Pre-chamber Spark Plug Geometry for Engine Ignition
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Solution Overview
Problem
Conventional internal combustion engines face challenges in achieving efficient and low-emission operation, particularly under low load conditions and with the use of poor-quality fuels, due to premature ignition and insufficient ignitable mixtures in the combustion chamber.
Innovation Solution
The design of a pre-chamber spark plug with specific hole geometry and positioning ensures a sufficient rinsing of the pre-chamber with fuel-air mixture during the intake stroke, creating an ignitable mixture that can be safely ignited and burned in the combustion chamber, even under low load conditions, using a central opening with diagonal passage direction and secondary openings distributed around it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pre-chamber is fluidically separated from the combustion chamber with small opening areas, then the ceramic isolator is protected from pressure waves, but the rinsing of the pre-chamber with inlet gas comprising fuel and air is insufficient
Solution Approach 1:
The patent changes the geometric parameters of the openings (central opening with diagonal passage direction and secondary openings distributed around it) to optimize the balance between protecting the ceramic isolator and ensuring sufficient rinsing of the pre-chamber with fuel-air mixture during the intake stroke
2Power
If conventional spark plugs are used in downsized engines with extreme pressure waves, then the engine can operate, but the spark plug breaks due to highly indexed transverse force
Solution Approach 1:
The patent divides the combustion chamber into two separate spaces: the combustion chamber and the pre-chamber. The pre-chamber contains the spark plug and isolator, separating it from the extreme pressure waves in the combustion chamber, thereby protecting the spark plug components while maintaining engine power
Solution Approach 2:
The pre-chamber acts as an intermediary space between the spark plug and the combustion chamber. It provides a protected environment for the spark plug while still enabling ignition of the fuel-air mixture that is rinsed into the pre-chamber during the intake stroke
3Quantity of substance
If the pre-chamber openings have large total area, then sufficient fuel-air mixture can be rinsed into the pre-chamber, but the ceramic isolator is exposed to harmful pressure waves
Solution Approach 1:
The patent optimizes the parameters of the openings (central opening with diagonal passage direction and secondary openings distributed around it) to achieve sufficient rinsing of the pre-chamber while limiting exposure of the ceramic isolator to harmful pressure waves
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 solution ensures reliable ignition and burning of the fuel-air mixture across various operating ranges, including low load conditions, while protecting the ceramic isolator from pressure waves and maintaining robustness against premature ignition.
Implementation Method 1
at the ignition point, by means of the pre-chamber spark plug, in particular by means of an electrode of the pre-chamber spark plug arranged at least partially in the pre-chamber, the at least one ignition spark is generated in the pre-chamber
Implementation Method 2
during an operation of the internal combustion engine, during an induction stroke of the internal combustion engine, a rinsing of the pre-chamber with inlet gas comprising at least fuel and air occurs
Implementation Method 3
the mixture ignited in the pre-chamber can enter the combustion chamber via openings in the pre-chamber, whereby the mixture of fuel and air can be safely ignited in the combustion chamber and, as a result, burn through
Data Source
AI summary
An internal combustion engine for a motor vehicle has at least one cylinder for accommodating a piston and at least one pre-chamber spark plug allocated to the combustion chamber of the cylinder. The engine also has a pre-chamber, fluidically connected with the combustion chamber via several openings, in which at least one ignition spark is generable by the pre-chamber spark plug. At the induction stroke of the internal combustion engine, a rinsing of the pre-chamber with inlet gas including at least fuel and air occurs, so that, at the ignition point, an ignitable mixture of fuel and air is accommodated in the pre-chamber.