# US 2019/0316504 A1 · Exhaust gas aftertreatment system for diesel engine and method of detecting abnormal injection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0316504 A1 - Document ID: US20190316504A1 - Status: Published application - Kind: A1 - Application number: 16/469,859 - Filed: 2016-12-16 - Published: 2019-10-17 - Earliest claimed: 2016-12-16 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Yujiang Xu; Ling Li; Honglong Zhou; Siwei Dong - Web page: https://patentgrep.com/patent/US20190316504A1 ## CPC - F01N 3/18: characterised by methods of operation; Control - F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent} - F01N 3/085: {Sulfur or sulfur oxides} - F01N 3/28: Construction of catalytic reactors - F01N 9/007: {Storing data relevant to operation of exhaust systems for later retrieval and analysis, e.g. to research exhaust system malfunctions} - F01N 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus - F01N 2550/00: Monitoring or diagnosing the deterioration of exhaust systems - F01N 2610/02: the substance being ammonia or urea - F01N 2610/146: Control thereof, e.g. control of injectors or injection valves - F01N 2900/0408: using a feed-back loop - F01N 2900/0416: using the state of a sensor, e.g. of an exhaust gas sensor - F01N 2900/06: Parameters used for exhaust control or diagnosing - F01N 2900/1808: Pressure - F01N 2900/1812: Flow rate - Y02T 10/12: Improving ICE efficiencies - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Disclosed is an exhaust gas aftertreatment system (1) for a diesel engine, the exhaust gas aftertreatment system comprising: a treatment agent tank (2) for storing an exhaust gas treatment agent; a metering injection module (4), with the injection of the metering injection module (4) being controlled with a determined duty ratio signal according to a desired injection amount; a supply module (3) connected between the treatment agent tank (2) and the metering injection module (4) for supplying the exhaust gas treatment agent to the metering injection module (4); an exhaust gas treatment agent pipe (6) connected between the metering injection module (4) and the supply module (3); a pressure sensor for measuring the system pressure in the exhaust gas treatment agent pipe (6); and a controller (7); wherein the controller (7) is configured to receive a system pressure signal from the pressure sensor during injection of the metering injection module (4), and detect an injection abnormality of the metering injection module (4) based on at least a first amount, which represents an actual injection amount and is determined by the system pressure signal, and a second amount, which represents a theoretical injection amount and is determined by a corresponding duty ratio signal. A corresponding injection abnormality detection method is further disclosed. The injection abnormality detection method is simple and reliable. ## Claims ### Claim 1 An exhaust gas aftertreatment system (1) for a diesel engine, the exhaust gas aftertreatment system comprising: a treatment agent tank (2) for storing an exhaust gas treatment agent; a metering injection module (4), with the injection of the metering injection module (4) being controlled with a determined duty ratio signal according to a desired injection amount; a supply module (3) connected between the treatment agent tank (2) and the metering injection module (4) for supplying the exhaust gas treatment agent to the metering injection module (4); an exhaust gas treatment agent pipe (6) connected between the metering injection module (4) and the supply module (3); a pressure sensor for measuring a system pressure in the exhaust gas treatment agent pipe (6); and a controller (7); wherein the controller (7) is configured to: receive a system pressure signal from the pressure sensor during injection of the metering injection module (4), and detect an injection abnormality of the metering injection module (4) based on at least a first amount, which represents an actual injection amount and is determined by the system pressure signal, and a second amount, which represents a theoretical injection amount and is determined by a corresponding duty ratio signal. ### Claim 2 (depends on 1) The exhaust gas aftertreatment system (1) of claim 1, wherein the amplitude of the predetermined operating frequency of the metering injection module (4) is determined by means of frequency analysis of a system pressure signal, and from the average value of the corresponding duty ratio signal according to the predetermined relation. ### Claim 3 (depends on 1) The exhaust gas aftertreatment system (1) of claim 1, wherein the amplitude of a predetermined operating frequency of the metering injection module (4) is determined by transforming a system pressure signal from a time domain to a frequency domain. ### Claim 4 (depends on 3) The exhaust gas aftertreatment system (1) of claim 3, wherein (a) the system pressure signal is transformed from the time domain to the frequency domain using a discrete Fourier transform; (b) the injection abnormality of the metering injection module (4) is detected according to the relative deviation of the first amount and the second amount; (c) the controller (7) is a separately provided controller or an electronic control unit of the diesel engine; or a combination of (a), (b), and (c). ### Claim 5 An injection abnormality detection method for an exhaust gas aftertreatment system (1) for a diesel engine, the exhaust gas aftertreatment system (1) including a treatment agent tank (2) for storing an exhaust gas treatment agent; a metering injection module (4), with the injection of the metering injection module (4) being controlled with a determined duty ratio signal according to the desired injection amount; a supply module (3) connected between the treatment agent tank (2) and the metering injection module (4) for supplying the exhaust gas treatment agent to the metering injection module (4); an exhaust gas treatment agent pipe (6) connected between the metering injection module (4) and the supply module (3); a pressure sensor for measuring the system pressure in the exhaust gas treatment agent pipe (6); and a controller (7); and the method comprising: receiving a system pressure signal from the pressure sensor and acquiring a corresponding duty ratio signal during injection of the metering injection module (4); and detecting, by the controller (7), an injection abnormality of the metering injection module (4) at least based on a first amount, which represents an actual injection amount and is determined by the system pressure signal, and a second amount, which represents a theoretical injection amount and is determined by the corresponding duty ratio signal. ### Claim 6 (depends on 5) The injection abnormality detection method of claim 5, wherein the amplitude of the predetermined operating frequency of the metering injection module (4) is determined by means of frequency analysis of a system pressure signal, and from the average value of the corresponding duty ratio signal according to the predetermined relation. ### Claim 7 (depends on 5) The injection abnormality detection method of claim 5, wherein a deviation amount is determined by subtracting the second amount from the first amount; a relative deviation coefficient is determined by dividing the deviation amount by the second amount; and if the relative deviation coefficient is greater than a predetermined deviation threshold, it is at least initially determined that there is an injection abnormality. ### Claim 8 (depends on 6) The injection abnormality detection method of claim 6, wherein (a) the predetermined deviation threshold is 50%; (b) the predetermined relation is a linear relation; or a combination of (a) and (b). ### Claim 9 (depends on 7) The injection abnormality detection method of claim 7, wherein if the relative deviation coefficient is not greater than the predetermined deviation threshold, enabling a counter to return to zero and waiting for the next abnormality detection; otherwise accumulating the counter once and determining whether the value of the counter is greater than a first predetermined count threshold; if the value of the counter is greater than the first predetermined count threshold, determining that there is an injection abnormality, otherwise waiting for the next abnormality detection; or if the relative deviation coefficient is not greater than the predetermined deviation threshold, decreasing the counter once and waiting for the next abnormality detection; otherwise accumulating the counter once and determining whether the value of the counter is greater than a second predetermined count threshold; and if the value of the counter is greater than the second predetermined count threshold, determining that there is an injection abnormality, otherwise waiting for the next abnormality detection. ### Claim 10 (depends on 5) The injection abnormality detection method of claim 5, wherein the system pressure signal is transformed from the time domain to the frequency domain, a target frequency interval is set centering at a predetermined operating frequency of the metering injection module (4), and the sum of all amplitudes for the target frequency interval is calculated as the first amount.