Hybrid Vehicle Electric Motor Torque Control for Shift Lag
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Solution Overview
Problem
Hybrid electric vehicles with manual shift modes in automatic transmissions experience a time lag between driver input and torque transmission to the drive wheels, leading to decreased responsiveness and insufficient deceleration torque during shifting, as the automatic transmission temporarily goes into a neutral state, preventing power transmission and engine braking.
Innovation Solution
A control apparatus that detects shift operations and generates motor torque to decrease torque differences by controlling the electric motor to provide regenerative torque during shifting, ensuring deceleration torque is transmitted to the drive wheels, even when the automatic transmission is in a neutral state, by increasing regenerative torque to match the torque expected after shifting is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the automatic transmission shifts from first stage to second stage, then the transmission ratio changes to match driver demand, but torque transmission is interrupted during shifting causing lag and insufficient deceleration torque
Solution Approach 1:
The electric motor generates motor torque in advance during the shifting process to compensate for the torque difference between stages. This preliminary action ensures that deceleration torque is maintained throughout the shift, eliminating the lag sensation and preventing torque transmission interruption.
2Productivity
If the automatic transmission shifts stages, then transmission performance is optimized, but the transmission enters neutral state temporarily preventing power transmission and engine braking
Solution Approach 1:
The electric motor acts as an intermediary to maintain torque transmission during the neutral state of automatic transmission shifting. It generates motor torque that compensates for the interrupted power flow, ensuring continuous deceleration torque is transmitted to the drive wheels even when the automatic transmission is in neutral.
3Reliability
If regenerative torque is increased to match expected deceleration torque, then torque consistency is improved, but energy recovery efficiency may be reduced
Solution Approach 1:
The control apparatus calculates the torque difference in advance and generates motor torque preliminarily to compensate for it. This preliminary action ensures torque consistency during shifting while minimizing unnecessary regenerative torque generation, thereby maintaining energy recovery 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
This solution improves responsiveness to driver inputs by ensuring consistent deceleration torque is applied, enhancing the vehicle's deceleration rate and reducing the feeling of lag in shift operations, thus improving the overall driving experience and fuel efficiency.
Implementation Method 1
an electric motor 20... The electric motor controller 23 is configured to control the electric motor 20 to generate motor torque
Data Source
AI summary
A control apparatus for hybrid electric vehicle includes a shift operation detector and an electric motor controller. The shift operation detector detects an input of a shift operation. The electric motor controller controls an electric motor of the hybrid electric vehicle to generate motor torque directed to decreasing of torque difference, on a condition that: the input of the shift operation from a first stage into a second stage is detected by the shift operation detector; and first torque and second torque are different in magnitude from each other by the torque difference. The first torque is torque that is to be transmitted to a drive wheel during shifting of the automatic transmission. The second torque is torque that is to be transmitted to the drive wheel after the shifting of the automatic transmission is completed.