Pre-Chamber Ignition for Cold Start Emission Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secondary air introduction systems for internal combustion engines, such as PETA systems, are costly and complex, and they do not effectively reduce hydrocarbon emissions before the catalyst reaches its light-off temperature.
Innovation Solution
A method utilizing a turbulent jet ignition system to introduce secondary air into the exhaust system by initiating combustion in the cylinder via a spark plug and using a pre-chamber to provide oxygen-rich air, which reacts with unburnt hydrocarbons, reducing emissions before the catalyst reaches its light-off temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a PETA system is used to provide secondary air to the exhaust passage, then hydrocarbon emissions may be reduced, but the cost and complexity of the vehicle system increases
Solution Approach 1:
The pre-chamber and igniter system is designed to perform multiple functions: it serves as both an ignition system for initiating combustion in the cylinder and as a thermactor system for reducing hydrocarbon emissions during cold start. By integrating these two functions into a single system, the patent eliminates the need for a separate PETA system, thereby reducing vehicle system complexity while maintaining emission reduction capability.
Solution Approach 2:
The patent combines the ignition system and thermactor system into a single integrated pre-chamber system. The pre-chamber receives air from the air delivery passage and uses the igniter to initiate combustion, producing hot exhaust gases that are directed to the catalyst. This merging of functions reduces the number of separate components and simplifies the overall vehicle system architecture.
2Object-generated harmful factors
If a PETA system is used to provide secondary air to the exhaust passage, then hydrocarbon emissions may be reduced, but the vehicle system cost increases
Solution Approach 1:
The pre-chamber and igniter system is designed to perform multiple functions: it serves as both an ignition system for initiating combustion in the cylinder and as a thermactor system for reducing hydrocarbon emissions during cold start. By integrating these two functions into a single system, the patent eliminates the need for a separate PETA system, thereby reducing vehicle system complexity while maintaining emission reduction capability.
Solution Approach 2:
The patent combines the ignition system and thermactor system into a single integrated pre-chamber system. The pre-chamber receives air from the air delivery passage and uses the igniter to initiate combustion, producing hot exhaust gases that are directed to the catalyst. This merging of functions reduces the number of separate components and simplifies the overall vehicle system architecture.
3Loss of time
If the catalyst is placed in a close-coupled position to the engine, then catalyst warm-up time is reduced, but heat losses are minimized less effectively
Solution Approach 1:
The system performs preliminary heating action by introducing air to the pre-chamber and igniting it with the igniter during cold start conditions. This creates hot exhaust gases that are directed to the catalyst upstream of the exhaust manifold, pre-heating the catalyst before the main combustion process begins. This preliminary action ensures the catalyst reaches its light-off temperature faster without excessive heat losses from the main combustion chamber.
Solution Approach 2:
The system changes the temperature parameter of the exhaust gases directed to the catalyst by controlling the air-fuel ratio in the pre-chamber. By maintaining a rich air-fuel ratio in the pre-chamber during cold start, the combustion produces higher temperature exhaust gases that more effectively heat the catalyst, thereby reducing warm-up time while managing heat losses through controlled combustion parameters.
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 approach reduces hydrocarbon emissions before the catalyst reaches its light-off temperature, enhances hydrocarbon oxidation due to higher in-cylinder temperatures, and lowers vehicle costs and complexity by eliminating the need for external thermactor systems.
Implementation Method 1
initiating combustion in a cylinder via a spark plug directly coupled to the cylinder and providing secondary air via a turbulent jet system having an igniter
Implementation Method 2
The oxygen-rich air may react with unburnt hydrocarbons in the exhaust passage prior to reaching the emission control device
Implementation Method 3
a pre-chamber and an igniter coupled to the pre-chamber. In this way, the pre-chamber may be used to provide ignition and/or thermactor air
Data Source
AI summary
Methods and systems are provided for reducing emissions during an engine cold start. In one example, a method may include, during emission control device heating, initiating combustion in a cylinder via a spark plug directly coupled to the cylinder and providing secondary air via a turbulent jet ignition system. In this way, an amount of hydrocarbons in feedgas provided to the emission control device prior to the emission control device reaching its light-off temperature may be reduced.