One key contributor to its unusual quietness is its rigid compacted graphite iron (CGI) block and bedplate. CGI typically reduces combustion noise 0.5 to 1.5 dBA vs. conventional gray iron.
The classic image of a V-8 is big and thirsty. Engineers set out to dispel that notion by making the small-block Gen V engines extremely efficient. Along the way, some dynamometers also got toasted.
Fuel cells have been a chicken-and-egg proposition between vehicle technology and infrastructure. The Hyundai Tucson Fuel Cell proves the vehicle technology now is ready for prime time.
Surprisingly, it was planned as a small-volume engine for high-performance compact S4s and S5s. Now it is Audi's only V-6 available in midrange A6s and A7s, the flagship A8 sedan and Q5, SQ5 and Q7 CUVs.
Honda engineers achieved impressive fuel efficiency and output without dual-overhead camshafts or direct fuel injection, which add substantial cost, complexity, mass and package size.
Clearly it will take time to find a following like VW has developed over decades in the U.S. But as far as the engine itself is concerned, the GM 2.0L turbodiesel is a strong start.