Active Prechamber Assembly for Lean Burn Ignition
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Solution Overview
Problem
Standard spark ignition engines face challenges in burning lean air-fuel mixtures due to insufficient discharge from standard spark plugs, leading to misfire or no-burn conditions, and integrating active prechambers into engines increases manufacturing costs and requires significant redesigns.
Innovation Solution
A compact active prechamber assembly with a fuel injector and electrode arrangement, where the prechamber housing and nozzle are aligned with the main axis, allowing for efficient fuel injection and spark generation within a prechamber space that communicates with the main chamber, minimizing the need for engine redesign and using existing cylinder heads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard spark plugs are used to ignite lean air-fuel mixture, then the engine structure remains simple, but the discharge arc is insufficient to burn the lean mixture, resulting in misfire or no-burn conditions
Solution Approach 1:
The combustion chamber is divided into two parts: a prechamber and a main chamber. The prechamber contains a rich air-fuel mixture that is easier to ignite, while the main chamber contains the lean air-fuel mixture. This segmentation allows the ignition system to work more reliably by first igniting the rich mixture in the prechamber, which then ignites the lean mixture in the main chamber through turbulent jet ignition.
Solution Approach 2:
The prechamber acts as an intermediary between the ignition system and the main combustion chamber. It generates hot radicals and turbulent flow that serve as a mediator to ignite the difficult-to-burn lean mixture in the main chamber, thereby improving ignition reliability without requiring a more complex ignition system.
2Productivity
If an active prechamber assembly with fuel injector and spark plug is integrated into the engine, then combustion efficiency is improved, but manufacturing cost increases and significant redesign of cylinder head is required
Solution Approach 1:
The fuel injector and spark plug are merged into a single integrated assembly with the prechamber. This combined design allows both components to share the same mounting space and structural support, reducing the overall complexity of integration into the cylinder head and simplifying the manufacturing process while maintaining the combustion efficiency benefits of active prechamber turbulent jet 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 solution enables efficient turbulent jet induced lean burn combustion with reduced hardware costs, assembly time, and weight, while maintaining engine durability and performance.
Implementation Method 1
a fuel injector positioned to spray a fuel into the prechamber space
Implementation Method 2
an electrode arrangement including an electrode shaft and an electrode ring, the electrode ring circumscribing the electrode shaft to form a spark gap within the prechamber space
Implementation Method 3
a prechamber is used to combust a small quantity of fuel. The burn moves from the prechamber into the main chamber in the form of rich radicals that are hot and have high velocities to penetrate deep into the main chamber and ignite the lean mixture
Implementation Method 4
The prechamber nozzle and prechamber housing may define a prechamber space that extends along the main axis
Data Source
AI summary
An active prechamber device may include a prechamber housing longitudinally aligned with a main axis. The active prechamber device may also include a prechamber nozzle forming a cap at an end of the prechamber housing. The prechamber nozzle and prechamber housing may define a prechamber space that extends along the main axis. The prechamber nozzle may have a plurality of orifices fluidly connected to the prechamber space. Additionally, a fuel injector may be in a linear arrangement with the prechamber housing along the main axis. The fuel injector may have a fuel injection nozzle positioned to spray a fuel into the prechamber space. An electrode arrangement may be formed within the prechamber space. The electrode arrangement may include an electrode shaft and an electrode ring. The electrode ring may circumscribe the electrode shaft to form a spark gap within the prechamber space.