Heat Engine Cylinder Control for Fluctuating Pressure

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Solution Overview

Problem

Existing heat engines face inefficiencies in decoupling work from cylinder-piston units, particularly in managing fluctuating ambient conditions and maintaining optimal preload pressures for expansion fluids like liquid carbon dioxide, which affects their operational efficiency and environmental impact.

Innovation Solution

The heat engine employs a dual-pressure system where the preload fluid also serves as the working fluid, using check valves to create pressure differences for hydraulic load and mechanical work, with a control device adjusting the number of cylinder-piston units in heating and cooling phases and pressure ranges to maintain optimal operating conditions, and incorporates forced cooling mechanisms for enhanced efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a common preload fluid is used to establish uniform preload pressure in all cylinder-piston units, then the system structure is simplified, but the ability to adapt to fluctuating ambient conditions and maintain optimal individual pressures is reduced

Engineering Contradiction:
Improvesystem structureVSAvoidadaptation to fluctuating conditions
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent divides the common preload fluid system into individual preload circuits for each cylinder-piston unit. Each unit has its own preload pump and control valve, allowing independent pressure regulation. This segmentation enables each cylinder to adapt to fluctuating ambient conditions while maintaining overall system simplicity through modular architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic pressure control for each cylinder-piston unit through programmable control valves that can adjust preload pressure in real-time based on ambient conditions and operational requirements. This dynamic adjustment capability allows the system to maintain optimal performance despite fluctuations in temperature and load conditions.

Inventive Principle:
Principle #15Dynamics

2Productivity

If liquid carbon dioxide is used as expansion fluid with high coefficient of thermal expansion, then operational efficiency in low-temperature range is improved, but maintaining minimum preload pressure under fluctuating conditions becomes more difficult

Engineering Contradiction:
Improveoperational efficiencyVSAvoidmaintenance of minimum preload pressure
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent incorporates pressure sensors in each cylinder-piston unit that continuously monitor preload pressure and provide feedback to the control system. When pressure drops below the minimum required level, the control valve automatically adjusts to restore pressure, ensuring reliable operation of the liquid carbon dioxide expansion fluid under all ambient conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses programmable control to anticipate and prevent pressure drops below minimum levels. The control system is configured with predetermined pressure thresholds and automatically activates corrective actions before reliability is compromised, ensuring continuous optimal operation of the expansion fluid.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the number of cylinder-piston units in heating and cooling phases is balanced, then system stability is improved, but responsiveness to rapidly changing ambient conditions is reduced

Engineering Contradiction:
Improvesystem stabilityVSAvoidresponsiveness to changing conditions
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The patent implements periodic switching of cylinder-piston units between heating and cooling phases with programmable timing. This allows the system to maintain overall stability through balanced operation while responding rapidly to changing conditions by adjusting the phase timing and sequence of individual units according to real-time ambient conditions.

Inventive Principle:
Principle #19Periodic action

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 configuration enhances the heat engine's efficiency by adapting to fluctuating conditions, ensuring minimum preload pressures are maintained, and allows for environmentally friendly CO2 recycling, contributing to carbon sequestration through optimized operation and reduced greenhouse gas emissions.

Implementation Method 1

each of which contains an expansion fluid that is under a preload pressure, which changes its volume when the temperature changes and thus moves the piston

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

by creating two pressure levels in the preload fluid, which are separated from one another by the check valves mentioned during the extension movement (high pressure) and retraction movement (low pressure) of the pistons, a pressure difference can be obtained which is direct used to drive a hydraulic load and converted there into mechanical work

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 3

a control device that controls the heat supply device in order to alternately heat and cool each expansion fluid and thereby move the pistons

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

a control device that controls the heat supply device in order to alternately heat and cool each expansion fluid and thereby move the pistons

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP2668374B1Heat engine
Publication Date: 2015.07.29 LOIDL WALTER
  • EP2668374B1 patent drawingFigure 1
  • EP2668374B1 patent drawingFigure 2a~2c
  • EP2668374B1 patent drawingFigure 3

AI summary

Heat engine (1) having at least two cylinder/piston units (2-5) which in each case contain an expansion fluid (8) under a charging pressure, a device (16-20) for the individually controllable heat supply to the expansion fluid (8) of each cylinder/piston unit (2-5), and a control device (21) which controls the heat supply device (16-20), wherein the pistons (7) of the cylinder/piston units (2-5) are loaded by a common charging fluid (9), the charging fluid (8) is guided from the cylinder/piston units (2-5) via first non-return valves (12') to an inlet (11') and via second non-return valves (12'') which are directed in the opposite direction to an outlet (11'') of a hydraulic load (10), the control device (21) is equipped with a first pressure gauge (22'') for the pressure (p2) of the charging fluid (9) at the outlet (11'') of the load (10), and the control device (21) controls the heating and cooling phases of the heat supply device (16-20) at least depending on the measured outlet pressure (p2), in order to keep said pressure within a predetermined first range (P2,min, P2,max).