Torque Range Check for Hybrid Drive Safety
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Solution Overview
Problem
Existing torque monitoring systems for vehicles with hybrid drives, which include both internal combustion engines and electric motors, fail to account for the unique requirement of managing negative torque, leading to potential unintentional vehicle acceleration due to unmet torque requests from electric drives, especially when they operate outside their adjustable range.
Innovation Solution
Implementing a torque range check within the vehicle control unit's monitoring level to ensure that target torques are within the adjustable range of individual drives, thereby preventing excessive drive torque requests and enhancing vehicle safety and controllability by having drives report their current operating limits and checking if setpoint torques are within these limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If torque monitoring is performed only at the functional level comparing total target torque with permissible torque, then the monitoring system remains simple, but it fails to detect when individual drive torques exceed their adjustable ranges leading to unintentional acceleration
Solution Approach 1:
The monitoring system is segmented into two levels: the functional level (first level) that monitors total drive torque, and the monitoring level (second level) that monitors individual drive torque components. This segmentation allows comprehensive monitoring without overwhelming complexity by distributing monitoring tasks across hierarchical levels.
Solution Approach 2:
The system performs preliminary checks at the functional level to determine if total target torque exceeds permissible torque. Based on this preliminary assessment, it selectively activates more detailed monitoring at the monitoring level only when needed, avoiding continuous full-detail monitoring and reducing overall system complexity.
2Measurement precision
If the monitoring level simulates the functional level to perform comprehensive torque monitoring, then detection accuracy improves, but development and application effort increases significantly
Solution Approach 1:
The patent extracts only the essential monitoring functions needed at the monitoring level rather than fully simulating the functional level. It takes out the specific torque component monitoring requirements and implements them independently, avoiding the need to replicate the entire functional level simulation and thereby reducing development effort.
3Reliability
If individual drive torque ranges are monitored continuously, then safety against unintentional acceleration improves, but computational load and system complexity increase
Solution Approach 1:
The monitoring system dynamically adjusts its operation based on operational conditions. It activates detailed individual drive torque monitoring selectively rather than continuously, adapting the monitoring intensity to actual safety needs and thereby reducing average system complexity while maintaining safety when required.
Data Source
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AI summary
The invention relates to a method for controlling a vehicle drive unit (32) comprising at least two individual drives (34, 36), at least one of said drives applying a negative torque. A continuous torque comparison (24) is carried out in a monitoring plane (14) in a vehicle control appliance (10), and an admissible torque Mzul is determined. A torque range check (56) is used to determine whether determined nominal torques Msoll, V (38), Msoll, E (40) lie within torque ranges (50, 54) of the at least two individual drives (34, 36).