Plasma Ignition for Lean Combustion Stability
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Solution Overview
Problem
Internal combustion engines face challenges in achieving stable, low-temperature combustion at highly dilute operating conditions, particularly in lean air/fuel mixtures, which can lead to inefficiencies and increased emissions.
Innovation Solution
The implementation of a plasma ignition system with a dielectric barrier-discharge igniter and a direct-injection fuel injector, where the fuel injector delivers a first fuel pulse before igniter activation, followed by a plasma energy pulse, facilitating controlled auto-ignition and enhancing combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional spark plug ignition system is used in lean air/fuel mixtures, then the engine can operate at dilute conditions, but stable low-temperature combustion cannot be achieved
Solution Approach 1:
The patent replaces the conventional thermal spark plug ignition system with a plasma ignition system that uses electrical discharge to generate plasma. This substitution enables controlled auto-ignition at lower temperatures by creating a radicalized environment through plasma, allowing stable combustion in lean air/fuel mixtures where conventional spark plugs fail.
Solution Approach 2:
The patent changes the ignition mechanism from thermal-based (spark plug) to plasma-based (electrical discharge). This parameter change in the ignition system enables the engine to achieve stable combustion at lower temperatures and higher air/fuel ratios, fundamentally altering the combustion characteristics to resolve the contradiction between temperature and combustion stability.
2Quantity of substance
If the fuel injector is positioned far from the igniter, then the fuel spray pattern is improved, but combustion efficiency decreases
Solution Approach 1:
The patent introduces plasma as an intermediary between the fuel injector and igniter. The plasma, generated by electrical discharge in the region between these components, acts as a mediator that enhances fuel-air mixing and prepares the mixture for efficient combustion. This intermediary plasma field enables both good fuel spray distribution and high combustion efficiency to coexist.
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 configuration enables stable low-temperature combustion at highly dilute conditions, reducing emissions and improving engine efficiency by creating a radicalized environment for efficient fuel combustion.
Implementation Method 1
a plasma ignition system having an in-cylinder dielectric barrier-discharge igniter
Implementation Method 2
the igniter initiates a plasma energy pulse
Data Source
AI summary
An internal combustion engine includes a plasma ignition system having an in-cylinder dielectric barrier-discharge igniter, and a direct-injection fuel injector having an in-cylinder fuel nozzle. The fuel nozzle protrudes into the combustion chamber proximal to the igniter. A controller operatively connects to the internal combustion engine, the plasma ignition system and the fuel injection system. The controller controls the internal combustion engine at an air/fuel ratio that is lean of stoichiometry. The fuel injector injects a first fuel pulse prior to activation of the igniter, and then the igniter initiates a plasma energy pulse. The fuel injector is controlled to inject a second fuel pulse during the plasma energy pulse.