Hybrid Drive Electric Machine Decoupling Control
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Solution Overview
Problem
Existing hybrid drive systems for vehicles face inefficiencies due to the parasitic drag caused by electric machines, which consume energy even when not needed, leading to suboptimal energy balance and increased operational costs.
Innovation Solution
A method is introduced to determine and compare two types of energy requirements: the energy needed to drag the electric machine by the internal combustion engine and the energy required for decoupling and subsequent recoupling. The electric machine is only decoupled when the energy for decoupling and recoupling is lower, optimizing the energy balance by considering factors like driver requests, vehicle speed, and storage device charge state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electric machine is continuously coupled to the internal combustion engine, then the vehicle can utilize electric torque assistance, but parasitic drag increases energy consumption
Solution Approach 1:
The patent applies dynamics by making the coupling state of the electric machine variable rather than fixed. The electric machine is dynamically coupled or decoupled based on real-time operating conditions including driver torque requests, vehicle speed, and charge state of the storage device. This dynamic adjustment allows the system to optimize between torque assistance and parasitic drag losses.
Solution Approach 2:
The patent changes the operational parameters of the hybrid drive system by introducing conditional coupling/decoupling based on multiple parameters: driver torque request thresholds, vehicle speed ranges, and charge state levels. These parameter changes enable the system to transition between different operational modes (coupled for torque assistance, decoupled to reduce parasitic drag) based on the current state of the system.
2Loss of energy
If the electric machine is decoupled to reduce parasitic drag, then energy consumption decreases, but coupling and decoupling operations consume additional energy
Solution Approach 1:
The patent applies preliminary action by evaluating the energy balance before executing coupling or decoupling operations. The control device calculates the expected energy savings from reduced parasitic drag and compares it against the energy required for coupling/decoupling operations. This preliminary energy balance assessment ensures that decoupling operations are only performed when they will result in net energy savings.
Solution Approach 2:
The patent implements feedback by continuously monitoring the charge state of the energy storage device and using this information to determine optimal coupling/decoupling timing. The system feedback loop ensures that decoupling operations are coordinated with charging opportunities, maximizing energy efficiency while maintaining adequate charge levels for when coupling is needed.
3Loss of energy
If the electric machine is frequently coupled and decoupled to optimize energy balance, then parasitic drag losses are reduced, but the complexity of control increases
Solution Approach 1:
The patent applies segmentation by dividing the control logic into distinct decision modules: torque request evaluation, vehicle speed assessment, charge state monitoring, and energy balance calculation. Each module handles a specific aspect of the coupling/decoupling decision, making the overall control system more manageable and easier to implement despite the complexity of optimizing multiple parameters simultaneously.
Data Source
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AI summary
The invention relates to a method for operating a drive apparatus (1) of a vehicle (2), which drive device comprises at least one internal combustion engine (3) and at least one electric machine (4) for generating a common torque, wherein the electric machine (4) can be uncoupled and coupled as desired, comprising the following steps: - determining a first power (E1) which is expected to be required in order to drag the electric machine (4) by means of the internal combustion engine (3), - determining a second power (E2) which is expected to be required to uncouple and subsequently couple the electric machine (4), - comparing the first power (E1) with the second power (E2), wherein the electric machine (4) is uncoupled only when the second power (E2) is less than the first power (E1). Furthermore, the invention relates to a device for operating a drive apparatus of a vehicle. In addition, the invention relates to a computer program product.