Exhaust Emission Measurement
Low emissions? Not automatically
Vehicles from the USA are not automatically referred to as low-emission cars in Germany, albeit most passenger cars with a controlled catalytic converter and a model year of 1983 from the USA are categorised here as low-emission vehicles. Yet, this does not apply for so-called light duty trucks (pick-ups and (mini-)vans). According to the US-exhaust emission regulations, these vehicles were allowed to emit significantly more exhaust gas and are thus not to be categorised as low-emission vehicles.
From 1993 on, the measuring cycle in Europe has become so significantly different from the one in America, that it is now impossible to make any conclusions for EU-regulations only by meeting US-standards.
What are the differences in the measuring cycle?
Before an exhaust emission measurement, the vehicle needs to be pre-conditioned for about 6-8 hours, i.e. it is brought to a specified initial temperature in a tempered room, among other things.
Then, it is secured on the chassis dynamometer test bench and the emission hoses are connected. During measurement, a specified cycle needs to be driven off, the length of which varies between Europe and the USA.
The Euro-driving cycle consists of 2 parts:
- the City-driving cycle with considerably lower speeds and
- the motorway driving cycle, recording speeds of up to 120 km/h (EU DC).
The produced exhaust emissions are collected in bags and analysed afterwards. This procedure tells
- whether the exhaust gas components are within the specified thresholds, and
- how the vehicle is to be classified in terms of taxes.
From this brief and admittedly heavily simplified description of an exhaust emission measurement, you can easily tell why measurements like these result in not all-too insignificant costs, and that there is no connection with the biannual exhaust emission measurement, the so-called AU (Abgasuntersuchung – exhaust emission check). This AU is carried out, more or less, to check the functioning of all engine components involved in emitting exhaust gases, and cannot be used to evaluate the exhaust emission characteristics.
What are the differences in the technology?
Since the exhaust emission test cycles in Europe are so different from the ones in the USA, what are the technical differences between the European and American version of a vehicle type?
Due to the very strict exhaust emission limits for newer cars, the manufacturers are forced to deliver their models for the respective destination market with optimised exhaust emissions in order to not exceed the threshold, i.e. the technical equipment (e.g. control devices) considers peculiarities of the measuring cycle to be met.
That’s why European controlled catalytic converters are smaller than the ones in American cars, for instance, since with our driving cycle the cold running lasts longer. The control devices have an adapted software. The engine air intake and exhaust pipe components need to consider the EU noise emission regulations and thus in turn have an impact on the performance and exhaust emission characteristics etc.
When do I not need to have my imported vehicle measured on the test bench?
The following applies: If your vehicle has an exhaust emission classification, based on the VIN, from good authority (e.g. vehicle manufacturer / importer), there is no need for an expensive separate measurement on the test bench, of course!
The IGA department already has made exhaust emission tests for many American vehicles and thus is able to make these test results in form of an exhaust emission certificate available to you for a fee.