Hydraulic Line Pressure Signal Analysis for Injector Control
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Solution Overview
Problem
Current methods for determining the injection quantity or rate of a fluid through a hydraulic line into an injector are not precise enough, leading to inaccuracies in fluid delivery, especially in diesel engines, due to reflections in pressure measurement signals caused by continuous hydraulic sine pressure waves.
Innovation Solution
A method and device that measure fluid pressure in the hydraulic line using pressure sensors and determine the transmission function of the line, allowing for precise calculation of the injection quantity or rate by transforming pressure signals into frequency space and using a stored model to determine fluid pressure at the injector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous hydraulic sine pressure waves are used to determine the transmission function of the hydraulic line, then the transmission function can be determined, but reflections occur in the pressure measurement signal making it impossible to determine the transmission function correctly
Solution Approach 1:
The patent uses periodic pressure waves with specific frequencies to excite the hydraulic line. By applying periodic excitation signals at multiple frequencies and analyzing the resulting pressure responses, the transmission function can be determined without suffering from reflections that plague continuous wave methods. The periodic nature allows for clear distinction between forward and reflected waves through frequency analysis.
Solution Approach 2:
The patent changes the frequency parameter of the excitation signal to determine the transmission function across different frequency ranges. By varying the frequency of the pressure waves and measuring the system response at each frequency, the transmission function is constructed as a frequency-dependent parameter, avoiding the reflection problems of continuous single-frequency excitation.
2Measurement precision
If the injection quantity is determined by comparing with pump delivery quantity, then a determination method is provided, but high delivery precision is required which incurs high costs
Solution Approach 1:
The patent replaces the mechanical pump-based measurement method with a pressure-based measurement system. Instead of relying on precise mechanical pump delivery measurements, the system uses pressure sensors to measure pressure waves in the hydraulic line and determines injection quantity through signal analysis and transmission function calculations, reducing mechanical complexity.
Solution Approach 2:
The patent introduces pressure waves as an intermediary medium to transfer information about the injection quantity. Rather than directly measuring pump delivery or injection flow, the system uses pressure wave propagation characteristics as an intermediary to indirectly and accurately determine the injection quantity with simpler hardware.
3Ease of operation
If lambda control is used for petrol injection, then injection quantity control is achieved, but this method cannot be directly applied to diesel or fluid injection systems
Solution Approach 1:
The patent develops a universal measurement method based on pressure wave analysis that can be applied to both petrol and diesel injection systems, as well as other fluid injection systems. The method uses fundamental hydraulic principles and pressure sensor measurements that are independent of the specific fuel type or injection system design, providing broad adaptability while maintaining ease of operation.
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 accurate determination of injection quantity or rate, reducing emissions and operational costs by providing precise fluid delivery, even with greater pressure and component tolerances, and facilitating on-board diagnosis for vehicles.
Implementation Method 1
measurement of the fluid pressure in the hydraulic line by means of a pressure sensor
Implementation Method 2
a fluid which is transported to an injector through a hydraulic line
Data Source
AI summary
A method and a device for determining the injection quantity or the injection rate of a fluid which is transported to an injector through a hydraulic line and is injected into a reaction space by the injector. The fluid pressure in the hydraulic line is measured by a pressure sensor, the fluid pressure at the injector is determined using the pressure measured by the pressure sensor and a stored transmission function of the hydraulic line, and the injection quantity or the injection rate of the fluid injected by the injector is determined using the fluid pressure determined at the injector.