I remember in the mid '70s looking under the hood of my family's enormous station wagon and being greeted by a solid surface of hoses and valves, all dedicated

I remember in the mid '70s looking under the hood of my family's enormous station wagon and being greeted by a solid surface of hoses and valves, all dedicated to meeting the recently-boosted emissions standards. Open an internal-combustion hood now, and it's much, much simpler.