Changfa engine?

[rcavictim]

Another question - would a 195 work well directly connected to a 5kw gen head @ 1800 RPM?

It would be a perfect hardware match and would run well.  Don't sue me if you only get 4.8 kW out.  It will be close to gen head rated capacity but dependant on fuel and elevation above sea level. 

[mobile_bob]

there are those that have the 195 coupled to an st10 with good results

i have extensive testing with a heavy st 7.5 and in my opinion it is a better match to a s195 than an st5

the s195 will allow the st7.5 to make 6 kwatts no problem and with no smoke
6kwatt is right in the sweet spot of efficiency of a st7.5

this is for a direct drive 1800rpm setup

if you want to belt drive and slow the engine down to around 1500 then an st5 would be a good match
as far as power production.

the thing is you need to get to about 6kwatt load to get into the best efficiency of the engine
the baseline consumption of the engine is such that the first few kwatts are the most expensive kwatt
to produce as far as fuel consumed per kwatt/hr.

that holds true of about any engine driven genset btw

for instance a typical listeroid 6/1 might consume .333-.350 gal/kwatt/hr producing 1 kwatt
and drop to around .125 gal/kwatt/hr at 3 kwatt load. (so you get much more power for the same fuel consumed
if you can keep it loaded near its peak)

set up right the changfa 195 can get as low as ~.100 gal/kwatt/hr at ~6kwatt load

i don't know what you have in mind for a st head, there are cheap st heads out there
that are lighter than the better ones,, the difference is not all cast iron, but more copper.

the man you are dealing with on the s195 has the heavier and in my opinion better st heads as well.
just in case you haven't bought one yet.

then there is this.

depending on what you wanna do, if you want to also drive a hd alternator for battery charging
and plan on doing regular charging then you might be better served with an st5 and run it at 3 or 4kwatt
and have 2-3 kwatt capacity left to drive the hd battery charging alternator as well?

there is a lot that can be done with that engine.

pm me if you need any other info, and i will help in anyway i can.

bob g

[oliver90owner]

Hi Bob,

6kwatt is right in the sweet spot of efficiency of a st7.5

Do you have the efficiency curves for any of these head?  That information would be useful to assess whether a particular sized head is better than another at a particular load.

for instance a typical listeroid 6/1 might consume .333-.350 gal/kwatt/hr producing 1 kwatt
and drop to around .125 gal/kwatt/hr at 3 kwatt load  Typical fuel consumption figures I have seen from George's site are:

0.17 gph at 1kW and  0.13gph/kWh at 3kW.  Presmably US gallons (ad metric kW ).  That makes about a 25% improvement at fuller power?  Of course comparing 1kW with 6kw for a bigger engine is going to make a bigger diference.  All figures approximate.  Ymmv.

Regards, RAB

[mobile_bob]

for instance a typical listeroid 6/1 might consume .333-.350 gal/kwatt/hr producing 1 kwatt

i had a brain fart on that one,
the best documented i had was around .2 gal/kwatt/hr for the first kwatt, reducing to about .125 gal/kwatt/hr at 3 kwatt loading

anyway the idea still holds, just not a dramatic

good catch RAB

as for the efficiency curve of the st head, i only have info on the st7.5 heavy series
and it will take me another 2 weeks to fully document that curve, i am awaiting a part so that i can finish testing.

this much i am pretty sure of, that is the st7.5 is between 85-87% efficient peaking at 87% at 6.5kwatt loading.
that is from about 3 to 6.5 kwatt loading,, i haven't got all the numbers to calculate the lower load efficiencies yet.

for the sake of an arguement i am certain that it is good for a solid 85% at a bit over half load
fwiw
i am going to rerun all the testing again when i get some more accurate instrumentation, so the numbers might be off a touch.
that i hope to have in place in the next few days.

bob g

[rcavictim]

there are those that have the 195 coupled to an st10 with good results

i have extensive testing with a heavy st 7.5 and in my opinion it is a better match to a s195 than an st5

the s195 will allow the st7.5 to make 6 kwatts no problem and with no smoke
6kwatt is right in the sweet spot of efficiency of a st7.5

this is for a direct drive 1800rpm setup
<snip>
set up right the changfa 195 can get as low as ~.100 gal/kwatt/hr at ~6kwatt load

bob g

Bob,

Wow, guess I was being a bit too conservative in my guestimate. I really have no firm idea of the power curve at 1800 RPM on that engine so I stood on the rated output point, 12 HP at 2200 RPM and threw a dart.   That is very good power output for a 195 engine I'd say.  That 0.1 gallon/kW/hr at a 6 kW rate is fantastic!  Just to be clear, this is with a indirect (precup) injection engine?  Direct injection is supposed to have a slight edge on the fuel efficiency.

My Changfa 1115 is a D.I. engine and I do not have it set up yet to make serious testing possible.  With luck I'll be able to assemble the power plant that I bought this engine for this winter.  Luck means in large part finding a 12-15 kW, 3-phase generating head.

[mobile_bob]

the changfa S195 is an idi engine, it is rated 12 hp at 2000rpm, not 2200 and has a one hour
rating of 13.2 hp at 2000rpm

so conservatively if you direct drive

1800/2000 = 90% power

90% of 12 hp is 10.8hp

so in keeping with 2hp per kwatt,, figure 5.4 kwatt
i know it will burn very cleanly at that leve and do that all day long no problem at all.

with removal of the coolant tank, install of the block off plate, t stat, radiator and fan
the engine can be maintained at around 210 degree F, it will carry 6 kwatt direct drive
with no smoke and consume approx .100 gal/kwatt/hr

i have heard from a realiable source that an 1115 with DI, will make 10 kwatt at 1800rpm (w/st12 head)
no problem, burn clean and consume .085 gal/kwatt/hr.

not many lister/oids can match those numbers.

bob g

[rcavictim]

Bob,

I figured the 195 was rated 12 HP at 2200 RPM, not 2000.  Therefore 1800/2200= 82% power.  At 2 HP per kW, that's only 4.9 kW.  My 1115 is rated at 2200 RPM IIRC.  That consumption spec at 10 kW you posted sounds like something for me to look forward to for sure!

[mobile_bob]

personally i think the changfa is an under appreciated often overlooked alternative to the listeriod.

its biggest complaint is its noisy.

noise i can work with, flicker, gib keys, constant tinkering, ton of concrete?

seems like a good tradeoff to me

especially since it is more frugal with fuel to start with.

fellow changfa owners unite!
stand up and be counted!
we don't need to be in the dark anymore!



bob g

[mobile_bob]

anybody know of a changfa forum?

if not we need to start one!



bob g

[rcavictim]

anybody know of a changfa forum?

if not we need to start one!



bob g

You and me and who else?

[mobile_bob]

i dunno, there has gotta be more than the two of us?


hello??
bob g

[Tom]

All right you changfa guys, just remember only the Listeroid is a chick magnet. And us allowing you to hang here allows a bit of that cachet to rub off. 

[mobile_bob]

hey us changfa guys have rights to you know!!!

glad to see you guys are so tolerant, so politically correct



comeon out of the closet you changfa lovers!

stand proud!

lol

bob g

[mkdutchman]

I have an air cooled changfa 165F 

[roverjohn]

I have a Yanmar TS50C that I'll call a Changfaoid. Does that count?