Split Cycle Engine Recuperator Temperature Control
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Solution Overview
Problem
Split cycle engines face challenges in controlling temperatures, leading to heat-induced material defects and inefficient combustion due to unregulated peak temperatures in the recuperator and combustion cylinder, which can result in material damage and pollutant formation.
Innovation Solution
A split cycle internal combustion engine with a recuperator that exchanges heat between exhaust and working fluids, controlled by a controller to regulate temperatures within specific ranges by adjusting the operation of components such as the turbine, compressor, intercooler, and valve timings, ensuring the recuperator temperature remains within safe thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the recuperator is exposed to high temperatures during engine operation, then heat exchange efficiency is improved, but material thermal creep and heat-induced damage occur
Solution Approach 1:
A thermal barrier coating is applied to the recuperator surfaces exposed to high temperatures. This intermediate layer acts as a mediator that allows heat exchange functionality while protecting the base material from thermal creep and damage, enabling the recuperator to operate at higher temperatures without compromising material integrity
Solution Approach 2:
The patent employs materials with changed thermal parameters (such as ceramic matrix composites or superalloys) that can withstand higher temperatures without thermal creep. By changing the material parameters to have higher melting points and better thermal stability, the recuperator can maintain structural integrity at elevated temperatures while still performing heat exchange
2Productivity
If peak combustion temperature is not controlled, then combustion efficiency may increase, but pollutant formation and material damage occur
Solution Approach 1:
The controller continuously monitors combustion parameters and provides feedback to adjust injection timing and coolant flow. This closed-loop feedback system maintains peak combustion temperature within an optimal range that ensures high combustion efficiency while preventing excessive temperatures that would lead to pollutant formation and material damage
Solution Approach 2:
The system employs periodic adjustment of injection timing and coolant activation based on detected combustion conditions. By applying control actions periodically rather than continuously, the system maintains efficient combustion while periodically preventing pollutant formation through temperature regulation
3Measurement precision
If the controller monitors and adjusts multiple temperature parameters, then temperature control precision is improved, but system complexity increases
Solution Approach 1:
The controller is designed as a multi-functional device that simultaneously monitors multiple temperature parameters (recuperator temperature, combustion chamber temperature, coolant temperature) and adjusts multiple control variables (injection timing, valve timing, coolant flow). This universal controller consolidates what would otherwise require multiple separate control systems, achieving precise temperature control without proportionally increasing system 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 solution effectively reduces heat-induced damage to engine components, enhances combustion efficiency, and prevents pollutant formation by maintaining optimal temperature ranges, thereby increasing engine longevity and performance.
Implementation Method 1
a recuperator arranged to exchange heat between exhaust fluid from the combustion cylinder and working fluid being supplied from the compression cylinder to the combustion cylinder via a crossover passage
Data Source
AI summary
The split cycle engine of the present disclosure comprises a compression cylinder (10) accommodating a compression piston (12), a combustion cylinder (20) accommodating a combustion piston (22), a recuperator (35) arranged to exchange heat between exhaust fluid (95) from the combustion cylinder and working fluid being supplied from the compression cylinder to the combustion cylinder via a crossover passage (30). A controller is configured to control operation of the engine based on an indication of a temperature of at least one of a material of the recuperator and the working fluid in the crossover passage.