Integrated Fuel Delivery System for Engine Starting
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Solution Overview
Problem
Current two-step starting systems for internal combustion engines in hand-held power tools are complex with many moving parts, making them difficult to manufacture and maintain, and require separate activation of purging, priming, and fuel enrichment systems for easy and quick engine starting.
Innovation Solution
A novel fuel delivery system that integrates a diaphragm carburetor with a start preparation system and a fuel enrichment system, where the fuel enrichment system is activated through the start preparation system, reducing the number of moving parts and simplifying the design by combining the activation of these systems into a two-step process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional purging system and separate fuel enrichment system are used, then the engine can be started with fresh fuel and stable cranking, but the device complexity increases with many moving parts
Solution Approach 1:
The patent combines the purging system and fuel enrichment system into a single integrated start preparation system. The bulb assembly serves dual functions: when depressed it activates both the purging operation (removing residual air/fuel) and the fuel enrichment operation (supplying extra fuel) simultaneously. This merging eliminates the need for separate activation mechanisms and reduces the number of moving parts while maintaining reliable engine starting.
Solution Approach 2:
The start preparation system is designed as a multi-functional unit that performs multiple operations through a single activation mechanism. The bulb assembly can activate purging, priming, and fuel enrichment functions depending on the operational state of the engine. This universal design allows one component to serve multiple purposes, reducing overall system complexity while ensuring reliable starting under various conditions.
2Reliability
If multiple separate systems (purging, priming, fuel enrichment) are activated separately, then complete fuel preparation is achieved, but the ease of operation decreases due to multiple activation steps
Solution Approach 1:
The patent merges multiple activation functions into a single bulb assembly operation. Instead of requiring separate activations for purging, priming, and fuel enrichment, the user simply depresses the bulb assembly once, which triggers all necessary fuel preparation operations simultaneously. This combining of activation steps maintains complete fuel preparation while dramatically simplifying the user operation to a single intuitive action.
Solution Approach 2:
The start preparation system performs all necessary fuel preparation actions in advance of engine cranking. By activating the bulb assembly before the pull cord is pulled, the system pre-charges the carburetor with fresh fuel, purges residual air, and enriches the fuel mixture. This preliminary action ensures that when cranking begins, the engine immediately receives the optimal air-fuel mixture, eliminating the need for multiple sequential操作步骤 during the starting process.
3Ease of operation
If a two-step starting system with integrated activation is used, then the ease of operation improves with simpler procedure, but manufacturing precision requirements increase
Solution Approach 1:
While integrating multiple functions, the patent maintains functional segmentation within the bulb assembly design. The purging mechanism, priming mechanism, and fuel enrichment mechanism remain as distinct functional modules that are activated through the common bulb depression action. This segmentation allows each subsystem to be manufactured and tested independently with standard tolerances, while the integration point (bulb assembly) uses straightforward mechanical linkages that do not require ultra-precise alignment, thus balancing ease of operation with manufacturability.
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 allows for a simpler design with reduced manufacturing and maintenance costs, enabling easier and more stable engine starting by providing a rich air-fuel mixture through a single activation mechanism, thus improving the starting procedure for hand-held power tools.
Implementation Method 1
a diaphragm carburettor (102) for mixing fuel and air in correct ratios
Implementation Method 2
The choke system is used to create an increased vacuum in the air passage, which draws extra fuel from fuel circuits of the carburettor
Implementation Method 3
The purging system and the priming system are typically actuated by a purge bulb and a primer bulb respectively
Data Source
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AI summary
A fuel delivery system (100) for an internal combustion engine. The fuel delivery system (100) includes a diaphragm carburettor (102) for mixing air and fuel, a start preparation system (104) for introducing fuel into the carburettor before a start of the engine, and a fuel enrichment system (106) for providing an enriched fuel and air mixture when the engine is cranked.