Hybrid Vehicle Drive Torque Control via Precomputed Target Values
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Solution Overview
Problem
In hybrid vehicles, it is challenging to predict and control the torque produced by the second electric machine when operating in generator mode, leading to noticeable torque fluctuations and difficulties in switching between operating modes, which affects the driver's experience and the battery's loading.
Innovation Solution
A method for controlling the vehicle's drive system that computes a precontrol or target torque for the second electric machine and the combustion engine based on drive torque and machine parameters, allowing for open-loop or closed-loop control of each machine individually, enabling faster and more accurate torque adjustments and reducing noticeable torque changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the second electric machine is operated in generator mode under closed-loop control to supply electrical energy, then the battery loading is reduced, but the torque produced becomes difficult to predict and fluctuations occur
Solution Approach 1:
The patent applies preliminary action by pre-calculating the target torque for the second electric machine based on the drive torque request and machine parameters before actual operation. This pre-computation allows the control system to anticipate and prepare the appropriate torque value, eliminating prediction difficulties during real-time generator mode operation and reducing torque fluctuations.
2Manufacturing precision
If the internal combustion engine is adjusted to provide target torque for the hybrid axle, then the torque requirement is met, but the engine cannot respond with sufficient dynamics causing noticeable fluctuations
Solution Approach 1:
The control system performs preliminary computation of the target torque for the internal combustion engine based on the drive torque request and current operating conditions. This pre-calculation allows the engine control to be prepared in advance, enabling faster response without sacrificing torque precision, as the target value is already determined before the adjustment is needed.
3Adaptability or versatility
If switching between operating modes is implemented, then operational flexibility is achieved, but control stability deteriorates due to difficulty in mode transition
Solution Approach 1:
The patent implements preliminary determination of target torques for different operating modes based on current drive conditions and machine parameters. By pre-calculating the appropriate target values before mode transitions, the system ensures smooth and stable switching between modes, eliminating control instability that would otherwise occur during transitions.
Solution Approach 2:
The control system continuously monitors actual torque production and compares it with the pre-computed target torque, using feedback to make real-time adjustments. This feedback mechanism ensures that during mode transitions, the system can detect deviations and correct them, maintaining control stability while preserving operational flexibility.
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 significantly reduces torque fluctuations and improves control stability, allowing for faster reaction to changes and minimizing the capacity of the energy storage device, thereby enhancing the driving experience and reducing battery loading.
Implementation Method 1
the first electric machine as a function of the drive torque
Implementation Method 2
a second electric machine which is coupled to at least one combustion engine supplies electrical energy for the purpose of driving the first axle by way of the first electric machine
Data Source
AI summary
A method for controlling a drive of a vehicle with at least one first axle having at least one mounted wheel. A drive torque is specified by a driver of the vehicle, and the first axle is driven by means of a first electric machine dependent on the drive torque. A second electric machine which is coupled to an internal combustion engine provides electrical energy for driving the first axle with the first electric machine. A respective control or target torque assigned to the second electric machine and the internal combustion engine is computed while taking into consideration the drive torque and machine parameters of at least the second electric machine. The second electric machine and the internal combustion engine are each regulated with respect to the assigned control torque or with respect to the assigned target torque.