Venturi Tube Inlet Pressure Calculation Using Correction Maps
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Solution Overview
Problem
The challenge is to accurately calculate the flow rate of exhaust gas in a Venturi tube, which requires measurements from three sensors, but it is difficult to arrange these sensors due to limited space on the Venturi tube.
Innovation Solution
A method and device that acquire pressure P2 in an intake pipeline and differential pressure ΔP between the inlet and throat of the Venturi tube, correct these values using predetermined correction maps to calculate the pressure at the inlet of the Venturi tube, thereby eliminating the need for a sensor at the inlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three sensors are arranged on the Venturi tube to measure flow rate, then measurement precision is improved, but device complexity increases and space requirements are not met
Solution Approach 1:
The patent extracts the function of measuring inlet pressure from the physical sensor arrangement and relocates it to a calculation-based approach. Instead of placing a sensor directly on the Venturi tube inlet, the system uses an intake pipeline pressure sensor combined with correction maps to compute the inlet pressure, thereby reducing the number of physical sensors required on the Venturi tube while maintaining measurement precision.
Solution Approach 2:
The patent introduces correction maps as an intermediary between the intake pipeline pressure measurement and the actual Venturi tube inlet pressure. These correction maps compensate for pressure losses and variations, acting as a mediator that enables accurate inlet pressure determination without requiring a direct pressure sensor at the inlet location.
2Measurement precision
If three sensors are arranged on the Venturi tube, then flow rate calculation accuracy is improved, but the space constraint is violated
Solution Approach 1:
The patent removes the requirement for a pressure sensor at the Venturi tube inlet by extracting this measurement function and replacing it with a calculation approach using intake pipeline pressure and correction maps. This eliminates the need for additional space on the Venturi tube for sensor installation.
Solution Approach 2:
The patent creates a virtual copy of the inlet pressure measurement through calculation rather than physical sensing. By computing the inlet pressure from intake pipeline pressure data and correction factors, the system replicates the measurement function without requiring physical sensor presence at the inlet location.
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 allows for the calculation of exhaust gas flow rate without the need for a pressure sensor at the inlet of the Venturi tube, reducing the number of sensors required and addressing the space constraint issue.
Implementation Method 1
A Venturi tube is arranged in an exhaust gas recirculation pipeline (EGR pipeline) of an engine
Data Source
Figure 1~2
Figure 3~4
AI summary
A method for calculating a pressure of a Venturi tube, comprising acquiring a pressure value P2 of an air inlet tube, and acquiring a pressure difference ΔP between an inlet and a throat of the Venturi tube; performing correction on the P2 by using a predetermined first correction MAP, and obtaining a pressure PA of a first point before an EGR mixer; performing correction on the ΔP by using a predetermined second correction MAP, and obtaining a pressure loss PB of the Venturi tube; and summing the PA and the PB to obtain the pressure of the Venturi tube. According to the method for calculating the pressure of the Venturi tube, an inlet pressure of the Venturi tube can be collected and calculated by using a calculation mode rather than a sensor. Therefore, it is not necessary to arrange an inlet pressure sensor of the Venturi tube, the number of sensors arranged on the Venturi tube is reduced, and an exhaust flow can also be calculated. Further provided is a device for calculating the pressure of the Venturi tube.