Adapting Reducing Agent Dosing Control via Valve Shift Delay Compensation
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Solution Overview
Problem
Existing reducing agent dosing systems in combustion engine emission control face challenges due to time delays in valve position shifting, leading to non-optimal dosing of reducing agents, which can be attributed to inherent characteristics like temperature and viscosity, as well as wear and tear of the dosing unit.
Innovation Solution
A method and system that continuously determine prevailing pressure and current levels to accurately determine time intervals for valve state changes, allowing for precise control of the reducing agent dosing unit, eliminating the need for time-consuming calibration and ensuring reliable and accurate dosing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve unit is controlled by applying voltage to overcome spring force, then the dosing system can achieve controlled opening and closing of the valve, but time delays occur in valve position shifting due to inherent characteristics like temperature, viscosity, and wear
Solution Approach 1:
The system performs preliminary determination of time intervals for valve position changes by monitoring pressure changes that occur when the valve transitions between open and closed states. These pre-determined time intervals are then used to compensate for the inherent delays in valve response, allowing the control unit to adjust the timing of voltage application to achieve accurate dosing despite the physical delays in valve actuation
2Adaptability or versatility
If the dosing unit operates under varying conditions like temperature and viscosity changes, then the system can function in different environmental conditions, but the valve response time varies leading to non-optimal dosing
Solution Approach 1:
The system continuously monitors the actual pressure in the reducing agent line and compares it with expected pressure values. Based on this feedback, the control unit determines the actual time intervals for valve position changes and adjusts the dosing timing accordingly. This closed-loop feedback mechanism allows the system to adapt to varying operational conditions while maintaining precise dosing control
3Ease of operation
If the valve unit is spring biased for reliable closing, then the valve can be controlled by simple voltage application, but the spring force creates additional time delay in valve position shifting
Solution Approach 1:
The system changes the temporal parameters of valve control by determining the actual time intervals required for the valve to transition between open and closed states under current operating conditions. The control unit uses these determined time intervals to precisely time the application and removal of voltage, compensating for the delay introduced by the spring bias and ensuring accurate dosing timing
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
This approach achieves high dosing accuracy and reliability by using determined time intervals to adapt control of the reducing agent dosing unit, ensuring the intended dosing period is maintained during each cycle, even in varying system conditions.
Implementation Method 1
The valve unit is spring biased, whereby the control unit can control a position of the valve unit by applying a voltage to an induction arrangement. Hereby an induction force is overcoming the force applied by the spring
Data Source
AI summary
Disclosed is a method for adapting control of a reducing agent dosing unit in a reducing agent provision system for emission control of a combustion engine. Characteristics relating to pressure variations associated with a dosing cycle are used for determining a first time period and a second time period. The time periods relate to a delay between activation of dosing and de-activation of dosing, respectively. The first time period and second time period are used for adapting operation of said reducing agent dosing unit.