Hybrid Vehicle Clutch Control Stabilizing Torque
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Solution Overview
Problem
In hybrid vehicles, the mechanical oil pump's control pressure for clutch engagement can be insufficient when increasing input torque demand, leading to unstable clutch transmission torque capacity, which affects engine starting performance and generates noise and vibration.
Innovation Solution
A starting control apparatus for hybrid vehicles that uses a control valve in the line pressure circuit to regulate hydraulic fluid pressure, calculating transmission input torque and executing engine start control when it exceeds a preset threshold, ensuring stable clutch engagement pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the control pressure is increased to meet higher input torque demand, then the transmission torque capacity is improved, but the clutch engagement pressure becomes insufficient leading to unstable clutch transmission torque capacity
Solution Approach 1:
The hydraulic system is divided into two independent circuits: a line pressure circuit for transmission torque control and a clutch control circuit for clutch engagement. This segmentation allows each circuit to independently control its respective function without interference, resolving the contradiction between transmission torque capacity and clutch engagement stability.
Solution Approach 2:
A clutch control pump is introduced as an intermediary component to specifically supply hydraulic pressure to the clutch control circuit. This mediator ensures that clutch engagement pressure remains stable and sufficient even when line pressure increases to meet higher torque demands, preventing the instability that would otherwise occur.
2Power
If the mechanical pump pressure is increased for higher torque demand, then the transmission performance is improved, but the clutch engagement pressure becomes insufficient causing deterioration in engine starting performance
Solution Approach 1:
The hydraulic system is segmented into separate line pressure and clutch control circuits, allowing independent optimization of each function. The clutch control circuit maintains stable pressure for reliable engine starting regardless of line pressure variations.
Solution Approach 2:
The clutch control pump acts as an intermediary that ensures sufficient and stable hydraulic pressure to the clutch during engine starting, preventing performance deterioration even when the mechanical pump pressure is increased for higher torque demands.
3Power
If the control pressure is increased to meet torque demand, then the transmission torque capacity is improved, but noise and vibration are generated due to unstable clutch transmission torque capacity
Solution Approach 1:
By segmenting the hydraulic system into separate circuits for line pressure and clutch control, the invention eliminates the coupling that causes instability. This prevents the generation of noise and vibration that would result from unstable clutch engagement during high torque operation.
Solution Approach 2:
The clutch control pump serves as a mediator that stabilizes clutch engagement pressure, preventing the torque capacity fluctuations that generate noise and vibration during high torque demand conditions.
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 stabilizes clutch transmission torque capacity, preventing engine startability deterioration and noise/vibration issues, even with increased input torque requests.
Implementation Method 1
the engagement of the clutch is generally performed by the hydraulic fluid supplied from the mechanical oil pump which in turn is driven by rotation of the motor / generator
Implementation Method 2
the clutch engagement pressure is supplied from a mechanical pump via a control valve disposed in a line pressure circuit for delivering operating hydraulic fluid
Data Source
AI summary
Provided is a starting control apparatus for a hybrid vehicle, the apparatus being capable of stabilizing and controlling the amount of torque transmitted by the clutch during engine start up. The hybrid vehicle includes a first clutch (CL1) disposed between an engine (Eng.) and a motor/generator (MG), and an engaging pressure is supplied to the first clutch (CL1) from a line pressure regulating valve to a line pressure circuit (101) into which a mechanical oil pump (O/P) delivers operating fluid. The starting control apparatus for a hybrid vehicle is characterized in that a starting control section that performs the starting control in which the clutch (CL1) is engaged, torque is input to the engine (Eng.) and the engine (Eng.) is started in response to an engine start request while traveling in EV mode is provided with a start determining section (step S2) that executes starting control when the transmission input torque (TQCVT) input to a belt-type continuously variable transmission (CVT) exceeds a preset input torque based on the operating fluid pressure.