New European Driving Cycle
The NEDC, which is supposed to represent the typical usage of a car in Europe, is repeatedly criticised for delivering economy-figures which are unachievable in reality.
The figures made available to the general public are: The following parameters are also generally measured to validate the compliance to European emission standards: Some or all of the following parameters are measured depending upon the requirements of the region implementing the test: The region implementing the test defines limits for each of the pollutants, for instance the Euro level within the EU.
This type of bench is equipped with an electrical machine to emulate resistance due to aerodynamic drag and vehicle mass (inertia).
The test is conducted with all ancillary loads turned off (Air conditioning compressor and fan, lights, heated rear window, etc.)
[10] The UK consumer group Which?, criticized the NEDC test procedure as being out-of-date as its most recent update was made in 1997;[11] before hybrid cars and stop-start technology was generally available.
The group claimed the test did not replicate real-world driving conditions and had numerous loopholes which cause the results to be unachievable in practice.
However, the fixed speeds, gear shift points and accelerations of the NEDC offer possibilities for manufacturers to engage in what is called 'cycle beating' to optimise engine emission performance to the corresponding operating points of the test cycle, while emissions from typical driving conditions would be much higher than expected, undermining the standards and public health.
[8] In one particular instance, research from two German technology institutes found that for diesel cars no 'real' NOx reductions have been achieved after 13 years of stricter standards.
[13] In addition, the height of the simulated wind fan could alter the performance of after-treatment systems due to changes in temperature and, consequently, modify the pollutant emissions values.
[15] The European Commission intends to introduce a type approval procedure to measure the energy efficiency of mobile air conditioning systems in vehicles, as well as its effect on fuel consumption and emissions, and display an efficiency label on the vehicle; the work is being performed by TU Graz (Institute for Internal combustion engines and Thermodynamics), Aristotle University of Thessaloniki (Laboratory of Applied Thermodynamics), TNO and ACEA.
