Electric Oil Pump Control for Automatic Transmission Shift Speed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automatic transmissions experience decreased shift speed due to insufficient oil flow rate, particularly when the engine's rotation speed is low, as the mechanical oil pump's flow rate is insufficient to fill the clutch's oil chamber quickly, leading to potential engagement failures and slow shift speeds.
Innovation Solution
A controller-driven system that activates the electric oil pump during vehicle travel when the calculated oil flow rate required by the automatic transmission exceeds the margin flow rate of the mechanical oil pump, ensuring sufficient hydraulic pressure and preventing shift speed decreases by compensating for the insufficient flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the mechanical oil pump is used alone during vehicle traveling, then the device complexity is reduced, but the shift speed decreases when engine rotation speed is low due to insufficient oil flow rate
Solution Approach 1:
The oil pump system is segmented into two independent units: a mechanical oil pump for normal operation and an electric oil pump for supplemental support. This segmentation allows each pump to be optimized for specific operating conditions, with the electric pump activating only when needed to maintain shift speed without requiring full system complexity to always be engaged
Solution Approach 2:
The system dynamically switches between mechanical-only and combined mechanical-electric oil pump operation based on real-time monitoring of engine rotation speed and oil flow requirements. This dynamic adaptation ensures optimal shift speed is maintained during low-speed conditions while avoiding unnecessary electric pump operation during normal conditions
2Speed
If the electric oil pump is driven continuously to ensure sufficient oil flow rate, then the shift speed is maintained, but the energy consumption increases
Solution Approach 1:
The electric oil pump operates periodically rather than continuously, activating only during specific low-engine-speed conditions where the mechanical pump's output is insufficient. This periodic operation maintains shift speed requirements while minimizing energy consumption by keeping the electric pump dormant during normal operating conditions
Solution Approach 2:
The system monitors and responds to changes in engine rotation speed parameters, activating the electric oil pump only when the parameter threshold for insufficient flow rate is reached. This parameter-based control ensures the electric pump provides supplemental flow only when necessary, optimizing the balance between shift speed maintenance and energy consumption
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 electric oil pump is actively driven to maintain optimal oil flow, preventing shift speed reductions and ensuring reliable engagement and lubrication, even at low engine rotation speeds, thereby enhancing transmission performance and efficiency.
Implementation Method 1
an electric oil pump driven by an electric motor, the electric oil pump supplying oil to the automatic transmission
Implementation Method 2
a mechanical oil pump driven by an engine, the mechanical oil pump supplying oil to the automatic transmission
Data Source
AI summary
An automatic transmission includes a mechanical oil pump, an electric oil pump, and a controller. The controller calculates a flow rate of oil necessary for the automatic transmission during the vehicle travels, and drives the electric oil pump when the calculated flow rate of the oil necessary for the automatic transmission is higher than a margin flow rate of the mechanical oil pump generated in a state where a hydraulic pressure necessary for the automatic transmission is ensured.