Compensating Plunger Fuel Pump Cambox Pressure Stabilization
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Solution Overview
Problem
High pressure fuel pumps experience pressure fluctuations due to the reciprocating motion of the plunger in the cambox, leading to undesirable issues in supply and return lines, which conventional pressure regulators struggle to compensate effectively.
Innovation Solution
A drive arrangement featuring a compensating plunger that reciprocates out of phase with the pump plunger, with one end contacting the cam at a point opposite to the pump plunger's contact point, maintaining constant effective cambox volume through a bore in the cambox wall and fluid connection to the back-leak channel, minimizing pressure spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a plunger is used to pressurise fuel in a cambox, then high pressure fuel supply is achieved, but pressure fluctuations and pressure spikes occur in the cambox due to changing effective volume
Solution Approach 1:
A compensating plunger is introduced that moves in the opposite direction to the pump plunger. When the pump plunger moves into the cambox reducing volume, the compensating plunger moves out of the cambox increasing volume, and vice versa. This preliminary counteracting action compensates for the volume changes and stabilizes cambox pressure, preventing pressure spikes and fluctuations.
2Power
If the pump plunger reciprocates into the cambox, then fuel is pressurised, but the effective cambox volume changes causing pressure spikes
Solution Approach 1:
The compensating plunger is configured to move in opposition to the pump plunger. As the pump plunger enters the cambox and reduces effective volume (causing pressure spike), the compensating plunger simultaneously exits the cambox and increases effective volume, counteracting the pressure rise before it becomes problematic.
3Stability of the object's composition
If conventional pressure regulators are used to compensate pressure fluctuations, then pressure regulation is attempted, but inertia and lag prevent effective compensation
Solution Approach 1:
The patent replaces the conventional pressure regulator system (which suffers from inertia and lag) with a mechanically coupled compensating plunger system. The compensating plunger is directly driven by the cam mechanism that also drives the pump plunger, creating a synchronous mechanical response that eliminates the time lag and inertia problems of pressure regulators.
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 significantly reduces pressure fluctuations in the cambox, improving the stability of the fuel supply by maintaining a constant effective volume and minimizing pressure peaks, as shown in the plots comparing prior art and compensated designs.
Implementation Method 1
The compensating plunger is urged in a direction such that its contact end is held in contact with the cam by spring means.
Data Source
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AI summary
A drive arrangement for a plunger operated fuel pump including said arrangement including a pump plunger adapted to reciprocate along a first axis, and being driven by a rotating cam in contact with one end of said plunger, and where said cam and said contact end of said plunger are located in a cambox housing, characterised wherein said housing includes a bore, within which is located a compensating plunger arrangement, one end of which is adapted to contact said cam, such that the cam provides reciprocating movement to said compensating plunger.