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Thanks for the explanation! (Wow, so it is really possible to explain how the
steam engine works without using a single picture!)
In lugnet.off-topic.geek, Larry Pieniazek writes:
> Now, how to regulate speed? You use a thing called the throttle. This is
> essentially a bar that, via linkages that adjust the valve gear(2),
> regulates the proportion of the total stroke cycle that steam is
> admitted to the cylinder. The longer, proportionally, that the steam is
> admitted, the more expansion you get and the more work done against the
> piston face. As work increases beyond that required to maintain steady
> state you get acceleration.
This looks like the PWM (pulse width modulation) method RCX uses to control
its motor powers.
Why the steam engine here uses the throttle to control the _duration_ that the
steam is admitted, but not the _amount_ of the steam admitted (while keeping
the duration fixed), as in the internal combustion engines?
Thanks,
Hoa-yang Wang
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Message has 1 Reply:
 | | Re: Engine Speed Regulation
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| Well, James corrected me and he's right(1). The Throttle is a restrictor (if you look up throttle, one meaning is to cut off airflow) in the steamline. Restricting the flow reduces the pressure in the steam chest. However most valve gear (cf. (...) (25 years ago, 2-Nov-99, to lugnet.off-topic.geek, lugnet.trains)
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Message is in Reply To:
| | Re: Engine Speed Regulation
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| (...) Working from memory and I could be wrong. But I doubt it. Review. Reciprocating steam engines function by admitting pressurised steam into a chamber (the cylinder) where it expands, doing work against the walls. One of the walls (the piston (...) (25 years ago, 29-Oct-99, to lugnet.off-topic.geek, lugnet.trains)
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