Split Cycle Engine Combustion Temperature Control
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Solution Overview
Problem
Conventional internal combustion engines face a trade-off between efficiency and NOx emission reduction, as increased efficiency leads to higher temperatures that enhance NOx formation, posing health risks and requiring additional engine complexity for emission control.
Innovation Solution
A split cycle internal combustion engine with a controller that regulates peak combustion temperatures below a threshold using a coolant system, inlet valve timing, and reactivity adjuster to inhibit NOx and particulate generation, ensuring efficient combustion while minimizing harmful emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If efficiency of the engine cycle is increased, then performance is improved, but NOx formation increases due to higher temperatures
Solution Approach 1:
The engine cycle is divided into two separate cylinders: a compression cylinder and a combustion cylinder. The compression cylinder compresses the working fluid to high pressure, which is then transferred to the combustion cylinder where fuel is injected and combusted. This segmentation allows the compression process to occur at lower temperatures (reducing NOx formation) while maintaining high pressure for efficient power generation.
Solution Approach 2:
The compression cylinder performs preliminary compression of the working fluid before it enters the combustion cylinder. By pre-compressing the fluid to the required high pressure in a separate stage, the system avoids the need for high-temperature compression in the combustion chamber, thereby preventing NOx formation while still achieving the necessary pressure for efficient combustion and power output.
2Object-generated harmful factors
If peak combustion temperature is reduced to inhibit NOx formation, then emissions are reduced, but combustion efficiency may be compromised
Solution Approach 1:
The system changes the temperature parameter during the combustion process by introducing cooled working fluid from the compression cylinder into the combustion cylinder before fuel injection. This allows combustion to occur at controlled, lower peak temperatures that inhibit NOx formation while maintaining sufficient temperature for complete fuel combustion and high efficiency.
Solution Approach 2:
The compression cylinder acts as an intermediary system that prepares the working fluid at controlled temperatures and pressures before it enters the combustion cylinder. This intermediary stage allows decoupling of the compression and combustion processes, enabling efficient combustion at lower temperatures by providing pre-compressed, temperature-controlled working fluid to 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 solution effectively reduces NOx and particulate emissions by controlling peak combustion temperatures, enhancing environmental and health benefits while maintaining engine performance.
Implementation Method 1
a controller configured to control a coolant system so that a peak temperature of combustion in a combustion cylinder is below a selected threshold
Implementation Method 2
The formation of NOx compounds occurs in areas where the temperature of an air fuel mixture rises above 2100K
Data Source
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AI summary
A split cycle internal combustion engine comprising a compression cylinder accommodating a compression piston;a combustion cylinder accommodating a combustion piston;a crossover passage between the compression cylinder and the combustion cylinder arranged to provide working fluid to the combustion cylinder; a controller arranged to determine a peak temperature of combustion in the combustion cylinder based on a received indication of a peak temperature of combustion in the combustion cylinder; and a coolant system arranged to regulate a temperature of the working fluid supplied to the combustion cylinder;wherein, in response to determining that the peak temperature of combustion exceeds a selected threshold, the controller is configured to control the coolant system to regulate the temperature of the working fluid supplied to the combustion cylinder so that a peak temperature of combustion in the combustion cylinder is less than the selected threshold.