Drive Unit Slope Start Control via Torque Converter
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Solution Overview
Problem
Electric vehicles tend to move backward when starting on a slope if the braking operation is released, due to the lack of control over torque output during braking release.
Innovation Solution
A drive unit incorporating an electric motor, torque converter, brake sensor, and controller that maintains motor rotation during vehicle stoppage on slopes, allowing smooth starting without backward movement by controlling torque output based on braking operation and accelerator input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction braking and regenerative braking are used to reduce vehicle velocity, then braking control is achieved, but the vehicle moves backward when starting on a slope after braking release
Solution Approach 1:
The controller activates the electric motor before the braking operation is fully released, generating torque in advance to counteract the gravitational force on the slope. This preliminary action ensures that when the brake is released, the vehicle has sufficient driving force to move forward immediately without rolling backward.
Solution Approach 2:
The controller detects the braking operation amount and applies opposing torque from the electric motor to counteract the backward rolling tendency caused by gravity on the slope. This anti-action is applied in advance based on the detected braking state, preventing the harmful backward movement before it occurs.
2Use of energy by moving object
If the vehicle stops on a slope without maintaining motor rotation, then energy consumption is reduced, but the vehicle cannot smoothly start without moving backward
Solution Approach 1:
The controller dynamically adjusts the motor rotation state based on real-time detection of braking operation amount and vehicle velocity. The motor rotates and generates torque when braking is detected on a slope, and stops rotating when not needed, creating a dynamic response that balances energy efficiency with starting performance.
Solution Approach 2:
The controller continuously detects the braking operation amount and vehicle velocity, using this feedback information to determine when to activate or deactivate the electric motor. This closed-loop control ensures the motor operates only when necessary for preventing backward movement, optimizing energy consumption while maintaining starting smoothness.
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
Prevents backward movement of electric vehicles when starting on slopes by maintaining motor rotation and adjusting torque output, ensuring smooth acceleration without reversing.
Implementation Method 1
a torque converter, which is a device to which a torque outputted from the motor is inputted
Data Source
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AI summary
It is intended to prevent a vehicle from moving backward in starting movement on a slope. A drive unit (100) includes a motor (2), a torque converter (3), a brake sensor (81) and a controller (80). The torque converter (3) is a device to which a torque, outputted from the motor (2), is inputted. The brake sensor (81) detects a braking operation amount. The controller (80) executes a first control of controlling the torque outputted from the motor (2) based on the braking operation amount.