Electric Drivetrain Tribology Diagnosis via Electrical Idling
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Solution Overview
Problem
In motor vehicles with electric drive trains, distinguishing between electrical and mechanical losses is challenging, leading to inaccurate identification of wear in drive train components, especially due to factors like temperature and performance dependencies.
Innovation Solution
A method where the first drive machine is operated in electrical idling and coupled to the wheels, allowing for the measurement of mechanical losses without being affected by electrical losses, enabling more accurate determination of the tribological state by acquiring performance measures while the second drive machine maintains vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If consumption monitoring is used to estimate dissipation in the drive train, then energy loss can be detected, but electrical losses cannot be distinguished from mechanical losses
Solution Approach 1:
The drive train is divided into two separate drive machines (first and second drive machines), each capable of independently propelling the vehicle. This segmentation allows for separate performance measurements that can distinguish between electrical losses in one machine and mechanical losses in the other, enabling accurate wear identification.
Solution Approach 2:
The first drive machine operates in electrical idling mode while the second drive machine performs the actual driving function. The first drive machine acts as an intermediary that introduces controlled mechanical resistance without contributing electrical losses to the measurement, thereby isolating the mechanical loss component for accurate wear detection.
2Measurement precision
If performance measurement is taken during normal operation, then real-world conditions are captured, but electrical losses and temperature effects contaminate the wear measurement
Solution Approach 1:
The first drive machine periodically operates in electrical idling mode during normal vehicle operation. This periodic action creates distinct measurement phases where electrical losses are eliminated, allowing for clean tribological state determination while maintaining overall normal operation conditions.
Solution Approach 2:
The operational parameters of the first drive machine are changed to electrical idling mode (zero electrical output, mechanical coupling maintained). This parameter change eliminates electrical losses from the system while preserving mechanical connections, thereby isolating mechanical wear effects for accurate measurement.
3Measurement precision
If the first drive machine is electrically disconnected during measurement, then electrical losses are eliminated, but the mechanical connection to wheels must be maintained
Solution Approach 1:
The first drive machine's electrical connection is dynamically controlled - disconnected during measurement phases to eliminate electrical losses, and reconnectable during normal operation. This dynamic configuration allows the system to switch between measurement and operational modes while maintaining the mechanical connection to the wheels throughout.
Data Source
AI summary
A method for determination of state information, especially describing a tribological state of a drive train of a motor vehicle, wherein the drive train comprises an electric machine as a first drive machine and a second drive machine, wherein upon fulfillment of a diagnostic condition the first drive machine is operated in an electrical idling mode, in which it is electrically separated from all current sources and current sinks and coupled to at least one of the wheels of the motor vehicle, and during the operation of the first drive machine in the electrical idling mode a performance measure is acquired for the performance of the second drive machine, while at least one of the wheels of the motor vehicle is driven by the second drive machine, after which the state information is determined in dependence on the performance measure and given reference information.