Three Gallons Per Hour

On Apr 13, 8:02*pm, "Peter Dohm" wrote:

And the Wilksch Airmotive numbers for specific fuel consumption are
resoundingly unimpressive for a diesel. *It sure is light though!

Peter- Hide quoted text -


Not sure if you are being sarcastic about the weight, but you do
realize the weight was in kilograms, right? 127 kilograms = 279
pounds, which is pretty heavy for a three-cylinder engine.

Phil

On Apr 13, 12:29 pm, Denny wrote:
Hmmm, My BS meter is twitching...This is a BSFC of ~0.142
------------------------------------------------------------------------

No it isn't :-)

Jet fuel is about 6.8lbs/gal. 3gph is about 20.5 lbs. SFC for a
turbosupercharged diesel is considerably better than the 0.5 used for
normally aspirated gasoline engines. Even the old Packard radial
diesel did pretty well in the SFC department.

Based on the available data, the figures are credible, in my opinion.

-R.S.Hoover

Phil J wrote:
On Apr 13, 6:21?pm, M wrote:
On Apr 13, 4:13 pm, Phil J wrote:



Indus claimed three gallons per hour for a flight from Dallas, Texas
to Lakeland, Florida. ?I would guess that they throttled back to the
leanest possible cruise.

No doubt that 3gph figure must be an economic cruise power setting,
likely below 50% power.

BTW on a diesel, the combustion is well lean of stoichiometric even at
the max rated power. ?The air intake is not throttle and the
"throttle" control in a diesel engine is the fuel flow control.
There's no such thing as lean of peak or best power mixture :-) ?You
reduce the fuel flow and the engine produces less power. ?You increase
the fuel flow and the engine produces more power - until you reach the
soot limit or other thermo/mechanical limit for the particular engine
and that's the max rated power.

See this is what I like about this newsgroup. I am always learning
something new. I've never had direct experience with a diesel engine,
although I suspect that there are going to be more of them in cars as
American fuel prices rise.

Diesel used to be cheaper then gasoline and people started buying
diesel cars.

Diesel now costs about the same as gasoline and people have stopped
buying diesel cars.

Unless the price of diesel drops significantly with respect to gasoline,
there is no reason to think diesel cars will make a comeback.


--
Jim Pennino

Remove .spam.sux to reply.

On Apr 13, 10:35*pm, wrote:
Phil J wrote:
On Apr 13, 6:21?pm, M wrote:
On Apr 13, 4:13 pm, Phil J wrote:

Indus claimed three gallons per hour for a flight from Dallas, Texas
to Lakeland, Florida. ?I would guess that they throttled back to the
leanest possible cruise.

No doubt that 3gph figure must be an economic cruise power setting,
likely below 50% power.

BTW on a diesel, the combustion is well lean of stoichiometric even at
the max rated power. ?The air intake is not throttle and the
"throttle" control in a diesel engine is the fuel flow control.
There's no such thing as lean of peak or best power mixture :-) ?You
reduce the fuel flow and the engine produces less power. ?You increase
the fuel flow and the engine produces more power - until you reach the
soot limit or other thermo/mechanical limit for the particular engine
and that's the max rated power.
See this is what I like about this newsgroup. *I am always learning
something new. *I've never had direct experience with a diesel engine,
although I suspect that there are going to be more of them in cars as
American fuel prices rise.

Diesel used to be cheaper then gasoline and people started buying
diesel cars.

Diesel now costs about the same as gasoline and people have stopped
buying diesel cars.

Unless the price of diesel drops significantly with respect to gasoline,
there is no reason to think diesel cars will make a comeback.

--
Jim Pennino

Remove .spam.sux to reply.- Hide quoted text -

- Show quoted text -

True. It all depends on the price difference between gasoline and
diesel. But diesels typically get 30-35 percent more miles per gallon
than gasoline. I would think a small diesel in a hybrid would make
for a very fuel-efficient car.

Phil

On Mon, 14 Apr 2008 03:35:04 +0000, jimp sayeth:


Diesel now costs about the same as gasoline and people have stopped
buying diesel cars.

Unless the price of diesel drops significantly with respect to gasoline,
there is no reason to think diesel cars will make a comeback.

At least in the past 6 months since I've owned a diesel car, diesel fuel
has always costs much more than regular gas. Right now premium is about
$3.60, and diesel is right around $4.

Usually you take the difference between regular and premium, multiply by
1.5, then add that to the cost of premium to get the approximate price of
diesel.

Phil J wrote:
On Apr 13, 10:35?pm, wrote:
Phil J wrote:
On Apr 13, 6:21?pm, M wrote:
On Apr 13, 4:13 pm, Phil J wrote:

Indus claimed three gallons per hour for a flight from Dallas, Texas
to Lakeland, Florida. ?I would guess that they throttled back to the
leanest possible cruise.

No doubt that 3gph figure must be an economic cruise power setting,
likely below 50% power.

BTW on a diesel, the combustion is well lean of stoichiometric even at
the max rated power. ?The air intake is not throttle and the
"throttle" control in a diesel engine is the fuel flow control.
There's no such thing as lean of peak or best power mixture :-) ?You
reduce the fuel flow and the engine produces less power. ?You increase
the fuel flow and the engine produces more power - until you reach the
soot limit or other thermo/mechanical limit for the particular engine
and that's the max rated power.
See this is what I like about this newsgroup. ?I am always learning
something new. ?I've never had direct experience with a diesel engine,
although I suspect that there are going to be more of them in cars as
American fuel prices rise.

Diesel used to be cheaper then gasoline and people started buying
diesel cars.

Diesel now costs about the same as gasoline and people have stopped
buying diesel cars.

Unless the price of diesel drops significantly with respect to gasoline,
there is no reason to think diesel cars will make a comeback.

--
Jim Pennino

Remove .spam.sux to reply.- Hide quoted text -

- Show quoted text -

True. It all depends on the price difference between gasoline and
diesel. But diesels typically get 30-35 percent more miles per gallon
than gasoline. I would think a small diesel in a hybrid would make
for a very fuel-efficient car.

Modern internal combustion engines all have the same efficiency no
matter what the fuel is.

Diesel has about 15% more energy per gallon than gasoline.

So, for equal weight, aerodynamics, and engine power, a diesel car has
a 15% advantage on a per gallon basis.

There are some other minor differences such as a X HP diesel will weigh
a little more than a X HP gasoline engine and slightly different
HP vs RPM curves, etc., but they will all be trivial to the overall
milage numbers over any significant amount of time.


--
Jim Pennino

Remove .spam.sux to reply.

It takes more crude oil to make a gallon of diesel than a gallon of
gasoline.

I don't have any figures immediately available, but I expect there's
no real advantage in going to diesel on a miles per barrel of oil
basis. It might seem that way on a dollars at the filling station
basis, but that's due more to tax policy than energy efficiency.


On Apr 14, 6:08 am, Phil J wrote:

True. It all depends on the price difference between gasoline and
diesel. But diesels typically get 30-35 percent more miles per gallon
than gasoline. I would think a small diesel in a hybrid would make
for a very fuel-efficient car.

Phil

wrote in message
...
...
Modern internal combustion engines all have the same efficiency no
matter what the fuel is.

If that were true, I wouldn't have a job...


Diesel has about 15% more energy per gallon than gasoline.

So, for equal weight, aerodynamics, and engine power, a diesel car has
a 15% advantage on a per gallon basis.

Nope. A "typical" diesel has a higher compression ratio - that increases the
efficiency. They "typically" aren't throttled which reduces pumping work and
increases the efficiency (more a factor for automobiles than aircraft which
tend to run at higher power (except when doing pattern work)). The
stratified nature of the combustion reduces the heat loss to the walls /
coolant which improves the efficiency.

On the other hand, the higher pressures require stronger stuctures, and the
stratified combustion reduces the abilty of the engine to use the air which
reduces power /displacement and power / weight which leads to lower
"installed" efficiency and is why turbos are so popular on diesels.

The final advantage then depends on a lot of variable (including how the
engine is used) but it will typically exceed the simple advantage of the
increased energy density of the fuel.

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

"Phil J" wrote in message
...

True. It all depends on the price difference between gasoline and
diesel. But diesels typically get 30-35 percent more miles per gallon
than gasoline. I would think a small diesel in a hybrid would make
for a very fuel-efficient car.

++++++++++++++++++++++++++++++++

You don't get the same payback from the hybrid with a diesel since they
don't suffer as much of an efficiency loss at lower loads that typical
gasoline engines do.

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

Capt. Geoffrey Thorpe The Sea Hawk At Wow Way D0t C0m wrote:
wrote in message
...
...
Modern internal combustion engines all have the same efficiency no
matter what the fuel is.

If that were true, I wouldn't have a job...


Diesel has about 15% more energy per gallon than gasoline.

So, for equal weight, aerodynamics, and engine power, a diesel car has
a 15% advantage on a per gallon basis.

Nope. A "typical" diesel has a higher compression ratio - that increases the
efficiency. They "typically" aren't throttled which reduces pumping work and
increases the efficiency (more a factor for automobiles than aircraft which
tend to run at higher power (except when doing pattern work)). The
stratified nature of the combustion reduces the heat loss to the walls /
coolant which improves the efficiency.

On the other hand, the higher pressures require stronger stuctures, and the
stratified combustion reduces the abilty of the engine to use the air which
reduces power /displacement and power / weight which leads to lower
"installed" efficiency and is why turbos are so popular on diesels.

The final advantage then depends on a lot of variable (including how the
engine is used) but it will typically exceed the simple advantage of the
increased energy density of the fuel.

Granted, but not by a whole lot for a car application with both engines
using all the techo advantages available today and constrained by
EPA requirements over 100,000 miles of usage.

Comparing anything other than car engine to car engine is apples and
oranges.

For aircraft applications, the biggest motivator is the fact that
AVGAS has become a boutique fuel with a good chance of disappearing
in the future while JET-A will always be around short of Armageddon.


--
Jim Pennino

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