EGR Valve Control via 3D Map for Flow Precision
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Solution Overview
Problem
Existing EGR systems face challenges in accurately controlling the complex flow of EGR gas due to insufficient pressure differences between the intake and exhaust systems, leading to difficulties in controlling the amount of EGR gas recirculated, especially when using a single motor to control both the intake throttle and EGR valves.
Innovation Solution
A method is introduced that forms a 3-dimensional map based on the equivalent orthogonal cross-section, intake air for each cylinder, and engine speed to accurately determine and control the opening angle of the EGR valve, using equations to calculate the air flow and equivalent cross-section, thereby improving control stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single motor controls both the intake throttle valve and EGR valve, then device complexity is reduced, but control precision of EGR gas flow deteriorates due to insufficient pressure difference and coupled valve control
Solution Approach 1:
The patent transitions from one-dimensional valve opening control to three-dimensional control by introducing engine speed as an additional dimension. The control method calculates EGR valve opening angle based on engine speed, intake air amount, and equivalent cross-section, creating a multi-parameter control space that enables precise EGR gas flow control despite using a single motor for both valves.
Solution Approach 2:
The patent dynamically changes control parameters by using engine speed as a variable in the control calculation. Instead of fixed valve opening maps, the system continuously adjusts the EGR valve opening angle based on real-time engine speed, intake air amount, and equivalent cross-section measurements, enabling precise control across varying operating conditions.
2Reliability
If pressure difference between intake and exhaust systems is insufficient, then EGR gas flow control becomes difficult, but adding more valves or increasing pressure difference increases device complexity
Solution Approach 1:
The patent replaces mechanical pressure difference reliance with an electronic control solution. Instead of depending on natural pressure differential between intake and exhaust systems, the system uses a motor-controlled EGR valve with electronic feedback control based on engine speed and intake air amount, substituting mechanical flow control with electronic regulation.
Solution Approach 2:
The patent implements a feedback control mechanism where the engine controller continuously monitors engine speed and intake air amount, calculates the required EGR valve opening angle based on these parameters and the equivalent cross-section, and adjusts the EGR valve accordingly. This closed-loop feedback ensures reliable EGR gas flow control regardless of pressure difference conditions.
Data Source
AI summary
A method for controlling an exhaust gas recirculation (EGR) system which is provided with an intake throttle valve and an EGR valve driven by a motor may include detecting an engine speed and an amount of intake air for each cylinder of an engine while the engine is operating, determining an amount of air flow supplied to the engine based on the engine speed and the amount of intake air for each cylinder, determining an equivalent cross-section of the EGR valve based on the amount of air flow, determining an opening angle of the EGR valve based on the engine speed, the amount of intake air for each cylinder, the amount of air flow, and the equivalent cross-section of the EGR valve, and controlling the EGR valve according to the opening angle of the EGR valve.