VERA - Vehicle Emission Retrofit Activities
Project duration: 2023 - 2026
Funded by: Horizon EU
Project team: Matzer, Hausberger, Landl
In the Horizon Europe project VERA, existing solutions for retrofit systems for road vehicles and underground trains are being analysed and new innovative systems are being developed and demonstrated. Particular attention is being paid to PN, NOx and NH3 exhaust emissions from motor vehicles as well as brake emissions from road vehicles and underground trains.
As part of the VERA project, the Emissions department is analysing the gasoline particulate filter (GPF) retrofit solutions available on the market, particularly for plug-in cars with petrol engines. The analysis takes into account the pollutant and noise emissions as well as the costs of such systems. The assessment also includes a gap analysis. The findings are used for the development of new systems.
As there are no findings on GPF retrofit systems for plug-in petrol cars, a VW Golf GTE meeting the Euro 6b emissions standard is being tested. This vehicle has a three-way catalytic converter close to the engine and a three-way catalytic converter as well as centre and rear silencers in the underbody. This vehicle is not equipped with an GPF as standard, which is why it is well suited for the investigation of GPF retrofit systems. The investigations on this vehicle are currently underway and are focussing on the following issues, among others:
- Are there sufficient operating points for passive regeneration of the GPF retrofit system in real operation?
- Can a retrofitted GPF be monitored with sufficient safety?
- Can an GPF be retrofitted without having to adapt the engine control unit software?
- What separation efficiencies are achieved with GPF retrofit systems?
In order to answer these questions, the vehicle was or will be measured on the test bench and on the road in its original condition, directly after the conversion and six and twelve months after the conversion. In addition, the vehicle was also equipped with measurement technology that records exhaust gas temperatures, differential pressures and OBD data such as lambda, vehicle speed and engine speed via the OBD interface. Over 4,400 km of measurement data has now been collected in the original condition of the vehicle on the test bench and on the road in hybrid mode. In early 2024, the first GPF retrofit system is to be installed in the underbody instead of the second three-way catalytic converter or the centre silencer and tested using measurement technology.
The measurement data to date indicates that GPF regeneration in urban operation will be a challenge for the retrofit system. Regeneration requires sufficiently high temperatures (above approx. 550 °C) and oxygen for soot burn-off. Figure 1 shows the analysis of the frequency of exhaust gas temperatures with excess air in the underbody of the measurement data collected to date. It can be seen that the possible regeneration windows for passive regeneration are less than 8 % of the time, in pure urban operation it is significantly less than 1 %. The investigations will show whether this is sufficient for GPF retrofit systems.
Figure 1: Frequency of exhaust gas temperatures with excess air in the underbody of a plug-in petrol vehicle, derived from 4,400 km of measurement data