Dual-Chamber Fastener Driver With Exhaust Gas Recirculation
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Solution Overview
Problem
Combustion-powered fastener-driving tools face inefficiencies due to high in-cylinder temperatures, soot formation, objectionable exhaust fumes, and the need for a fan motor and fan blade, which add size, weight, and potential failure points, as well as issues with rapid-fire functionality due to freezing conduits and poor liquid fuel combustion.
Innovation Solution
A fastener-driving tool with two combustion chambers and an exhaust gas recirculation (EGR) system, where a portion of exhaust gases is recirculated to cool and mix with incoming air, reducing combustion temperatures and eliminating the need for a fan motor, while ensuring fuel vaporization and enabling rapid-fire functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single combustion chamber is used with rich fuel/air mixture, then sufficient power is generated, but high in-cylinder temperatures cause soot formation and inefficient combustion
Solution Approach 1:
The single combustion chamber is divided into two separate combustion chambers. The first combustion chamber receives a rich fuel/air mixture to generate power, while the second combustion chamber receives a leaner mixture to burn residual gases and reduce soot formation. This segmentation allows different combustion conditions in different zones, resolving the contradiction between power generation and soot reduction.
Solution Approach 2:
A partition wall with openings acts as an intermediary between the two combustion chambers. This partition allows controlled interaction between the rich and lean combustion processes, enabling the lean chamber to burn residual hydrocarbons and reduce soot while maintaining power output from the rich chamber.
2Productivity
If a fan motor and fan blade are added to mix air and fuel, then combustion efficiency improves, but device complexity and weight increase
Solution Approach 1:
The fan motor and fan blade components are completely removed from the system. Instead of using mechanical agitation to mix air and fuel, the invention relies on natural turbulence and flow patterns created by the dual combustion chamber configuration and exhaust gas recirculation, achieving combustion efficiency without mechanical mixing devices.
Solution Approach 2:
The system uses its own exhaust gases and natural flow dynamics to achieve fuel/air mixing. The exhaust gas recirculation creates turbulence and promotes spontaneous mixing without requiring external mechanical energy input from a fan motor, making the system self-sufficient for mixing.
3Temperature
If exhaust gases are recirculated to cool combustion chambers, then combustion temperatures reduce and soot decreases, but combustion efficiency may be compromised
Solution Approach 1:
Different regions of the combustion system are given different qualities: the first combustion chamber maintains higher temperatures for efficient power generation, while the second combustion chamber uses recirculated exhaust gases to maintain lower temperatures that prevent soot formation. Each chamber is optimized for its specific function, resolving the contradiction between temperature control and combustion efficiency.
Solution Approach 2:
The invention changes the temperature parameter spatially by introducing exhaust gas recirculation to the second combustion chamber. This creates a temperature gradient where the first chamber operates at high temperature for power, while the second chamber operates at lower temperature to reduce soot, maintaining overall combustion efficiency through parameter differentiation.
4Productivity
If fuel is dispensed rapidly for successive actuations, then rapid-fire functionality is achieved, but the fuel conduit freezes due to cold liquid fuel
Solution Approach 1:
The system pre-heats the fuel conduit using exhaust gas recirculation before cold liquid fuel is dispensed. By maintaining the conduit temperature through continuous exposure to warm exhaust gases, the system prevents freezing of the fuel conduit even during rapid successive actuations, ensuring reliable rapid-fire 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
The tool achieves efficient combustion with reduced soot and fumes, smaller size and weight, and improved rapid-fire capability by using two combustion chambers and an EGR system to cool and mix exhaust gases with incoming air, eliminating the need for a fan motor and reducing power consumption.
Implementation Method 1
an exhaust gas recirculation (EGR) system, where a portion of exhaust gases is recirculated to cool and mix with incoming air, reducing combustion temperatures
Implementation Method 2
using two combustion chambers and an EGR system to cool and mix exhaust gases with incoming air
Implementation Method 3
Combustion-powered fastener-driving tools use a small internal combustion assembly as their power source
Data Source
Figure 1
Figure 2~3
AI summary
Various embodiments of the present disclosure provide a combustion-powered fastener-driving tool including multiple combustion chambers and an exhaust gas recirculation system.