Oil Lubricated Common Rail Diesel Pump Guide Flow Passages
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Solution Overview
Problem
Oil lubricated common rail diesel pumps face issues with large irregular pressure pulses at high pumping speeds, which can damage drivetrain seals and force oil into the fuel circuit, compromising engine performance, especially when using poor quality diesel fuels.
Innovation Solution
An oil lubricated common rail diesel pump design featuring a drivetrain assembly with a guide that includes flow passages between chambers, allowing for oil backflow and immediate lubrication, minimizing pressure pulses and preventing oil from entering the fuel circuit, while enabling various mounting angles and reduced engine tilt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump housing is filled with oil for lubrication, then lubrication performance is improved, but large irregular pressure pulses occur at high pumping speeds
Solution Approach 1:
The pump housing is divided into two separate chambers: a first chamber for the drivetrain assembly filled with oil, and a second chamber for the pumping assembly. This segmentation isolates the oil-filled environment to only where it is needed for lubrication, preventing oil from being displaced into the fuel pumping circuit while maintaining excellent lubrication performance.
Solution Approach 2:
The oil-filled lubrication environment is extracted from the entire pump housing and confined to only the drivetrain chamber. This removes the harmful effect of oil displacement from the fuel circuit while preserving the beneficial lubrication effects in the drivetrain assembly.
2Loss of time
If the pump housing is filled with oil, then immediate lubrication is provided, but oil can be forced into the fuel circuit compromising engine performance
Solution Approach 1:
The pump housing is segmented into separate chambers, isolating the oil-filled drivetrain chamber from the fuel pumping chamber. This prevents oil from being forced into the fuel circuit while maintaining immediate lubrication availability in the drivetrain assembly upon engine start-up.
Solution Approach 2:
A seal assembly acts as an intermediary barrier between the oil-filled first chamber and the fuel-containing second chamber, preventing oil from contaminating the fuel circuit while allowing the drivetrain to benefit from immediate oil lubrication.
3Quantity of substance
If poor quality diesel fuel is used for lubrication, then cost is reduced, but lubrication performance deteriorates
Solution Approach 1:
The lubrication function is extracted from the diesel fuel and assigned to a dedicated oil lubrication system. This allows poor quality diesel fuel to be used without compromising lubrication, as the oil lubrication system independently provides the necessary lubrication performance.
Solution Approach 2:
The drivetrain assembly serves itself with oil lubrication from the dedicated oil-filled chamber, making it independent of the quality of diesel fuel used for fuel injection. The oil lubrication system automatically provides the required lubrication without needing high-quality fuel.
4Object-generated harmful factors
If a seal is provided between chambers, then oil is prevented from entering the fuel circuit, but the seal is subjected to irregular pressure pulses reducing its service life
Solution Approach 1:
The seal assembly is designed to accommodate and withstand the irregular pressure pulses generated in the oil-filled chamber. By selecting appropriate seal materials and designs that can handle the pressure variations, the seal's service life is maintained while still preventing oil contamination of the fuel circuit.
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 provides stable lubrication, maintains seal integrity, and prevents oil from entering the fuel circuit, enhancing engine performance and longevity by minimizing pressure pulses and ensuring immediate lubrication upon engine start-up.
Implementation Method 1
the guide comprises at least one flow passage communicating between the first chamber and the second chamber of the drivetrain housing
Implementation Method 2
the oil-filled drivetrain housing provides for immediate lubrication at engine cranking
Data Source
Figure 1
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Figure 4
AI summary
The present invention provides an oil lubricated common rail diesel pump (1) comprising a pumping assembly (10) and a drivetrain assembly (20). The pumping assembly (10) comprises a pump housing (12) and a plunger (14) mounted along a pumping axis (Α-Α'). The drivetrain assembly (20) comprises a driveshaft (24) and a cam (26) mounted within a first chamber (28) of a drivetrain housing (22). The plunger (14) is arranged for reciprocating linear movement along the pumping axis (Α-Α') within a second chamber (30) of the housing (22) upon rotation of the cam (26). The drivetrain assembly (20) further comprises a guide (40) mounted within the housing (22) between the cam (26) and the plunger (14) and being adapted to receive a cam follower (16). At least the housing (22) is adapted to be substantially filled with oil in use and the guide (40) comprises at least one flow passage (48) communicating between the first chamber (28) and the second chamber (30).