Fuel Pump Gear Offset to Reduce Noise
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Solution Overview
Problem
Existing fuel pump timing systems for internal combustion engines suffer from issues such as gear tooth impacts, torsional vibration, noise, vibration, and harshness, which affect performance and noise levels.
Innovation Solution
A fuel system with a fuel pump gear offset relative to engine top dead center by a predetermined angle, optimized to minimize sound pressure levels and reduce unwanted vibrations, by determining the optimal angular offset through measurement and analysis of sound pressure levels across various engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel pump timing is adjusted to optimize performance, then fuel delivery efficiency is improved, but gear tooth impacts and noise increase
Solution Approach 1:
The patent implements variable fuel pump timing that dynamically adjusts the phase relationship between the fuel pump gear and engine crankshaft based on operating conditions. This dynamic adjustment allows the system to optimize fuel delivery efficiency at different engine speeds while minimizing gear tooth impacts and noise by selecting optimal timing positions that avoid resonant frequencies and impact conditions.
Solution Approach 2:
The patent changes the timing parameter (angular offset between fuel pump gear TDC and engine crankshaft TDC) as a variable parameter rather than a fixed value. By adjusting this timing parameter across different operating ranges, the system achieves improved fuel delivery efficiency while avoiding the noise and vibration problems that occur at specific timing positions, thus resolving the contradiction between productivity and harmful factors.
2Productivity
If fuel pump gear is offset from engine top dead center, then fuel pump timing is optimized, but torsional vibration and noise increase
Solution Approach 1:
The system dynamically adjusts the fuel pump gear offset angle based on real-time engine operating conditions. By making the offset angle variable rather than fixed, the system can optimize fuel pump timing for different load and speed conditions while avoiding offset positions that excite torsional vibrations and noise in the drivetrain, thus resolving the contradiction between productivity optimization and stability.
3Device complexity
If traditional fuel pump timing is used, then mechanical simplicity is maintained, but noise and vibration harshness increase
Solution Approach 1:
The patent introduces a variable timing mechanism that adjusts the fuel pump gear phase relative to the engine crankshaft based on operating conditions. This dynamic adjustment capability, while adding some mechanical complexity, significantly reduces noise and vibration harshness by avoiding resonant conditions and optimizing gear meshing, thus resolving the contradiction between device simplicity and harmful factor reduction.
Data Source
AI summary
One embodiment is a fuel system for an internal combustion engine including a fuel pump having a fuel pump gear operable to drive the fuel pump to pressurize fuel. The fuel pump gear is offset relative to engine top dead center by a predetermined angle to reduce a sound or noise. The offset can be determined by selecting the minimum sound produced over a range of offsets or operating conditions.