Electric Oil Pump Speed Control for Vehicle Noise Masking
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Solution Overview
Problem
Existing vehicle driving systems face challenges in minimizing noise from electric oil pumps while ensuring adequate oil supply to cooling and lubrication systems, particularly at low vehicle speeds, where the noise from the electric oil pump becomes conspicuous and the operation of the pump is limited.
Innovation Solution
A driving system with an electric motor, an electric oil pump, and a controller that adjusts the rotation speed of the electric oil pump based on the accelerator operation amount and other factors to mask the noise from the electric oil pump with other vehicle noises, ensuring sufficient oil supply and reducing noise perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric oil pump operates at high rotation speed to ensure adequate oil supply, then the cooling and lubrication performance is improved, but noise from the electric oil pump becomes conspicuous
Solution Approach 1:
The controller dynamically adjusts the rotation speed parameter of the electric oil pump based on accelerator operation amount and vehicle speed, changing it from a fixed high value to a variable value that adapts to different driving conditions, thereby balancing noise reduction with adequate oil supply
Solution Approach 2:
The system transitions from static oil pump operation to dynamic control where the rotation speed continuously adapts to changing vehicle conditions, allowing the pump to operate at lower speeds when possible and higher speeds only when necessary for cooling and lubrication
2Object-generated harmful factors
If the electric oil pump operation is limited to reduce noise, then noise perception is reduced, but the amount of oil supplied to the cooling and lubrication required portion becomes insufficient
Solution Approach 1:
The controller uses feedback from accelerator operation amount and vehicle speed sensors to continuously monitor driving conditions and adjust the oil pump rotation speed accordingly, ensuring adequate oil supply is maintained while minimizing pump operation noise
Solution Approach 2:
The control system integrates multiple functions including noise reduction, cooling management, and lubrication management into a single unified control strategy that adjusts oil pump operation based on overall vehicle operating conditions
3Reliability
If the electric oil pump operates continuously to ensure oil supply at low vehicle speed, then cooling and lubrication is maintained, but noise from the electric oil pump remains conspicuous
Solution Approach 1:
The controller applies partial action by operating the electric oil pump at reduced rotation speeds during low vehicle speed conditions with small accelerator operation amounts, providing just enough oil supply to maintain cooling and lubrication while significantly reducing noise emission
Data Source
AI summary
A rotation speed of an electric oil pump in the case where an accelerator operation amount falls within a predetermined range is controlled to a rotation speed lower than the rotation speed of the electric oil pump in the case where the accelerator operation amount falls outside the predetermined range. When the range outside the predetermined range of the accelerator operation amount is set to a range in which noise that occurs from a source other than the electric oil pump is large, noise that occurs from the electric oil pump is masked by the noise that occurs from a source other than the electric oil pump and becomes inconspicuous in this range even when the rotation speed of the electric oil pump increases.