Slow Speed Diesel Engines > Changfa Engines
Slow rpm Chang fa?
bigbad:
I am looking at websites for the Chang fa and related and I only see conflicting info - mostly look at the mfg page. One part they say 800ish rpm and on another part of the same page they say something like 2,500 rpm. Is there a Chang fa that is really a slow speed engine?
guest18:
I don’t know of any Changfa, Chang-Chai (Chinese) diesels that are designed to operate continuous at speeds below or near 1000 rpm.
All the S195 and larger horizontal single cylinder (Changfa, Chang-Chai) Chinese diesels operate, I believe up to 2,200 rpm’s. Most work fine direct driving an 1800 rpm 60hz or 1500 rpm 50hz generator head. They are tough engines that proven themselves to take quite a beating and still able to run for long hours. All engines are designed to run at certain speeds and it’s best to stay within the parameters the manufacturer spec’d the engine run.
Veggie is a member here and on the microcogen.info forum. He has modified S195 engines to operate at lower speeds successfully. He spent hours on his projects and acquired the knowledge to get these engines to run at lower speeds reliably. It does cost money for the average person to do these modifications. I believe Veggie had access, or known people in a machine shop to machine the parts for his engines. His work is beautiful I would recommend checking out some of his builds.
I my opinion, Veggie is an exception to the rule of staying within manufacturer’s spec’d engine operating parameters.
38ac:
Member here Veggie modified one to run at maximum efficiency when running slow and his work is impeccable.
That being said they are all variable speed governed. You can run one anywhere from just off idle to full RPM and have good governor response without doing anything to it other than adjusting the throttle. If you intend to run one at a lowered RPM, AND and at full load AND continuous then it would be beneficial to back down the injection timing a few degree. Other than that don't worry about it. Remember that when you lower the operating speed that the availabile HP also drops. A 195 is probably a 6HP engine at 1000 RPM, just guessing from experience.
mobile_bob:
i did a lot of testing back around '07-'09 with a changfa s195
it had no problem running and carrying a load at 1000rpm
i didn't back off the timing, and used it to drive a 555 alternator at 2880watts at 28.8 volts
no problems at all, and i think i could have gone lower with as suggested reduced timing, but because the unit was setup to run dual speed 1800 and 1000 i didn't want to alter the timing.
tough as nails engine's that likely could be made to run at lower rpms, and do it well.
i always figured that 1000rpm was a good spot to run at, but i know veggie got one running slower.
bob g
guest18:
Yes Veggie did get one to run slower than a 1000 rpm.
On one of Veggie’s projects he machined the flywheel to accept additional weight. The additional weight helps with rotational stability (inertia). +1 on retarding injection pump timing.
Here is a topic of his slow running S195.
http://www.microcogen.info/index.php?topic=477.0
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