Hybrid Vehicle Controller Torque Pulsation Damping
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Solution Overview
Problem
Existing technologies fail to sufficiently reduce vibration noise in hybrid vehicles due to torque pulsation from internal combustion engines, as the pulsation compensation torque from electric motors is often absorbed by looseness in the power transmission path, leading to incomplete transmission to the drive shaft.
Innovation Solution
A controller for hybrid vehicles that uses a combination of pulsation compensation torque and pressing torque to ensure effective damping of drive shaft vibrations, where the pulsation compensation torque is adjusted based on the electric motor's torque output, and the pressing torque is applied to fill looseness between the electric motor and drive shaft, thereby ensuring the pulsation compensation torque is transmitted effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If pulsation compensation torque is supplied from the electric motor to cancel torque pulsation of the internal combustion engine, then torque pulsation can be calculationally cancelled, but the pulsation torque is absorbed by looseness in the power transmission path and is not sufficiently transmitted to the drive shaft, resulting in insufficient vibration noise reduction
Solution Approach 1:
The controller applies pressing torque to the electric motor before supplying pulsation compensation torque, ensuring that the power transmission path is pre-compressed and free of looseness. This preliminary action guarantees that subsequent pulsation torque is effectively transmitted to the drive shaft without being absorbed by backlash or gaps in the transmission components.
Solution Approach 2:
The pressing torque acts as an intermediary force that eliminates the harmful looseness in the power transmission path between the electric motor and drive shaft. By maintaining continuous contact and compression in the transmission components, the pressing torque ensures reliable torque transmission while the pulsation compensation torque performs its vibration cancellation function.
2Measurement precision
If PWM control mode is used to achieve high controllability and accurate torque response for pulsation compensation, then torque control accuracy improves, but electric power consumption increases
Solution Approach 1:
The controller dynamically switches between PWM control mode and rectangular wave control mode based on the operating conditions and torque requirements. PWM mode is used when high torque control accuracy is needed for effective pulsation compensation, while rectangular wave mode is used when lower precision is acceptable, thereby optimizing the balance between control accuracy and energy efficiency.
Solution Approach 2:
The control strategy changes the operating parameters of the electric motor by selecting different control modes (PWM vs. rectangular wave) and adjusting the pressing torque magnitude based on looseness detection. This parameter adaptation allows the system to achieve sufficient torque transmission reliability while minimizing unnecessary energy consumption from high-precision control when not required.
Data Source
AI summary
A controller controls an electric motor such that a pulsation compensation torque corresponding to a pulsation component of a torque of an internal combustion engine, which appears in a drive shaft, is supplied to the drive shaft as a damping torque for suppressing vibrations of a hybrid vehicle. A determination is made as to whether a torque of the electric motor, excluding the pulsation compensation torque, is smaller than a predetermined value. When it is determined that the torque excluding the pulsation compensation torque is smaller than the predetermined value, the controller selects one mode having a highest energy efficiency of the hybrid vehicle from among a plurality of modes, and controls the internal combustion engine and the electric motor based on the selected mode.