Series Hybrid Regenerative Torque Control for Floor Vibration
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Solution Overview
Problem
Series hybrid vehicles experience increased floor vibration due to the resonant rotational speed region being offset towards high-rotational-speeds when the drive motor generates torque, potentially leading to resonance and excessive vibration during internal combustion engine operation.
Innovation Solution
A control method for series hybrid vehicles that restricts the upper limit of regenerative torque generated by the drive motor, ensuring the floor vibration generation region remains below the internal combustion engine's rotational speed, thereby preventing resonance and excessive vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the drive motor generates torque in a series hybrid vehicle, then the engine mount spring constant increases and the resonant rotational speed region offsets toward high-rotational-speed side, but this causes floor vibration to increase when the engine operates at low rotational speeds
Solution Approach 1:
The control device applies preliminary anti-action by detecting when the engine rotational speed is in the low-speed region and the drive motor is generating torque, then actively controlling the drive motor to generate counter torque that offsets the resonant vibration before it can significantly affect the floor. This preventive approach addresses the vibration issue at its source rather than reacting to it after occurrence.
Solution Approach 2:
The control device changes the operational parameters of the drive motor by adjusting the torque output based on engine rotational speed conditions. When the engine operates at low speeds and the drive motor generates torque that would cause resonance, the control device modifies the drive motor's torque parameter to generate counter torque, thereby changing the vibrational characteristics and suppressing floor vibration.
2Productivity
If the upper limit of engine rotational speed is restricted to promote catalyst warm-up, then the engine can operate at lower speeds for fuel efficiency, but the engine rotational speed may enter the resonant rotational speed region causing excessive floor vibration
Solution Approach 1:
The control device implements feedback control by continuously monitoring the engine rotational speed and the torque generation state of the drive motor. When the system detects that the engine speed is in the low-speed region and the drive motor is generating torque that would cause resonance, the control device provides feedback control signals to adjust the drive motor's torque output, thereby preventing floor vibration while maintaining the restricted engine speed range for catalyst warm-up.
Solution Approach 2:
The control device applies dynamics by making the drive motor torque adaptive rather than fixed. The drive motor dynamically adjusts its torque output based on real-time engine operational conditions, particularly when operating in the restricted low-speed range. This dynamic adjustment allows the system to maintain catalyst warm-up efficiency while avoiding resonant vibrations through real-time torque modulation.
3Loss of energy
If the drive motor generates regenerative torque during deceleration, then energy recovery is improved, but the resonant rotational speed region may overlap with the engine operational range causing floor vibration
Solution Approach 1:
The control device applies preliminary anti-action during deceleration by detecting when regenerative torque generation would cause the resonant rotational speed region to overlap with the engine operational range. Before significant vibration occurs, the control device adjusts the regenerative torque to avoid the resonant frequency range, thereby preventing floor vibration while still recovering energy during deceleration.
Solution Approach 2:
The control device changes the regenerative torque parameter dynamically during deceleration based on engine rotational speed conditions. When the engine speed is in the low-speed region, the control device adjusts the regenerative torque parameter to ensure that the resonant rotational speed region does not overlap with the engine operational range, thereby suppressing floor vibration while maintaining energy recovery efficiency.
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 control method effectively suppresses floor vibration by maintaining the resonant rotational speed region below the engine's operational range, even when the upper limit of the engine rotational speed is restricted, ensuring safe and comfortable vehicle operation.
Implementation Method 1
causes an electric power generation motor to generate electric power, the electric power generation motor being driven by motive power of the internal combustion engine
Implementation Method 2
actuates the drive motor by using the generated electric power and drives drive wheels
Implementation Method 3
causes the drive motor to generate regenerative torque that corresponds to a deceleration request during deceleration
Data Source
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AI summary
A control method for controlling a series hybrid vehicle in which a drive motor and an internal combustion engine are supported in a vehicle body via a plurality of mount members in an integrated state, the method being one in which a controller: causes an electric power generation motor to generate electric power, the electric power generation motor being driven by motive power of the internal combustion engine; actuates the drive motor by using the generated electric power and drives drive wheels; and causes the drive motor to generate regenerative torque that corresponds to a deceleration request during deceleration, wherein the upper limit of the regenerative torque is restricted to a magnitude at which the engine rotational speed of the internal combustion engine during generation of electric power is higher than a floor vibration generation region established based on of the upper limit of the regenerative torque, said region being an engine rotational speed region in which resonance of a vehicle body floor is produced, such that the regenerative torque is generated by the drive motor.