Pioneers in RDE Validation

IAV Kagera generates synthetic real-driving emission (RDE) cycles on the basis of real measurements and, for the first time, provides statistical information on whether emission tests meet the RDE targets

Engine developers are facing a new challenge: since 2017, vehicles must demonstrate in real driving that they comply with the comprehensive requirements of RDE legislation under all conditions. However, test drives cannot be performed in any random number. This is where IAV Kagera comes into play. Just a few RDE drives provide the basis for generating thousands to millions of synthetic driving cycles that can be used for predicting emissions. IAV Kagera is currently the only development tool on the market to provide this level of statistically backed information on the basis of real-world data and to give OEMs such a high level of certainty.

In contrast to defined driving cycles, the RDE test procedure delivers measured values that come close to actual emission behavior in real-world driving. It also verifies whether the vehicle’s pollutant emissions determined in the laboratory (WLTC) keep within the emission limits. This is done in test drives with a prescribed mix of urban and cross-country roads as well as expressways. Among other emissions, portable measurement equipment (PEMS, Portable Emissions Measurement System) measures the nitrogen oxide emissions and the number of particles in the exhaust gas.

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New cycles from various real driving maneuvers

However, the RDE test results are heavily influenced by the specific trip and vary within a very wide range. Even identical routes deliver different emission values for similar driving styles. The driver and traffic conditions also play a key part. One possible solution for OEMs is to increase the number of test drives – a very time consuming and expensive way of validation. IAV Kagera provides an intelligent alternative because even ten real-world test drives are sufficient for generating a large number of synthetic RDE cycles and robustly estimating emission behavior.

“In our projects, we have seen the need for a softwaretool that supports my colleagues from calibration in respect of the new statutory requirements. This is how the idea for IAV Kagera was born. In close cooperation, we defined the requirements and implemented the development result. We have now been successfully using our in-house development in diesel and gasoline engine calibration for two years”, explains Florian Seele, software development engineer in the Powertrain Mechatronics division. “We are constantly improving the method and widening the application spectrum. At present the focus is on validation, but in future it is also to be used in the early stages of the vehicle development process”, says product manager Yelda Leibinger.

The four-stage process with potential to become industry standard

To begin with, thev alues measured during RDE trips are loaded into a database. IAV Kagera defines a test drive as a sequence of various driving maneuvers. Methods of machine learning provide a meaningful segmentation of data and causes of emission peaks are analyzed and checked for plausibility. These segments use used for generating synthetic cycles, with RDE conformity being verified. All major influences, such as driver, traffic and route topology, are taken into account, covering the greatest possible engine speed/load range. The software can then be used for examining, analyzing and exporting specifically selected cycles as well as for generating relevant reports. Identifying critical cycles, in particular, makes it possible to deduce needs for opti-mization in the development process. To use the tool, a regular workstation computer is sufficient; no special hardware or software is needed.

From fall 2018, the IAV product will be available on the market. “IAV Kagera makes us pioneers in the field of RDE validation and we want to establish the method as a standard process”, Leibinger says. “No other product on the market provides such robust, statistically backed information and gives OEMs such a high level of RDE confirmity assurance.” We will gladly be of assistance if you have any questions and are interested in the product or would like a solution tailored to your needs.

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