Electric Compressor Thermal Management via Automatic Gearbox Downshifting
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Solution Overview
Problem
Existing methods for managing electric compressors in vehicles with single combustion engines and automatic gearshift gearboxes are inadequate, as they fail to effectively prevent overheating and maintain performance without relying on hybrid engine configurations.
Innovation Solution
A method that involves using the electric compressor during a rolling phase, determining its temperature, modifying its power when reaching a maximum threshold, deactivating it by downshifting the gearbox ratio to increase engine speed and decrease torque, and reactivating it when the temperature drops below a second threshold, allowing gear ratio changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electric compressor is operated at high power to increase engine performance, then the engine torque increases, but the compressor temperature exceeds the maximum threshold causing damage
Solution Approach 1:
The patent applies dynamics by making the gearbox ratio adjustable and changeable in real-time based on compressor temperature conditions. The control system dynamically selects between different gear ratios (first ratio for normal operation, second ratio for cooling) to manage compressor temperature while maintaining engine performance capability.
Solution Approach 2:
The patent changes the physical parameter of gearbox ratio to control compressor operating conditions. By switching between a first gear ratio (when temperature is below threshold) and a second gear ratio (when temperature exceeds threshold), the system modifies engine operating parameters to prevent overheating while preserving performance.
2Temperature
If the compressor power is reduced to prevent overheating, then the compressor temperature is controlled, but the engine torque decreases affecting vehicle performance
Solution Approach 1:
The patent introduces the gearbox as an intermediary mechanism between the engine and the compressor system. By adjusting the gearbox ratio, it mediates the relationship between engine torque output and compressor power input, allowing temperature control without directly reducing compressor power or engine performance capability.
Solution Approach 2:
The system dynamically adjusts the gearbox ratio based on real-time temperature monitoring. When compressor temperature exceeds the maximum threshold, the control system switches to a second gear ratio that reduces compressor power input and enables cooling, then switches back to the first gear ratio when temperature decreases, maintaining performance when safe to operate.
3Productivity
If the compressor is continuously operated to maintain engine performance, then the engine torque is maximized, but the compressor overheats and requires shutdown for cooling
Solution Approach 1:
The patent implements a feedback control system that continuously monitors compressor temperature and adjusts the gearbox ratio accordingly. The control unit receives temperature data, compares it against the maximum threshold, and automatically selects appropriate gear ratios to maintain operation within safe temperature limits, ensuring both performance and reliability.
Solution Approach 2:
The system employs periodic temperature monitoring and cyclic gear ratio adjustments. When temperature rises above the threshold, the gearbox switches to a cooling-oriented ratio; when temperature drops below the threshold, it switches back to the performance-oriented ratio. This periodic action prevents continuous overheating while maintaining engine performance.
4Temperature
If the gearbox ratio is changed to control compressor temperature, then the compressor is protected from overheating, but the vehicle speed and engine operating point change
Solution Approach 1:
The patent changes the gearbox ratio parameter to control compressor temperature. By switching between different gear ratios, the system modifies the relationship between engine speed and vehicle speed, allowing temperature management while accepting transient changes in operating conditions that are naturally compensated by the automatic gearbox control.
Data Source
Figure 1~2
AI summary
The invention proposes a method for managing the use of an electric compressor of a motor vehicle engine associated with an automatic gear shifting gearbox. When the temperature of the compressor reaches a predefined maximum threshold, the gearbox ratio is downshifted. For the same driving power of the vehicle, the engine speed increases and the torque decreases depending on the change in the gearbox gear ratio. The compressor is deactivated so that it can cool.