Fluidic Metering System Quantity Deviation Detection
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Solution Overview
Problem
Current fluidic or hydraulic metering systems in internal combustion engines, particularly those with conveying pumps and pressure sensors, face challenges in precisely identifying deviations in quantity due to internal leakage, which varies over the pump's service life and is influenced by production tolerances and mechanical rigidity, limiting their accuracy and requiring complex computations.
Innovation Solution
A method involving a test injection and pressure drop analysis using an analytical approximate solution to compare measured pressure drops with theoretically expected drops, allowing for the identification of system parameters that influence the result, thereby reducing production tolerances and costs by minimizing the effects of internal leakage and external return flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional monitoring methods are used to identify quantity deviations, then the system can detect potential leakage, but the accuracy is substantially determined by the variable mechanical or fluidic rigidity of the line system which depends on ageing and production tolerances
Solution Approach 1:
The patent changes the measurement parameter from direct quantity monitoring (which requires knowledge of system rigidity) to pressure drop monitoring over time. By measuring pressure at different time points during a test injection and computing the pressure drop, the system eliminates the need to know system rigidity parameters, thereby improving measurement accuracy without requiring complex computations.
2Measurement precision
If system rigidity is computed to improve measurement accuracy, then quantity deviations can be identified, but the results are substantially influenced by internal leakage of the conveying pump which varies over service life
Solution Approach 1:
The patent extracts the measurement from the influenced parameters by measuring pressure drop directly during a test injection rather than computing it from system rigidity and quantity data. This extraction removes the measurement from the influence of internal leakage variations, ensuring reliable and stable measurements throughout the pump's service life.
3Measurement precision
If very precise manufacturing of individual system components is required to achieve accurate quantity deviation identification, then measurement accuracy improves, but manufacturing costs and device complexity increase
Solution Approach 1:
The patent replaces the mechanical approach of ensuring precise manufacturing of components with a measurement approach that is insensitive to manufacturing variations. By using pressure drop measurement over time, the system achieves accurate quantity deviation identification without requiring very precise manufacturing of individual components, thereby easing manufacturing requirements.
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 method enables precise determination of quantity deviations with reduced production costs and improved accuracy in metering systems, applicable to all fluidic or hydraulic systems, including SCR exhaust gas post-treatment systems, by systematically combining analytical solutions with existing components.
Implementation Method 1
the pressure drop in the metering system is detected depending on time
Data Source
AI summary
A method for identifying deviations in quantity in the case of a fluidic metering system (100-165), in particular an internal combustion engine of a motor vehicle, in which at least one conveying pump (125) for conveying a fluid, and at least one pressure sensor (135) for determining a fluidic pressure in the metering system (100-165), are disposed, wherein it is provided in particular that a test admeasurement of fluid is carried out (205), that a temporal pressure drop in the metering system (100-165) is detected (210), that the detected temporal pressure drop is compared with a pressure drop (215) that is to be theoretically expected (220), and that a deviation in quantity of the metering system (100-165) is determined based on the result of the comparison (225).