Fuel Pump Assembly Crank Shaft Cam Drive
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Solution Overview
Problem
Conventional fuel pump assemblies for internal combustion engines often rely on gear trains to drive unit pumps, leading to noise and stress issues, as well as potential vulnerabilities in pump placement.
Innovation Solution
Mounting unit pumps directly on the crank shaft eliminates the need for gear train components, using the crank shaft's cam to drive the pumping plungers, and allows for either accessible or tamper-proof placement within the engine block, reducing noise and stress while enhancing security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unit pumps are mounted on the cam shaft via a gear train, then the pump assembly can be driven reliably, but gear train noise and stress increase
Solution Approach 1:
The patent extracts and eliminates the gear train components from the drive system. By mounting the unit pumps directly on the crank shaft, the intermediate gear train is removed entirely, thereby eliminating the noise and stress generated by gear meshing while maintaining reliable pump operation through direct drive connection.
Solution Approach 2:
The patent merges the pump drive function directly with the crank shaft. Instead of using separate gear train components to transmit power from the cam shaft to the unit pumps, the unit pumps are integrated directly onto the crank shaft, combining the driving function into a single unified structure that eliminates intermediate transmission elements.
2Ease of manufacture
If unit pumps are mounted on the cam shaft, then the pump assembly follows conventional design, but the location may be vulnerable to tampering
Solution Approach 1:
The patent extracts the unit pumps from the conventional cam shaft mounting location and relocates them directly to the crank shaft. This relocation places the pumps in a more secure position within the engine structure, making them less accessible to potential tampering while maintaining manufacturing feasibility through direct mounting arrangements.
3Object-generated harmful factors
If unit pumps are mounted directly on the crank shaft, then gear train noise and stress are eliminated, but the crank shaft structure must accommodate additional components
Solution Approach 1:
The patent merges the unit pump mounting function directly into the crank shaft structure. By integrating the pump mounting features into the crank shaft itself, the design eliminates the need for separate gear train components while incorporating all necessary drive functions into a unified structure, thereby reducing overall system complexity despite the modified crank shaft design.
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 reduces gear train noise and stress, improves assembly efficiency, and provides a tamper-proof location for the unit pumps, ensuring reliable and efficient fuel delivery to engine cylinders.
Implementation Method 1
The crank shaft carries a cam which is arranged to drive the pumping plungers of the unit pumps
Data Source
Figure 1~3
Figure 2
Figure 4~5
AI summary
A fuel pump assembly (10) for an internal combustion engine comprising at least one engine cylinder into which fuel is injected, each cylinder having an associated cylinder piston which reciprocates within the associated cylinder in use. The fuel pump assembly comprises a plurality of unit pumps (28a, 28b), each unit pump having a pumping plunger (34) for pressurising fuel within an associated pump chamber (44) for delivery of fuel to an associated fuel injector of the engine; and a crank shaft (12) which is driven rotationally by means of the or each cylinder piston. The crank shaft comprises a power output end (26), at which an engine gearbox is mounted, and an end (22) remote from the power output end. The crank shaft carries a cam (36) which is arranged to drive the pumping plungers of the unit pumps and further carries at least one crank assembly (18, 20) which is coupled to a respective one of the cylinder pistons, in use. The plurality of unit pumps (28a, 28b) are radially spaced around the crank shaft and located at the same axial position along the crank shaft so that each of the unit pumps is driven, in use, by the same cam (36).