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Why use a turbocharged engine for the backup generator? Wouldn't a naturally aspirated engine be simpler, cheaper and more reliable? Also, it would not require more expensive high octane gas. Typically turbochargers are used to boost horsepower for acceleration. If an engine/generator runs at a constant speed and load won't that make a turbocharger unnecessary? Would it be a water or air cooled engine? This may be a good application for an air cooled engine. If the engine runs only when the car is moving there would be a constant flow air for cooling. An air cooled engine would eliminate the need for a radiator, pump and what not for cooling making it cheaper and lighter. What other engine options have been considered? Will GM offer different engine options.

Thank you for your consideration,

jed
 

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Jed,

You are correct about turbocharging normally boosting acceleration performance. What turbocharging does for the Volt's ICE is give it more horsepower at the modest rpm/rpm range it will operate in. Without turbocharging the small ICE might have to operate at a higher rpm to cover the duty cycle which would consume more fuel.

Think of it this way, under heavy loads the generator might strain the ICE and cause it to kick up to and maintain a higher rpm and resultant HP and gas consumption. With turbocharging this HP would be available at a lower rpm saving fuel.

Turbocharging may also benefit the E85 performance of the Volt's ICE, at least theroetically, but this remains to be seen. The theory is that because turbos have an effective compression ratio that's greater than its mechanical because of pre-compression at BDC. E85 at 110+ octane needs high compression for efficiency and to compensate for lower energy.
 

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Flat-4

Why don't they use a "Flat-4", seeing as they don't need some much displacement, you could possibly turbo-charge and air cool in a flat 4 configuration. Like a scaled down covair.... Only, GM will hopefully mind the rear suspension this time around...

chevy was the first to market with the turbo, flat-6.... why not bring back the old breakthru, better and badder than before???
 
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