Vehicle emission testing is crucial for assessing fuel consumption, CO2, and pollutant emissions. Standardized laboratory tests ensure that results are reproducible and comparable across different car models. This standardized approach allows consumers to make informed comparisons. The automotive industry has transitioned from the New European Driving Cycle (NEDC) to the Worldwide harmonised Light-duty vehicle Test Procedure (WLTP) to provide more realistic and accurate data, reflecting advancements in testing methodologies and potentially relevant even to high-performance vehicle sub-systems.
The New European Driving Cycle (NEDC): An Overview
The NEDC was the established European standard for measuring fuel consumption and emissions in passenger cars and light commercial vehicles. Originating in 1970 with a focus on urban driving, it expanded in 1992 to include an extra-urban phase. Since 1997, NEDC has been the benchmark for consumption and CO2 emission measurements. However, its composition became outdated, failing to represent contemporary driving styles and typical road distances. With an average speed of just 34 km/h and a maximum speed of 120 km/h, NEDC’s low accelerations were no longer in sync with real-world driving scenarios.
The Worldwide Harmonised Light-Duty Vehicle Test Procedure (WLTP): A Modern Approach
Introduced in Europe on September 1, 2017, the WLTP represents a significant advancement in vehicle testing. It utilizes Worldwide harmonised Light-duty vehicle Test Cycles (WLTC) to offer consumers more realistic fuel consumption, CO2, and pollutant emission data, aligning better with actual vehicle usage. The WLTP procedure incorporates a more dynamic driving profile characterized by more substantial acceleration.
Key Improvements in WLTP Testing
The WLTP protocol features several key enhancements over NEDC:
- Increased Maximum Speed: The maximum speed is raised from 120 km/h to 131.3 km/h.
- Higher Average Speed: The average speed increases to 46.5 km/h.
- Extended Cycle Time: The total cycle time is 30 minutes, a 10-minute increase from NEDC.
- Greater Distance Travelled: The test distance doubles from 11 km to 23.25 km.
WLTP tests are divided into four parts based on maximum speed – Low, Medium, High, and Extra-high – simulating urban, suburban, extra-urban roads, and motorway driving conditions. Furthermore, WLTP considers all optional vehicle features impacting aerodynamics, rolling resistance, and vehicle mass. This comprehensive approach results in a CO2 value that accurately reflects the specific configuration of an individual vehicle.
Conclusion: Embracing Realistic Vehicle Testing
The transition from NEDC to WLTP marks a crucial step towards more accurate and realistic vehicle emission and fuel consumption testing. By adopting a more dynamic and comprehensive testing procedure, WLTP provides consumers with data that better reflects real-world driving experiences and vehicle performance characteristics, moving beyond the limitations of older testing standards.
