It's really interesting to see Mazda take a lead in engine design. Once one would have expected this more from Honda. However, it's not all good. Apparently di

It's really interesting to see Mazda take a lead in engine design. Once one would have expected this more from Honda. However, it's not all good. Apparently direct injection gasoline engines emit more particulates than conventional gasoline engines. This may be a manageable problem and new regulations are supposedly in effect from 2017 in the US (unless they got caught in Trumps emissions control rollback), but that does not clean up the several years of cars with direct injection before now.