A method for an SCR system comprising a dosing unit (250) for dosing reducing agent into an engine exhaust duct (290) upstream of a SCR catalytic converter (270) for reducing the NOx level in an exhaust flow from the engine. The SCR system comprises a pressurizing device (230) for feeding reducing agent from a container (205) to the dosing unit (250) arranged so as to dose reducing agent to the exhaust duct (290) under pressure. The method includes the step of: reducing, during periods of non-continuous dosing of reducing agent during continued maintained operation of the pressurizing device (230), the pressure (s301; s320) of the reducing agent at the dosing unit (250) compared to the pressure during continuous dosing. Also a computer program product containing program code (P) for a computer (200; 210) for implementing a method according to the invention. The invention also concerns an SCR system and a motor vehicle that is equipped with that system.

An exemplary vehicle exhaust system includes, among other things, a housing defining a fluid chamber and at least one pressure sensor positioned within the fluid chamber. The housing has a fluid inlet configured to receive fluid from a fluid supply and a fluid outlet. A heater heats fluid supplied from the fluid supply such that heated fluid can be injected into a vehicle exhaust component via the fluid outlet. A controller is configured to receive pressure data from the at least one pressure sensor and to determine optimal timing for dosing of the vehicle exhaust component based on the pressure data.

Methods and systems are provided for adjusting a location of a fuel injection in response to a substitution rate and a desired EGR flow. In one example, a method may include injecting a first fuel to a combustion chamber via a direct injector positioned to inject directly into the combustion chamber, injecting a second, different, fuel to the combustion chamber via an exhaust port injector positioned to inject toward an exhaust valve of the combustion chamber, and combusting the first and second fuels together in the combustion chamber.

A device for adjusting and controlling the actual supplied amount of urea entering an exhaust system comprises an electronic control unit (1), a compressed air supply device (2), a urea storage device (3), a compressed air control device (4), a metering pump or a metering valve (5), a spray nozzle (6), a main pipeline (7), a urea pipeline (8), and a urea control device (9). The urea control device (9) is in communication with the electronic control unit (1) and controls the actual supplied amount of urea injected into the exhaust system from the spray nozzle according to the starting time point and the finishing time point. A method for adjusting and controlling the actual supplied amount of urea entering an exhaust system is also disclosed. The present device and method effectively prevent the excessive urea from being injected into the exhaust system, and enable the original exhaust system to match with stricter emission standards through a low cost improvement.

The present disclosure describes methods for evaluating quality of DEF dosed to an EAS including a close coupled SCR unit a downstream SCR unit. A NOx conversion efficiency of the close coupled SCR unit and a NOx conversion efficiency of the downstream SCR unit are used to evaluate quality of DEF. In some embodiments, the NOx conversion efficiency of close coupled SCR unit is used to evaluate quality of DEF. Operation of an EAS using the results of the evaluation of quality of DEF are described.

A reduction-causing agent supply device includes a tank to store a reduction-causing agent, a pumping unit to pump the reduction-causing agent, a reduction-causing agent supply passage to supply the reduction-causing agent, an injection nozzle to inject the reduction-causing agent into an exhaust pipe, a drawing-back unit to draw the reduction-causing agent toward the tank, and a controller. After stop of an engine, the controller performs: reduction-causing agent drawing-back process of drawing the reduction-causing agent toward the tank and introducing exhaust gas from the injection nozzle into the reduction-causing agent supply passage; and gas discharge process of supplying the reduction-causing agent to compress the exhaust gas inside the reduction-causing agent supply passage, discharging the compressed exhaust gas from the injection nozzle, and closing a valve of the injection nozzle before the reduction-causing agent reaches the injection nozzle.

A computer implemented method to performing sensor analysis in an exhaust gas aftertreatment system (EATS) coupled downstream of an internal combustion engine (ICE). The methodology is specifically adapted for determining a scale factor for a NOx sensor that is arranged downstream of a position where an amount of a reductant is injected into exhaust gases from the ICE.

An aftertreatment system comprises an aftertreatment component structured to decompose constituents of an exhaust gas produced by an engine. A reductant insertion assembly is fluidly coupled to the aftertreatment component and configured to insert a reductant therein. A controller is operatively coupled to the reductant insertion assembly and configured to instruct the reductant insertion assembly to insert the reductant into the aftertreatment component for a first insertion time between first time intervals. The controller determines an operating condition of the engine, and determines if the operating condition satisfies a predetermined condition. In response to the predetermined condition being satisfied, the controller instructs the reductant insertion assembly to insert the reductant into the aftertreatment component for a second insertion time between second time intervals. The second insertion time is longer than the first insertion time.

Various embodiments include a method for monitoring the tank content of a storage tank comprising: metering a fluid from the tank into the exhaust gas tract, wherein the fluid has a concentration with respect to a reducing agent; acquiring a current concentration value for the reducing agent; calculating a change in concentration of the reducing agent on the basis of the current concentration value in comparison with a stored concentration value; determining a current operating state of the vehicle to identify an operating state in which refueling cannot be carried out; and carrying out a plausibility check of the calculated change in concentration if the calculated change in concentration exceeds a predetermined threshold value and the operating state is identified. The plausibility check includes acquiring the current tank filling level of the fluid.

Systems are provided including a selective catalytic reduction catalyst structured to receive first exhaust gas from a first fuel source of a dual fuel engine system and second exhaust gas from a second fuel source of the dual fuel engine system, a first fuel of the first fuel source differing from a second fuel of the second fuel source, an ammonia slip catalyst positioned downstream of the selective catalytic reduction catalyst to receive a flow of exhaust gases from the selective catalytic reduction catalyst without an intervening catalyst, and an oxidation catalyst positioned downstream of the ammonia slip catalyst to receive the flow of exhaust gases from the ammonia slip catalyst without an intervening catalyst.