New European Driving Cycle

This article is part of the Driving cycles series.

Europe

NEDC ECE 15

United States

FTP 72 FTP 75

SFTP US06 SFTP SC03

Japan

10-15 Mode

The New European Driving Cycle is a driving cycle consisting of four repeated ECE-15 driving cycles and an Extra-Urban driving cycle (EUDC). The NEDC is supposed to represent the typical usage of a car in Europe, and is used, among other things, to assess the emission levels of car engines. It is also referred to as MVEG cycle (Motor Vehicle Emissions Group).

Plot

Note: The old European driving cycle ECE-15 driving cycle lies between the time period 0s to 800s. For the urban drive cycle the ECE-15 driving cycle is used, and for urban/sub-urban drive cycle the New European Driving Cycle (NEDC) is used to simulate representative driving conditions.

Test procedure

The cycle must be performed on a cold vehicle at 20-30°C (typically run at 25°C). The cycles may be performed on a flat road, in the absence of wind. However, to improve repeatability, they are generally performed on a roller test bench. This type of bench is equipped with an electrical machine to emulate resistance due to aerodynamic drag and vehicle mass (inertia). For each vehicle configuration, a look-up table is applied: each speed corresponds to a certain value of resistance (reverse torque applied to the drive wheels). This arrangement enables the use of a single physical vehicle to test all vehicle body styles (Sedan, hatchback, MPV...) by simply changing the look-up table. A fan is coupled to the roller bench to provide the vehicle air intakes with an airflow matching the current speed. Many more tests can be performed during vehicle development with this arrangement than with conventional road tests.

The test is conducted with all ancillary loads turned off (Air conditioning compressor and fan, lights, heated rear window, etc.)

Measurements

Several measurements are usually performed along the cycle. The figures made available to the general public are:

• Urban fuel economy (first 800 seconds)
• Extra-Urban fuel economy (800 to 1200s)
• Overall fuel economy (complete cycle)
• CO₂ emission (complete cycle)

The following parameters are also generally measured to validate the compliance to European emission standards:

• Carbon monoxide
• Unburnt hydrocarbons
• Nitrogen oxides
• Particulate matter

Criticism

• Applicability to current vehicles:

The NEDC was conceived at a time when European vehicles were lighter and less powerful. The transient velocities are much steeper in practice and more dynamic caused by the power surplus of modern engines^[1]. Drivers tend to use this excess power failing to achieve the EDC-values in practice. The worst scenario is the absence of regulations above 120 km/h whilst on German motorways velocities above 200km/h are driven. A new version of the driving cycle should be realistic towards the daily use of ancillary units and gadgets which tend to invade modern vehicles.

• Cycle beating:

For the emission standards to deliver real emission reductions it is crucial to use a test cycle that reflects real-world driving style. It was discovered that engine manufacturers would engage in what was called 'cycle beating' to optimise emission performance to the test cycle, while emissions from typical driving conditions would be much higher than expected, undermining the standards and public health. In one particular instance, research from two German technology institutes found that for diesel cars no 'real' NO_x reductions have been achieved after 13 years of stricter standards.^[2]

References

1. ^ The 0-60mph time decreased from 14 to 10 sec from the eighties to today on average[1]
2. ^ Transport Environment.org Transport & Environment, Bulletin - News from the European Federation for Transport and Environment, No 146, March 2006, WHO adds pressure for stricter Euro-5 standards

External links

ETC test cycle, ELR test, ESC test more...

• http://www.dieselnet.com/standards/cycles/ece_eudc.html