Steady-State Site Driving Conditions for Reproducible NEV Range Tests
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Solution Overview
Problem
The challenge of reproducing laboratory transient driving conditions on real roads for new energy vehicles (NEVs) is significant due to varying driving habits and inconsistent test results, leading to discrepancies between laboratory and actual driving environments.
Innovation Solution
A method to develop a steady-state site driving condition based on transient-state driving conditions, involving fragmentation, pretreatment, merging, and conversion of motion segments to create a unified test condition that can be replicated on real roads, ensuring consistent and comparable range test results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laboratory chassis drum transient-state driving conditions are used for testing, then test results can be obtained in controlled environment, but drivers cannot reproduce these conditions on real test sites leading to inconsistent results
Solution Approach 1:
The patent segments the transient-state driving condition curve into multiple motion segments based on speed changes and acceleration characteristics. Each segment represents a specific driving phase (acceleration, deceleration, constant speed) that can be independently reproduced by drivers on test sites, thereby maintaining reliability while improving ease of operation.
Solution Approach 2:
The patent creates a simplified copy of the laboratory transient-state driving conditions by extracting key motion characteristics (speed-time relationships, acceleration patterns) and representing them as steady-state motion segments. This copy can be reproduced by drivers without requiring them to exactly replicate complex transient behaviors, thus improving reproducibility while maintaining test validity.
2Ease of operation
If drivers follow varying driving habits on test sites, then natural driving behavior is maintained, but speed and acceleration become inconsistent among different vehicles
Solution Approach 1:
The patent transforms the static, rigid transient-state curve into dynamic steady-state motion segments that accommodate natural driving variations. The motion segments define speed ranges and acceleration patterns rather than exact trajectories, allowing drivers to maintain natural behavior while ensuring consistency through standardized segment structures.
Solution Approach 2:
The patent changes the parameters from exact transient-state speed-time values to steady-state motion segment characteristics (speed ranges, acceleration rates, segment durations). This parameter transformation allows natural driving variations within defined bounds while maintaining overall consistency and comparability across different vehicles and drivers.
3Ease of operation
If constant-speed running or vehicle following is used on test sites, then driving is simplified, but the test does not reflect complex and changeable real driving environments
Solution Approach 1:
The patent segments the driving condition into multiple steady-state motion segments that collectively represent complex driving environments. Each segment is simple enough for drivers to follow, but the sequence and variety of segments (different speeds, accelerations, durations) collectively adapt to reflect real-world driving complexity and variability.
Data Source
AI summary
The present disclosure discloses a steady-state site driving condition development method based on a transient-state driving condition, including: fragmenting a laboratory chassis drum transient-state speed-time curve to obtain transient-state motion segments; fragmenting the transient-state motion segment that is not pretreated with reference to a minimum speed of the pretreated transient-state motion segments to obtain transient-state sub-motion segments; merging the transient-state sub-motion segments, calculating maximum constant speeds and mean accelerations and mean decelerations of steady-state motion segments; converting acceleration and deceleration processes into uniform acceleration and uniform deceleration processes, calculating acceleration and deceleration durations of the steady-state motion segments to obtain steady-state motion segment; connecting steady-state motion segments according to time axes, inserting idle segments between the steady-state motion segments and at the beginning and end of a steady-state driving condition, so as to obtain a steady-state site test driving condition.