Starting Clutch Pressure Learning With Input Shaft Rotation Restraint
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In single-motor parallel hybrid vehicles, learning the engagement start pressure of the starting clutch is challenging due to potential rotation of the input member caused by drag torque when the motor is rotating during learning control, making it difficult to determine the clutch's engagement start pressure accurately.
Innovation Solution
A vehicle drive device with a control system that includes a control device to manage the engagement and disengagement of clutches using hydraulic and electrical commands, utilizing mechanical and electric oil pumps to control oil pressure, and a learning control process that stabilizes the input shaft to prevent rotation during the learning phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If learning control is performed with the motor rotating during clutch engagement, then the engagement start pressure can be learned, but the input member rotates due to drag torque making it difficult to obtain accurate torque change data
Solution Approach 1:
The control device applies a counteracting torque to the motor in advance to prevent the input member from rotating due to drag torque. By generating a torque that opposes the drag torque before the clutch engagement learning begins, the system maintains the input member in a stable non-rotating state, enabling accurate measurement of torque changes during clutch engagement.
2Ease of operation
If the vehicle is at a complete stop with the speed change mechanism in P range or N range, then the engine connection clutch learning can be performed, but the same condition causes input member rotation during starting clutch learning
Solution Approach 1:
The control device acts as an intermediary by introducing a counteracting torque mechanism between the motor and the starting clutch. This intermediary action compensates for the drag torque effect that occurs during learning control in stationary conditions, allowing the starting clutch engagement start pressure to be learned accurately even when the vehicle is at a complete stop with the speed change mechanism in D range.
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
Enables accurate learning of the starting clutch's engagement start pressure by preventing input shaft rotation, ensuring precise clutch engagement control and enhancing vehicle responsiveness and fuel efficiency.
Implementation Method 1
a hydraulic control device (40) that supplies oil pressure to a hydraulic servo (90) of the starting clutch (WSC)
Implementation Method 2
a starting clutch (WSC) that connects and disconnects power transmission between the motor generator (MG) and the speed change mechanism (5), wherein the starting clutch (WSC) includes a friction engagement element (91)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A vehicle drive device includes: a rotating electrical machine; a speed change mechanism including an input member and an output member drivingly connected to wheels, and configured to change a speed ratio between the input member and the output member; a friction engagement device interposed between the rotating electrical machine and the input member and including a friction engagement element configured to connect and disconnect power transmission between the rotating electrical machine and the input member as an engagement pressure is supplied and discharged; and a control device that controls the rotating electrical machine and the friction engagement device. The control device performs learning control when the input member is held stationary and non-rotatable, the learning control being control in which the control device drives the rotating electrical machine while controlling the engagement pressure to an engagement start pressure at which the friction engagement element starts to engage, and learns the engagement start pressure based on a change in driving state of the rotating electrical machine at the time the friction engagement element starts to engage.