Fuel Pump Indexing Means for Timing Precision
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Solution Overview
Problem
The poor timing of the high-pressure pump relative to the crankshaft in combustion engines leads to fluctuating forces, potentially causing damage to the timing belt, bearings, and shafts, and affects engine reliability and starting efficiency, especially in automatic stop-and-start systems.
Innovation Solution
A device with an indexing means, comprising extensions and a toothed wheel, ensures precise timing by immobilizing the toothed wheel in a predefined position, using radial elasticity to secure it on the pump body, allowing for correct alignment during assembly and reducing torque fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the high-pressure pump is driven via a transmission structure (belt, chain), then the pump can be positioned separately from the crankshaft, but timing fluctuations occur causing damage to the timing belt, bearings, and shafts
Solution Approach 1:
The patent applies preliminary action by pre-positioning the pump at its correct operational timing relative to the crankshaft during assembly. The indexing means (extensions 24, 24') are inserted into orifices (21, 21') to preliminarily set the pump's angular position before the timing belt is installed, ensuring that when the system operates, the pump is already correctly synchronized with the crankshaft, thereby preventing timing fluctuations and damage.
2Measurement precision
If the pump is driven directly by the crankshaft, then timing is precise, but no separate transmission structure is needed reducing design flexibility
Solution Approach 1:
The patent uses an intermediary approach by introducing the indexing means (extensions 24, 24') as a mediator between the pump and the crankshaft drive system. These extensions insert into orifices to establish precise angular positioning of the pump relative to the crankshaft while still allowing the use of a timing belt or chain as the drive medium. This intermediary indexing mechanism enables both precise timing and design flexibility with separate pump positioning.
3Ease of manufacture
If the pump timing is not optimized, then assembly is simpler, but engine starting time increases and stop-and-start system performance deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-setting the pump's angular position using the indexing means (extensions 24, 24') during assembly. This preliminary positioning ensures that when the engine is assembled and later started, the pump is already correctly timed with the crankshaft, enabling optimal engine starting performance and proper operation of stop-and-start systems without requiring complex adjustment 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 solution ensures accurate timing between the fuel pump and engine, enhancing mechanical strength and reliability, reducing the risk of damage and noise, and facilitating smooth engine starting by maintaining optimal alignment throughout the engine cycle.
Implementation Method 1
these extensions have radial elasticity so as to be held on the fuel pump under the effect of this elasticity
Data Source
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Figure 3~4
AI summary
The invention relates to a device comprising: ● a fuel pump (1) for an internal combustion engine, including a toothed wheel (11) for its drive, ● an indexing means (2) for immobilizing the toothed wheel (11) in a given position relative to a body of the pump. The invention also relates to the associated method of mounting a fuel pump on an internal combustion engine.