Laser Igniter Prechamber Nozzle Geometry for Lean Burn
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lean-burn operation in stationary natural gas engines is limited by ignition challenges, particularly under high in-cylinder pressures, where standard spark ignition systems fail to reliably ignite lean air-fuel mixtures, leading to reduced efficiency and increased NOx emissions.
Innovation Solution
A laser spark plug with a prechamber featuring a microlaser and a circumferential wall with staggered, angularly offset nozzle holes of varying diameters, which focuses laser energy to create multiple ignition sites for faster and more efficient combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If standard spark ignition is used in lean-burn operation, then NOx emissions are reduced, but ignition reliability deteriorates under high in-cylinder pressures
Solution Approach 1:
The patent replaces the conventional mechanical/electrical spark ignition system with a laser-based ignition system. The laser produces a plasma kernel through optical energy concentration, which then ignites the lean air-fuel mixture. This substitution enables reliable ignition under high pressure conditions where traditional spark systems fail, while maintaining the lean-burn operation needed for low NOx emissions.
Solution Approach 2:
The patent changes the ignition mechanism from electrical discharge to optical energy concentration. By using laser energy to create a plasma kernel with specific temperature and pressure parameters, the system achieves reliable ignition in lean mixtures at high in-cylinder pressures, overcoming the limitations of standard spark ignition.
2Reliability
If laser ignition is used to ignite lean mixtures, then ignition reliability is improved, but flame speed reduces offsetting efficiency gains
Solution Approach 1:
The patent uses a prechamber with multiple nozzle holes to divide the combustion process into multiple simultaneous ignition events. The prechamber generates multiple flame kernels that exit through different nozzles, creating distributed ignition points in the main combustion chamber. This segmentation of the ignition process increases overall flame speed and combustion efficiency while maintaining reliable lean mixture ignition.
Solution Approach 2:
The patent introduces a spatial dimension to the ignition process by using a prechamber structure with multiple nozzle holes arranged in specific patterns. This creates a three-dimensional distribution of flame kernels throughout the combustion chamber, increasing the effective flame surface area and accelerating overall combustion speed.
3Speed
If optical means are used to achieve multi-point ignition, then combustion speed is improved, but system complexity and cost increase
Solution Approach 1:
The patent merges the laser ignition system with a prechamber structure into a single integrated component. The laser focal point is positioned within the prechamber, combining the optical ignition source with the combustion preparation chamber. This integration simplifies the overall system compared to using separate optical components while achieving multi-point ignition through the prechamber nozzle arrangement.
Solution Approach 2:
The prechamber serves multiple functions: it prepares the air-fuel mixture, generates multiple flame kernels, and distributes them to the main combustion chamber through the nozzle holes. This self-service capability of the prechamber structure eliminates the need for additional complex optical components to achieve multi-point ignition.
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 prechamber-equipped laser ignition system extends the lean ignition limit, reduces NOx emissions, and achieves higher efficiency by facilitating earlier and faster combustion, with improved ignition stability and reduced cyclic variation.
Implementation Method 1
A microlaser produces laser energy. A laser focal point is disposed within the prechamber interior space in alignment with the longitudinal axis. Laser energy is focused on the laser focal point.
Implementation Method 2
Laser energy is focused on the laser focal point.
Implementation Method 3
The prechamber-equipped laser ignition system extends the lean ignition limit, reduces NOx emissions, and achieves higher efficiency by facilitating earlier and faster combustion
Data Source
AI summary
A laser igniter that avoids autoignition and soot formation within the prechamber and will minimize the formation of Nitrogen Oxides (NOx). The laser igniter has a laser spark plug with a microlaser and a prechamber integrally formed with the laser spark plug. The prechamber has six nozzle holes with three of the nozzle holes having a large diameter and three of the nozzle holes having a small diameter. The large and small nozzle holes are in a staggered arrangement.