Hybrid Vehicle Torque Control for Driver Intent
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Solution Overview
Problem
In hybrid electric vehicles, the torque limit value of the motor is set based solely on road surface gradient, leading to battery consumption that does not align with driver requirements, resulting in inefficient energy use and potential driver discomfort due to abrupt torque changes.
Innovation Solution
A hybrid electric vehicle drive apparatus that includes a torque limit value setting portion to adjust the driving torque limit based on vehicle speed and accelerator pedal position, allowing for dynamic adjustment of torque limits to match driver behavior, with additional features like starting torque derivation and vehicle speed acquisition to optimize engine and motor collaboration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the torque limit value of the motor is set based solely on road surface gradient, then the motor can output sufficient torque to satisfy acceleration requirements on slopes, but the battery consumption increases excessively and does not align with driver requirements
Solution Approach 1:
The torque limit value is dynamically adjusted based on multiple parameters including accelerator pedal position, vehicle speed, and gradient. When the accelerator pedal is fully depressed, the torque limit is set to maximum regardless of gradient. When the pedal position and vehicle speed indicate the driver does not require high acceleration, the torque limit is reduced even on slopes, thereby aligning battery consumption with actual driver requirements while maintaining adequate torque when needed
Solution Approach 2:
The system changes the torque limit parameter based on the combination of accelerator pedal position, vehicle speed, and gradient. By monitoring these parameters, the system adjusts the torque limit value to appropriate levels - using higher limits only when driver input and vehicle state indicate acceleration is required, and using lower limits when the same conditions suggest the driver does not need high acceleration, thus optimizing battery usage
2Speed
If the torque limit value is increased to satisfy acceleration on slopes, then the acceleration requirement is met, but the battery is consumed according to gradient rather than driver requirement
Solution Approach 1:
The system adjusts the torque limit parameter based on the combination of accelerator pedal position, vehicle speed, and gradient. By monitoring these parameters, the system adjusts the torque limit value to appropriate levels - using higher limits only when driver input and vehicle state indicate acceleration is required, and using lower limits when the same conditions suggest the driver does not need high acceleration, thus optimizing battery usage
3Force
If the torque limit is set high for gradient compensation, then acceleration on slopes is improved, but driver discomfort occurs due to abrupt torque changes that do not match driver intent
Solution Approach 1:
The system continuously monitors accelerator pedal position and vehicle speed as feedback from the driver's operational input. This feedback is used to adjust the torque limit value in real-time, ensuring that torque changes align with driver intent. When the accelerator pedal position and vehicle speed indicate the driver does not require high acceleration, the torque limit is reduced even on slopes, preventing abrupt torque changes that would cause discomfort while maintaining adequate torque when driver input indicates acceleration is desired
Data Source
AI summary
A hybrid electric vehicle drive apparatus has a setting portion for setting a limit value of a driving torque that a motor outputs when driving a hybrid electric vehicle by the power of the motor only, based on a maximum torque that the motor enables to output and a starting torque used to start an internal combustion engine by the motor. The setting portion sets the limit value to a first value and sets the limit value to a second value which is greater than the first value when a vehicle speed of the vehicle does not increase even though an accelerator pedal position degree increases while the vehicle is being driven only by the motor.