Laser Ignition for High-Pressure Combustion Chambers
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Solution Overview
Problem
Existing ignition systems in high-pressure combustion chambers, such as spark plugs and glow plugs, are prone to damage due to extreme conditions and can lead to detonations, which are dangerous and inefficient in compacting metal and ceramic powders at high pressures.
Innovation Solution
A laser beam ignition system that focuses the light at the center of the combustion chamber or along its axis using a lens or collimator to initiate ignition, preventing detonations by concentrating energy and ensuring controlled combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spark plugs or glow plugs are used inside the combustion chamber for ignition, then ignition can be achieved, but the devices are damaged by high pressure and temperature
Solution Approach 1:
The patent replaces mechanical ignition devices (spark plugs, glow plugs) with a laser-based optical ignition system. The laser beam ignites the gas mixture through optical energy concentration without physical contact, eliminating mechanical wear and thermal damage to ignition components in the high-temperature combustion environment.
Solution Approach 2:
The patent introduces a laser window as an intermediary component that transmits laser energy into the combustion chamber while isolating the laser source from the harsh combustion environment. This allows the ignition function to be performed without exposing sensitive ignition components to extreme temperatures and pressures.
2Reliability
If ignition occurs at one end of the chamber, then ignition is achieved, but detonations may occur in elongated chambers
Solution Approach 1:
The patent transitions from one-dimensional ignition (at one end of the chamber) to three-dimensional ignition (throughout the chamber volume). By directing the laser beam axially through the center of the elongated chamber, ignition occurs simultaneously at multiple points along the beam path, preventing the formation of dangerous pressure waves that lead to detonations.
Solution Approach 2:
The patent effectively segments the ignition process into multiple ignition zones along the laser beam path. Instead of a single ignition point, the laser creates multiple ignition locations distributed along the chamber axis, which prevents the uncontrolled propagation of flames that characterizes detonations in elongated chambers.
3Temperature
If continuous laser with lower power is used, then energy is distributed over moving fluid, but ignition temperature is insufficient
Solution Approach 1:
The patent employs pulsed laser operation instead of continuous laser delivery. The pulsed mode concentrates all laser energy into a brief time window (less than 10 ns), creating extremely high peak power that achieves the necessary ignition temperature in the turbulent, moving gas mixture, whereas continuous lower power would be dispersed by fluid motion.
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 laser beam ignition system effectively avoids detonations and maintains equipment integrity by achieving controlled ignition and higher compaction pressures, allowing for efficient dynamic compaction of metal and ceramic powders without damaging the ignition device.
Implementation Method 1
the light is concentrated at one point to create a very high temperature to initiate ignition at the point
Implementation Method 2
The laser beam enters the gas filled combustion chamber through a thick sapphire window... Ignition and combustion of the gas and air mixture in the chamber
Implementation Method 3
A lens is mounted before the window for focusing the beam and initiating ignition at one point in the chamber
Implementation Method 4
a collimator is mounted between the laser source and the window to reduce the beam diameter in the case of providing ignition along the center axis of the chamber
Implementation Method 5
The laser beam enters the gas filled combustion chamber through a thick sapphire window. This window is constructed to withstand the high pressures and temperatures produced by the combustion.
Data Source
AI summary
A chamber is pressurized with a natural gas and air mixture. The pressure moves a piston and die to compress material to be formed into a part. The pressurized gas and air mixture is ignited with a laser beam focused with a lens or collimator into a point or fine line in a center of the chamber. Rapid combustion of the gas and air mixture drives the piston and die, compacting the part into a net shape. The focused laser beam centrally ignites pressurized gas and air mixture providing controlled combustion in the chamber and preventing damaging detonation. The focused point beam is used in chambers having length to diameter L/D aspect ratio of 2 or less than 2. The collimated thin beam is used in chambers having L/D greater than 2.