Hybrid Drive Torque Excitation Control for Torsional Damping
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Solution Overview
Problem
Existing hybrid drive systems for motor vehicles face challenges in maintaining comfort and dynamics while reducing consumption, particularly in transitioning from electric to hybrid or combustion engine modes, where torsional vibrations can cause discomfort and inefficiency.
Innovation Solution
A control device and method for a hybrid drive system that includes a combustion engine, an electric machine, a torsional vibration stabilizer, and an electronic control unit. The electronic control unit simulates cylinder-ignition-dependent torque excitations during electric driving to maintain torsional vibration damping, and uses the electric machine to replace missing torque excitations during partial cylinder deactivation, ensuring consistent damping across different engine modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the combustion engine is switched off during electric driving mode, then energy consumption is reduced, but torsional vibration damping is lost causing comfort impairments
Solution Approach 1:
The electric machine generates simulated torque excitations that copy the cylinder-ignition-dependent torque patterns of the switched-off combustion engine. This creates artificial torque fluctuations that match the original engine's excitation characteristics, allowing the torsional vibration stabilizer to maintain its damping function during electric driving mode.
Solution Approach 2:
The electric machine acts as an intermediary between the switched-off combustion engine and the torsional vibration stabilizer. By generating simulated torque excitations, it mediates the connection and maintains the functional relationship needed for vibration damping without requiring the actual combustion engine to be running.
2Use of energy by moving object
If cylinders are deactivated to reduce consumption, then energy efficiency improves, but torsional vibration damping deteriorates
Solution Approach 1:
The electric machine copies the torque excitations of the deactivated cylinders by generating corresponding torque fluctuations. This maintains the complete set of excitation patterns that the torsional vibration stabilizer needs to function effectively, even when actual cylinder combustion is reduced for efficiency.
Solution Approach 2:
The system changes the operational parameters of the electric machine to generate specific torque excitations that match the frequency and amplitude characteristics of the deactivated cylinders. This parameter adjustment ensures the torsional vibration stabilizer receives the correct excitation patterns for effective damping.
3Reliability
If the torsional vibration stabilizer is optimized for full cylinder mode, then vibration damping is maximized in combustion mode, but damping performance decreases in electric mode
Solution Approach 1:
The electric machine serves multiple functions: it provides propulsion torque during electric driving mode and simultaneously generates simulated torque excitations for torsional vibration damping. This multi-functionality allows the torsional vibration stabilizer to maintain optimized damping performance across different drive modes without requiring mode-specific hardware configurations.
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
The solution effectively maintains comfort and dynamics by ensuring consistent torsional vibration damping across different drive modes, reducing energy expenditure during transitions, and minimizing drag torque on the combustion engine, thereby enhancing overall vehicle performance and efficiency.
Implementation Method 1
the electric machine at least almost identically simulates one or more of the cylinder-ignition-dependent torque excitations of the switched-off combustion engine by means of electric motor generated torque excitations
Implementation Method 2
the torsional vibration stabilizer is designed for optimum vibration damping with the full number of cylinders of the combustion engine in combustion engine mode
Implementation Method 3
a property of a torsional vibration damper (in particular a rotary mass oscillator) is that oscillating damping masses are functionally matched to the cylinder number-specific excitations of the combustion engine
Data Source
AI summary
A hybrid drive includes an internal combustion engine, an electrical machine, at least one torsional vibration damper, and an electronic control unit. The torsional vibration damper is designed for optimal vibration damping during operation of the internal combustion engine with the full number of cylinders of the internal combustion engine switched-on in internal-combustion-engine mode. The electronic control unit is further designed such that, in purely electric-motor mode where no cylinders are switched on, the electrical machine simulates the cylinder-ignition-dependent torque excitations of the switched-off internal combustion engine substantially identically until the internal combustion engine is switched back on.