High-Pressure Fuel Pipe Volume Range for Stable Pressure Boosting
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Solution Overview
Problem
Conventional high-pressure fuel pipes for single-cylinder or two-cylinder engines face challenges in determining an appropriate volume that balances pressure fluctuation suppression and quick pressure boosting, leading to startability issues and pressure fluctuations.
Innovation Solution
A high-pressure fuel pipe with a volume calculated using specific arithmetic expressions, such as k×Q/ΔP/1000×n or q/0.6, where k is the volume modulus, Q is the maximum discharge amount, ΔP is the pressure difference, and n is the number of boosting times, ensuring the volume is optimized for both single and two-cylinder engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the volume of the high-pressure fuel pipe is increased to suppress pressure fluctuation, then pressure stability is improved, but startability deteriorates due to pressure boost delay
Solution Approach 1:
The patent applies parameter changes by establishing a specific volume range for the high-pressure fuel pipe using arithmetic expressions that relate pipe volume to pump discharge amount and pressure differential. This quantitative approach determines the optimal balance between pressure stability and boost speed, resolving the contradiction through precise parameter specification rather than qualitative design.
2Speed
If the volume of the high-pressure fuel pipe is decreased to improve startability, then pressure boost speed is improved, but pressure fluctuation increases
Solution Approach 1:
The patent resolves this contradiction by defining a minimum volume threshold through arithmetic expressions that ensure sufficient pressure stability while allowing rapid pressure boosting. The specified volume range prevents both excessive fluctuation and unnecessary delay, achieving optimal startability.
3Stability of the object's composition
If the volume of the high-pressure fuel pipe is increased to suppress pressure fluctuation, then fuel pressure stability is improved, but relief valve operation is triggered
Solution Approach 1:
The patent prevents relief valve operation by specifying a volume range that maintains fuel pressure within acceptable limits. The arithmetic expressions ensure the pipe volume is sufficient to dampen pressure fluctuations but not so large as to cause excessive pressure buildup that would trigger the relief valve.
Data Source
AI summary
A high-pressure fuel pipe is a pipe disposed between an injector and a high-pressure fuel pump, the high-pressure fuel pump is provided on a downstream side of a low-pressure fuel pump, an engine is a single cylinder or a two-cylinder, the high-pressure fuel pump is a plunger type that performs pressurization once or twice per rotation in synchronization with a camshaft of the engine, and a volume of the high-pressure fuel pipe is k×Q/ΔP/1000×n or less, where k is a volume modulus of fuel, Q is a maximum discharge amount of the fuel in one reciprocation of the high-pressure fuel pump, ΔP is a difference between a target fuel pressure boosted by the high-pressure fuel pump and a feed fuel pressure boosted by the low-pressure fuel pump, and n is the number of times of boosting in one rotation of the high-pressure fuel pump.