Test Stand Simulation Correction for Real-World Emissions Cycles
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Solution Overview
Problem
Standardized test cycles on a test stand cannot accurately replicate real-world driving conditions, leading to vehicles passing emissions tests but failing in real-world RDE tests due to random influences, making it difficult for manufacturers to predict compliance with pollutant emission limits during vehicle development.
Innovation Solution
A method and test stand that detect deviations between simulation and reference values using a detection unit and correction unit, adjusting reference values to reduce deviations and ensure accurate simulation of real-world driving conditions, allowing for continuous correction during the test run.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standardized test cycles are used on a test stand, then emissions can be measured and checked, but the test conditions cannot be compared with real driving conditions leading to vehicles passing tests but failing in real-world RDE tests
Solution Approach 1:
The patent applies preliminary action by pre-defining multiple predetermined driving scenarios (city driving, country driving, motorway driving) with specific reference values for speed, acceleration, and route characteristics before the actual test run. These scenarios are prepared in advance to cover various real-world driving conditions, allowing the test stand to simulate conditions that more closely match actual RDE test environments rather than using a single standardized cycle
2Reliability
If real driving conditions are simulated on a test stand, then RDE test compliance can be predicted, but the complexity of the test system increases due to multiple driving scenarios and correction mechanisms
Solution Approach 1:
The patent segments the complex RDE test simulation into multiple predetermined driving scenarios (city driving, country driving, motorway driving), each with its own set of reference values and characteristics. This segmentation allows the system to handle complexity by dividing it into manageable, pre-configured modules rather than requiring a single complex continuous simulation
Solution Approach 2:
The patent implements dynamics by continuously monitoring the actual driving parameters during the test run and dynamically selecting and switching between different predetermined driving scenarios based on matching reference values. The system adaptively adjusts which scenario is active by comparing actual speed, acceleration, and route data with stored reference data, allowing flexible adaptation to varying test conditions
3Measurement precision
If multiple predetermined driving scenarios are stored and processed, then more accurate simulation of real-world conditions is achieved, but the data processing time and computational requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple complete driving scenarios with all associated reference values (speed, acceleration, route characteristics) before the test run. This preprocessing eliminates the need for complex real-time calculations during the actual test, as the system only needs to retrieve and compare against pre-prepared data sets
Solution Approach 2:
The patent implements partial action by storing and processing only the essential reference values needed for scenario matching (speed, acceleration, route characteristics) rather than complete detailed simulations of all driving parameters. This selective storage of critical data reduces computational burden while maintaining sufficient accuracy for RDE compliance prediction
Data Source
AI summary
Various embodiments of the present disclosure are directed to a method for carrying out a test run on a test stand. The method in some embodiments reduces a deviation between a comparison simulation value and a comparison reference value when carrying out a test run on a test stand with a test object by simulating via a simulation unit a number of simulation values using a number of specified reference values starting from a selected reference value, determining a corrected reference value which is specified to the simulation unit for simulating a corrected simulation value and determining at least one setpoint variable using the corrected simulation value.