Hybrid Lock-Up Clutch Slip Control for Comfortable Decoupling
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Solution Overview
Problem
Existing methods for operating a parallel hybrid drive train struggle to decouple the lock-up clutch quickly and comfortably, leading to potential discomfort and inefficiencies during the start-up of an internal combustion engine by an electric motor.
Innovation Solution
The method involves bringing the lock-up clutch into slip when the slip reaches a threshold, setting a target rotational speed for the electric motor, and adjusting it to that speed to facilitate rapid and comfortable decoupling, with additional control mechanisms to manage torque and rotational speed changes to maintain comfort and prevent disruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lock-up clutch is decoupled using the prior art method with rotational speed control of the electric motor, then comfort is maintained during start-up, but the decoupling time is extended
Solution Approach 1:
The lock-up clutch is brought into slip before the rotational speed control of the electric motor begins. This preliminary action prepares the clutch for decoupling by establishing the necessary slip condition in advance, allowing the subsequent speed control to proceed more quickly while maintaining comfort.
Solution Approach 2:
The system dynamically adjusts the operational state of the lock-up clutch during the decoupling process. The clutch transitions from a closed state to a slip state, and the electric motor's rotational speed is dynamically controlled to achieve the target speed, enabling both rapid decoupling and comfort maintenance.
2Productivity
If the lock-up clutch is brought into slip earlier to reduce decoupling time, then decoupling speed increases, but comfort may be compromised
Solution Approach 1:
The control system continuously monitors the slip condition of the lock-up clutch and adjusts the electric motor's rotational speed accordingly. This feedback mechanism ensures that the clutch remains in the optimal slip state for rapid decoupling while preventing excessive slip that would compromise comfort.
Solution Approach 2:
The system changes the operational parameters of the lock-up clutch and electric motor in a coordinated manner. The clutch slip threshold and the electric motor's target rotational speed are adjusted as controlled parameters to achieve the optimal balance between decoupling speed and comfort.
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 allows for faster and more comfortable decoupling of the lock-up clutch, ensuring smooth start-up of the internal combustion engine while maintaining control over torque and rotational speed, thus enhancing the overall operational efficiency and comfort of the drive train.
Implementation Method 1
a lock-up clutch (6B) connected parallel to the converter (6A)
Implementation Method 2
a hydrodynamic start-up element with a converter (6A) and a lock-up clutch (6B)
Data Source
AI summary
A method for operating a drive train of a motor vehicle is provided, the drive train featuring a first drive assembly formed as an internal combustion engine a second drive assembly formed as an electric motor, a start-up element and a transmission). The start-up element features a converter and a lock-up clutch and is connected between the electric motor and the transmission. The electric motor is connected between the internal combustion engine and the start-up element. If a decoupling of the lock-up clutch is requested, the lock-up clutch of the start-up element is initially brought into slip. If the slip at the lock-up clutch of the start-up element reaches a threshold or is greater than the threshold, a target rotational speed is subsequently predetermined for the electric motor and the rotational speed of the electric motor is adjusted to such target rotational speed.