A survey of small passenger vehicle hybrid architectures relating to emissions testing and type approval procedures for the European market

The emergence of hybrid vehicle technology poses novel challenges to the emissions regulators and testers due to the unique and varied ways in which the systems may be implemented and the options for vehicle operation. In addition to this, the various technologies are relatively immature and are liable to change radically over the coming years and decades. This situation has led to a major revision of the emissions regulations to allow type approval for the new products in the EU market. The small passenger vehicle hybrid market thus far has been dominated by Japanese parallel hybrid designs but series hybrid implementations are in development by western manufacturers with many configurations conceived of but not yet realised. The purpose of this paper is to highlight the implications of a set of hybrid vehicle architectures with respect to emissions diagnosis and type approval testing.