Dual-Mode Ignition System for Lean-Burn Combustion Stability
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Solution Overview
Problem
Internal combustion engines face challenges in achieving consistent and complete combustion with lean fuel-air mixtures due to slow flame propagation, leading to misfires or incomplete combustion, especially at low engine loads.
Innovation Solution
A dual-mode ignition system that employs a conventional spark plug for high load conditions and a high-speed pulser for lean-burn mode, generating non-thermal plasma to promote multi-point volumetric combustion, with an engine control unit determining the mode based on engine speed and load to improve thermal efficiency and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional spark plug is used to ignite the mixture in lean-burn mode, then the device complexity is low, but the combustion completeness deteriorates due to slow flame propagation
Solution Approach 1:
The combustion chamber is divided into multiple ignition zones by placing several high speed pulsers at different locations instead of using a single spark plug. This segmentation allows simultaneous ignition at multiple points, significantly improving flame propagation speed and combustion completeness in lean-burn mode while maintaining relatively simple device structure
Solution Approach 2:
The conventional thermal spark ignition system is replaced with a non-thermal plasma ignition system using high speed pulsers. This substitution generates highly reactive species through electrical discharge that can ignite lean mixtures much more effectively than traditional thermal sparks, resolving the contradiction between simple device structure and reliable combustion
2Reliability
If a high speed pulser is used to generate non-thermal plasma for lean-burn mode, then the combustion completeness is improved, but the device complexity increases
Solution Approach 1:
The ignition system is designed with multi-functionality to handle both conventional and lean-burn modes. The ECU controls the selection between conventional spark plugs and high speed pulsers based on operating conditions, allowing the system to achieve reliable combustion in lean-burn mode while maintaining simplicity in conventional modes, thus balancing combustion completeness with device complexity
Solution Approach 2:
The ignition system dynamically adapts its configuration based on engine operating conditions. The ECU selectively activates conventional spark plugs for high-load operations and switches to high speed pulsers for lean-burn low-load operations. This dynamic switching optimizes combustion completeness across different operating ranges while minimizing unnecessary device complexity
3Use of energy by moving object
If dual-mode ignition system is implemented, then the thermal efficiency is improved across entire operating range, but the device complexity increases
Solution Approach 1:
The dual-mode ignition system dynamically switches between conventional spark plug mode and high speed pulser mode based on real-time engine operating conditions monitored by the ECU. This dynamic adaptation ensures optimal thermal efficiency across the entire operating range by using the appropriate ignition method for each condition, while the selective activation minimizes the practical impact of increased device complexity
Solution Approach 2:
The system changes operational parameters by switching between two distinct ignition modes. In conventional mode, traditional thermal spark parameters are used for high-load efficiency. In lean-burn mode, non-thermal plasma parameters from high speed pulsers are used for low-load efficiency. This parameter switching resolves the contradiction by optimizing thermal efficiency across different operating conditions rather than requiring a single complex system
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 dual-mode ignition system enhances engine thermal efficiency and performance across the entire operating range by stabilizing lean-burn combustion at low loads and maintaining efficiency at high loads, reducing emissions and improving fuel economy.
Implementation Method 1
The high speed pulser is configured to generate a non-thermal plasma in the combustion chamber and promote multi-point volumetric combustion in the lean-burn mode
Implementation Method 2
The spark plug provided in the internal combustion engine (e.g., a gasoline engine) plays a role of igniting the compressed mixture by spark discharge due to high voltage current generated from an ignition coil
Data Source
AI summary
An ignition system for an engine of a vehicle, comprising: a spark plug which includes: a central electrode electrically connected to an ignition coil, and a ground electrode, where the spark plug ignites a mixture of fuel and air in a normal mode of the engine; a high speed pulser to ignite the mixture of fuel and air in a lean-burn mode of the engine; a pulser controller to control the high speed pulser to ignite the mixture of fuel and air in the lean-burn mode of the engine; an engine control unit (ECU) that determines the normal and lean-burn modes based on an engine speed and an engine load, and controls the pulser controller and an ignition of the spark plug based on a determined mode among the normal mode and the lean-burn mode.