Electrohydraulic Pump Start Current Calibration from Engine Torque
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current calibration methods for electrohydraulic propel systems, particularly for start current parameters, are inefficient and require additional sensors, skilled technicians, or specialized equipment, making them costly and time-consuming, and lack the ability to be performed automatically or repeatedly without complex setups.
Innovation Solution
A system utilizing load sensors and a micro-controller with software to automatically calibrate electrohydraulic pumps by converting internal analog drive signals into output signals, determining start current values based on engine torque signals, and performing the calibration process without manual adjustments or extra sensors, allowing for repeatable calibration on a stationary vehicle with wheels on the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are used to provide feedback for calibration, then measurement precision of pump start current is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the calibration function from a complex sensor-based system and implements it using existing engine torque signals and controller resources. The calibration process is taken out of the domain requiring additional hardware sensors and placed in the domain of software-based parameter adjustment using available data.
Solution Approach 2:
The system uses its own existing sensors and controllers to perform calibration without requiring external measurement devices. The engine torque signal, already present for propulsion control, is repurposed to provide feedback for pump start current calibration, making the system self-sufficient.
2Manufacturing precision
If temporary pressure sensors are installed at end of assembly for calibration, then manufacturing precision is improved, but loss of time and productivity decrease
Solution Approach 1:
The calibration process is designed to be performed as a preliminary step during vehicle assembly using the vehicle's own existing components. By using the engine torque signal and controller that are already part of the vehicle, the calibration can be completed during assembly without requiring subsequent installation of temporary sensors or specialized equipment.
Solution Approach 2:
The engine torque signal serves multiple functions: it controls the propulsion system during normal operation and simultaneously provides the feedback signal needed for pump start current calibration. This multi-functionality eliminates the need for dedicated calibration sensors or equipment.
3Reliability
If driving calibration on test track is used, then reliability of calibration is improved, but ease of operation and productivity worsen
Solution Approach 1:
The patent replaces the mechanical driving calibration process (requiring test tracks, wheel lifts, or road testing) with an electronic/software-based calibration process. The calibration is performed by adjusting electrical parameters and analyzing electronic sensor signals while the vehicle remains stationary, eliminating the need for mechanical test setups.
Solution Approach 2:
The controller serves as an intermediary that translates the relationship between pump control current and engine torque into calibrated parameters. Instead of directly observing vehicle motion on a test track, the controller mediates the calibration process by analyzing torque signals and automatically adjusting start current parameters.
4Measurement precision
If manual adjustment by skilled technician is used, then measurement precision is improved, but loss of time and productivity decrease
Solution Approach 1:
The calibration process is designed to be performed automatically by the vehicle's own controller without requiring skilled technicians for manual adjustment. The controller reads engine torque signals, processes the data according to calibration algorithms, and automatically determines the appropriate start current parameters, making the system self-calibrating.
Solution Approach 2:
The system implements automatic feedback control during calibration: the controller adjusts pump start current parameters based on real-time engine torque signal feedback, automatically iterating to find optimal values without requiring manual intervention or expert judgment.
Data Source
Figure 1
Figure 2
AI summary
A method for calibrating an electrohydraulic pump (18) in a system (10) comprising a machine (12) having a propel system (14) that includes an engine (16) connected to an electrohydraulic pump. A micro-controller (20) having software (22) and an input device (24) is connected to a plurality of sensors (26) mounted about the machine. The software uses a plurality of parameters to convert internal analog drive signals into analog output signals to control the electrohydraulic pump and motion of the machine where the parameters include a forward start current value and a reverse start current value.