Power Tool Fuel Pump Cooling Zone Buffer Partition
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Solution Overview
Problem
Existing power tools with internal combustion engines face challenges in effectively cooling the fuel pump, leading to excessive heating and potential gas bubble formation, which can hinder fuel delivery to the engine.
Innovation Solution
The introduction of a buffer zone separated from both the first and second cooling zones by partitions, positioning the fuel pump in the second cooling zone to receive cooler combustion air directly, and arranging the injection valve and fuel pulsation damper in the buffer zone for enhanced cooling, along with a drain passage for liquid drainage and vibration gap for thermal separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fuel pump is arranged in the first cooling zone to simplify the structure, then the device complexity is reduced, but the fuel pump temperature increases excessively leading to gas bubble formation and fuel delivery failure
Solution Approach 1:
The cooling zone is segmented into a first cooling zone for the cylinder and a second cooling zone for the fuel pump, separated by a buffer zone with partitions. This segmentation allows the fuel pump to be cooled by separate cooler air from the first cooling zone, preventing excessive temperature rise while maintaining structural simplicity through integrated zone design.
2Volume of stationary object
If the fuel pump is positioned closer to the cylinder to reduce space, then the power tool volume is reduced, but the fuel pump overheats during operation and afterheating
Solution Approach 1:
The second cooling zone is nested within the housing structure, with the fuel pump positioned in a dedicated cooling compartment that is thermally isolated from the cylinder area. The buffer zone acts as a thermal barrier layer between the high-temperature cylinder zone and the fuel pump zone, enabling compact arrangement while preventing heat transfer to the fuel pump.
3Device complexity
If cooling air is conveyed through the first cooling zone only, then the cooling system is simple, but the fuel pump is not adequately cooled during operation
Solution Approach 1:
Different cooling conditions are provided for different zones: the first cooling zone receives cooler ambient air for cylinder cooling, while the second cooling zone receives air that has been relatively cooled by the buffer zone separation. The buffer zone creates a local thermal environment that protects the fuel pump from excessive heat while maintaining a relatively simple cooling air conveyance system.
4Temperature
If partitions are made seal-tight to completely separate cooling zones, then thermal separation is maximized, but manufacturing complexity and cost increase
Solution Approach 1:
The partitions are designed to provide substantial thermal separation between the first and second cooling zones without requiring complete seal-tight construction. The buffer zone configuration and partition arrangement achieve sufficient thermal isolation to prevent fuel pump overheating while allowing simpler manufacturing processes and assembly procedures.
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 prevents excessive heating of the fuel pump, ensures effective cooling, and maintains efficient fuel delivery even after engine shutdown, reducing heat transfer and gas bubble formation.
Implementation Method 1
a buffer zone is formed that is separated from the first cooling zone by means of at least one first partition and from the second cooling zone by means of at least one second partition... The buffer zone effects an excellent thermal separation of the first and the second cooling zones
Implementation Method 2
a fan wheel that is driven by the internal combustion engine... wherein the fan wheel conveys cooling air through the first cooling zone
Implementation Method 3
The combustion air that is sucked in by the internal combustion engine... is somewhat cooler than the cooling air that is conveyed by the fan wheel... the fuel pump is arranged in the flow path of the cooling air that is flowing in through the intake opening
Data Source
AI summary
A power tool has an internal combustion engine with a cylinder. An injection valve supplies fuel to the internal combustion engine. A fuel pump conveys fuel from a fuel tank to the injection valve. A fan wheel is provided that is driven by the internal combustion engine. The cylinder is arranged in a first cooling zone of the power tool and the fan wheel conveys cooling air through the first cooling zone. The fuel pump is arranged in a second cooling zone of the power tool. Between the first cooling zone and the second cooling zone a buffer zone is arranged. The buffer zone is separated by at least one first partition from the first cooling zone and by at least one second petition from the second cooling zone.