Posted by Robert Morein on September 3, 2004, 6:23 pm
Are 1800 rpm gensets significantly more fuel efficient that 3600 sets?
Is fuel consumption more or less predictable?, based upon the combination
of:
1. displacement
2. number of cylinders
3. speed
Posted by William P.N. Smith on September 3, 2004, 8:33 pm
>Is fuel consumption more or less predictable?, based upon the combination
Look at the engine manufacturer's fuel consumption specs.
Posted by Robert Morein on September 3, 2004, 9:45 pm
<William P.N. Smith> wrote in message
> >Is fuel consumption more or less predictable?, based upon the combination
> Look at the engine manufacturer's fuel consumption specs.
I've been doing that.
However, they don't answer the question precisely, because they are usually
quoted for full/half load.
Now if my power requirement is generally, say, in some region like 4KW, that
isn't answered by the published figures, unless full/half corresponds to
4KW. At other values, the specs don't apply.
In the case of one generator I'm interested in, the Honda EB12-D,
http://www.hondapowerequipment.com/eb12.htm , fuel consumption specs are not
given at all.
If non-turbocharged diesel technology is stable, that would imply that there
should exist a formula based on displacement, number of cylinders, and
engine speed.
Posted by Me on September 3, 2004, 10:46 pm
> <William P.N. Smith> wrote in message
> > >Is fuel consumption more or less predictable?, based upon the combination
> >
> > Look at the engine manufacturer's fuel consumption specs.
> >
> I've been doing that.
> However, they don't answer the question precisely, because they are usually
> quoted for full/half load.
> Now if my power requirement is generally, say, in some region like 4KW, that
> isn't answered by the published figures, unless full/half corresponds to
> 4KW. At other values, the specs don't apply.
>
> In the case of one generator I'm interested in, the Honda EB12-D,
> http://www.hondapowerequipment.com/eb12.htm , fuel consumption specs are not
> given at all.
> If non-turbocharged diesel technology is stable, that would imply that there
> should exist a formula based on displacement, number of cylinders, and
> engine speed.
>
>
Fuel consumption in small (less than20Kw) diesel gensets can be
calculated empirically. Run the genset unloaded for two hours
and measure the fuel use. Run the genset at 25% load for two hours
and measure the fuel use. Run the genset at 50% load for two hours
and measure the fuel use. Run the genset at 100% load for two hours
and measure the fuel use. Build a spreadsheet with excel using the data
extracted and then graph it with the charting software in excel.
Then you will have your answer for that particular genset. You will
be able to extraploate between data points very easliy, and the line
will be very linear from 25% to 100%. I have charts for all my gensets,
from the 3Kw Onans, on up to the 20Kw Northen Lights units, and found the
charts to be very close to observed operation. bigger than 20Kw you get
similar results but the equasions get a bit messy, when cogeneration
is added in. CAT had a very good PFD on their website, that explained
how they figured the graphs for their BIG Prime Power Units.
Me
Posted by Robert Morein on September 3, 2004, 11:15 pm
> > <William P.N. Smith> wrote in message
> > > >Is fuel consumption more or less predictable?, based upon the
combination
> > >
> > > Look at the engine manufacturer's fuel consumption specs.
> > >
> > I've been doing that.
> > However, they don't answer the question precisely, because they are
usually
> > quoted for full/half load.
> > Now if my power requirement is generally, say, in some region like 4KW,
that
> > isn't answered by the published figures, unless full/half corresponds to
> > 4KW. At other values, the specs don't apply.
> >
> > In the case of one generator I'm interested in, the Honda EB12-D,
> > http://www.hondapowerequipment.com/eb12.htm , fuel consumption specs are
not
> > given at all.
> > If non-turbocharged diesel technology is stable, that would imply that
there
> > should exist a formula based on displacement, number of cylinders, and
> > engine speed.
> >
> >
> Fuel consumption in small (less than20Kw) diesel gensets can be
> calculated empirically. Run the genset unloaded for two hours
> and measure the fuel use. Run the genset at 25% load for two hours
> and measure the fuel use. Run the genset at 50% load for two hours
> and measure the fuel use. Run the genset at 100% load for two hours
> and measure the fuel use. Build a spreadsheet with excel using the data
> extracted and then graph it with the charting software in excel.
> Then you will have your answer for that particular genset. You will
> be able to extraploate between data points very easliy, and the line
> will be very linear from 25% to 100%. I have charts for all my gensets,
> from the 3Kw Onans, on up to the 20Kw Northen Lights units, and found the
> charts to be very close to observed operation. bigger than 20Kw you get
> similar results but the equasions get a bit messy, when cogeneration
> is added in. CAT had a very good PFD on their website, that explained
> how they figured the graphs for their BIG Prime Power Units.
> Me
I appreciate the knowledgable response. Unfortunately, I can't do this
because I don't own the gensets.
I'm looking at the Yamaha EDL6500S, which is a 2 cyl 570cc engine.
It looks like it burns a little more gas than the Chinese 1 cyl 406cc genny
I have on order.
I got the Chinese set below cost, so I could probably cancel the order.
The Yamaha is rated at 6KW, the Chinese unit at 5.5.
The Chinese unit has something called capacitor regulation with a brushless
alternator, which I gather is a passive system.
The Yamaha has AVR and brushes.
How inferior is capacitor regulation?
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