Active Expansion Chamber for Compressed Air Engine

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Solution Overview

Problem

Conventional regulators for compressed air engines are inefficient, have low flow rates, and are sensitive to icing, leading to poor performance and reduced efficiency in expanding compressed air from high-pressure storage tanks.

Innovation Solution

An engine with an active expansion chamber featuring a variable volume and a dynamic regulator, which allows for a four-phase thermodynamic cycle including isothermal expansion, quasi-isothermal expansion with work, polytropic expansion, and exhaust at ambient pressure, using a thermal heater and a thermochemical method to increase energy efficiency and reduce pollutant emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional regulators are used to expand compressed air from high-pressure storage tanks, then the device structure is simple, but the flow rate is low and performance is poor

Engineering Contradiction:
Improveflow rateVSAvoiddevice structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The expansion process is divided into two distinct stages: first, high-pressure compressed air expands in the expansion chamber from high pressure to intermediate pressure; second, the air is further regulated to the final working pressure. This segmentation allows each stage to be optimized independently, achieving high flow rates while maintaining manageable device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An expansion chamber is introduced as an intermediary device between the high-pressure storage tank and the conventional regulator. The expansion chamber performs the initial expansion from high pressure to intermediate pressure, reducing the burden on the subsequent regulator and enabling high flow rates without excessive complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If conventional regulators are used for compressed air expansion, then the device structure is simple, but the regulator is highly sensitive to icing from humidity in cooled air

Engineering Contradiction:
Improveicing sensitivityVSAvoiddevice structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The expansion chamber extracts and isolates the cooling and initial expansion process from the regulator. By performing the first stage of expansion in the expansion chamber, the air is cooled and condensed there rather than in the regulator, protecting the regulator from icing issues while maintaining structural simplicity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The expansion chamber serves as an intermediary that handles the problematic cooling and condensation process, acting as a buffer between the high-pressure source and the regulator. This protects the regulator from direct exposure to cold, humid air that causes icing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If the expansion chamber volume is increased to improve energy efficiency, then the energy efficiency increases, but the device complexity and size increase

Engineering Contradiction:
Improveenergy efficiencyVSAvoiddevice structure
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The expansion chamber is designed with a variable volume capability, allowing the chamber size to be dynamically adjusted based on operating conditions. This enables optimization of energy efficiency for different compression ratios and flow rates without requiring a permanently oversized chamber, thus avoiding excessive device complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system allows adjustment of the expansion chamber volume as a variable parameter to optimize performance. By changing the chamber volume according to specific operating requirements, the system achieves high energy efficiency without permanently increasing device complexity to accommodate all possible operating conditions.

Inventive Principle:
Principle #35Parameter changes

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 engine achieves increased energy efficiency, reduced pollutant emissions, and improved performance by optimizing the expansion process and using additional energy sources, allowing for dual-energy operation and autonomous operation without a high-pressure storage tank.

Implementation Method 1

the compressed air, which is stored at very high pressure in the tank but the pressure of which decreases as the tank empties, to a stable intermediate pressure known as the end-use pressure

Methodology Applied
Scientific EffectAdiabatic expansion: Adiabatic Cooling

Implementation Method 2

the compressed air, before being introduced into the combustion and/or expansion chamber, from the storage tank, is directly, or after having been passed through the heat exchanger or exchangers of the ambient thermal energy recovery device, and before being introduced into the combustion chamber, is conveyed to a thermal heater where, as a result of its temperature increasing, it will further increase in pressure and/or in volume

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 3

after having been passed through the heat exchanger or exchangers of the ambient thermal energy recovery device

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP2059654B1Improved compressed-air or gas and/or additional-energy engine having an active expansion chamber
Publication Date: 2021.06.30 MDI MOTOR DEV INT SA
  • EP2059654B1 patent drawingFigure 1
  • EP2059654B1 patent drawingFigure 2
  • EP2059654B1 patent drawingFigure 3~4

AI summary

The invention proposes an engine supplied with compressed air comprising a main drive piston (1) driving a crankshaft (5) and one active expansion chamber (13) of a variable volume allowing work to be produced and which is connected, by a passage (6), with the volume contained in the driving cylinder (2), characterized in that the said passage (6) comprises a shutter (7) thus allowing the said active expansion chamber to be isolated from or to be placed in contact with the dead volume, in such a manner that the engine works according to a four-phase thermodynamic cycle: an isothermal expansion without work; a transfer-slight expansion with work said to be quasi-isothermal; a polytropic expansion with work; an exhaust at ambient pressure.