This document proposes that the engine is first tested without REC using the appropriate cycle for that engine to establish that it fulfils the relevant requirements for that base engine. Emissions are then measured with the REC fitted using the appropriate cycle for the emission level to be achieved, which may not be the same as that for the original engine approval. In the 3rd and 4th steps, the engine is tested without and then with the REC on the weighted cold+hot WHTC or NRTC (as appropriate) to determine the relative reduction rate of the REC. The same cycles could also be applied for the NO2 part of the test programme. It was noted that the flow chart (Annex 12) will need to be modified.

In considering the testing burden it was said that, with appropriate definitions of REC families, it could be possible for HDV to certify for the whole range of engines with 3 to 4 families. Section 10 allows the definition of families that incorporate different engine manufacturers. It was suggested that aligning the family definitions with Euro VI Annex XI (replacement pollution control devices) might help minimise the requirements.

It was agreed that appropriate preconditioning procedures should also be addressed in the Regulation to ensure reproducibility whilst maintaining realistic loadings of PM and ammonia at the start of test. Germany agreed to draft preconditioning proposals and AECC offered to provide information on the processes that had been used to give realistic loadings in the AECC HD and NRMM test programmes.

Members were reminded that the ‘worst case’ Type II system for NO2 is different from that for PM, so requires additional tests. This could be considered in more detail later. One suggestion was that the ‘worst case’ system should only need to be tested once across the range of engine families. In response to concerns that ‘worst case’ might be a combination of substrate size and PGM loading that is not actually offered, it was clarified that the intent is to test the worst-case within the range of systems in the manufacturer’s portfolio and that the ‘worst case’ system would have to be agreed with the Type Approval authority.

The German proposal for the test cycles was accepted and it was agreed that Germany and AECC would work together on a pre-conditioning proposal to achieve good reproducibility.