Turning car off at stoplights

[Racer X]

Forrest wrote:
It would not be safe on older vehicles to swich off the engine approaching a stop, because you would loose power steering and brakes. Hybrid vehicles are designed to turn the ICE off and still run the power steering and brakes - I assume these systems run on electric power.

Yes, they do. FAR more efficient.

I know these are really old numbers, but they illustrate the idea.

At full speed, a water pump driven fan can suck up 15 horsepower on an old American V-8 auto or truck. 765 watts equals 1 horsepower. That's @55 amps at 14 volts, assuming no power loss. So, a water pump driven fan can consume a massive amount of energy, and all but a tiny amount is wasted. An electric cooling fan, or even 2 11" or 12" ones can consume between 6 to 18 amps, depending on design. So, even a pair of big inefficient cooling fans only need 1/4 horsepower, assuming no power loss. Now you know why they went to electric cooling fans. Add to that electric power steering, electric water pumps, and electric A/C compressors. The power savings are HUGE.