Pre-chamber Engine Ignition for Catalytic Heating
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Solution Overview
Problem
High-performance internal combustion engines face challenges in rapidly heating the catalytic system during engine start-up, leading to inefficient emission reduction, particularly at low power requirements, due to the need for strategies that balance spark delay and combustion stability.
Innovation Solution
The engine design incorporates a pre-chamber with a second spark plug for ignition and an injector positioned adjacent to the spark plug, allowing for spark coupled injection and counterflow fuel injection, which stabilizes combustion and enhances catalytic system heating at low loads, while maintaining high performance at full loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If spark delay strategy is used to heat catalytic system rapidly, then catalytic system heating speed is improved, but combustion stability deteriorates
Solution Approach 1:
The combustion chamber is segmented into a main chamber and a pre-chamber separated by a communication hole. The pre-chamber acts as an independent combustion zone that stabilizes the flame and prevents misfire during delayed spark timing, while the main chamber handles the primary combustion. This segmentation allows the spark to be delayed for catalytic heating without compromising combustion stability.
Solution Approach 2:
The pre-chamber serves as an intermediary structure that mediates between the delayed spark timing and the main combustion chamber. It provides a controlled environment for flame initiation and propagation, ensuring stable combustion even when the main spark timing is delayed to maximize catalytic system heating.
2Reliability
If spark coupled injection is used to stabilize combustion, then combustion stability is improved, but device complexity increases
Solution Approach 1:
The injector is positioned adjacent to the spark plug, merging the fuel injection function with the ignition system. This spatial integration enables spark coupled injection where fuel is injected just before or during spark timing, stabilizing combustion through localized fuel-air mixing near the ignition source without requiring a separate complex injection system.
3Temperature
If high power requirement is used to heat catalytic system, then catalytic system temperature is improved, but vehicle performance requirement increases
Solution Approach 1:
The pre-chamber is pre-filled with a combustible mixture during the intake and compression strokes. When the spark fires (even with delayed timing), the pre-chamber mixture ignites first, creating a stable flame kernel that then propagates to the main chamber. This preliminary preparation of the mixture in the pre-chamber enables effective catalytic heating without requiring high vehicle power output.
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 configuration enables rapid catalytic system heating and reduced emissions at start-up, while minimizing detonation risks and improving air-fuel mixture homogenization, achieving high performance and low emissions across all operating conditions.
Implementation Method 1
a pre-chamber (26) communicating with the combustion chamber (15) through one or more free connection ports or holes (27), without valves, and fed with a mixture of air and fuel; and a second spark plug (28) projecting inside the pre-chamber (26) for cyclically and selectively determining ignition of the mixture present in the pre-chamber (26)
Implementation Method 2
a second spark plug (28) projecting inside the pre-chamber (26) for cyclically and selectively determining ignition of the mixture present in the pre-chamber (26)
Implementation Method 3
an injector (22) which can be selectively activated to supply uncombusted fuel inside the respective combustion chamber (15) of the corresponding cylinder (2)
Data Source
AI summary
An internal combustion engine generally includes at least a cylinder; at least an intake valve acting on an intake port for controlling the airflow entering the cylinder; at least an injector for supplying uncombusted fuel to the cylinder; at least an outlet valve acting on a respective outlet port for controlling the flow of the exhaust gases at the outlet of the cylinder; a piston sliding in a linear manner within the cylinder; at least a first spark plug arranged in a position adjacent to the injector and acting within the combustion chamber; a pre-chamber communicating with the combustion chamber; and a second spark plug acting within the pre-chamber; the first spark plug is arranged in an intermediate position between the pre-chamber and the injector.