Vehicle Load Detection Using Static and Dynamic Mass Comparison
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Solution Overview
Problem
Existing methods for determining vehicle load and mass during driving can lead to inaccurate results due to changing suspension information over time, potentially causing dangerous situations and requiring removal of overload, especially in electric vehicles where load-dependent range forecasting is crucial.
Innovation Solution
A method that determines static mass by measuring wheel strokes and suspension information when the vehicle is stationary, and compares this with dynamic mass determined during driving using drive-dynamical parameters, correcting suspension information to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mass is determined exclusively while driving using dynamic parameters, then the method can be implemented during operation, but the vehicle may start with inaccurate load determination leading to dangerous situations and incorrect range forecasts
Solution Approach 1:
The patent applies preliminary action by determining the static mass of the vehicle before driving begins. The system measures wheel strokes when the vehicle is stationary and uses suspension information to calculate the static mass, enabling load verification before the vehicle is put into operation. This prevents dangerous situations and incorrect range forecasts that would arise from starting with inaccurate load determination.
2Measurement precision
If suspension information is used to determine static mass, then static mass can be calculated before driving, but suspension information changes over time due to settling processes and material fatigue reducing accuracy
Solution Approach 1:
The patent implements feedback by continuously monitoring wheel strokes during driving and comparing the dynamically determined mass with the previously determined static mass. When deviations exceed a threshold, the system triggers a recalibration of the suspension information. This feedback mechanism compensates for changes in suspension characteristics due to settling processes and material fatigue, maintaining measurement accuracy over time.
Solution Approach 2:
The patent applies parameter changes by adapting the suspension information based on the comparison between static and dynamic mass measurements. When the vehicle is subjected to specific driving conditions, the system updates the suspension parameters to reflect current vehicle characteristics, thereby maintaining accuracy despite changes in suspension behavior over time.
3Measurement precision
If static mass determination is performed before driving, then accurate load information is available for range forecasting, but the vehicle must be stationary during measurement requiring specific conditions
Solution Approach 1:
The patent applies partial action by performing static mass determination under partially relaxed conditions. Instead of requiring completely ideal stationary conditions, the system can perform measurements during brief stationary periods, including temporary stops during driving. This partial approach allows static mass determination to be performed more easily while still achieving sufficient accuracy for load verification and range forecasting.
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
Enhances the precision of load determination by accounting for suspension changes and hysteresis, allowing for accurate static mass calculation and improved load-dependent range forecasting in electric vehicles.
Implementation Method 1
suspension information that characterizes the suspension behavior of the vehicle body, particularly relative to the unsprung components
Implementation Method 2
suspension information that characterizes the suspension behavior of the vehicle body
Data Source
AI summary
The load can be detected for a vehicle having a chassis with vehicle wheels on a ground surface, a vehicle body supported in a sprung manner on unsprung components of the chassis. A wheel stroke for each vehicle wheel characterizes a vertical distance from the vehicle body. With the vehicle at rest, one or more wheel strokes are determined as static wheel stroke data, which are used with suspension information characterizing suspension behavior of the vehicle body to determine a static mass of the vehicle and/or vehicle body. While the vehicle is travelling, at least one drive-dynamical parameter of the vehicle is determined on the basis of which a dynamic mass of the vehicle and/or the vehicle body is determined. Suspension information is produced or corrected based on a comparison of the dynamic mass and the static mass.