EGR Valve Control for Boosting Apparatus
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Solution Overview
Problem
In engine systems with boosting apparatuses, excessive driving conditions lead to improper control of EGR rates, resulting in increased smoke, NOx emissions, and deteriorated exhaust gas purification performance due to the turbocharger's impact on boost and exhaust pressures.
Innovation Solution
A control method that adjusts the supply of EGR gas by simultaneously controlling a supercharger and turbocharger based on pre-input driving maps, reflecting driving conditions, and correcting operating amounts to maintain optimal EGR gas supply through the EGR valve, utilizing detection units for oxygen and air flow measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the turbocharger operates at high speed to compress intake air and improve charging efficiency, then power output and driving performance are improved, but boost pressure and exhaust pressure change excessively causing improper EGR rate control
Solution Approach 1:
The controller continuously monitors actual EGR gas supply amounts and driving conditions, comparing them against target values. When deviations are detected (such as excessive EGR gas supply during high-power operations), the controller adjusts the EGR valve open degree and turbocharger/supercharger operating parameters in real-time to maintain accurate EGR rate control while preserving power output.
Solution Approach 2:
The system dynamically adjusts EGR valve control parameters and boosting apparatus operating parameters based on real-time driving conditions. The controller modifies EGR valve open degree, turbocharger compressor ratio, and supercharger fan speed according to engine load, RPM, and detected EGR gas flow rates, enabling adaptive control that maintains accuracy across varying power demands.
2Quantity of substance
If the EGR valve open degree is increased to supply more EGR gas, then exhaust gas recirculation amount is improved, but smoke and NOx emissions increase deteriorating exhaust gas purification performance
Solution Approach 1:
The controller monitors actual EGR gas supply amounts through sensors detecting exhaust gas composition and flow rates. When EGR gas supply exceeds target values (indicating potential smoke and NOx generation), the controller automatically reduces the EGR valve open degree and adjusts boosting apparatus parameters to bring EGR supply back to optimal levels, preventing harmful emissions while maintaining necessary recirculation for NOx reduction.
Solution Approach 2:
The system changes multiple operating parameters simultaneously including EGR valve open degree, turbocharger compressor ratio, supercharger fan speed, and air-fuel ratio to optimize EGR gas supply. By coordinating these parameters, the controller achieves accurate EGR rate control that prevents both insufficient recirculation (causing NOx) and excessive recirculation (causing smoke and NOx), thereby optimizing exhaust gas purification performance.
3Object-generated harmful factors
If the EGR valve open degree is decreased to reduce EGR gas supply, then smoke and NOx emissions are reduced, but exhaust gas purification performance deteriorates due to insufficient EGR gas
Solution Approach 1:
The controller continuously monitors EGR gas supply amounts and exhaust gas composition to assess purification performance. When EGR gas supply falls below target values (indicating potential purification deterioration), the controller increases the EGR valve open degree and adjusts boosting apparatus parameters to restore adequate EGR supply, maintaining effective NOx reduction while preventing smoke generation.
Solution Approach 2:
The system coordinates multiple parameter adjustments including EGR valve open degree, turbocharger compressor ratio, supercharger fan speed, and air-fuel ratio to achieve optimal EGR gas supply. By dynamically adjusting these parameters based on real-time monitoring, the controller maintains EGR supply at levels that prevent both insufficient recirculation (purification deterioration) and excessive recirculation (smoke and NOx generation), thereby optimizing overall exhaust gas purification performance.
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 enhances engine driving efficiency by accurately controlling EGR gas supply, reducing smoke and NOx emissions, and improving exhaust gas purification performance by converting a low-pressure to low-pressure EGR system into a low-pressure to high-pressure system with improved responsiveness.
Implementation Method 1
a turbine rotates at a high speed by the pressure of exhaust gas to compress intake air using a compressor and to supply the compressed air to an intake side so as to improve charging efficiency of intake air
Implementation Method 2
the supply amount of EGR gas is controlled so as to satisfy an EGR rate which is pre-inputted to the controller based on differential pressure between boost pressure compressed by the turbocharger and exhaust pressure
Data Source
AI summary
A control method of a boosting apparatus includes: driving the boosting apparatus according to driving maps pre-input to a controller, judging driving conditions of an engine, selecting a driving map pre-input to the controller and reflecting the driving conditions in the selected driving map, correcting the driving maps of the boosting apparatus based on the selected driving map and driving the boosting apparatus based on the corrected driving maps, and confirming whether variations in operating amounts of the boosting apparatus are generated and, when the variations are confirmed, correcting the operating amounts of the boosting apparatus and reflecting the corrected operating amounts in the driving maps. In particular, the controller controls an EGR valve according to driving conditions through operation of the boosting apparatus and thus controls the amount of EGR gas supplied to the engine.