Dosing Valve Blockage Detection via Hydraulic Stiffness Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current SCR catalytic converter systems face challenges in identifying dosing quantity deviations due to blockages in spray openings of the dosing valve, which cannot be accurately detected through pressure profile gradients or pump rotational speed deviations, necessitating the use of an additional mass flow sensor.
Innovation Solution
A method that determines the stiffness of the hydraulic system by analyzing pressure profiles before and after closing or adjusting the dosing valve, allowing for the identification of blockages without a mass flow sensor, by calculating the cross-sectional area of the dosing valve from these profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an additional mass flow sensor is installed in the hydraulic system to identify dosing quantity deviations, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses pressure as an intermediary parameter to indirectly measure dosing quantity deviations. Instead of directly measuring mass flow with a sensor, the system measures pressure differences in the hydraulic system and uses these pressure variations to infer dosing quantity deviations, thereby avoiding the need for additional mass flow sensors while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical/electrical mass flow sensor with a pressure-based detection system. By substituting direct mass flow measurement with pressure differential measurement and calculation, the system achieves the same measurement function without adding complex sensor hardware to the hydraulic system
2Device complexity
If pressure profile gradient evaluation is used to identify dosing quantity deviations, then device complexity is maintained, but measurement precision deteriorates
Solution Approach 1:
The patent performs preliminary characterization of the hydraulic system by determining stiffness values under known conditions before actual dosing operations. This preliminary action creates a reference model that enables more accurate real-time detection of dosing quantity deviations during normal operation, improving measurement precision without adding complexity
Solution Approach 2:
The patent changes the approach from directly evaluating pressure profile gradients to using pressure data in conjunction with calculated stiffness parameters. By transforming the measurement approach to use stiffness-corrected pressure analysis, the system achieves higher measurement precision while maintaining the same hardware configuration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the detection of dosing valve blockages without the need for a mass flow sensor, facilitating accurate identification and potential system adjustments to maintain nitrogen oxide emission compliance.
Implementation Method 1
The delivery module comprises a pump which is connected by means of lines to the dosing valve and if appropriate to a reducing agent return line. Said line system is referred to as hydraulic system.
Implementation Method 2
a first pressure profile in the hydraulic system in a delivery module of the SCR catalytic converter system is determined
Implementation Method 3
The dosing valve is subsequently opened, a second pressure profile in the hydraulic system in the delivery module of the SCR catalytic converter system is determined
Implementation Method 4
In an SCR (selective catalytic reduction) catalytic converter, nitrogen oxides in the exhaust gas of the internal combustion engine are reduced, in the presence of a reducing agent, to form nitrogen.
Data Source
AI summary
The invention relates to a method for identifying a blockage of one or more spray openings of a dosing valve of an SCR catalytic converter system. Said method comprises the closure of the dosing valve, the determination of a first pressure profile in the hydraulic system in the delivery module of the SCR catalytic converter system, and the determination of the stiffness of the hydraulic system from the first pressure profile. The dosing valve is subsequently opened, a second pressure profile in the hydraulic system in the delivery module of the SCR catalytic converter system is determined, and a blockage of one or more spray openings of the dosing valve is determined from the stiffness and from the second pressure profile.