High Pressure Fuel Pump Stroke Increasing Arrangement
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Solution Overview
Problem
High pressure fuel pumps with slipper-tappet design face challenges in increasing load capacity without compromising pump capacity or ease of assembly, particularly due to the need for larger support bearings which reduce the throw or offset of the rider journal, impacting stroke length and pump capacity.
Innovation Solution
A drive assembly with a stroke-increasing arrangement between the rider and the pumping assembly, featuring an enlarged rear bearing and angled members that translate movement along one axis to another, increasing plunger lift and drop, thereby enhancing load capacity and maintaining pump capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the size of support bearings is increased to prevent driveshaft failure under greater load, then the load capacity and durability are improved, but the throw or offset of the bearing relative to the rider journal is reduced, negatively impacting stroke length and pump capacity
Solution Approach 1:
A stroke-increasing arrangement acts as an intermediary mechanism between the rider and the plunger. This arrangement includes a stroke-increasing member with a first end connected to the rider and a second end connected to the plunger, enabling independent optimization of bearing size and stroke length by decoupling these two parameters through the intermediate stroke-increasing mechanism
Solution Approach 2:
The stroke-increasing arrangement introduces an additional dimensional element to the drive mechanism. By adding the stroke-increasing member that can move relative to both the rider and plunger, the system gains an extra degree of freedom that allows the stroke length to be extended beyond what would be limited by the bearing offset
2Ease of manufacture
If the rider journal eccenter is reduced to allow larger bearings, then the bearing size can be increased without compromising rider passage, but the throw or offset is significantly decreased, reducing pump capacity
Solution Approach 1:
The stroke-increasing arrangement serves as a mediator that decouples the relationship between rider journal eccentricity and pump capacity. The stroke-increasing member translates the motion from the rider while adding incremental stroke, allowing the rider journal to be designed with smaller eccentricity for easier assembly while maintaining high pump capacity through the additional stroke mechanism
3Reliability
If the throw or offset of the bearing relative to the rider journal is reduced, then larger bearings can be fitted to handle increased load, but the stroke length is decreased, impacting pump capacity
Solution Approach 1:
The stroke-increasing arrangement acts as a mediator between the driveshaft and plunger, allowing the driveshaft to be designed with larger, more reliable bearings for increased durability while the stroke-increasing member compensates for the reduced throw by adding incremental motion, thereby maintaining pump capacity
Solution Approach 2:
The drive mechanism is segmented into distinct functional components: the driveshaft with bearings for reliability, the rider for motion conversion, and the stroke-increasing member for stroke extension. This segmentation allows each component to be optimized independently - the driveshaft for durability and the stroke-increasing arrangement for maintaining capacity
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
The solution effectively increases the durability of the driveshaft to handle higher loads while maintaining or improving pump capacity, allowing for easier assembly and potentially removing the need for protective coatings on sliding surfaces, with the ability to vary stroke length by swapping angled members.
Implementation Method 1
a stroke-increasing arrangement (40) disposed between the rider (30) and the pumping assembly (10)... an assembly that effects an increased plunger lift and drop
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The invention comprises a high pressure fuel pump comprising at least one pumping assembly (10) and a drive assembly (20). The pumping assembly (10) comprises a plunger (12) arranged for reciprocal movement along a pumping axis (A-A'). The drive assembly (20) comprises a drive means and a driveshaft (22) comprising a rider journal (24) and a rear bearing (26), whoses axes (B-B', C-C') are offset relative to each another. A rider (30) is fitted on said rider journal (24) to effect movement of the rider (30) along an eccentric rotational path. The drive assembly (20) comprises a stroke-increasing arrangement (40) disposed between the rider (30) and the pumping assembly (10). The stroke-increasing arrangement (40) comprises at least two angled, preferably triangular, members configured to translate movement along a first axis (D-D') to along the pumping axis (A-A').