European vehicle emission tests are to be performed on the road as much as possible, in the near future. A fallback option, for example, if no mobile measurement equipment is available, is testing on the chassis dynamometer in the laboratory. For example, for particulates, this may be a viable option. In order to cover a wide range of driving behaviour, and possible risks of high emissions, the Random Cycle Generator is developed.
The central idea behind the Random Cycle Generator is the second-by-second changes in accelerations for a given velocity. If a person accelerates, there is a high probability to remain accelerating. This also depends on the magnitude of acceleration. These probabilities are determined from the WLTP database, and they form the basis of the second-by-second changes in the generated cycle.
The average velocities over periods of about a minute are also determined. They are called "road-types" but are really a characterization of the average velocities, grouped into 10 velocity bands. The probabilities of a transition from one road-type to the next is also determined from the WLTP database, and they are the probabilities of the minute-by-minute transitions in the generator. With these two sets of probabilities we span the short-time dynamics and the medium-time dynamics.
Vehicle limitations and gear shift strategy require some vehicle specific information to be entered.
Based on European driving data
The cycles generated span the European driving behaviour as recorded for the development of the WLTC and fulfil the trip requirements of the European Real Driving Emissions (RDE) legislation.
Download Software and instructions
See the PDF with instructions for downloading the software and how to install it (read the License agreement first).