Hybrid Vehicle Generator Torque Control for Rattling Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In hybrid vehicles, rattling noise occurs due to gear collisions when motor torque is near 0 Nm, and existing methods to reduce this noise by increasing engine rotation speed lead to increased engine noise, making it difficult to control torque in motoring states where engine torque is affected by friction and torque pulsation.
Innovation Solution
A control method for hybrid vehicles that uses rotation speed control of the electric generator, involving a model matching compensator and disturbance observer to calculate a torque command value based on rotation speed command and detection values, reducing rattling noise without increasing engine rotation speed by filtering and compensating for disturbance torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If engine rotation speed is increased to reduce rattling noise, then rattling noise is reduced, but engine noise increases
Solution Approach 1:
The patent replaces mechanical torque control of the engine with electrical torque control of the electric generator. By controlling the electric generator's torque and rotation speed through electrical means rather than mechanically increasing engine speed, the system reduces rattling noise without increasing engine noise, as the engine operates at constant speed while the electric generator absorbs or provides torque as needed.
Solution Approach 2:
The patent changes the control parameter from engine rotation speed to electric generator rotation speed. Instead of varying engine speed to control rattling noise, the system maintains constant engine speed and varies the electric generator's rotation speed parameter to achieve the same noise reduction effect without the adverse side effect of increased engine noise.
2Object-affected harmful factors
If engine rotation speed is increased to reduce rattling noise, then gear collision noise is reduced, but fuel consumption increases
Solution Approach 1:
The patent substitutes mechanical engine speed variation with electrical control of the electric generator. The electric generator can provide or absorb torque independently of engine speed, allowing rattling noise reduction through electrical torque management rather than increasing engine speed, thereby avoiding additional fuel consumption.
Solution Approach 2:
The patent converts the electric generator into a tool for noise reduction. By utilizing the electric generator's ability to absorb torque and control rotation speed, the system turns what could be a source of noise (motor-generat or interaction) into a solution that reduces rattling noise without the penalty of increased fuel consumption associated with higher engine speeds.
3Object-affected harmful factors
If torque control is attempted in motoring state, then rattling noise can be reduced, but control is impossible due to friction and torque pulsation
Solution Approach 1:
The patent replaces mechanical torque control attempts in the motoring state with electrical torque control of the electric generator. Since the electric generator is driven by the engine via gears rather than directly by the motor, it responds more predictably to electrical control signals, enabling effective torque management for noise reduction despite the presence of friction and torque pulsation in the mechanical system.
Solution Approach 2:
The electric generator acts as an intermediary between the engine and the control system. By controlling the electric generator's torque output rather than attempting to control motor torque directly in the motoring state, the system overcomes the difficulties of friction and torque pulsation, as the electric generator provides a controllable interface for torque management.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The control method for the hybrid vehicle includes a rotation speed control torque calculation step of, based on a rotation speed command value for the electric generator and a rotation speed detection value of the electric generator, calculating a torque command value for controlling the rotation speed of the electric generator, and an electric generator control step of controlling the electric generator according to the torque command value. The rotation speed control torque calculation step calculates, using the model matching compensator and based on a value obtained by filtering the rotation speed detection value through the low-pass filter and the rotation speed command value, a basic torque command value that makes a torque response of the electric generator coincide with a preset model response, calculates, using the disturbance observer including the transfer function composed of the inverse system of the control object model patterned after a power transmission system of the electric generator connected to the engine via the gears and a disturbance observer filter, and based on the rotation speed detection value, a disturbance torque that is input into the power transmission system, and calculates the torque command value based on the basic torque command value and the disturbance torque. The relative degree of the disturbance observer filter is set so that the relative degree of the transfer function becomes 1 or more.