Gas Mixer Axial Displacement for Fuel-Air Ratio Control

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Solution Overview

Problem

Existing gas mixers for internal combustion engines face challenges in precisely controlling the fuel-to-air ratio and maintaining efficient air flow while minimizing turbulence, which can lead to suboptimal engine performance and increased emissions.

Innovation Solution

A gas mixer design featuring a housing with a narrowed air path, an axially displaceable displacement body, and an adjusting unit connected via a control rod, which allows for precise adjustment of the fuel-to-air ratio using a servomotor, minimizing turbulence and optimizing the mixing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional gas mixer design is used, then the structure is simple, but the fuel-to-air ratio control precision is insufficient

Engineering Contradiction:
Improvefuel-to-air ratio control precisionVSAvoidmixer structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a displacement body that can be axially displaced within the air passage to dynamically adjust the air flow cross-sectional area. This dynamic adjustment mechanism, controlled by a servomotor through a control rod, enables precise control of the fuel-to-air ratio by varying the air flow characteristics without requiring complex multi-component systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameter of the air passage by displacing the displacement body axially, thereby altering the cross-sectional area and flow characteristics. This parameter change approach allows precise control of the air-fuel mixing ratio through simple geometric modification rather than complex control systems.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the air path is narrowed to improve mixing, then the mixing efficiency increases, but the air flow turbulence increases

Engineering Contradiction:
Improvemixing efficiencyVSAvoidair flow turbulence
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The displacement body provides dynamic control over the air passage cross-sectional area, allowing the system to optimize the balance between mixing efficiency and turbulence generation. By adjusting the displacement position, the narrowed portion can be precisely controlled to enhance mixing while minimizing excessive turbulence that would harm engine performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention creates a localized narrowed portion in the air path rather than uniformly constricting the entire passage. This localized quality change intensifies mixing at the critical mixing zone while maintaining smoother flow characteristics in other regions, thereby reducing overall turbulence.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If a rigid venturi mixer assembly is used, then the manufacturing is simple, but the adaptability to different operating conditions is limited

Engineering Contradiction:
Improveadaptability to operating conditionsVSAvoidmixer assembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transforms the static rigid venturi structure into a dynamic system by introducing the axially displaceable displacement body. This allows the air passage cross-sectional area to be adjusted in real-time according to different operating conditions, enabling the mixer to adapt to varying fuel-to-air ratio requirements without changing the overall assembly structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The displacement body with adjustable axial position serves multiple functions: it controls air flow area, adjusts fuel-to-air mixing ratio, and adapts to different operating conditions. This single component provides multi-functionality that would otherwise require multiple separate adjustment mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables precise control of the fuel-to-air ratio, reducing emissions and improving engine efficiency by maintaining a stoichiometric mixture, thus enhancing the engine's operational range and reducing pollutants like NOx.

Implementation Method 1

a displacement body axially displaceable and coaxially arranged within the air path... an adjusting unit disposed within the air path and connected to the displacement body via a control rod... The adjusting unit is configured to axially displace the displacement body

Methodology Applied
Scientific EffectMechanical displacement: Displacement

Implementation Method 2

a housing defining an air path including a narrowed portion... The displacement body and the housing define an air passage disposed at the narrowed portion

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentEP2895727B1Gas mixer for internal combustion engines
Publication Date: 2019.01.09 CATERPILLAR ENERGY SOLUTIONS
  • EP2895727B1 patent drawingFigure 1
  • EP2895727B1 patent drawingFigure 2
  • EP2895727B1 patent drawingFigure 3

AI summary

Gas mixers (100) of internal combustion engines are commonly used to mix gaseous fuel and air. An exemplary disclosed gas mixer (100) comprises a housing (110) defining an air path (120) having a narrowed portion (124), and a fuel inlet (130) fluidly connected to the air path (120) in the vicinity of the narrowed portion (124). The fuel inlet (130) is configured to supply gaseous fuel to the air path (120). The gas mixer (100) further comprises a displacement body (140; 240) axially displaceable and coaxially arranged within the air path (120), wherein the displacement body (140; 240) and the narrowed portion (124) define a air passage (126). The gas mixer (100) further includes an adjusting unit (180; 280) disposed at least partially within the air path (120) and connected to the displacement body (140; 240), wherein the adjusting unit (180; 280) is configured to axially displace the displacement body (140; 240).