Hydraulic Pump Leakage Detection via Volumetric Flow Comparison
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Solution Overview
Problem
Existing hydraulic systems for actuating drive train devices in motor vehicles lack effective methods to continuously determine wear and leakage, particularly in the pump, which affects the functional condition over the service life, as leakage from the slave cylinder and switch valve is negligible and difficult to isolate.
Innovation Solution
A method is introduced to control the hydraulic system by comparing the first and second volumetric flows generated by an electrically operated pump and a switch valve, using equations to calculate the leakage of the pump, considering mechanical constants, temperature influences, and rotational parameters of the electric motor, thereby monitoring the wear and functional condition of the hydraulic system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If leakage detection is performed by pressure comparison during slave cylinder actuation, then leakage can be determined, but the method cannot isolate pump leakage from other hydraulic components
Solution Approach 1:
The patent segments the leakage measurement process into two distinct phases: a first measurement phase during slave cylinder actuation that captures total system leakage, and a second measurement phase during hold position that captures leakage from components excluding the pump. By comparing these segmented measurements, the pump-specific leakage can be isolated and identified.
Solution Approach 2:
The control unit acts as an intermediary that coordinates two separate measurement processes and synthesizes their results to identify pump leakage specifically. It processes the first leakage value from actuation phase and the second leakage value from hold phase, using logical comparison to determine the pump's contribution to total leakage.
2Productivity
If the hydraulic system operates continuously, then productivity is maintained, but wear and leakage develop over time affecting functional condition
Solution Approach 1:
The system implements continuous feedback by repeatedly performing leakage measurements during normal operation. The control unit regularly compares the currently determined leakage value with the initial leakage value from the first measurement phase, enabling real-time monitoring of wear development and functional condition changes without interrupting productivity.
Solution Approach 2:
The patent establishes a baseline leakage value during the first measurement phase before significant wear occurs. This preliminary measurement serves as a reference point for detecting future degradation, allowing the system to identify functional condition changes by comparing current measurements against this pre-established baseline.
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 method allows for continuous monitoring of leakage and wear in the hydraulic system, enabling early detection of pump malfunctions and maintaining the hydraulic system's efficiency by isolating and measuring the pump's leakage, thus extending its service life.
Implementation Method 1
a pump shaft of which is electrically driven by an electric motor
Implementation Method 2
a first volumetric flow of a pressure medium is provided by an electrically operated pump
Implementation Method 3
a second volumetric flow generated from the first volumetric flow... by means of a switch valve controlled by the control unit
Implementation Method 4
actuates and linearly displaces a slave cylinder piston of a slave cylinder along an actuation path for actuating the drive train device
Data Source
AI summary
A method for controlling a hydraulic system for actuating a drive train device of a drive train of a motor vehicle includes a first volumetric flow of a pressure medium being provided by an electrically operated pump, and a slave cylinder piston of a slave cylinder being actuated along an actuation path, in a manner controlled by a switch valve, via a second volumetric flow generated from the first volumetric flow. A leakage in the hydraulic system is determined from a comparison of the first and second volumetric flows.