Common Rail Hydraulic Actuator for Dynamic Bearing Load Simulation
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Solution Overview
Problem
Current bearing test rigs fail to accurately replicate the dynamic load conditions experienced by internal combustion engine bearings, lacking the capability to apply sufficiently large and rapidly varying forces, which limits the effectiveness of wear and fatigue life testing.
Innovation Solution
An apparatus and method utilizing a common rail injection system with a piston and injectors to supply hydraulic fluid at elevated pressures, enabling the generation and application of linear forces in the range of 20 kN to 300 kN with rapid load changes, simulating the load history of internal combustion engine bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic systems are used to apply large loads, then the load magnitude can reach combustion engine levels (20 kN to 300 kN), but the rate of load change is insufficient due to large hydraulic fluid flow rates and compliance
Solution Approach 1:
The patent uses a hydraulic system with a pump, hydraulic fluid, and actuator to generate the required large forces (20 kN to 300 kN) that cannot be achieved with mechanical or electromagnetic systems alone. The hydraulic fluid is pressurized and delivered through controlled flow paths to the actuator.
Solution Approach 2:
The system dynamically adjusts the hydraulic fluid flow rate and pressure in real-time to achieve both high load magnitude and high rate of load change. The controller modulates the pump operation and valve positioning to replicate the dynamic loading conditions of combustion engine bearings, transitioning from static to dynamic control.
2Force
If mechanical systems are used to generate large forces, then sufficient load magnitude can be achieved, but the load range and speed coverage are limited
Solution Approach 1:
The hydraulic system provides a wide adjustable load range from low to high forces (20 kN to 300 kN) and can operate at various speeds by controlling fluid flow rate and pressure, making it versatile for different bearing test conditions without requiring multiple specialized systems.
Solution Approach 2:
The hydraulic actuator system serves multiple functions: it can apply static loads, dynamic loads, high-magnitude forces, and rapid load changes depending on controller commands. This single system replaces what would traditionally require multiple separate mechanical, electromagnetic, or pneumatic systems.
3Reliability
If existing bearing test rigs are used, then basic wear testing can be performed, but the load conditions do not accurately replicate combustion engine bearing loading history
Solution Approach 1:
The system uses sensors to measure actual bearing loads, displacements, and test parameters in real-time, feeding this data back to the controller. The controller adjusts hydraulic fluid pressure and flow rate accordingly to accurately track and replicate the target combustion engine bearing loading history, ensuring precise measurement and control.
Solution Approach 2:
The test rig transitions from static loading to dynamic loading by using a programmable controller that applies time-varying hydraulic forces. The system can replicate the characteristic load cycles, transient loads, and varying speeds of combustion engine bearings, providing accurate measurement of wear, scuff onset, and fatigue life under realistic conditions.
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 replicates the load conditions of internal combustion engine bearings, enhancing the testing of wear, scuff onset, and fatigue life, and allowing for more accurate evaluation of bearing performance under various conditions.
Implementation Method 1
The first common rail is configured to store the hydraulic fluid at an elevated pressure of 1,000 bar or greater
Implementation Method 2
The first plurality of injectors are configured to inject a hydraulic fluid from the common rail into the first working volume
Implementation Method 3
displacement of the piston alters the first working volume
Implementation Method 4
The first plurality of injectors are configured to inject a hydraulic fluid from the common rail into the first working volume
Data Source
AI summary
An apparatus including a piston bore, exhibiting a longitudinal axis, and a piston, including a piston head and a piston shaft. The piston being axially displace-able within the piston bore along the longitudinal axis. The piston bore and a first surface of the piston head form a first working volume and displacement of the piston alters the first working volume. The apparatus also includes a first plurality of injectors coupled to the first working volume and a first common rail. The first plurality of injectors are configured to inject a hydraulic fluid from the common rail into the first working volume. The first common rail is configured to store the hydraulic fluid at an elevated pressure of 1,000 bar or greater. The apparatus includes a flow path between the first working volume and a reservoir for the hydraulic fluid.