Composite Internal Combustion and Steam Engine Waste Heat Recovery
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Solution Overview
Problem
Internal combustion engines suffer from significant thermal inefficiencies due to the loss of fuel heating value through radiation, engine coolant, and exhaust, with existing systems for recovering waste heat being bulky, expensive, and inefficient, and prior combination internal combustion and steam engines face issues like steam condensation on cylinder walls, reducing power output and efficiency.
Innovation Solution
A high-efficiency composite internal combustion and steam engine design that utilizes superheated steam within a closed circuit, employing a uniflow steam operation mechanism with series-connected steam pressure balanced valves and steam recompression, integrated into the combustion piston to minimize clearance volume and prevent condensation, allowing for efficient steam utilization and variable steam cutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a separate steam expander and steam generator are added to recover waste heat, then energy recovery efficiency is improved, but device complexity and volume increase significantly
Solution Approach 1:
The patent combines the steam generator, steam expander, and condenser into an integrated system where the steam generator utilizes exhaust gases directly, the expander is coupled to the engine crankshaft, and the condenser recycles condensate back to the steam generator, eliminating the need for separate components and reducing overall system complexity while maintaining waste heat recovery efficiency
Solution Approach 2:
The exhaust system serves multiple functions: it acts as the heat source for the steam generator, provides the driving force for the expander through pressure differentials, and the condenser simultaneously cools and condenses steam while preparing condensate for reuse, creating a multi-functional integrated system that reduces component count
2Power
If steam is admitted into the cylinder in prior combination engines, then supplemental power is obtained, but steam condenses on cylinder walls reducing power output and efficiency
Solution Approach 1:
The patent pre-heats the cylinder walls and piston surfaces using the hot exhaust gases that pass through the cylinder during the exhaust stroke, ensuring the surfaces are sufficiently warm before steam admission to prevent condensation, thereby preserving steam energy and maintaining power output
Solution Approach 2:
The system maintains continuous steam generation and admission cycles where the exhaust gases continuously heat the cylinder surfaces, and steam is continuously admitted and expanded, preventing the intermittent cooling that leads to condensation and maintaining consistent power output and efficiency
3Device complexity
If counterflow steam operation is used, then steam flow is simplified, but steam temperature drops and condensation increases reducing efficiency
Solution Approach 1:
The patent inverts the conventional counterflow approach by using uniflow operation where steam is admitted at one end of the cylinder and exhausts at the other, maintaining steam temperature and pressure gradients throughout the expansion stroke, preventing condensation on cooler surfaces, and improving thermal efficiency while keeping the flow mechanism relatively simple
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 design achieves a 25% improvement in steam rate and higher efficiency compared to conventional counterflow engines, with the ability to recover waste heat more effectively, reducing fuel consumption and emissions while maintaining compactness and reliability.
Implementation Method 1
an expandable chamber inward of the piston that is powered by steam generated from what would have been waste heat from the combustion chamber
Implementation Method 2
employing a uniflow steam operation mechanism with series-connected steam pressure balanced valves and steam recompression, integrated into the combustion piston to minimize clearance volume and prevent condensation
Implementation Method 3
steam generated from what would have been waste heat from the combustion chamber
Data Source
AI summary
A high efficiency combined cycle internal combustion and steam engine includes a cylinder with a combustion chamber outward of a piston, a cylinder cap slideably mounted within the piston and a steam expansion chamber inside the piston. The cap can be heated to reduce condensation of steam. Steam remaining when a steam exhaust valve closes can be recompressed prior to admitting the next charge of steam. One valve or a pair of steam inlet valves connected in series act in cooperation to help maximize efficiency. The amount of steam admitted each stroke is regulated by shifting the phase of one steam admission valve of a pair to vary their overlap for determining the steam mass admitted each cycle. Other valves balance steam displacement with the steam generator output to use steam more efficiently.