Residual Gas Control in Internal Combustion Engines
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Solution Overview
Problem
Internal combustion engines face challenges in controlling residual gas mass and purge air mass during gas exchange processes, leading to incomplete gas exchange and increased pollutant emissions, which affect engine power and emissions compliance.
Innovation Solution
A method and device for controlling residual gas mass and purge air mass using an inverse residual gas model to determine setpoint positions for actuators such as cam phase adjusters and pressure influencers, ensuring optimal cylinder air mass and reduced emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If valve overlap is increased to reduce residual gas mass and increase cylinder air mass, then engine power increases, but purge air mass entering exhaust manifold increases causing catalytic converter restriction and pollutant emissions rise
Solution Approach 1:
The control device uses feedback from sensors monitoring exhaust manifold pressure, intake pipe pressure, and engine operating parameters to dynamically adjust camshaft phase adjusters. This closed-loop control ensures that valve overlap is optimized to maximize cylinder air mass while preventing excessive purge air from entering the exhaust manifold, thus maintaining both engine power and emissions compliance
Solution Approach 2:
The system dynamically changes the valve overlap parameter by adjusting camshaft phase based on operating conditions. The control device calculates optimal camshaft phase positions using a residual gas model that predicts residual gas mass and purge air mass, allowing the engine to operate at full load with increased valve overlap for maximum power while avoiding catalytic converter restriction at other operating points
2Power
If valve overlap is set to maximize cylinder air mass, then engine power increases, but residual gas mass control becomes difficult leading to incomplete gas exchange
Solution Approach 1:
The system replaces traditional mechanical valve timing with electronically controlled camshaft phase adjusters that can be precisely positioned based on real-time calculations from the control device. This substitution of mechanical timing with electronically controlled adjustment enables precise control of residual gas mass and valve overlap optimization for maximum cylinder air mass
Solution Approach 2:
The control device uses a residual gas model to calculate and predict the required camshaft phase positions in advance based on desired residual gas mass and purge air mass targets. This preliminary calculation allows the system to proactively adjust valve timing to achieve optimal gas exchange and maximize cylinder air mass before combustion occurs
3Productivity
If camshaft phase adjusters are used to control residual gas mass, then gas exchange efficiency improves, but device complexity increases
Solution Approach 1:
The control device integrates multiple functions into a single control system that manages camshaft phase adjusters, monitors sensor inputs, calculates optimal valve timing using residual gas models, and adjusts actuators in real-time. This multi-functional approach improves gas exchange efficiency while consolidating control complexity into a unified system rather than separate control mechanisms
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 effectively maximizes cylinder air mass and engine power while maintaining low exhaust gas emissions within legal limits, preventing catalytic converter restriction and optimizing scavenging operations across various operating conditions.
Implementation Method 1
the functioning of the catalytic converter is temporarily restricted
Data Source
AI summary
Various embodiments may include a method for controlling the residual gas mass remaining in a cylinder of an internal combustion engine after a gas exchange process and/or the purge air mass introduced into an exhaust manifold during a gas exchange process, the method comprising: specifying at least one of a desired residual gas mass or a purge air mass of the cylinder of the internal combustion engine; determining a setpoint position of an actuator which influences the specified mass, based on an inverse residual gas model; and setting the determined setpoint position of the actuator.