Clutch Hydraulic Pressure Control for Smooth Engine Restart
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Solution Overview
Problem
The existing control devices for vehicles with engines and motors face instability in hydraulic pressure during engine starting, leading to potential starting shocks and reduced drivability due to insufficient hydraulic oil flow rates, which affects the clutch's control state switching.
Innovation Solution
A control device with an electronic control unit that outputs specific command values to the hydraulic control circuit to manage the clutch's state transition, including a rapid filling hydraulic pressure command to ensure stable hydraulic pressure for clutch actuation, particularly during engine start-ups when the required pressure is not secured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the hydraulic pressure is increased rapidly to switch the clutch control state during engine starting, then the clutch engagement response is improved, but the hydraulic pressure becomes unstable when the hydraulic oil flow rate is insufficient
Solution Approach 1:
The electronic control unit determines whether to output the rapid filling hydraulic pressure command value in advance by checking if the vehicle is in a predetermined state (insufficient hydraulic oil flow rate). When not in this state, the unit outputs the command value immediately to achieve rapid clutch engagement. This preliminary assessment prevents hydraulic pressure instability while maintaining fast response when conditions permit.
2Productivity
If the rapid filling hydraulic pressure command value is output immediately during engine starting, then the clutch control state switching is accelerated, but drivability deteriorates when hydraulic pressure is not secured stably
Solution Approach 1:
The electronic control unit continuously monitors the vehicle state to determine whether hydraulic oil flow rate is sufficient before outputting the rapid filling hydraulic pressure command value. This feedback mechanism ensures that rapid clutch engagement is only commanded when hydraulic pressure can be maintained stably, preventing drivability deterioration while maximizing switching speed when conditions allow.
3Reliability
If the hydraulic pressure is lowered due to insufficient flow rate, then the clutch control state cannot be switched as intended, but increasing the flow rate requirement may cause other hydraulic components to malfunction
Solution Approach 1:
The electronic control unit dynamically adjusts the hydraulic pressure control strategy based on real-time vehicle state. When insufficient flow rate is detected, the unit suppresses the rapid filling command to allow gradual pressure build-up, ensuring other hydraulic components function properly. When flow rate is sufficient, the unit enables rapid filling for fast clutch engagement. This dynamic adaptation maintains clutch switching reliability without compromising overall hydraulic system versatility.
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 the hydraulic pressure for clutch actuation, improving the initial response and preventing drivability deterioration by ensuring the clutch's control state is switched reliably, thus enhancing engine starting performance.
Implementation Method 1
a hydraulic control circuit system that supplies an adjusted hydraulic pressure to the clutch actuator
Implementation Method 2
the first command value being a command value for supplying the hydraulic pressure to the clutch actuator so as to reduce a pack clearance in the clutch
Data Source
AI summary
An electronic control unit is configured to: output a first command value to the hydraulic control circuit system and then output a second command value to the hydraulic control circuit system during a transition in which the control state of the clutch is switched from a disengaged state to an engaged state when starting the engine; perform first control in which the motor outputs the cranking torque, and second control in which the engine starts operation, when starting the engine; and when the vehicle is in a predetermined state in which a required hydraulic pressure is not secured stably when starting the engine, start output of the first command value when the vehicle is not in the predetermined state, the required hydraulic pressure being a hydraulic pressure supplied from the hydraulic control circuit system to the clutch actuator and required to switch the control state of the clutch.