From: stephen@sprunk.org
On 06-Sep-15 14:00, danny burstein wrote:
> Stephen Sprunk writes:
>
>>> The related problem is that during the speedup/slowdown, there's
>>> even more ugliness until the engine stabilizes at the new speed.
>>
>> I'm not sure what you're referring to here.
>
> Let's say your engine is rotating at 2,000 RMP and you press down on
> the accelerator, boosting it to 3,000
>
> Even if they're both within that power band, there's all sorts of
> inertia before the fuel and air flow re-optimizes. It's much faster
> than in the carb. days, but it still takes time.
Ah, okay. I'd never thought about that; how significant is it with a
fuel-injected car? I've never driven a carbureted car, so perhaps I
just never noticed such a lag or connected it to that.
>> Parallel hybrids aren't that different from regular cars; the ICE
>> has to work over just as wide a range, just with the electric motor
>> adding or removing power that is stored in the batteries.
>
> In a properly designed parallel hybrid, when you pusj down the
> accelerator to gain more speed, some of the demand is inititally
> transferred, or provided by, the electric motor and batteries. Hence
> in stead of the gaoline engine going from 2,000 to 3,000 RMP [as fast
> as it can], the ramp up is (for illustration) only to 2,500 and can
> take a second or three.
In practice, the ICE will still go from 2k to 3k RPM but provide only
half as much power because it's half the size; the electric motor
provides the missing other half of the power. When you're done
accelerating, the gearing shifts and the engine drives the motor to
recharge the battery; when that's done, it drops back to 2k RPM.
S
--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking
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