SYSTEM AND METHOD FOR DIAGNOSING REAGENT DISPENSING Russian patent published in 2018 - IPC F01N3/20 F01N11/00 

FIELD: engines and pumps.

SUBSTANCE: invention relates to purification of internal combustion engine exhaust gases. Method for diagnosing the reagent dosing system involves: determining the amount of reagent, which must be injected by means of a dispensing system per dosing cycle in order to treat the exhaust gas in the exhaust system that contains a selective catalytic reduction catalyst, herewith the dosing cycle comprising a plurality of dosing periods and a dispenser operating time and the dispenser downtime in each dosing period, wherein a predetermined portion of the reagent amount is injected during the dispensing operating time of each dosing period; determining the operation of the dispensing system for injecting the amount of reagent into the exhaust system during the dosing cycle, herewith the operation of the dispensing system involves monitoring the pump of the dispensing system by means of a pressure feedback check in order to maintain the operational pressure of the dispensing system, when the spray gun is open; determining the diagnostic dosing period basing on the dosing periods within the dosing cycle; pausing the pump pressure feedback check while maintaining the pump speed during the diagnostic period; measuring the dispensing system pressure drop downstream of the pump during the operating time of the dispenser for the diagnostic dosing period and determining the failure condition of the dispensing system when the amount of reagent is supplied in response to the pressure drop measured during the diagnostic dosing period. System, which implements the disclosed method, is proposed.

EFFECT: method for diagnosing the reagent dispensing system is proposed.

18 cl, 4 dwg