Estimating Rotating Electrical Machine Temperature After Engine Shutdown
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Solution Overview
Problem
In vehicles with automatic stop-start technology, the temperature information retrieved from rotating electrical machines after engine shutdown is often incorrect due to the lack of memory in these machines, leading to suboptimal performance during restarts.
Innovation Solution
A motor vehicle system where a temperature sensor supplies the engine computer with the rotating electrical machine's temperature value before shutdown, allowing the engine computer to estimate and provide a reliable temperature value upon restart, using duration of extinction and ambient temperature data, and establishing a thermal decay curve to calculate an accurate temperature for the rotating electrical machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the rotating electrical machine lacks memory components, then the device complexity is reduced and manufacturing cost is lowered, but the temperature information accuracy deteriorates after engine shutdown
Solution Approach 1:
The engine computer serves as an intermediary that stores temperature information on behalf of the rotating electrical machine. When the engine shuts down, the current temperature is saved in the engine computer's memory. Upon restart, the engine computer estimates the temperature based on the stored value and time elapsed, providing accurate temperature data without requiring memory components in the rotating electrical machine itself.
Solution Approach 2:
The system performs preliminary action by storing the temperature value before engine shutdown occurs. The engine computer captures and preserves the temperature information in advance, so that when the engine restarts, this pre-stored data can be used as a basis for temperature estimation, eliminating the need for the rotating machine to retain memory.
2Measurement precision
If the engine computer estimates temperature using thermal decay models, then the temperature accuracy upon restart is improved, but the computational complexity increases
Solution Approach 1:
The system changes parameters by using a simplified thermal decay model that considers only the most significant factors: initial temperature, time elapsed since shutdown, and ambient temperature. This approach provides sufficiently accurate temperature estimation without requiring complex multi-parameter thermal models, thus balancing accuracy with computational simplicity.
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
Ensures accurate temperature estimation for the rotating electrical machine upon restart, enhancing performance and reliability without the need for additional memory in the machine, thus improving the efficiency and accuracy of engine restarts.
Implementation Method 1
a sensor measuring a temperature of the rotating electrical machine
Implementation Method 2
a rotating electrical machine, which rotating electrical machine is a machine for driving the combustion engine on start-up
Data Source
Figure 1
AI summary
The invention relates to a motor vehicle in which, on switching off the internal combustion engine (1.2,3.4), a temperature sensor (3) supplies an engine control unit (4) with a temperature value of a rotating electrical machine (1) and the engine control unit (4) estimates a value of the temperature of the rotating electric machine (1) attained by the rotating electrical machine (1) on a restart of the internal combustion engine (1.2,3.4).