Adjustable Pre-Chamber Orifice for Engine Ignition
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Solution Overview
Problem
Passive pre-chambers without series gap igniters face reliability issues over a wide range of engine operating conditions, often requiring a second spark plug, increasing costs and reducing space for other components, and series gap igniters can experience hot spots leading to pre-ignition and reduced engine performance.
Innovation Solution
A pre-chamber system with a moveable element that adjusts the orifice opening area in response to engine load, allowing for enhanced combustion conditions without a second spark plug and reducing the risk of hot spots by optimizing flame propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a passive pre-chamber without a series gap igniter is used, then the device complexity is reduced, but the reliability of ignition over the full range of engine operating conditions deteriorates
Solution Approach 1:
The pre-chamber incorporates a moveable element that can adjust the orifice opening area between a first position (larger opening) and a second position (smaller opening) based on engine operating conditions. This dynamic adjustment allows the system to maintain reliable ignition across varying loads and speeds without requiring complex multi-spark-plug systems, thus resolving the contradiction between device simplicity and ignition reliability.
2Reliability
If a series gap igniter is used, then ignition reliability is improved, but the packaging size of the pre-chamber increases
Solution Approach 1:
The moveable element dynamically adjusts the orifice opening area to optimize combustion conditions across different engine loads. This allows the pre-chamber to maintain compact dimensions while achieving reliable ignition performance that would otherwise require a larger series gap igniter configuration.
3Loss of energy
If the orifice opening area is increased, then fuel economy is improved, but combustion stability at high engine load deteriorates
Solution Approach 1:
The system dynamically adjusts the orifice opening area based on engine load conditions. At low to medium loads, the opening is larger to enhance fuel economy by improving mixture preparation and combustion efficiency. At high loads, the opening reduces to maintain combustion stability and prevent misfire, thus resolving the contradiction between fuel efficiency and combustion stability across the full operating range.
4Reliability
If a second spark plug is added, then ignition reliability is improved, but the cost increases
Solution Approach 1:
The moveable element provides a cost-effective solution by enabling a single spark plug to achieve reliable ignition across all operating conditions through dynamic orifice area adjustment. This eliminates the need for expensive dual spark plug systems while maintaining ignition reliability, thus resolving the contradiction between reliability and device complexity.
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 adjustable orifice opening enhances fuel economy and extends the life of the ignition device by maintaining reliable ignition across a broader range of engine conditions and preventing hot spots, thereby improving engine power and stability.
Implementation Method 1
a fraction of the air-fuel mixture is inducted into the passive pre-chamber via a pressure differential between the passive pre-chamber and the cylinder during a compression stroke of the cylinder
Implementation Method 2
the spark plug in the pre-chamber is actuated, igniting the fraction of the air-fuel mixture in the pre-chamber
Implementation Method 3
After the fraction of the air-fuel mixture is ignited in the pre-chamber, jets of flame and hot gas may exit the pre-chamber and enter the cylinder via one or more holes in the pre-chamber walls
Data Source
AI summary
Methods and systems are provided for a pre-chamber. In one example, the pre-chamber includes a moveable element configured to adjust an orifice opening area of the pre-chamber in response to conditions.