Scania Cv Ab

Mikael Lundström

Ola Stenlåås

Christer Lundberg

Sebastian Zamani

Astrid Simovits

Carl Wahlström

Anders Simon

Magnus Fröberg

Ola STENLÅÅS

A method of diagnosing an operational performance of a combustion engine assembly is disclosed, the combustion engine assembly comprising a combustion engine, and an exhaust system. The exhaust system comprises a SCR catalyst and a NOx sensor arranged downstream of the SCR catalyst. The method comprises the steps of providing a first NOx value (v) using the NOx sensor during a supply period (p) of an exhaust additive, providing a second NOx value (v) using the NOx sensor during a stop period (p) of a supply of exhaust additive, and diagnosing the operational performance of the combustion engine assembly based on a ratio between the first and second NOx values (v, v). The present disclosure further relates to a computer program, a computer-readable medium, a control arrangement, a combustion engine assembly, and a vehicle.

Method of diagnosing a combustion engine assembly, control arrangement, combustion engine assembly, and vehicle

Disclosed is a method for diagnosing a first exhaust treatment component for treatment of an exhaust gas stream comprising means for oxidizing nitric oxide into nitrogen dioxide. A first reduction catalytic converter is arranged upstream said means for oxidizing nitric oxide into nitrogen dioxide, and a second reduction catalytic converter is arranged downstream said means. A reagent is for reduction of nitrogen oxides in said first catalytic converter, and a first sensor measures an occurrence of nitrogen oxide downstream said means but upstream said second reduction catalytic converter. The method comprises: causing a supply of reagent upstream said first reduction catalytic converter to an extent exceeding the extent to which reagent is consumed by the first reduction catalytic converter, determining a first measure of the occurrence of reagent downstream said means for oxidizing, and diagnosing said means for oxidizing nitric oxide into nitrogen dioxide based on said first measure.

Method and system for diagnosing oxidation of a substance in an exhaust gas stream

A method that determines a cause for the impaired performance of a catalytic configuration of the exhaust gas of a combustion engine (), the method including determining (s) a course of a NOx-conversion ratio; determining (s) a prevailing temperature of the catalytic configuration; increasing (s) the temperature of the catalytic configuration from a prevailing temperature below a predetermined temperature value (Te) to a temperature (TSred) above the predetermined temperature value above which sulphur is removed from the catalytic configuration; and/or decreasing (s) the temperature of the catalytic configuration from a prevailing temperature (TSred) above the predetermined temperature value (Te) to a temperature below the predetermined temperature value so as to impair the performance of the catalytic configuration in case sulphur is present; and determining (s) one cause out of a set of causes on the basis of the course of the NOx-conversion ratio thus determined.

System and a method for determining a cause for impaired performance of a catalytic configuration

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.

Method and system for diagnosing an aftertreatment system

Provided is a method for diagnosing exhaust sensors, where at least one substance resulting from combustion is reduced by an additive. A first sensor intended to measure an occurrence of said substance upstream said supply of additive, and a second sensor intended to measure an occurrence of said substance downstream said supply of additive. The method comprises: determining whether the locations of said first and second sensors are reversed by: determining if a second measurement value of said second sensor exceeds a corresponding first measurement value of said first sensor at least to a first extent, and when this condition occurs, determining that the locations of said first and second sensors sensor are reversed, said measurement values are determined when a supply of additive is set to obtain at least a first reduction of said at least one substance to be reduced.

Method and system for diagnosing exhaust sensors

A method for diagnosing an aftertreatment component, wherein nitrogen oxide is reduced using a first catalytic converter upstream said aftertreatment component and a second catalytic converter downstream said aftertreatment component, said aftertreatment component oxidizing nitric oxide into nitrogen dioxide. A first sensor measure nitrogen oxide downstream said first catalytic converter but upstream said aftertreatment component, and a second sensor measure nitrogen oxide downstream said aftertreatment component. The method includes: supplying additive upstream said first catalytic converter; using said first and second sensors, performing a first measurement at a first temperature of said first aftertreatment component; using said first and second sensors, performing a second measurement at a second temperature of said first aftertreatment component; and diagnosing oxidation of nitric oxide into nitrogen dioxide in said aftertreatment component using said first and second measurements.

Method and system for diagnosing an aftertreatment component subjected to an exhaust gas stream

The present invention relates to a method for correcting a supply of additive to an exhaust gas stream resulting from combustion in an internal combustion engine. A first aftertreatment component being arranged for oxidation of nitric oxide into nitrogen dioxide, and a reduction catalytic converter being arranged downstream said first aftertreatment component. Additive is supplied to said exhaust gas stream for reduction of nitrogen oxides in said reduction catalytic converter, the additive being supplied in proportion to an occurrence of nitrogen oxides in said exhaust gas stream, said proportion being subject to correction. The method includes: supplying unburned fuel to said exhaust gas stream upstream said first aftertreatment component to reduce oxidation of nitric oxide into nitrogen dioxide in said first aftertreatment component, and correcting said supply of additive to said exhaust gas stream when supplying unburned fuel to said exhaust gas stream.

Method and system for use when correcting supply of an additive to an exhaust gas stream

The present invention relates to a method for restricting work produced by combustion in a combustion chamber, wherein an aftertreatment system is arranged for reduction of at least one substance resulting from the combustion, wherein the work produced by the combustion is restricted when there is a malfunction regarding reduction of the at least one substance. The method includes: performing a first evaluation regarding the reduction of the at least one substance, when the first evaluation indicates a malfunction, performing a second evaluation regarding the reduction of the at least one substance, the second evaluation being different from the first evaluation, and restricting work produced by the combustion only when a malfunction regarding reduction of the at least one substance is indicated also by the second evaluation.

Method for restricting work produced by a combustion engine

The present invention relates to a method for restricting work produced in a combustion chamber, wherein a substance resulting from combustion is reduced by supplying additive comprising a reagent to the exhaust gas stream. The method comprising: determining if a quality of said additive, estimated by means of a first sensor, being subjected to said additive, is below a first quality; determining if signals from a second sensor, being subjected to the exhaust gas stream, indicate insufficient reduction of said at least one substance; determining if a correction of the supply of additive has reached an upper limit; and restricting work produced by combustion only when: said estimated quality of said additive is below said first quality, said correction has reached said upper limit, and said measurement in the exhaust gas stream indicates insufficient reduction.

The present invention relates to a method for determining when to correct supply of additive to an exhaust gas stream resulting from combustion in at least one combustion chamber, wherein the additive is arranged for reduction of at least one substance resulting from said combustion by supplying the additive to an exhaust gas stream resulting from said combustion. The quantity of additive being supplied is subjectable to correction, and a sensor is subjected to the exhaust gas stream and arranged to measure occurrence of said at least one substance. The method comprises: by means of sensor signals from said sensor, determining a level of occurrence of said first substance in said exhaust gas stream, and determining when to correct said supply of additive on the basis of said occurrence of said first substance in said exhaust gas stream.

A method for cleaning an SCR system, wherein reducing agent is supplied to an exhaust flow upstream of an SCR catalyst (), NOcontents of the exhaust flow are determined upstream and downstream of the SCR catalyst () and reducing agent crystals are removed by a high-temperature procedure. The steps are determining (s) a ratio (K1) between NOcontents downstream and upstream of the SCR catalyst (), raising the temperature (s) of the exhaust flow to vaporize reducing agent crystals with a view to cleaning, determining (s) a ratio (Kn) between respective NOcontents determined downstream and upstream of the SCR catalyst () at a temperature (T2) of the SCR catalyst () at which reducing agent crystals vaporize, comparing (s) the ratios (K1, Kn) and using this comparison as a basis for deciding whether reducing agent crystals have been removed to an intended extent. Also a computer program product containing program code (P) for a computer () for implementing the method according to the invention. The invention relates also to a device and a motor vehicle equipped with the device.

Device and method for cleaning of an SCR system

A method for troubleshooting in an SCR system which has a dosing unit () for dosing of reducing agent into an engine's exhaust duct () upstream of an SCR catalytic converter () for reduction of NOcontent in an exhaust flow from said engine and a DOC unit (). The method comprises steps of: determining (s) NOcontent in the exhaust flow downstream of said SCR catalytic converter (); determining satisfactory operation of said SCR catalytic converter (); progressively altering the dosage of said reducing agent; determining whether said SCR system can reduce NOcontent of the exhaust flow downstream of said SCR catalytic converter to a predetermined extent during altered dosing; using the results of determinations as a basis for deciding whether said DOC unit () is faulty or not. Also disclosed is a computer program product having the program code (P) for a computer () for implementing the method according to the invention. Also disclosed is a device for troubleshooting in an SCR system and to a motor vehicle equipped with the device.

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Hägersten, Sweden

Mikael Lundström