Vehicle Clutch Pressure Control for Faster Engine Cranking
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Solution Overview
Problem
Existing vehicle control systems require a predetermined time to switch the clutch from a released state to an engaged state, which delays engine cranking and subsequent vehicle output, leading to increased time in achieving desired vehicle performance.
Innovation Solution
A control apparatus that outputs a higher cranking hydraulic-pressure command value before the predetermined time to quickly eliminate clutch pack clearance and initiate cranking torque, allowing earlier engine starting and reduced vehicle output time, with additional features like surge hydraulic-pressure commands and adjusted delay times to enhance responsiveness and torque synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch is switched from released state to engaged state using conventional hydraulic pressure control, then the clutch pack clearance is eliminated and the clutch is prepared for torque transmission, but the process requires a predetermined time that delays engine cranking and reduces vehicle output responsiveness
Solution Approach 1:
The hydraulic control unit begins eliminating clutch pack clearance before the predetermined time elapses by outputting a first hydraulic pressure command value that maintains pack clearance elimination. This preliminary action allows the clutch to be ready for torque transmission earlier, reducing the delay in engine cranking while ensuring reliable engagement when needed.
Solution Approach 2:
The system dynamically adjusts hydraulic pressure command values based on real-time clutch state and vehicle conditions. The control unit switches between different pressure command values (first, second, and third) depending on whether cranking is needed, optimizing both the speed of engagement and the reliability of torque transmission.
2Reliability
If the cranking hydraulic-pressure command value is output after the predetermined time, then the clutch is ensured to be in pack-clearance-elimination completion state, but the engine cranking is delayed and vehicle output time is increased
Solution Approach 1:
The system outputs the first hydraulic pressure command value in advance to eliminate pack clearance before the predetermined time elapses. This preliminary preparation ensures the clutch is ready for torque transmission when cranking is initiated, maintaining reliability while reducing overall engagement time and improving vehicle output speed.
Solution Approach 2:
The control unit changes hydraulic pressure parameters by outputting different command values (first, second, third) based on operational needs. The first command value is used for preliminary clearance elimination, while the second and third values are used for active torque transmission during and after cranking, optimizing both reliability and productivity.
3Reliability
If the packing hydraulic-pressure command value is output during engine start, then the clutch pack clearance is eliminated, but the cranking torque transmission is delayed until the predetermined time elapses
Solution Approach 1:
The hydraulic control unit outputs the first hydraulic pressure command value to eliminate pack clearance before the predetermined time elapses. This preliminary action ensures the clutch is mechanically ready for torque transmission, allowing engine cranking to begin earlier without compromising engagement completeness, thus improving cranking speed.
Solution Approach 2:
The system maintains continuous hydraulic pressure application through the first command value during the period before predetermined time elapses. This continuous useful action keeps the clutch in a ready state for torque transmission, enabling seamless transition to cranking mode and improving engine cranking speed without sacrificing engagement reliability.
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 reduces the time required to achieve desired vehicle output by enabling earlier clutch engagement and cranking, improving responsiveness and torque synchronization, thus enhancing power performance and reducing delays in engine starting.
Implementation Method 1
a hydraulic control unit configured to supply a regulated hydraulic pressure that is to be used for switching an operation state of the clutch
Implementation Method 2
an electric motor connected to a power transmission path between the engine and the drive wheels... control the electric motor for causing the electric motor to output the cranking torque
Implementation Method 3
a clutch disposed between the engine and the electric motor in the power transmission path... a part of an output torque of the electric motor is applied to a crank shaft of the engine through the clutch
Data Source
AI summary
A vehicle control apparatus output a packing hydraulic-pressure command value and a cranking hydraulic-pressure command value higher than the packing hydraulic-pressure command value. The packing hydraulic-pressure command value is outputted to place a clutch in a pack-clearance-elimination completion state in a process of switching of the clutch from a released state to an engaged state. The cranking hydraulic-pressure command value is outputted, after elapse of a predetermined time required to place the clutch in the pack-clearance-elimination completion state, to cause the clutch to transmit a cranking torque required by a cranking by which a rotational speed of an engine is increased. In a case in which it is determined that a request to increase a vehicle power performance during output of the packing hydraulic-pressure command value, the cranking hydraulic-pressure command value is outputted in place of the packing hydraulic-pressure command value even before the elapse of the predetermined time.