Variable-Capacity Oil Pump Control for Hydraulic Responsiveness
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Solution Overview
Problem
Mechanical variable-capacity oil pumps in vehicles face responsiveness issues due to the need for hydraulic pressure sensors for feedback control, leading to time lags in adjusting discharge hydraulic pressure, especially with increased engine rotation speed causing oil leakage and reduced actual discharge hydraulic pressure.
Innovation Solution
An electronic control unit calculates the target discharge volume of the mechanical variable-capacity oil pump based on input torque and rotation speed, considering oil leakage, and adjusts the operation of both mechanical and electric oil pumps to maintain responsiveness without relying on actual discharge hydraulic pressure measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control is performed using a hydraulic pressure sensor to maintain target discharge hydraulic pressure, then discharge hydraulic pressure control accuracy is improved, but device complexity and cost increase due to the necessity of the sensor
Solution Approach 1:
The invention extracts and removes the hydraulic pressure sensor from the system. Instead of using a sensor to measure actual discharge hydraulic pressure for feedback control, the system calculates the target discharge volume based on engine rotation speed and load factor, then directly controls the variable-capacity oil pump to achieve the target volume without measurement feedback, thereby eliminating the sensor and reducing system complexity
Solution Approach 2:
The invention replaces the mechanical measurement-based feedback control system with a calculation-based open-loop control system. The ECU calculates the target discharge volume using engine rotation speed and load factor, then controls the oil pump based on this calculated value, substituting the need for physical pressure sensing and feedback mechanisms
2Reliability
If feedback control is performed after detecting actual discharge hydraulic pressure deficiency, then discharge hydraulic pressure is restored, but responsiveness deteriorates due to time lag in detection and control adjustment
Solution Approach 1:
The invention performs preliminary action by calculating the target discharge volume in advance based on engine rotation speed and load factor before actual discharge hydraulic pressure deficiency occurs. The variable-capacity oil pump is controlled proactively to maintain the target discharge volume, preventing pressure drops before they happen rather than reacting after detection
Solution Approach 2:
The invention implements a calculation-based feedback mechanism where the ECU continuously calculates the target discharge volume based on real-time engine rotation speed and load factor, and adjusts the variable-capacity oil pump accordingly. This calculation-based approach provides continuous adaptive control without the time lag associated with physical sensor detection and signal processing
3Reliability
If target discharge oil amount is increased to compensate for oil leakage at high engine rotation speed, then discharge hydraulic pressure is maintained, but fuel consumption increases
Solution Approach 1:
The invention dynamically changes the target discharge volume parameter based on engine rotation speed and load factor. The ECU calculates the appropriate target discharge volume that accounts for oil leakage at different rotation speeds, adjusting the parameter optimally rather than simply increasing it, thereby maintaining discharge hydraulic pressure while minimizing unnecessary energy consumption
Data Source
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AI summary
The hydraulic control device includes: a mechanical variable-capacity oil pump (201); and an electronic control unit (300) configured to (i) calculate a target discharge volume of the mechanical variable-capacity oil pump (201) using a plurality of parameters of the transmission (30), and (ii) control the mechanical variable-capacity oil pump (201) based on the target discharge volume.