EV Main Drive Acceleration Control for Steep Grade Speed Holding
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Solution Overview
Problem
Electric vehicles with reduced maximum torque settings for different driving profiles can struggle to maintain speed on steep inclines or with high payloads, leading to potential accidents due to unexpected speed reductions.
Innovation Solution
A method for operating the main drive of an electric vehicle that determines a first acceleration value based on the user's setting of the control element and a second acceleration value based on the deviation from a specified maximum acceleration, selecting the minimum of these two values as a control value to set the energization of the main drive, thereby ensuring the vehicle never exceeds the maximum acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the maximum torque is reduced for a selected driving profile, then the driving experience is improved and comfort is enhanced, but the vehicle cannot maintain speed on steep inclines or climb elevations
Solution Approach 1:
The system dynamically adjusts the maximum torque limit based on real-time vehicle conditions (speed, acceleration, gradient detection) rather than using a fixed limit for the entire driving profile. When a steep gradient is detected, the system temporarily increases the torque limit to maintain speed, then returns to the normal profile-based limit when the gradient condition resolves.
Solution Approach 2:
The system continuously monitors vehicle speed and acceleration to detect when speed loss occurs on steep gradients. This feedback triggers an automatic response to increase torque output, allowing the system to adapt to changing road conditions while maintaining the overall driving profile characteristics.
2Ease of operation
If the maximum torque is reduced for a selected driving profile, then acceleration is decreased for comfort, but safety is compromised due to unexpected speed reductions
Solution Approach 1:
The system proactively detects steep gradients before they cause significant speed loss and preemptively increases torque output to prevent speed reduction. This anticipatory action maintains consistent vehicle performance and prevents the unexpected deceleration that would compromise safety.
Solution Approach 2:
Continuous monitoring of speed and acceleration provides real-time feedback that triggers torque adjustments, ensuring safety is maintained while preserving the comfort-oriented driving profile characteristics during normal operation.
3Speed
If the torque is increased to maintain speed on steep roads, then the vehicle can overcome gradients, but the driving profile settings are violated and comfort is reduced
Solution Approach 1:
The system uses dynamic torque adjustment that temporarily overrides profile limits only when gradient conditions are detected, then automatically returns to the profile-based torque management. This selective dynamic adjustment maintains comfort during normal operation while ensuring speed maintenance on steep gradients.
Data Source
AI summary
A method for operating a main drive of an electric vehicle, in which a first acceleration value is determined on the basis of a setting of an operating element. Based on a deviation of a current acceleration from a predetermined maximum acceleration, a second acceleration value is determined, and the minimum of the first acceleration value and the second acceleration value is selected as a control value. An Energization of the main drive is adjusted in accordance with the control value. Furthermore, the invention provides a main drive of an electric vehicle and a computer program product.