Laser Ignition Optics With Ring Beam to Avoid Window Deposits
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Solution Overview
Problem
Laser ignition devices for internal combustion engines face a reduction in laser beam intensity due to deposit adhesion and accumulation on the optical window, particularly in the central area, which affects the efficiency of light condensation into the combustion chamber.
Innovation Solution
The laser ignition device shapes the pulsed laser light as a ring around the optical axis at the light passage position in the optical window, allowing it to pass through the outer peripheral area where deposits are less likely to adhere, thus maintaining the intensity of light condensed into the combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the laser beam passes through the central area of the optical window, then the light intensity is initially higher, but deposits adhere and accumulate causing reduction in light intensity over time
Solution Approach 1:
The patent applies local quality by directing the laser beam through a specific region (outer peripheral area) of the optical window where deposits are less likely to adhere. This regional differentiation exploits the temperature gradient across the window, creating a localized path with better optical properties and reduced contamination, thereby maintaining consistent light transmission without sacrificing intensity.
2Reliability
If the optical window is positioned in the hot combustion chamber environment, then it protects the condensing optical element, but deposits form on the window surface reducing laser beam transmission
Solution Approach 1:
The patent utilizes local quality by creating a temperature gradient across the optical window through selective cooling of its outer peripheral area. This results in a localized region with lower temperature and reduced deposit formation, providing a clean optical path that maintains high laser beam transmission while the window continues to protect the condensing optical element from the harsh combustion environment.
Solution Approach 2:
The optical window serves as an intermediary element between the combustion chamber environment and the condensing optical element. By positioning the laser beam path through the cooler outer peripheral area of this intermediary, the system maintains protection functionality while minimizing the harmful effects of deposit accumulation on light transmission.
3Reliability
If the entire optical window surface is exposed to combustion gases, then it provides complete protection, but the central area becomes hot and attracts deposit accumulation
Solution Approach 1:
The patent applies local quality by creating a differentiated temperature distribution across the optical window surface. The outer peripheral area is actively cooled to maintain lower temperatures, creating a localized zone resistant to deposit adhesion, while the rest of the window continues to provide protection against combustion gases. This spatial variation in thermal properties reduces harmful deposit accumulation without compromising the overall protection function.
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 prevents a reduction in light intensity at the combustion chamber, ensuring consistent ignitability and reducing the impact of deposits on the optical window, even if they form, by directing the laser light through the cooler outer peripheral area.
Implementation Method 1
a laser oscillation optical system that produces pulsed laser light
Implementation Method 2
a condensing optical element that condenses the pulsed laser light into a combustion chamber
Implementation Method 3
an optical window that is provided distally with respect to the condensing optical element in the housing and transmits the pulsed laser light
Data Source
AI summary
A laser ignition device includes a laser oscillation optical system that produces pulsed laser light, a condensing optical element that condenses the pulsed laser light into a combustion chamber, a housing that internally contains the condensing optical element, and an optical window that is provided distally with respect to the condensing optical element in the housing and transmits the pulsed laser light. The pulsed laser light is shaped as a ring around an optical axis at least at a light passage position in the optical window.