US 11,719,150 B2
Method and a control arrangement for a process of selective catalytic reduction after-treatment of an exhaust gas
David Tempelmann, Älvsjö (SE); Christer Lundberg, Rönninge (SE); Tobias Brännvall, Södertälje (SE); and Johan Lundström, Järna (SE)
Assigned to Scania CV AB, Södertälje (SE)
Appl. No. 17/802,574
Filed by Scania CV AB, Södertälje (SE)
PCT Filed Feb. 26, 2021, PCT No. PCT/SE2021/050163
§ 371(c)(1), (2) Date Aug. 26, 2022,
PCT Pub. No. WO2021/177875, PCT Pub. Date Sep. 10, 2021.
Claims priority of application No. 2050257-1 (SE), filed on Mar. 6, 2020.
Prior Publication US 2023/0143384 A1, May 11, 2023
Int. Cl. F01N 3/20 (2006.01)
CPC F01N 3/208 (2013.01) [F01N 2570/14 (2013.01); F01N 2610/02 (2013.01); F01N 2900/0418 (2013.01); F01N 2900/1812 (2013.01); F01N 2900/1821 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A method for counteracting solid deposits derived from an additive of selective catalytic reduction (SCR) after-treatment system of an exhaust gas of an exhaust gas stream from a combustion engine, wherein the selective catalytic reduction after-treatment system process comprises: injecting the additive in liquid form into the exhaust gas stream from the combustion engine; evaporating the additive to form a reducing agent, the reducing agent being added to the exhaust gas stream; and reducing nitrogen oxides of the exhaust gas stream in a reduction catalyst device through the use of the reducing agent added to the exhaust gas stream; wherein the method comprises:
defining an integrand to be the difference between a rate of injection of the additive and a rate of evaporation of the additive to the reducing agent multiplied by a coefficient, wherein the value of the coefficient is between zero and one;
producing, by usage of an integral controller, an integral controller output which is proportional to the integral of the integrand with time; and
requesting a countermeasure at least partly based on the integral controller output to counteract solid deposits derived from the additive.