Hybrid Vehicle Relay Opening After Clutch Release and Negative Torque
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Solution Overview
Problem
In hybrid vehicle systems, the K0 clutch release process can lead to a delay in reducing the motor generator's rotational speed, increasing the likelihood of electric arcs due to counter electromotive force, which affects relay durability and efficiency.
Innovation Solution
A hybrid vehicle controller is introduced that executes a negative torque application process to lower the motor generator's rotational speed after releasing the K0 clutch, and opens the relay when the speed falls below a threshold, thereby reducing the time required for the motor generator to slow down and minimizing the risk of electric arcs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the relay is opened after the K0 clutch is released, then the motor generator can be disconnected from the engine, but the rotational speed of the motor generator remains high causing electric arcs and reducing relay durability
Solution Approach 1:
The control device applies negative torque to the motor generator before opening the relay to reduce its rotational speed. This preliminary action of speed reduction ensures that when the relay is subsequently opened, the motor generator's rotational speed is sufficiently low, preventing electric arcs and protecting the relay from damage while maintaining the disconnection benefit.
2Loss of time
If the relay is opened immediately after K0 clutch release, then the system response is faster, but the high rotational speed causes counter electromotive force and electric arcs
Solution Approach 1:
The control device rapidly reduces the motor generator's rotational speed by applying negative torque, quickly bringing it through the high-speed dangerous zone. This allows the relay to be opened promptly once the speed threshold is reached, minimizing the time the system spends in a harmful state while preventing electric arcs.
3Reliability
If negative torque is applied to reduce motor generator speed, then relay durability is improved, but the control system complexity increases
Solution Approach 1:
The control device monitors the motor generator's rotational speed and uses this feedback to determine when to apply negative torque and when to open the relay. By continuously monitoring speed and comparing it against threshold values, the system automatically adjusts its control actions, achieving reliable relay operation through a relatively simple feedback-based control logic.
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
This approach reduces the time for the motor generator to reach a lower rotational speed, suppresses reverse rotation that could damage components, and adjusts the negative torque based on AT oil temperature to prevent electric arcs, enhancing the durability and efficiency of the hybrid vehicle system.
Implementation Method 1
the more likely it is that an electric arc will occur due to the counter electromotive force
Implementation Method 2
a negative torque application process that applies a negative torque, which is a torque for lowering a rotational speed of the motor generator, to the motor generator
Data Source
AI summary
A hybrid vehicle controller for controlling a hybrid vehicle including a hybrid system is provided. The hybrid system includes an engine, a motor generator, a battery configured to supply power with the motor generator, a clutch configured to connect the engine to the motor generator, and a relay configured to connect the motor generator to the battery. The hybrid vehicle controller includes processing circuitry. The processing circuitry is configured to execute, when an operation requesting opening of the relay is performed, a process that releases the clutch, a negative torque application process that applies a negative torque, which is a torque for lowering a rotational speed of the motor generator, to the motor generator, after releasing the clutch, and a process that releases the relay when the rotational speed of the motor generator becomes less than a threshold.