A method for detecting a dosing error of a reduction agent in a dosing module of an SCR catalytic converter system. The SCR catalytic converter system comprises the dosing module, which has a dosing valve and a flow valve as well as a delivery module with delivery pump. The SCR catalytic converter system, furthermore, has a return, in which a further flow valve is arranged. Said flow valve changes an effective cross-sectional area of the return. The method herein comprises the following steps: at the beginning, the dosing valve is closed (200). At a first pressure value (p.sub.1) in the system the delivery pump is switched off (201) and a measurement (202) of a first pressure rate (β.sub.RL.sup.dynamic) of the flow valve of the return subsequently takes place. Additional operation of the pump and the dosing valve occurs and a ratio of pressure rates is determined.

A method to control an internal combustion engine having an exhaust duct and an exhaust gas after-treatment system comprising at least one catalytic converter arranged along the exhaust duct; an oxygen sensor housed along the exhaust duct and arranged upstream of said at least one catalytic converter; and a burner suited to introduce the exhaust gases into the exhaust duct upstream of the oxygen sensor the method provides the steps of identifying the operation phases in which the internal combustion engine is turned off and the burner is turned on so that the oxygen sensor is exclusively hit by the exhaust gases produced by the burner; acquiring the signal generated by the oxygen sensor; and using the signal generated by the oxygen sensor to determine the objective fuel flow rate and the objective air flow rate to be fed to the burner.

A method for controlling exhaust flow in an EATS of a vehicle. A NO.sub.x sensor output parameter is monitored. It is determined that the NO.sub.x sensor output parameter is below a limit. When the NO.sub.x sensor output parameter is below the limit, it is determined that a first part of the exhaust flow should bypass at least a first area of the SCR unit and that a second part of the exhaust flow should be inputted to at least the first area of the SCR unit. It is initiated that the first part is bypassed and that the second part is inputted to at least the first area of the SCR unit. An amount of reductant that should be added to the second part of the exhaust flow is determined. Addition of the amount of reductant is initiated.

A method for controlling urea injection in an exhaust aftertreatment system includes injecting urea at a flow rate upstream of the first catalytic reduction device; measuring a level of nitrogen oxides downstream of the first catalytic reduction device and upstream of the second catalytic reduction device; controlling the flow rate of the urea injection until the measured level of nitrogen oxides fulfils a predetermined condition; if the measured level of nitrogen oxides is decreasing in response to reducing the flow rate of the urea injection, reducing the flow rate of the urea injection, and controlling a flow rate of urea injection using the second urea injector upstream of the second catalytic reduction device according to the measured level of nitrogen oxides downstream of the first catalytic reduction device and upstream of the second catalytic reduction device.

An auxiliary system with purge control automatically supplies diesel exhaust fluid (DEF) to an onboard DEF tank of a diesel engine to enable prolonged unattended operation. The system includes an auxiliary DEF tank, an auxiliary DEF supply line, a controller, a pump, an air inlet, and a three-way valve configured to switch the pump inlet between the auxiliary DEF tank and air. In response to low-level DEF, the pump delivers DEF through the supply line to replenish the onboard DEF tank. The controller may automatically calculate onboard DEF tank volume based on the delivered volume of DEF, and DEF level data received from an ECM, to enable replenishment control regardless of engine make and model. In response to high-level DEF, engine stoppage, or other system fault, the controller switches the valve to air and runs the pump for a predetermined time to purge DEF from the supply line. The auxiliary system may be skid-mounted, portable, and configured to supply DEF to multiple diesel engines.

A control module for an aftertreatment system that includes a selective catalytic reduction (SCR) catalyst and an oxidation catalyst, comprises a controller configured to be operatively coupled to the aftertreatment system. The controller is configured to determine an actual SCR catalytic conversion efficiency of the SCR catalyst. The controller determines an estimated SCR catalytic conversion efficiency based on a test sulfur concentration selected by the controller. In response to the estimated SCR catalytic conversion efficiency being within a predefined range, the controller sets the test sulfur concentration as a determined sulfur concentration in a fuel provided to the engine. The controller generates a sulfur concentration signal indicating the determined sulfur.

An auxiliary system automatically supplies diesel exhaust fluid (DEF) to a diesel engine onboard DEF tank to enable prolonged unattended operation. The system includes an auxiliary DEF tank and supply line, a controller, pump, air inlet, and three-way valve configured to switch the pump inlet between the auxiliary DEF tank and air. In response to low-level DEF, the pump delivers DEF to replenish the onboard DEF tank. The controller calculates onboard DEF tank volume based on the delivered volume of DEF, and DEF level data received from an ECM, to enable replenishment control regardless of engine make and model. In response to high-level DEF, engine stoppage, or system fault, the controller switches the pump inlet to air and runs the pump to purge DEF from the supply line. The auxiliary system may be skid-mounted, portable, and configured to supply DEF to multiple diesel engines.

Systems and apparatuses include a selective catalytic reduction system structured to receive exhaust gases from a dual fuel engine system and include a diesel exhaust fluid dosing unit, an ammonia slip catalyst positioned directly downstream of the selective catalytic reduction catalyst, an oxidation catalyst positioned directly downstream of the ammonia slip catalyst, and one or more processing circuits. The circuits receive a system out NOx value, a space velocity, an ammonia to NOx ratio, an exhaust temperature, a substitution rate, and a conversion efficiency target. The circuits determine a conversion efficiency differential, adjust the substitution rate based on the system out NOx value, adjust the ammonia to NOx ratio based on the space velocity, the ammonia to NOx ratio, the exhaust temperature, the substitution rate, the conversion efficiency target, and the conversion efficiency differential, and determine a diesel exhaust fluid dosing rate for the diesel exhaust fluid dosing unit.

A method for controlling urea injection in an exhaust aftertreatment system includes injecting urea at a flow rate upstream of the first catalytic reduction device; measuring a level of nitrogen oxides downstream of the first catalytic reduction device and upstream of the second catalytic reduction device; controlling the flow rate of the urea injection until the measured level of nitrogen oxides fulfils a predetermined condition; if the measured level of nitrogen oxides is decreasing in response to reducing the flow rate of the urea injection, reducing the flow rate of the urea injection, and controlling a flow rate of urea injection using the second urea injector upstream of the second catalytic reduction device according to the measured level of nitrogen oxides downstream of the first catalytic reduction device and upstream of the second catalytic reduction device.

Methods and systems for improving fuel economy and reducing emissions of a vehicle with an electric motor, an engine, an energy storage device, and a controller are disclosed. The method includes obtaining current state information including a current hybrid control surface, and determining a target hybrid control surface for the vehicle based on the current state information.