Dual Fuel Injector Dithering for Transient Engine Response
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Solution Overview
Problem
Internal combustion engines face performance degradation during transient conditions due to transport delays in fuel delivery, leading to suboptimal air/fuel ratios and catalyst operation outside specified limits.
Innovation Solution
The system includes a turbine-powered air/fuel compressor and a second fuel injector that injects a compressed fuel into the air/fuel stream, allowing for dynamic adjustment of the air/fuel ratio in response to transient conditions, with the second fuel injector powered separately to quickly react to changes in engine loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single fuel injector is used in the conventional fuel delivery system, then the system structure is simple, but the system cannot quickly respond to transient loading conditions due to transport delays
Solution Approach 1:
The fuel delivery system is segmented into two separate fuel injectors: a first fuel injector that delivers fuel under normal conditions and a second fuel injector that delivers fuel specifically during transient conditions. This segmentation allows the system to respond quickly to transient loading conditions by activating the second injector, while maintaining simple operation during steady-state conditions.
Solution Approach 2:
The system dynamically switches between one or two fuel injectors based on operating conditions. The controller activates the second fuel injector only when transient conditions are detected, making the fuel delivery system adaptable and responsive to changing engine loads without permanently increasing complexity.
2Productivity
If fuel rate is increased to compensate for transport delays during transient conditions, then engine performance during transients improves, but the catalyst operates outside specified limits and performance decreases
Solution Approach 1:
The second fuel injector is positioned to deliver fuel upstream in the exhaust system, allowing the fuel to be introduced earlier in the transient event. This preliminary action enables the catalyst to receive the additional fuel and adjust its operation within specified limits, preventing performance degradation while still improving engine response during transients.
3Ease of operation
If the second fuel injector is powered by the turbine, then the system uses available power sources, but the response to transient conditions is delayed due to turbine power availability
Solution Approach 1:
The controller periodically monitors engine operating conditions and activates the second fuel injector only when transient conditions are detected. This periodic monitoring and selective activation ensures the second injector responds quickly to transients while the turbine-powered first injector continues to operate normally, optimizing the use of available power sources.
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 enables the engine to maintain optimal performance during transient conditions by quickly adjusting the air/fuel ratio, reducing transport delays and ensuring efficient operation within specified limits, thereby improving engine performance and catalyst efficiency.
Implementation Method 1
a turbine powered by exhaust from the internal combustion engine
Implementation Method 2
the air/fuel compressor compresses the fuel/air stream to create the compressed fuel/air stream
Implementation Method 3
a charge air cooler that cools the compressed fuel/air stream
Implementation Method 4
a first fuel injector that injects a first fuel into an air stream to create a fuel/air stream
Data Source
AI summary
An apparatus for dithering fuel into an internal combustion engine includes a turbine that is powered by the internal combustion engine and a first fuel injector that injects a first fuel into an air stream to create a fuel/air stream. The apparatus also includes an air/fuel compressor that provides a compressed fuel/air stream to the internal combustion engine. The air/fuel compressor is powered by the turbine, and the air/fuel compressor compresses the fuel/air stream to create the compressed fuel/air stream. Additionally, the apparatus includes a second fuel injector that injects a second fuel into the compressed fuel/air stream prior to the compressed fuel/air stream entering the engine and after the compressed fuel/air stream exits the air/fuel compressor.