Electric Oil Pump Control via Motor Load Torque
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Solution Overview
Problem
Conventional methods for controlling the operation of electric oil pumps in hybrid vehicles rely on oil temperature measurements, which fail to accurately reflect the viscosity characteristics of oil over time, leading to suboptimal pump operation due to changing oil conditions.
Innovation Solution
An apparatus and method that utilize a current detector and rotational speed detector to calculate the load torque of the motor, allowing for the determination of a target rotational speed based on actual conditions, rather than relying on temperature measurements, thereby enabling more accurate control of the electric oil pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If oil temperature measurement is used to control electric oil pump operation, then the control system is simple to implement, but the viscosity characteristics of oil cannot be accurately reflected over time
Solution Approach 1:
The patent replaces the conventional temperature-based control system with a torque-based control system. Instead of using temperature sensors and lookup tables, the system directly measures the torque required to drive the oil pump motor, which provides a direct indication of oil viscosity. This substitution of the measurement principle resolves the contradiction by achieving accurate viscosity reflection without the complexity of temperature-based indirect measurement systems.
Solution Approach 2:
The patent introduces torque as an intermediary parameter that directly reflects oil viscosity characteristics. By measuring the torque required to rotate the oil pump at a given speed, the system obtains a direct measure of oil resistance (viscosity) without needing to infer it from temperature. This intermediary measurement resolves the contradiction by providing accurate viscosity information while keeping the control system relatively simple.
2Measurement precision
If torque-based control is implemented to accurately reflect oil viscosity, then measurement precision is improved, but device complexity increases due to additional sensors and calculation requirements
Solution Approach 1:
The patent makes the existing motor controller perform multiple functions: it not only controls the motor speed but also measures the torque required to drive the motor. By utilizing the current and speed data already available from the motor control system, the patent calculates torque without requiring separate dedicated torque sensors. This multi-functionality approach resolves the contradiction by achieving accurate viscosity measurement while minimizing additional device complexity.
Solution Approach 2:
The system uses its own operational parameters (current draw and rotational speed) to determine oil viscosity characteristics. The motor controller automatically calculates torque based on the electrical characteristics of the motor during normal operation, without requiring external measurement devices. This self-service approach resolves the contradiction by providing accurate viscosity measurement while avoiding the complexity of additional specialized sensors.
3Stability of the object's composition
If electric oil pump operates continuously to maintain hydraulic pressure, then pressure stability is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic control of the electric oil pump based on real-time torque measurements. Instead of continuous operation, the system adjusts the pump's rotational speed according to the actual torque requirements, which reflect the current oil viscosity and hydraulic system demands. This dynamic adjustment resolves the contradiction by maintaining pressure stability only when necessary while reducing power consumption during periods of lower demand.
Solution Approach 2:
The patent changes the operational parameters of the electric oil pump based on measured torque values. When torque indicates high viscosity conditions or high pressure demand, the pump operates at higher speeds; when torque indicates low viscosity or low demand, the pump reduces speed or stops. This parameter-based control resolves the contradiction by adapting the pump operation to actual system needs, maintaining pressure stability while minimizing unnecessary power consumption.
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 allows for precise control of the electric oil pump operation, reflecting the actual viscosity characteristics of the oil, resulting in improved hydraulic pressure management and reduced power consumption across various drive modes.
Implementation Method 1
calculating a load torque of the motor based on the detection values of the current detector and the rotational speed detector
Data Source
AI summary
The present invention provides an apparatus and method for controlling the operation of an electric oil pump for creating a working fluid pressure in a transmission and a clutch for a hybrid vehicle, which can accurately reflect the viscosity characteristics of oil to accurately control the operation of the pump, instead of measuring the temperature of the oil to reflect the state of the oil. In preferred embodiments, the present invention provides an apparatus for controlling the operation of an electric oil pump, the apparatus including: a current detector for detecting a current applied to a motor of an electric oil pump; a rotational speed detector for detecting a rotational speed of the motor; and a controller for calculating a load torque of the motor based on the detection values of the current detector and the rotational speed detector, calculating a target rotational speed based on the detection values, and controlling the operation of the motor based on the target rotational speed.