Electric Oil Pump Control for Vehicle Load Management
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Solution Overview
Problem
The existing vehicle driving systems face a challenge in efficiently managing the operation of electric oil pumps during ignition state transitions, leading to potential hydraulic pressure supply issues and reduced service life due to excessive start-ups when the electric oil pump is always activated upon ignition on.
Innovation Solution
The implementation of an electronic control unit that selectively starts the electric oil pump based on detected vehicle load and ignition state transitions, opting for the one-motor EV mode when the load is low and switching to the two-motor EV mode only when necessary, thereby reducing unnecessary operations and extending the pump's service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric oil pump is always started at the time when the vehicle is set to the ignition on state, then hydraulic pressure can be supplied, but the service life of the electric oil pump decreases due to increased number of start-ups
Solution Approach 1:
The control unit determines in advance whether to start the electric oil pump by checking if the vehicle has been in the ignition off state before transitioning to ignition on state. This preliminary determination prevents unnecessary start-ups while ensuring hydraulic pressure is supplied when required, thus extending pump service life without compromising reliability.
2Reliability
If the electric oil pump is always started at ignition on, then hydraulic pressure is available, but fuel efficiency decreases due to unnecessary operation
Solution Approach 1:
Instead of always starting the electric oil pump at ignition on, the control unit applies partial action by starting the pump only when necessary (when the vehicle has been in ignition off state). This reduces unnecessary energy consumption and improves fuel efficiency while maintaining sufficient hydraulic pressure supply for actual needs.
3Reliability
If the electric oil pump is frequently started, then hydraulic pressure can be ensured, but wear on the pump increases reducing durability
Solution Approach 1:
The control unit performs a preliminary check of the ignition state history before deciding to start the electric oil pump. By determining in advance whether the vehicle has been in the ignition off state, the system avoids unnecessary start-ups that would increase wear, thereby extending pump durability while ensuring hydraulic pressure is available when truly needed.
Data Source
AI summary
An electronic control unit stores a vehicle load at the time when the vehicle is switched into an ignition off state, stops operation of an electric oil pump when the vehicle load is small, and operates the electric oil pump when the vehicle load is large. Thus, a decrease in service life due to an increase in the number of times of the start of the electric oil pump is suppressed, and, when it is estimated that the vehicle load is large, the response of the start of a vehicle, which makes a driver experience a feeling of strangeness, is improved by starting the electric oil pump together with switching the vehicle into an ignition on state.