Electronic Control Unit Air Flow Estimation for Partial EGR
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Solution Overview
Problem
Existing methods for calculating the flow rate of air admitted into an internal combustion engine, particularly with partial low-pressure exhaust gas recirculation, are inefficient due to the need for expensive sensors and complexity, especially when dealing with partial recirculation of exhaust gases at low pressure.
Innovation Solution
A system and method using an electronic control unit that estimates the flow rate of air admitted into the engine based on temperature and pressure measurements from a reduced set of sensors, incorporating calculations for the flow of gases at the compressor inlet and air flow, which reduces the number of necessary sensors and provides accurate results comparable to dedicated sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flowmeter is used to measure air flow rate, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a virtual copy of the flowmeter function through calculation means that compute air flow rate from temperature and pressure sensor data, replacing the need for a physical flowmeter sensor while maintaining measurement capability
Solution Approach 2:
The patent replaces the mechanical/physical flowmeter sensor with an electronic calculation system that uses temperature and pressure sensors combined with computational algorithms to determine air flow rate, eliminating the need for dedicated flow measurement hardware
2Measurement precision
If a flowmeter is used to measure air flow rate, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent creates a virtual copy of the flowmeter function through calculation means that compute air flow rate from temperature and pressure sensor data, replacing the need for a physical flowmeter while maintaining measurement precision
Solution Approach 2:
The patent uses inexpensive temperature and pressure sensors instead of expensive flowmeters, accepting that these sensors may require more frequent calibration or replacement but achieving lower overall system cost
3Measurement precision
If the Barré de Saint-Venant formula is used for calculation, then air flow estimation is achieved, but device complexity and inapplicability to low-pressure EGR increase
Solution Approach 1:
The patent modifies the calculation approach by using simplified relationships between temperature, pressure, and flow rate that are specifically adapted for low-pressure EGR conditions, making the calculation applicable where traditional formulas fail
Solution Approach 2:
The patent divides the calculation into separate steps: first calculating compressor inlet gas flow from temperature and pressure, then calculating air flow admitted to the engine using additional temperature data, making the complex problem manageable and adaptable
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 precise calculation of air flow into the engine with a reduced number of sensors, improving accuracy and reducing costs, while effectively managing the compromise between smoke generation and nitrogen oxide emissions.
Implementation Method 1
The electronic control unit notably groups together all of the calculation means necessary for estimating the flow of fresh air. It is connected to a set of sensors and actuators to control the operation of the engine.
Implementation Method 2
This sensor is essentially composed of a wire heated by the passage of an electric current and immersed in the flow of the gas to be measured. After calibrating the sensor, a variation in gas flow results in a variation in current in the wire
Implementation Method 3
The first is the so-called high pressure partial exhaust gas recirculation, in which the gases are taken from the outlet of the exhaust manifold and reinjected into the intake manifold, i.e. after the compressor
Implementation Method 4
The partial exhaust gas recirculation circuit consists of an exhaust valve, a partial exhaust gas recirculation valve and a cooler
Data Source
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AI summary
The invention relates to a control system for estimating the fresh air flow entering an internal combustion engine, and to a method therefor. Said control system belongs to an internal combustion engine (1) and comprises a turbocompressor (3), a circuit for partial exhaust gas recirculation (EGR), and an electronic control unit (UCE) (11) provided with a means (12) for controlling the partial exhaust gas recirculation flow, and calculation means receiving the signals of temperature and pressure sensors. Said system is characterised in that the electronic control unit comprises a means for calculating the flow of the gases (13) at the inlet of the compressor and a means for calculating the air flow (14) entering into the motor, from a set of values of temperatures and pressures of the gases circulating in different parts of the engine.