Injection Rate Measurement Correction for Diesel Valves
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Solution Overview
Problem
Current hydraulic pressure increase analyzers for measuring injection valves in diesel engines face challenges in accurately determining the injection rate and hydraulic start of injection due to variations in transit time and noise filtering, which affect measurement precision.
Innovation Solution
A device and method that corrects the measured injection rate by accounting for the transit time of pressure waves and filter effects, using a characteristics map to determine the average speed of sound in the test fluid, and an ultrasonic sensor to enhance measurement accuracy, particularly by compensating for time shifts and noise filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the measured injection rate is corrected for transit time and filter effects, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The correction means determine the transit time of pressure waves before correcting the measured injection rate. By performing the transit time determination and correction calculations in advance and systematically, the patent resolves the contradiction between improved measurement precision and increased device complexity, as the correction process becomes a structured preliminary step rather than an ad-hoc complication.
2Reliability
If noise filtering is applied to pressure sensor measurements, then measurement reliability is improved, but time shift occurs reducing measurement precision
Solution Approach 1:
The correction means use feedback from the measured pressure signal to determine the transit time and compensate for time shifts introduced by noise filtering. By continuously monitoring the pressure signal characteristics and adjusting the correction accordingly, the patent reconciles the need for noise filtering (reliability) with the need for accurate timing (precision).
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
The solution significantly improves the measurement accuracy of injection rates and hydraulic start of injection, allowing for more precise control of fuel injection schedules, thereby enhancing diesel engine efficiency and environmental performance.
Implementation Method 1
a pressure sensor (6) arranged in the measuring volume (3)... determining the transit time of a pressure wave (12) emanating from the injection opening (2a) and propagating through the test fluid (4) to the pressure sensor (6)
Implementation Method 2
an ultrasonic sensor (10) for determining an average speed of sound cm,mess in the test fluid (4)
Implementation Method 3
the injection valve (injector) converts an electrical control into a mass flow of fuel... A test liquid is injected under pressure via the injection valve to be characterized
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
A device (1) for measuring the injection rate dm(t)/dt of an injection valve (2) for a fluid (4a), wherein m(t) is the injection quantity of the fluid (4a) as a function of the time (t), having a measurement volume (3) which is closed off on all sides and which is filled with a test fluid (4), having an opening (5a) in one wall (5) of the measurement volume (3) for the purposes of receiving the injection valve (2) such that the injection valve (2), in the installed position, projects with at least one injection opening (2a) into the measurement volume (3), and having a pressure sensor (6) which is arranged in the measurement volume (3), wherein correction means (8, 8a, 9a, 9b, 9c) are provided for determining the propagation time of a pressure wave (12), which originates from the injection opening (2a) and which propagates through the test fluid (4), to the pressure sensor (6) and for correcting the measured injection rate dm(t)/dt, taking said propagation time into consideration, to give a rectified injection rate dm'(t)/dt. A method for producing the device (1), wherein the characteristic map (8a) is determined by way of a fluid-dynamic simulation of the time-dependent and position-dependent local speed of sound c(t,x) in a partial volume of the measurement volume (3) which encompasses at least the path (11) from the injection opening (2a) to the pressure sensor (6), which simulation is based on at least one time-dependent boundary condition for the pressure (p) in the measurement volume (3) and/or for the injection quantity (dm). A method for measuring the injection rate dm(t)/dt of an injection valve (2) for a fluid (4a).