Hybrid AWD Torque Distribution Using Wheel Slip and Shift Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mechanical all-wheel-drive systems in vehicles face power loss due to transfer cases and inability to independently control front and rear wheels, making them ineffective in responding to changes in road conditions.
Innovation Solution
An all-wheel-drive hybrid electric vehicle configuration where an engine is connected to main drive wheels via a transmission and a motor is connected to auxiliary drive wheels, allowing for independent control of front and rear wheels through a method that adjusts torque input based on accelerator pedal depression, compares slip amounts, and performs variable shift-pattern and shift-time control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical all-wheel-drive system with a transfer case is used, then drive power can be transmitted to all four wheels, but power loss occurs due to the transfer case and independent control of front and rear wheels is impossible
Solution Approach 1:
The patent divides the drive system into two independent parts: an engine connected to front wheels via transmission, and a motor connected to rear wheels. This segmentation eliminates the need for a transfer case, allowing independent control of each axle while reducing mechanical power loss associated with mechanical all-wheel-drive systems
Solution Approach 2:
The patent replaces the mechanical transfer case with an electric powertrain configuration where the motor is independently controlled by a control unit. This substitution eliminates mechanical power loss in the transfer case while maintaining all-wheel-drive capability through electronic control of the motor based on wheel slip detection
2Reliability
If a mechanical all-wheel-drive system is used, then all four wheels receive drive power, but the system fails to effectively respond to changes in tire slip attributable to changes in road conditions
Solution Approach 1:
The patent implements dynamic control of the motor connected to rear wheels based on real-time detection of wheel slip conditions. The control unit adjusts motor output according to detected slip amounts, enabling the system to adapt to changing road conditions such as ice, snow, or wet surfaces, thereby improving responsiveness compared to fixed mechanical all-wheel-drive systems
Solution Approach 2:
The patent incorporates a feedback mechanism where wheel slip is detected by sensors and this information is fed back to the control unit. The control unit then adjusts motor output accordingly, creating a closed-loop control system that continuously adapts to road conditions and optimizes traction by reducing power to slipping wheels
3Ease of operation
If drive power is uniformly distributed to front and rear wheels according to drive mode, then simple control is achieved, but effective response to tire slip changes is impossible
Solution Approach 1:
The patent enables the system to automatically adjust power distribution based on detected wheel slip conditions without requiring manual intervention. The control unit independently monitors wheel slip and adjusts motor output accordingly, allowing the system to self-adapt to changing traction conditions while maintaining simple drive mode selection for the driver
Data Source
AI summary
A method of controlling driving of a hybrid electric vehicle having an engine connected to main drive wheels via a transmission and a motor connected to auxiliary drive wheels includes setting a drive mode, controlling an input torque of the transmission in response to an extent of depression of an accelerator pedal (APS) according to the drive mode, performing distribution of drive power to the main drive wheels and the auxiliary drive wheels and variable shift-pattern control based on a result of a comparison between an amount of slip of the main drive wheels and the amount of slip of the auxiliary drive wheels, and determining whether to perform variable shift-time control in consideration of a type of the variable shift-pattern control or a number of revolutions per minute (RPM) of the engine at beginning of a shift.