What's Wrong With What We've Got?
Most of us are driving or riding around with a similar engine to the DOHC poppet-valve piston engine pictured above.

Obviously it works.  So why do we need to change?

Aside from the human aspects of owning a car - the expense, the road rage, the chores that friends and family get you to run for them, the lack of exercise, the roading costs, the increasing difficulty of parking - there shouldn't be anything wrong.

It's what you aren't being told that is the problem.
Next page: Additives, Pollutants, and Ethics