Hybrid Drive Train Rotational Imbalance Reduction
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Solution Overview
Problem
Existing systems for reducing rotational imbalances in hybrid vehicle drive trains are limited in their ability to address a wide frequency spectrum, primarily absorbing low-frequency interferences and failing to effectively mitigate oscillations in the audible range.
Innovation Solution
The implementation of an adaptive feed forward control system that uses an electric machine to generate a torque inverse to the rotational imbalance, leveraging detected rotational speeds and frequency vectors to absorb or reduce oscillations across a broader frequency range, including audible frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive absorption elements like dual mass flywheel are used, then low-frequency rotational imbalances are absorbed, but the system cannot cover the entire frequency spectrum including audible range oscillations
Solution Approach 1:
The patent replaces passive mechanical absorption elements (dual mass flywheel) with an active electromagnetic system consisting of an electric machine and control unit. This substitution enables the system to actively generate compensating torques across a wide frequency spectrum including audible range oscillations, rather than passively absorbing only low-frequency imbalances.
Solution Approach 2:
The system transitions from static passive absorption to dynamic active compensation. The control unit continuously processes sensor signals and adjusts the electric machine's torque output in real-time, enabling the system to adapt to varying operating conditions and cover the entire frequency spectrum dynamically.
2Reliability
If classic automatic control is used to activate the electric machine, then low-frequency interferences up to approximately 15 Hz are absorbed, but oscillations in the audible range cannot be reduced
Solution Approach 1:
The system employs sensor feedback to detect rotational speeds, torques, and longitudinal accelerations, which are processed and compared with reference values by the control unit. This feedback mechanism enables the electric machine to generate compensating torques that actively reduce both low-frequency interferences and audible range oscillations.
Solution Approach 2:
The control system dynamically adjusts the electric machine's torque parameters based on real-time sensor data and reference value comparisons. This parameter adaptation enables the system to effectively reduce oscillations across the entire frequency spectrum, including the audible range, rather than being limited to low-frequency interferences.
3Extent of automation
If sensors and actuators with signal propagation times are used, then active compensation is achieved, but the useful bandwidth is limited with cut-off frequencies between 10 Hz and 20 Hz
Solution Approach 1:
The system uses pre-stored reference values for torques and longitudinal accelerations at various engine speeds. The control unit compares sensor signals with these reference values and triggers corresponding actuators based on detected deviations, enabling faster response by anticipating required compensation actions rather than reacting purely to current error signals.
Solution Approach 2:
The patent replaces traditional mechanical actuators with an electric machine that responds more rapidly to control signals. This substitution eliminates the inertia and mechanical lag associated with traditional actuators, significantly expanding the useful bandwidth beyond the 10-20 Hz cut-off frequency limitation.
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 enhances the quiet operation of internal-combustion engines, dampens unintended oscillations, and potentially eliminates the need for passive absorption elements like dual-mass flywheels, while improving noise acoustics and ensuring stable system performance.
Implementation Method 1
The actuation signal represents a desired torque to be generated by the electric machine, so that the electrical machine outputs a torque that is at least approximately inverse with respect to the rotational imbalance to the crankshaft
Data Source
AI summary
A system and a method for reducing a rotational imbalance of a drive train of a hybrid vehicle are provided. The drive train includes an internal-combustion engine, an electric machine, and a crankshaft. A reduction or nullification of the rotational imbalance takes place by actuating the electric machine. The actuation is implemented as an adaptive feed forward control, which provides an actuation signal for the electric machine. The actuation signal represents a desired torque to be generated by the electric machine, so that the electric machine outputs a torque that is at least approximately inverse with respect to the rotational imbalance to the crankshaft for the superimposition of the torque generated by the internal-combustion engine.