Staged Pre-Chamber Purging for Internal Combustion Engines
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Solution Overview
Problem
In internal combustion engines with pre-chambers, inefficient ignition can occur due to residual exhaust gas not being adequately vented during the intake stroke, leading to suboptimal combustion efficiency.
Innovation Solution
A staged purging system is implemented, where a first fluid path provides an intake charge with air and recirculated exhaust gas to the pre-chamber during the intake stroke, and a second fluid path introduces a richer fuel-air mixture without exhaust gas during a second purge stage, ensuring the pre-chamber is effectively purged and prepared for ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-stage purging system is used to remove residual exhaust gas from the pre-chamber, then the system complexity is low, but the combustion efficiency is insufficient due to inadequate purging
Solution Approach 1:
The purging process is divided into two distinct stages: a first purging stage that occurs during the intake stroke using the intake charge, and a second purging stage that occurs after intake valve closure using a dedicated purging passage. This segmentation allows each stage to perform a specific function - the first stage removes the bulk of exhaust gas while the second stage provides final purification, thereby improving combustion efficiency without requiring an overly complex system.
Solution Approach 2:
The first purging stage performs preliminary purging of the pre-chamber during the intake stroke before the second stage operates. By removing the majority of residual exhaust gas during the intake stroke when the intake charge is flowing, the system prepares the pre-chamber for more effective final purging in the second stage, improving overall combustion efficiency while maintaining system simplicity.
2Reliability
If the intake valve closes early to trap the intake charge, then the pre-chamber can be purged more effectively, but the main chamber combustion efficiency decreases
Solution Approach 1:
The purging function is segmented between two stages: the first stage uses the intake charge flowing during the intake stroke to purge the pre-chamber, and the second stage provides additional purging after intake valve closure. This segmentation allows the intake valve to remain open longer for better main chamber combustion while still achieving effective pre-chamber purging through the combined action of both stages.
Solution Approach 2:
The intake charge itself acts as an intermediary medium that performs the primary purging function during the intake stroke. By utilizing the existing intake charge flow to purge the pre-chamber, the system avoids the need to close the intake valve early, thereby maintaining both effective pre-chamber purging and good main chamber combustion efficiency.
3Reliability
If a two-stage purging system with separate fluid paths is implemented, then the pre-chamber purging is more effective, but the device complexity increases
Solution Approach 1:
The intake charge serves multiple functions: it fills the main combustion chamber, drives the turbocharger system, and simultaneously purges the pre-chamber during the first purging stage. By making the intake charge multi-functional, the system achieves effective pre-chamber purging without requiring separate dedicated purging components, thereby limiting the increase in device complexity.
Solution Approach 2:
The intake charge automatically performs the first purging function as it flows into the engine during the intake stroke. The system utilizes the natural flow of the intake charge to purge the pre-chamber without requiring additional active control mechanisms or complex valve timing, thereby achieving effective purging with minimal added 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
This staged purging method enhances combustion efficiency by diluting and removing residual exhaust gas, facilitating more reliable and energetic ignition across a broader range of engine operating conditions and temperatures.
Implementation Method 1
A first fluid path extends from the intake passage directly to the pre-chamber, and a second fluid path extends from the intermediate passage directly to the pre-chamber
Implementation Method 2
A common configuration of an internal combustion engine includes a combustion chamber formed as a cylinder with a reciprocal piston slideably disposed therein. Air is drawn into the cylinder by the downward motion of the piston
Data Source
AI summary
An internal combustion engine includes low and high pressure turbochargers connected in series. An engine cylinder has an intake valve that fluidly connects a main chamber of the engine cylinder with an outlet of the high pressure compressor through an intake passage. An exhaust gas recirculation passage is fluidly interconnected between exhaust and intake conduits. A pre-chamber encloses a spark plug and is fluidly open with the main chamber of the engine cylinder. A first fluid path extends from the intake passage directly to the pre-chamber, and a second fluid path extends from the intermediate passage directly to the pre-chamber.