DCT Oil Pump Control via Pressure Models
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Solution Overview
Problem
Existing Dual Clutch Transmission (DCT) systems face challenges in efficiently generating and stabilizing hydraulic pressure for multi-plate wet clutches while minimizing energy consumption and reducing costs, particularly due to the need for multiple hydraulic sensors.
Innovation Solution
An oil pump control method that estimates line pressure using regression models and solenoid valve control, eliminating the need for a specific line pressure sensor by managing pressure through a pressure-up and pressure-down model, and considering leakage and operational losses to maintain stable hydraulic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hydraulic pressure sensors are installed to measure line pressure for each clutch, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a copy of the pressure measurement approach by applying the same pressure-up and pressure-down models to both drive-side and non-drive-side clutches. Instead of installing separate sensors for each clutch, the system measures pressure at one location and uses mathematical models to estimate (copy) the pressure conditions for both clutches, thereby reducing sensor quantity while maintaining measurement capability
Solution Approach 2:
The patent creates universal pressure control models (pressure-up model and pressure-down model) that can be applied to both drive-side and non-drive-side clutches. These models serve multiple functions: they estimate line pressure, determine pump control timing, and predict pressure changes for both clutches using a single sensor input, making the measurement system multi-functional
2Reliability
If the oil pump operates continuously to maintain hydraulic pressure, then reliability is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic pump operation by alternately driving and stopping the oil pump based on real-time pressure estimation. The pressure-up model predicts when pressure will reach the upper limit, and the pressure-down model predicts when pressure will reach the lower limit, enabling the system to operate the pump in cycles rather than continuously, thus reducing energy consumption while maintaining pressure stability
Solution Approach 2:
The patent establishes a feedback control system where the controller continuously monitors actual pressure sensor data, compares it with model predictions, and adjusts pump operation accordingly. The pressure-up and pressure-down models provide feedback about future pressure states, allowing the controller to make proactive decisions about when to start or stop the pump, ensuring reliability while optimizing energy use
3Use of energy by moving object
If the oil pump stops frequently to reduce energy consumption, then energy efficiency is improved, but hydraulic pressure stability deteriorates
Solution Approach 1:
The patent applies preliminary action by using the pressure-up model to predict future pressure states before they occur. The controller estimates when line pressure will reach the upper limit or lower limit based on current conditions and model predictions, allowing it to stop or start the pump in advance, ensuring pressure stability is maintained without unnecessary pump operations
Solution Approach 2:
The patent implements dynamic pressure control by adjusting pump operation based on real-time conditions and predictive modeling. The system dynamically determines optimal stop and start timing using the pressure-up and pressure-down models, adapting to changing system conditions while maintaining pressure within acceptable ranges, thus achieving both energy efficiency and stability
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 approach reduces energy consumption, lowers costs by minimizing sensor usage, and enhances fuel efficiency and driving range by optimizing hydraulic pressure supply for DCT systems without requiring a separate line pressure sensor.
Implementation Method 1
a pressure sensor for measuring line pressure generated between the check valve and the two solenoid valves
Implementation Method 2
opening a solenoid valve supplying hydraulic pressure to a non-drive side clutch
Implementation Method 3
a check valve disposed to stop oil that flows back to the oil pump when the oil pump is stopped
Data Source
AI summary
An oil pump control method for a DCT may include estimating line pressure, using a pressure-up model formed from a relationship between an oil pump driving current and a hydraulic pressure; stopping the oil pump when the line pressure estimated from the pressure-up model is equal to or higher than a predetermined upper limit hydraulic pressure; estimating a dropping line pressure from a first pressure-down model for a predetermined first reference time after stopping the oil pump on the basis of the line pressure estimated when the oil pump is stopped as an initial value; forming a second pressure-down model by opening a solenoid valve supplying hydraulic pressure to a non-drive side clutch, and estimating a line pressure from the second pressure-down model, and returning to the pressure-up step when the line pressure reaches predetermined lower limit hydraulic pressure or less.