Tim,
That was the most informative article on BMW's turbosteamer since the initial articles.
Each hybrid system has it's advantages and drawbacks. The HSD is great in stop-and-go traffic, the IMA does better in highway traffic, the Turbosteamer may do better yet. The article quote that got my eye is the Turbosteamer got a 20% improvement in fuel economy cruising at 75mph.
I've been in discussion on the Turbosteamer and the detractors point out the complexity and the high pressure as drawbacks. The best thing that could happen for this technology is the development of a very strong, yet lighweight engine block to contain the steam pressures.
My dream car could be a "tribrid" - either and HCCI gas/electric powerplant or a diesel/electric powerplant. It would use waste heat for a turbosteamer. You might surmise I'm not afraid of complexity.
