Engine Control System for Stable Lean Air-Fuel Ratio Operation
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Solution Overview
Problem
Cogeneration systems face issues with sudden variations in engine RPM and torque due to lean air-fuel ratio driving, leading to power shocks, vibration, and reduced reliability, especially when load conditions change.
Innovation Solution
A method of controlling the engine by switching between lean air-fuel ratio and theoretical air-fuel ratio modes based on load variations, using engine RPM tracking control and adjusting air-fuel ratios, ignition angles, and electronic throttle control cycles to maintain stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine operates under lean air-fuel ratio driving mode to improve fuel efficiency, then fuel economy is improved, but sudden variation in engine RPM occurs and power shock happens
Solution Approach 1:
The system dynamically switches between theoretical air-fuel ratio mode and lean air-fuel ratio mode based on load conditions. The controller monitors load changes and transitions the engine operating mode accordingly, making the air-fuel ratio dynamic rather than fixed, thereby achieving both fuel efficiency improvement and operational stability
Solution Approach 2:
The invention changes the air-fuel ratio parameter based on operating conditions. By adjusting the air-fuel ratio from theoretical (1.0) to lean (greater than 1.0) depending on load variations, the system optimizes fuel efficiency while maintaining engine stability through parameter adaptation
2Productivity
If the engine enters lean air-fuel ratio driving mode to improve efficiency, then fuel consumption is reduced, but torque becomes insufficient and RPM sharply decreases
Solution Approach 1:
The system dynamically adjusts the air-fuel ratio based on real-time load conditions. When load increases, the system transitions from lean mode back to theoretical mode to maintain sufficient torque, while utilizing lean mode during stable load conditions to improve efficiency
Solution Approach 2:
The air-fuel ratio parameter is changed according to load conditions. The controller monitors load changes and adjusts the air-fuel ratio parameter dynamically, switching between theoretical and lean modes to balance efficiency gains with torque requirements
3Reliability
If the engine operates under theoretical air-fuel ratio mode to maintain stable RPM, then operational stability is maintained, but fuel efficiency is not optimized
Solution Approach 1:
The system uses dynamic mode switching between theoretical and lean air-fuel ratio operations based on load stability. During stable load conditions, lean mode is used for efficiency, while theoretical mode is activated when load changes are detected, creating a dynamic response that optimizes both stability and efficiency
Solution Approach 2:
The air-fuel ratio parameter is adaptively changed based on operating conditions. The system transitions from fixed theoretical ratio to variable ratio control, using lean ratio for efficiency during stable operation and returning to theoretical ratio when stability is needed, achieving parameter optimization
4Object-affected harmful factors
If sudden load variation occurs during lean air-fuel ratio driving, then vibration increases and part reliability deteriorates, but switching to theoretical mode reduces efficiency
Solution Approach 1:
The system takes preliminary action by monitoring load conditions and switching from lean mode to theoretical mode before severe vibration and instability occur. The controller detects load changes and proactively transitions the operating mode to prevent harmful effects
Solution Approach 2:
The system uses feedback from load monitoring to control air-fuel ratio mode selection. The controller continuously monitors load conditions and adjusts the operating mode based on this feedback, switching between lean and theoretical modes to maintain stability while optimizing efficiency
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 stabilizes engine RPM within a predetermined range, reduces vibration, enhances control reliability, and minimizes nitrogen oxide emissions, while efficiently managing load variations and improving engine efficiency.
Implementation Method 1
A method of operating an internal combustion engine, wherein a fuel-air mixture is burnt in the internal combustion engine
Data Source
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AI summary
Disclosed are a method of controlling an engine by changing an air-fuel ratio during power generation and an engine generation system using the same. The engine control method includes controlling an engine under the condition of theoretical air-fuel ratio driving, performing engine revolution-per-minute (RPM) tracking control so that the engine is driven at a target engine RPM when an external load connected to a generator varies, determining whether an engine RPM has been stabilized, changing an air-fuel ratio to a lean air-fuel ratio upon determining that the engine RPM has been stabilized, and controlling the engine under the condition of lean air-fuel ratio driving.