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Old 10-26-2012, 07:10 PM   #7 (permalink)
mort
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Hi P-hack,
It's a good idea, but you need a transmission in this car, the Atkinson engine operates almost full throttle all the time it is producing appreciable power.



Quote:
Originally Posted by P-hack View Post
I am not sure how many hp you need at 73 mph, 35? maybe the engine would be 50% loaded? so you go from 230g/kwh to 265? (%15 difference), so maybe go a little faster?
The engine is never 50% loaded. Power is regulated by changing rpm. If you are zipping along at 60 mph, using 15 hp, which you can get at about 1500 rpm, then hit a hill and need 50 hp the engine must rev up to 3700 rpm.

But, this report: A fundamental case study on the Prius and IMA drivetrain concepts from Technische Universiteit Eindhoven (about 2004) shows that MG1 has pretty poor efficiency at low rpm (or locked) and high torques. It looks like 50% efficiency at locked rotor and 80 Nm (60 ft-lb)

So I dunno what to do about that.

-mort
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