Transaxle Disconnect Control for EV Cabin Heat Recovery
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Solution Overview
Problem
Heat generated by transaxles in four-wheel drive vehicles is not effectively utilized for heating in the vehicle cabin when the disconnection mechanism is activated, leading to inefficiencies in energy consumption.
Innovation Solution
A control device manages torque transmission using a disconnection mechanism in the transaxles, connecting it when heating is requested and disconnecting it when heat dissipation exceeds a predetermined value or lubricating oil temperature is low, ensuring heat is effectively utilized for cabin heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the disconnection mechanism is activated to improve energy consumption efficiency, then energy consumption efficiency is improved, but heat generation from the transaxle is reduced
Solution Approach 1:
The disconnection mechanism dynamically switches between connected and disconnected states based on heating requirements. When cabin heating is needed, the mechanism connects to enable heat generation; when heating is not needed, it disconnects to improve energy efficiency. This dynamic adaptation resolves the contradiction by making the system's energy consumption and heat generation adjustable according to actual needs.
2Use of energy by moving object
If the disconnection mechanism is disconnected to suppress transaxle rotation, then energy consumption efficiency is improved, but heat utilization for cabin heating is reduced
Solution Approach 1:
The control device dynamically adjusts the disconnection mechanism's state based on heating requests. When heating is required, the mechanism is connected to generate and utilize heat; when heating is not required, it disconnects to improve energy efficiency. This dynamic control enables the system to adapt to different operational conditions and resolve the contradiction between energy efficiency and heat utilization.
3Temperature
If the disconnection mechanism is connected to generate heat, then heat generation is increased, but energy consumption efficiency is reduced
Solution Approach 1:
The control device uses feedback from heating requests to control the disconnection mechanism's state. When heating is needed, the mechanism connects to generate heat; when heating is not needed, it disconnects to conserve energy. This feedback-based control ensures that heat generation occurs only when necessary, resolving the contradiction between heat generation and energy consumption efficiency.
4Use of energy by moving object
If the disconnection mechanism is maintained in disconnected state, then energy consumption efficiency is improved, but heat dissipation to atmosphere increases
Solution Approach 1:
The control device monitors heating requests and adjusts the disconnection mechanism accordingly. When heating is needed, the mechanism connects to capture and utilize heat; when heating is not needed, it disconnects to improve energy efficiency. This feedback control prevents unnecessary heat dissipation by connecting the mechanism only when heat utilization is required, resolving the contradiction between energy efficiency and heat loss.
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
The solution allows for efficient utilization of transaxle heat for cabin heating while maintaining energy efficiency by connecting the disconnection mechanism during heating requests and optimizing lubricating oil temperature.
Implementation Method 1
a disconnection mechanism that connects and disconnects torque transmission
Implementation Method 2
heat generated by the transaxle that transmits a drive force of a drive motor (motor generator) to wheels
Implementation Method 3
heat (waste heat) generated in a transaxle that transmits a drive force
Implementation Method 4
heat management device that utilizes heat generated by the front wheel-side transaxle and heat generated by the rear wheel-side transaxle for the heating
Data Source
AI summary
The vehicle is a four-wheel drive vehicle based on a front-wheel drive. The front wheel-side transaxle includes a front wheel motor, a reduction gear, and a differential gear, and transmits a driving force of the front wheel motor to the front wheels. The front wheel-side transaxle includes a disconnection mechanism. The air conditioner uses the heat generated in the front wheel-side transaxle for heating the vehicle cabin. When there is a heating request and the disconnection mechanism is disconnected, the control ECU makes a connection request for the disconnection mechanism if the first condition is not satisfied. Heat generated by the front wheel-side transaxle can be used to heat the vehicle cabin.