But all the similar size Chevrolets are Korean designs now anyway !!
Peter Schreyer, as President of Kia Motors worldwide, has no say in which engines Kia America chooses to sell in their own market. By comparision to other world markets, North America still largely ignores diesels in cars so until public demand changes it's just not profitable for Kia, Hyundai or anyone else to make their existing diesels available - especially as they'll need to be built in Korea, and brought in for final assembly - at least initially as it'll need diesel production facilities in North America if and when diesel ever takes off.
Hyundai-Kia have already achieved something that GM have yet to do, design and build in-house a successful range of diesel engines for use in cars, after decades of experience with licence-built engines from VM Motori. Since 2009 they've been building, and selling in large numbers in "Rest of the World" the 2.0 / 2.2 R-series I4 and the related 3.0 V6 S-series
turbo-diesels to replace the now-outdated VM Motori engines that perversely Hyundai still build for GM Daewoo to put into Chevrolets!
GM has used a succession of other diesel car
cheap tires and engines, from Isuzu, VM Motori and Fiat and indeed now owns the rights to these engines but never developed them themselves - no wonder GM Europe (Opel/Vauxhall) struggles in markets dominated by diesels, which is everywhere except North America.