High Pressure Fuel Pump Eccentric Drive Friction Reduction
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Solution Overview
Problem
High-pressure fuel pumps in internal combustion engines face friction issues with existing drive mechanisms, particularly sliding friction in eccentric drives, which affects efficiency and robustness.
Innovation Solution
The introduction of a drive device with an eccentric ring and tappet system that utilizes pivoting bodies with arched contact surfaces and a bucket tappet to convert rotational movement into translational movement, reducing friction through rolling or pivoting contact instead of sliding friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sliding shoe is used to transmit movement from the eccentric ring to the piston, then the drive mechanism is simple and robust, but sliding friction occurs which reduces efficiency and increases energy consumption
Solution Approach 1:
The patent replaces the flat sliding shoe with a roller element that has a curved surface. This roller contacts the eccentric ring at a point or line rather than a flat surface, converting sliding friction into rolling friction. The curved geometry of the roller allows it to rotate as it moves along the eccentric ring surface, significantly reducing the frictional forces and energy losses while maintaining the robust mechanical connection.
Solution Approach 2:
The roller acts as an intermediary element between the eccentric ring and the piston drive mechanism. Instead of direct sliding contact between the shoe and eccentric ring, the roller mediates the motion transmission. This intermediate rolling element reduces direct frictional contact while still effectively transmitting the translational movement from the eccentric ring to the piston, thereby reducing energy loss without compromising reliability.
2Device complexity
If an eccentric ring with flat surface is used, then the structure is simple, but sliding friction occurs between the sliding shoe and eccentric ring surface
Solution Approach 1:
The patent introduces a roller with a curved surface that contacts the flat eccentric ring. This adds minimal geometric complexity while fundamentally changing the friction characteristics from sliding to rolling. The curved roller surface allows for smooth rotation and contact with the flat eccentric ring, reducing energy consumption without significantly complicating the overall eccentric drive structure.
Solution Approach 2:
The roller element introduces dynamic motion to the otherwise static sliding interface. Instead of a stationary sliding shoe, the roller rotates dynamically as it moves along the eccentric ring, adapting its orientation to the motion path. This dynamic behavior reduces frictional energy losses while maintaining structural simplicity.
3Loss of energy
If a roller tappet is used instead of sliding shoe, then rolling friction reduces energy loss, but the arrangement becomes less robust
Solution Approach 1:
The patent combines the advantages of both the sliding shoe and roller tappet into a unified design. The roller is integrated directly into the piston drive mechanism, merging the motion transmission functions. This hybrid approach maintains the robust mechanical connection of the sliding shoe while incorporating the low-friction rolling contact of the roller tappet, achieving both energy efficiency and reliability.
Solution Approach 2:
The drive mechanism uses composite construction with the roller element made from materials optimized for rolling contact, while the supporting structure maintains the robustness of traditional sliding shoe designs. This composite approach allows different parts of the mechanism to be optimized for their specific functions - the roller for low-friction motion and the supporting structure for mechanical strength and reliability.
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 provides a robust and energetically optimized drive mechanism with reduced frictional power requirements, leading to lower CO2 emissions and improved stability, allowing for efficient operation of high-pressure fuel pumps.
Implementation Method 1
reducing friction through rolling or pivoting contact instead of sliding friction
Data Source
AI summary
The present disclosure relates to internal combustion engines in general. Some embodiments may include a drive device for a high-pressure fuel pump of an internal combustion engine. It may include an eccentric ring in frictional connection with a drive shaft for converting a rotational movement of the drive shaft about a drive shaft rotational axis into a translational movement; a tappet spaced apart from the eccentric ring for passing on the translational movement from the eccentric ring; and at least two pivoting bodies disposed between the eccentric ring surface and the tappet surface and in contact with the eccentric ring surface and with the tappet surface. The eccentric ring may include at least one flat eccentric ring surface. The tappet may include at least one flat tappet surface. The pivoting bodies may each include a respective extension axis running parallel to the drive shaft rotational axis and pivot about the extension axis.