sub.x emission exceeds a reference value when the first reference period of time has elapsed; and correcting, by the controller, a model purification efficiency using a sensor purification efficiency when the difference between the accumulated values exceeds the reference value.

The disclosure relates to a method for purifying exhaust gas and to an electronic device therefor. The electronic device includes: a sensor module; a heating device; a memory; and a processor operatively coupled to the sensor module, the heating device, and the memory. The processor is configured to: control the heating device such that a catalytic converter of a vehicle is heated, measure an air-fuel ratio of exhaust gas passing through the catalytic converter using the sensor module during heating of the catalytic converter, and control the heating device such that heating of the catalytic converter is ended based on the air-fuel ratio of the exhaust gas.

A method for controlling an exhaust aftertreatment system for vehicles includes: determining, by a controller, whether or not a designated regeneration operation is finished; accumulating, by the controller, a first amount of NO.sub.x emission measured by a rear end NO.sub.x sensor of an selective catalytic reduction (SCR) apparatus and a second amount of NO.sub.x emission calculated by an NO.sub.x emission amount model respectively for a first reference period of time immediately after the regeneration operation is finished; determining, by the controller, whether or not a difference between an accumulated value of the first amount of NO.sub.x emission and an accumulated value of the second amount of NO.sub.x emission exceeds a reference value when the first reference period of time has elapsed; and correcting, by the controller, a model purification efficiency using a sensor purification efficiency when the difference between the accumulated values exceeds the reference value.

Controlling exhaust after-treatment in a heavy-duty motor vehicle includes operating a diesel engine of a heavy-duty truck such that the diesel engine generates an exhaust gas flow that enters an exhaust after-treatment system of the heavy-duty truck, the exhaust after-treatment system including a selective catalytic reduction system, measuring a level of NO.sub.x gases in the exhaust gas flow downstream of the selective catalytic reduction system, and controlling a diesel exhaust fluid injector upstream of the selective catalytic reduction system to inject diesel exhaust fluid into the exhaust gas flow upstream of the selective catalytic reduction system at an injection rate that is based on the measured level of NO.sub.x gases.

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 multi-cylinder opposed piston engine (100) can include one or more sensors, such as oxygen or nox sensors (132, 134, 136, 138, 142), for each cylinder (103) of the multi-cylinder opposed piston engine (100). The sensors (132, 134, 136, 138, 142) are in communication with an engine control unit (102) that can receive measurements and other data from the sensors. In one example, each cylinder (103) includes one or more sensors (132, 134) located adjacent to exhaust ports (144) of each individual cylinder (103). In another example, each cylinder (103) includes one or more sensors (136, 138) located in an exhaust passageway (146) of each individual cylinder (103). In some examples, the multi-cylinder opposed piston engine (100) can include multiple crankshafts (114, 116). For example, the multi-cylinder opposed piston engine (100) can include two crankshafts (114, 116), where each crankshaft (114, 116) engages, either directly or indirectly, one of two opposed pistons (104, 106) of a cylinder (103). In one example, each crankshaft (114, 116) includes one or more sensors, such as a torque sensor (120, 122), a speed sensor (124, 126), or a noise, vibration, and harshness (NVH) sensor (150, 152).

A method of manufacturing an on-board diagnostic (OBD) limit part and a method of testing to evaluate an OBD system. The method of manufacturing the OBD limit part includes introducing a contaminant to an selective catalytic reduction (SCR) catalyst and contacting the contaminant with the SCR catalyst for a selected period of time. The method of manufacturing utilizes a vessel, the contaminant, and the SCR catalyst. The OBD limit part is a combination of the contaminant and the SCR catalyst within the vessel. The method of testing to evaluate the OBD system includes collecting data related to an exhaust gas before and after the exhaust gas is exposed to the OBD limit part, collecting an indication provided by the OBD system, and comparing the data related to the exhaust gas and the indication provided by the OBD system. The method of testing to evaluate the OBD system utilizes a system that includes an exhaust gas source, a first and a second fluid path, the OBD limit part, and the OBD system.

The present invention relates to a method for diagnosing aftertreatment of exhaust gases resulting from combustion, wherein at least a first substance resulting from said combustion is reduced by supplying additive to an exhaust gas stream resulting from said combustion and use of a first reduction catalytic converter. The method includes: estimating an accumulated expected reduction of said first substance during a first period of time, determining an accumulated actual reduction of said first substance during a period of time at least substantially overlapping said first period of time, and generating a signal indicating a fault in said reduction of said first substance when said accumulated actual reduction differs from said accumulated expected reduction by a predetermined difference in occurrence of said first substance. The invention also relates to a corresponding system.