Powertrain Drive Synchronization With Force Ramp-Down
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Solution Overview
Problem
Current drive train synchronization methods often result in jerky accelerations and excessive stress on the vehicle due to sudden mechanical decoupling during synchronization, particularly in low drive torque situations, which can be uncomfortable for occupants.
Innovation Solution
A method where the synchronization force is initially increased to approach the target speed and then continuously reduced before reaching the target speed, avoiding sudden torque changes and ensuring a smooth, jerk-free coupling of drive elements, utilizing a friction synchronization device and controlled by an electronic computing device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the synchronizing force is continuously applied to match rotational speeds, then the synchronization accuracy is improved, but jerky accelerations and excessive stress occur during mechanical decoupling
Solution Approach 1:
The synchronizing force is applied in two distinct temporal phases: a first period where the force increases to approach target speed, and a second period where the force is continuously reduced before reaching target speed. This periodic modulation of the synchronizing force eliminates sudden torque changes during mechanical decoupling, preventing jerky accelerations while maintaining synchronization accuracy.
Solution Approach 2:
The synchronizing force is continuously reduced during the second period before the rotational speed actually reaches the target speed. This preliminary reduction of force prepares the system for upcoming mechanical decoupling, preventing excessive stress and jerky movements that would occur if full synchronizing force were maintained until the moment of coupling.
2Loss of time
If the synchronizing force is increased to quickly match speeds, then the synchronization time is reduced, but disturbing torque on the wheel increases
Solution Approach 1:
The synchronizing force follows a two-period temporal pattern: initially increased to rapidly approach target speed (reducing synchronization time), then continuously reduced before reaching target speed (minimizing disturbing torque during decoupling). This periodic action resolves the contradiction between speed and torque disturbance.
Solution Approach 2:
The continuous reduction of synchronizing force during the second period acts as a cushioning measure before mechanical decoupling occurs. This preliminary force reduction prevents excessive disturbing torque from being generated, while the initial force increase ensures quick synchronization is achieved.
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 minimizes disturbing torque on the wheel, reducing jerky accelerations and achieving a comfortable, rotationally fixed coupling of drive elements, enhancing synchronization efficiency and comfort, especially in low drive torque conditions.
Implementation Method 1
an actuator exerts a synchronizing force on a synchronizing device, thereby adjusting the rotational speed of the first drive element around an axis of rotation to a target speed of the second drive element via the synchronizing device
Data Source
AI summary
The invention relates to a method for synchronizing a first drive element, which can be rotated about a rotational axis, with a second drive element, which rotates about the rotational axis at a target rotational speed (20), of a powertrain of a motor vehicle. A synchronization force (24) is exerted onto a synchronization device by means of an actuator, whereby a rotational speed (22) at which the first drive element is rotating about the rotational axis is adapted to the target rotational speed (20) by means of the synchronization device. The synchronization force (24) is increased during a first time period (s1) such that the rotational speed (22) approximates the target rotational speed (20). The synchronization force (24) is continuously reduced during a second time period (s2) following the first time period (s1) before the rotational speed (22) corresponds to the target rotational speed (20).