Hybrid Vehicle Clutch Control Setpoint Adjustment
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Solution Overview
Problem
The existing vehicle control apparatuses for hybrid electric vehicles, particularly in the WSC drive mode, face issues with clutch overheating and deterioration due to prolonged slippage when the vehicle is stationary, leading to reduced efficiency and potential damage.
Innovation Solution
A vehicle control apparatus and method that includes an engine, an electric motor, and a clutch with hydraulic pressure regulation, allowing slippage between the electric motor and driving wheel elements, with a controller managing the clutch's torque transmission capacity and rotational speeds to prevent overheating by adjusting the control setpoint based on the vehicle's stationary state, specifically reducing the setpoint in the electric motor speed control drive mode while inhibiting this procedure in the engine speed control drive mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the clutch is allowed to slip continuously for a long period of time to maintain vehicle stationary position, then the vehicle can remain stationary, but the clutch overheats and deteriorates
Solution Approach 1:
The control system dynamically adjusts the clutch control setpoint based on the drive mode. In electric motor speed control drive mode, the system permits reduction of the control setpoint to minimize slippage and heat generation, while in engine speed control drive mode, the system maintains the original setpoint to ensure proper vehicle stationary positioning. This dynamic adjustment resolves the contradiction by adapting clutch behavior to the specific operational context.
Solution Approach 2:
The system changes the clutch control parameter (control setpoint) based on the detected drive mode. When the vehicle is stationary and the brake pedal is depressed, the controller reduces the control setpoint specifically in electric motor speed control drive mode to reduce slippage and prevent overheating, while maintaining the setpoint in engine speed control drive mode. This parameter change directly addresses the temperature issue while preserving stationary stability.
2Temperature
If the control setpoint is reduced to prevent clutch overheating, then clutch temperature decreases, but vehicle response to driver requests may be affected
Solution Approach 1:
The control system dynamically adjusts the clutch control setpoint based on the detected drive mode. In electric motor speed control drive mode, the system permits reduction of the control setpoint to minimize slippage and heat generation, while in engine speed control drive mode, the system maintains the original setpoint to ensure proper vehicle stationary positioning. This dynamic adjustment resolves the contradiction by adapting clutch behavior to the specific operational context.
Solution Approach 2:
The system applies different control strategies to different operational modes. The control setpoint reduction is applied locally only to electric motor speed control drive mode conditions, leaving engine speed control drive mode unaffected. This localized application of the control change prevents overheating where necessary while preserving vehicle response characteristics in other modes.
3Speed
If the clutch slippage is controlled to maintain quick vehicle start, then vehicle responsiveness improves, but clutch deterioration accelerates
Solution Approach 1:
The control system dynamically adjusts the clutch control setpoint based on the detected drive mode. In electric motor speed control drive mode, the system permits reduction of the control setpoint to minimize slippage and heat generation, while in engine speed control drive mode, the system maintains the original setpoint to ensure proper vehicle stationary positioning. This dynamic adjustment resolves the contradiction by adapting clutch behavior to the specific operational context.
Solution Approach 2:
The controller continuously monitors the drive mode and periodically adjusts the control setpoint accordingly. When the vehicle is stationary and the brake pedal is depressed, the system periodically reduces the control setpoint in electric motor speed control drive mode to prevent overheating, while maintaining normal operation in engine speed control drive mode. This periodic adjustment prevents cumulative heat damage while preserving necessary slippage for quick starts.
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 solution effectively prevents clutch overheating and deterioration by managing the clutch's torque transmission capacity and rotational speeds, ensuring smooth vehicle operation and extending the clutch's lifespan, while maintaining efficient energy use and responsiveness to driver requests.
Implementation Method 1
a clutch (CL2) including an electric motor side element (61) and a driving wheel side element (62), wherein the electric motor side element (61) is connected to the electric motor (MG) and the driving wheel side element (62) is connected to a driving wheel (RL, RR) of the vehicle (51), wherein the clutch (CL2) is configured to set according to hydraulic pressure (P2) a transmitted torque capacity (TCL2)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A hybrid electric vehicle has a first mode in which slippage of a clutch between an electric motor and a driving wheel is allowed and controlled by rotational speed control of the electric motor and a second mode in which the slippage of the clutch is allowed and controlled by rotational speed control of an engine. When the vehicle is stationary in the first mode, a controller reduces a control setpoint of hydraulic pressure of the clutch from an initial point. The controller identifies a reference point of the control setpoint with which actual output torque of the electric motor is substantially constant with respect to the reduction of the control setpoint. Then, the controller increases the control setpoint to a precharge point, and reduces the control setpoint to a corrected point that is lower than or substantially equal to the initial point and higher than the reference point.