COMPARISON OF FUEL CONSUMPTION AND EMISSIONS OF MODERN LIGHT DUTY VEHICLES IN THE EU CYCLE VS REAL WORLD DRIVING

As the emphasis on the environmental impact of transport is rising, vehicle emission limits are getting more and more stringent. In 2005 the Euro 4 limits will be in use. Vehicle manufacturers are working hard to reach these limits and are already achieving this for some vehicle models. For certification purposes, exhaust gas emissions of light duty vehicles are measured over a predefined vehicle test cycle, defined by a speed versus time profile. These test cycles are supposed to create repeatable emission measurement conditions and, at the same time, simulate real driving conditions. While technology is evolving, it is unclear if the cycle used for certification gives a clear picture of the emissions produced in real traffic. Within the DECADE project, carried out under the 5th Framework Programme of the European Commission, a software package is being developed to predict vehicle fuel consumption and emissions for a given distance-speed profile. To give input to the model, three modern light duty vehicles have been the subject of intensive measurement on engine dynamometers, on chassis dynamometers and on the road. The vehicles are a Euro 2 diesel delivery van, a Euro 3 diesel passenger car and a small Euro 4 gasoline passenger car. This paper gives an overview of the emissions measured on the road for the three vehicles in Belgium and in Spain (in city, rural and motorway traffic), and compares these with the results obtained on chassis dynamometers. The tests on chassis dynamometers were most focused on the EU cycle, but some tests were also performed using a cycle derived from real world speed profiles. When comparing emissions on a grams per kilometre basis, it was found that some of the emissions measured in the certification cycle differed dramatically from the real world emissions. For the covering abstract see ITRD E122175.