Hydraulic Circuit Line Pressure Boosting for Start-Stop Readiness
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Solution Overview
Problem
Existing hydraulic circuit devices face inefficiencies in managing line pressure boosting for start-stop functions in vehicles, particularly in determining optimal conditions for activating and deactivating the start-stop function to minimize fuel consumption and ensure immediate engine restart.
Innovation Solution
A hydraulic circuit device and method that utilize a control valve to determine various vehicle speed and system conditions to decide when to boost or stop line pressure in an accumulator, ensuring pressure is accumulated only when necessary for the start-stop function, thereby optimizing fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If line pressure is continuously boosted to ensure immediate engine restart capability, then the start-stop function activation readiness is improved, but fuel consumption increases due to unnecessary pressure accumulation
Solution Approach 1:
The control valve performs preliminary actions by boosting line pressure in advance when specific conditions are met (vehicle stopped, ignition on, transmission in Park or Neutral, clutch not engaged). This preliminary pressure accumulation ensures immediate engine restart capability while avoiding continuous pressure boosting that would waste fuel.
Solution Approach 2:
The system dynamically adjusts line pressure boosting based on real-time vehicle conditions. The control valve activates pressure boosting only when necessary (when the vehicle is stopped and restart conditions are met) and deactivates it when conditions change (vehicle starts moving, ignition off, etc.), creating a dynamic response that balances readiness with fuel efficiency.
2Loss of time
If line pressure boosting is activated early to ensure immediate engine restart, then the response time for start-stop function is improved, but the period of unnecessary pressure maintenance increases fuel consumption
Solution Approach 1:
The control valve performs preliminary pressure boosting when the vehicle is stopped and ignition is on, preparing the hydraulic system in advance for potential engine restart. This ensures immediate response capability without maintaining pressure during periods when restart is not needed.
Solution Approach 2:
The control valve continuously monitors vehicle conditions (speed, ignition state, transmission position, clutch engagement) and uses this feedback to determine when to activate or deactivate pressure boosting. This feedback mechanism ensures pressure is maintained only during the period when immediate restart is actually needed, not during extended idle periods.
3Measurement precision
If the control valve monitors multiple conditions for pressure boosting, then the precision of start-stop function activation is improved, but the complexity of the control system increases
Solution Approach 1:
The control valve divides the condition monitoring into distinct, independent checks: vehicle speed condition, ignition state condition, transmission position condition, and clutch engagement condition. Each condition is evaluated separately, and the control logic activates pressure boosting only when all conditions are satisfied, simplifying the overall control structure while maintaining high precision.
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 solution allows for efficient line pressure boosting before start-stop function activation and immediate clutch engagement, while preventing unnecessary pressure accumulation that could reduce fuel economy, thus enhancing fuel efficiency and operational readiness.
Implementation Method 1
The fluid pump is connected to the flow path to supply oil to the flow path
Implementation Method 2
The pressure generating device is connected to the flow path to supply oil to the flow path when the fluid pump does not function
Implementation Method 3
The control valve is connected to the flow path. The control valve is configured to boost a line pressure of the flow path to accumulate pressure in the pressure generating device
Data Source
AI summary
A hydraulic circuit device for a vehicle, includes a clutch, a flow path, a fluid pump, a pressure generating device, and a control valve. The control valve is configured to determine whether a transmission start-stop function activation condition other than a vehicle speed is satisfied, determine whether a system start-stop function activation condition related to a component of the vehicle is satisfied, the component being other than the transmission, determine whether the vehicle speed is equal to or lower than a first speed threshold, and boost a line pressure of the flow path to accumulate pressure in the pressure generating device for preparing activation of the start-stop function if it is determined that the transmission start-stop function activation condition and the system start-stop function activation condition are satisfied, and if it is determined that the vehicle speed is equal to or lower than the first speed threshold.