Hydraulically Actuated Piston Prechamber Ignition System
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Solution Overview
Problem
Prechamber ignition systems in internal combustion engines face challenges with sparkplugs requiring frequent servicing and performance degradation, particularly when dealing with stoichiometrically lean fuel and air mixtures, which are difficult to reliably and optimally ignite.
Innovation Solution
A hydraulically actuated piston system within a prechamber ignition system that increases the pressure of a fuel and air ignition charge to an autoignition threshold, using a hydraulic actuator to move the piston between retracted and advanced positions, allowing for compression ignition and extended service life compared to spark-ignition strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sparkplug is used to ignite fuel and air in a prechamber, then ignition can be achieved, but the sparkplug requires frequent servicing and performance degrades over time
Solution Approach 1:
The patent replaces the electrical spark ignition system with a hydraulic compression ignition system. A hydraulic actuator compresses the fuel-air mixture in the prechamber to achieve autoignition, eliminating the need for sparkplugs and their associated electrical components that degrade over time.
Solution Approach 2:
The patent changes the ignition mechanism from electrical discharge to mechanical compression. By controlling the compression ratio and hydraulic pressure parameters, the system achieves reliable autoignition of the fuel-air mixture without relying on electrical sparkplugs that suffer from performance degradation.
2Loss of energy
If stoichiometrically lean fuel and air mixtures are used, then fuel efficiency is improved, but ignition becomes difficult and unreliable
Solution Approach 1:
The patent applies hydraulic compression to increase the pressure and temperature of stoichiometrically lean fuel-air mixtures to the autoignition threshold. This parameter change enables reliable ignition of lean mixtures that would otherwise be difficult to ignite with conventional sparkplugs.
Solution Approach 2:
The patent uses a hydraulic actuator to compress the fuel-air mixture in the prechamber. The hydraulic system provides the necessary compression force to raise the mixture temperature to autoignition levels, enabling reliable ignition of lean mixtures.
3Reliability
If compression ignition is used to autoignite the fuel mixture, then ignition reliability is improved, but the system complexity increases
Solution Approach 1:
The hydraulic actuator serves multiple functions: it compresses the fuel-air mixture for ignition, controls the timing of the compression stroke, and regulates the pressure differential across the piston. This multi-functionality reduces the need for separate dedicated components.
Solution Approach 2:
The hydraulic fluid acts as an intermediary medium to transmit compression force from the hydraulic actuator to the fuel-air mixture. This allows for controlled, reliable compression ignition while simplifying the mechanical linkage between the actuator and the combustion chamber.
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 hydraulic actuation of the piston in the prechamber ignition system effectively autoignites the fuel and air mixture, producing robust combustion reactions that extend the service life of the ignition system and improve ignition reliability for lean fuel and air mixtures.
Implementation Method 1
applying a pressure of pressurized hydraulic fluid to a hydraulic actuation surface of an igniter piston exposed to the hydraulic chamber to cause the igniter piston to move toward an advanced position
Implementation Method 2
increase a pressure of an ignition charge of fuel and air within the combustion prechamber to an autoignition threshold
Implementation Method 3
conveying combustion gases of the ignition charge from the combustion prechamber into the main combustion chamber, and igniting the main charge within the main combustion chamber
Data Source
AI summary
An ignition system for an internal combustion engine includes an igniter having an igniter housing with a combustion prechamber formed therein, and a piston movable within the igniter housing to increase a pressure of an ignition charge of fuel and air within the combustion prechamber to an autoignition threshold. The ignition system includes a hydraulic actuator to apply an actuating force to the piston. Related methodology is disclosed.