EV Powertrain Oil Heating Control for Cold-Start Lubrication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
At very low temperatures, the viscosity of lubricating oil in electric vehicle power systems increases, leading to decreased lubricity and difficulty in starting the lube oil pump, which affects the normal operation of electric vehicles.
Innovation Solution
A powertrain system that disconnects the transmission connection between the drive motor and the wheel based on lube oil temperature and viscosity parameters, using a transmission device to stir the lube oil during idling, converting kinetic energy into heat to rapidly increase the oil temperature and improve lubricity, and an oil pump motor that runs in a locked-rotor state to generate heat for heating the lube oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lube oil pump is started at very low temperature, then the pump should provide lubrication, but the high viscosity of the lube oil causes the pump to be difficult to start and reduces lubricity
Solution Approach 1:
The system performs preliminary heating of the lube oil before attempting to start the lube oil pump. The drive motor is controlled to rotate in a first rotating direction to drive the lube oil pump and heat the lube oil, ensuring the oil reaches a suitable temperature and viscosity level before the pump is activated, thereby preventing starting difficulties and ensuring reliable operation
Solution Approach 2:
The system changes the physical parameters of the lube oil by controlling the drive motor to rotate in a first rotating direction, which heats the lube oil and reduces its viscosity. This parameter change (temperature increase and viscosity reduction) enables the lube oil pump to start reliably and function properly
2Temperature
If the drive motor rotates at high speed to heat the lube oil rapidly, then the temperature rises quickly, but energy consumption increases
Solution Approach 1:
The system uses periodic or staged rotation of the drive motor in the first rotating direction to heat the lube oil. Instead of continuous high-speed rotation, the motor rotates periodically to achieve the required temperature increase, thereby reducing overall energy consumption while still effectively heating the lube oil
Solution Approach 2:
The system maintains continuous useful action by using the drive motor's rotation in the first rotating direction to simultaneously achieve both heating of the lube oil and eventual pump operation. This continuous process eliminates the need for separate heating and pumping phases, improving energy 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
Facilitates smooth starting of the lube oil pump at low temperatures by rapidly increasing the temperature of the lubricating oil, enhancing its fluidity and reducing energy consumption as the temperature rises.
Implementation Method 1
In the process of idling of the drive motor, the lube oil in the transmission structure of the drive motor is rapidly stirred. In the process in which the lube oil is stirred, kinetic energy is converted into intrinsic energy, and the temperature rises rapidly.
Implementation Method 2
a lube oil pump is difficult to be started
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
This application discloses a powertrain, a control apparatus, a motor control unit, and an electric vehicle. The powertrain includes a drive motor and a transmission device. The transmission device disconnects a transmission connection between the drive motor and a wheel based on a result of a comparison between a temperature or a viscosity of a lube oil and a preset parameter value, and a rotational speed of the drive motor varies with the result of the comparison between the temperature or the viscosity of the lube oil and the preset parameter value. The drive motor stirs the lube oil through idling, to make the temperature of the lube oil rise rapidly. The control apparatus provided in this application is configured to control the motor control unit, the transmission device, and a lube oil pump motor. The powertrain, the control apparatus, the motor control unit, and the electric vehicle provided in this application can improve fluidity of the lube oil at a very low temperature, so that a lube oil pump can be started smoothly.