diesel on propane

[kriegsman]

Did anyone of you ever try to run a diesel (generator) on propane?
Ofcourse you still need about 5% diesel for the ignition, but the rest could
be propane (with the efficiency of a diesel.
Anyone any experience?

(In our country propane is much cheaper than diesel)
..

 

[Scott O'Hearen]

You're saying two things. Yes, diesel engines are converted to run on
propane. However, you seem to also be asking if they can be converted to
run a mix of diesel and propane - well, that's different - and, no I haven't
heard of that.

Diesel engines are converted to run on propane in the high KW ranges where
industrial gas engines are no longer available. They are converted in low
quantities and are expensive.

 

[Diana Moon Glampers]

Diesel engines are converted to run on propane in the high KW ranges where
industrial gas engines are no longer available. They are converted in low
quantities and are expensive.

That's very intriguing. Propane carburation (not really an accurate
term with propane) is and combustion is so similar to gasoline and so
different from diesel, I'm really curious how this could be done.
Any pointers?

TIA
;B

 

[daestrom]

That's very intriguing. Propane carburation (not really an accurate
term with propane) is and combustion is so similar to gasoline and so
different from diesel, I'm really curious how this could be done.
Any pointers?

Yeah, I was kind of curious about this too. Many large diesels use an
injector system that is driven from the cam shaft. The injector is
basically a plunger-style pump able to quickly develop the extreme pressure
needed to inject into the cylinder near TDC. This is like 1800 psi or so.
How to compress the right amount of propane and quickly 'pop' it into the
cylinder at the right instant?? Curious how this could be done???

daestrom

 

[Eric Tonks]

I remember a number of years ago the gas utility that I worked for was
really anxious to demonstrate natural gas cars and trucks and mandated that
all their vehicles were to be converted. They purchased gasoline engines for
most new vehicles since conversion was relatively easy. However, they had a
lot of construction equipment and heavy trucks that were diesel. They did do
a conversion to natural gas, but I understand that it was only a partial
conversion. They still ran on diesel fuel but were supplemented with natural
gas to reduce fuel oil consumption and still maintain the lubrication that
diesel fuel provided to the cylinder walls. My failing memory recalls it
reduced the fuel by 15%, this way they could claim that they ran on natural
gas.

 

[Scott O'Hearen]

Folks,

OK - you've now made me have to go and drag out some old spec sheets from
the closet. Converting diesels to 100% natural gas is a common practice in
the genset industry. As I say, gas engines for conversion to natural gas
are only available up to a certain power output, but there is still a demand
for natural gas gensets above that range (although it is low). Diesel
engines are then converted and you pay through the nose because of the low
volume. However, I don't know how it's done, because I never had a customer
with a specialized application that was willing to pay the high price for a
high powered natural gas genset; hence, I never had the opportunity to study
one up-close. As I recall, the engines are basically converted to mimick a
gasoline engine - so throw out all of the glow plugs, fuel injection, etc.,
and put in good-ol spark plugs. An example from an old distributor spec
sheet follows:

100% Natural Gas/Propane 1800 rpm Engine Generator Set:

Engine: Ford 460
KW: 100
List Price: $26,415 US (1997 price)

Engine: Cummins GTA-8.3 GS1 (1997 price)
KW: 125
List Price: $42,440

You see what I mean on the price jump for the extra 25KW -- that's why MOST
folks buy a diesel to get the 125KW.

 

[clare @ snyder.on .ca]

I believe you mean "fumigation". A Google search of the phrase "diesel
propane fumigation" brings up a bunch of sites on the subject. Seems
that adding a certain percentage (by weight) of LPG into the airstream
will help burn the fuel close to the cylinder walls (too cool for
complete combustion). The improvement percentage is dependent on
whether you have fuel injection into a pre-burn chamber ( I forget what
it's called) which gives 5-10% or so, or direct chamber injection, which
can give up to 20% plus. The mixture has to be metered rather closely,
though.

Yes, propane fumigation is the same thing, and yes, too much will do
in the engine. Just the right amout will virtually DOUBLE engine life
due to reduced pressure spikes and elimination of oil dilution and
carbon loading of oil.

 

[Fred B. McGalliard]

I believe you mean "fumigation".

Diesel "knock" is found in ordinary gasoline engines when they carbon up,
increasing the compression, perhaps providing a red hot spark to cause an
ignition too early in the cycle for the normal spark ignition. The
preignition makes a hell of a knock because of it's inappropriate timing.
While I have never done much with diesel engines I thought they used fuel
injection to obtain a smooth burn at near top dead center? Otherwise I don't
see how you could get a diesel to fire when you want if you let the
compression fire the charge. Isn't that steady burn the characteristic that
separates the Otto from the standard IC cycle?

 

[clare @ snyder.on .ca]

Diesel "knock" is found in ordinary gasoline engines when they carbon up,
increasing the compression, perhaps providing a red hot spark to cause an
ignition too early in the cycle for the normal spark ignition. The
preignition makes a hell of a knock because of it's inappropriate timing.
While I have never done much with diesel engines I thought they used fuel
injection to obtain a smooth burn at near top dead center? Otherwise I don't
see how you could get a diesel to fire when you want if you let the
compression fire the charge. Isn't that steady burn the characteristic that
separates the Otto from the standard IC cycle?

The initial ignition event is violent, and the ensuing burn is longer
and smoother. The shock of the initial burn is part of the reason
Deisels must be so robust in construction. You've heard the signature
deisel "clatter", right? Well, fumigated or augmented properly a warm
deisel has no clatter. And no visible smoke. Very little smell, either
oil or sulphur.

 

[ben williams]

The initial ignition event is violent, and the ensuing burn is longer
and smoother. The shock of the initial burn is part of the reason
Deisels must be so robust in construction. You've heard the signature
deisel "clatter", right? Well, fumigated or augmented properly a warm
deisel has no clatter. And no visible smoke. Very little smell, either
oil or sulphur.

OK. if I release propane into the air intake (in the proper amount of
course), shouldn't it effect the same results?
Thereby doing away with the high pressure propane injection and exact timing
?
Diesel engines have in effect the same type of air intake as a fuel injected
car, the fuel (gas or diesel) being injected into the cylinders
directly......
ben

 

[Vaughn]

OK. if I release propane into the air intake (in the proper amount of
course), shouldn't it effect the same results?
Thereby doing away with the high pressure propane injection and exact timing
?

In a true diesel, the injecters perform an important timing function,
they do not squirt the fuel until the exact moment it is needed to fire in
the cylinder. That said, I have seen diesels started many times by
squirting starter fluit down the intakes, I was also told it was not good
for them.

Vaughn

 

[ben williams]

In a true diesel, the injecters perform an important timing function,
they do not squirt the fuel until the exact moment it is needed to fire in
the cylinder. That said, I have seen diesels started many times by
squirting starter fluit down the intakes, I was also told it was not good
for them.

Vaughn

Granted, but the injectors are still 'doing their job' if the propane is in
the airstream.
As for the starting fluid (ether), a lot of the trucks running in cold
country use it to start. Complete with dash controlled 'squirting' from a
bottle of it and tubing to the air intake (the ether is in bottles identical
to a small propane bottle, painted a light brown color and bought at the
truck stops).
ben

 

[clare @ snyder.on .ca]

OK. if I release propane into the air intake (in the proper amount of
course), shouldn't it effect the same results?
Thereby doing away with the high pressure propane injection and exact timing
?
Diesel engines have in effect the same type of air intake as a fuel injected
car, the fuel (gas or diesel) being injected into the cylinders
directly......
ben

This is EXACTLY what fumigating or augmentation does - feeds it
directly into the intake, in metered dose.

 

[ben williams]

This is EXACTLY what fumigating or augmentation does - feeds it
directly into the intake, in metered dose.

And how do I meter these doses? Or what company sell the metering device?
Sounds promising if the payback time is reasonable.....
ben

 

[Vaughn]

Granted, but the injectors are still 'doing their job' if the propane is in
the airstream.

Sorry, but the reason for the timing function of the injectors is to
regulate the moment of ignition, much like the distributor (or computer)
does in a gas engine. If you simply introduce a fuel at the air intake, the
injectors are not "doing their job". If you are using the propane simply to
augment the diesel fuel from the injectors, then there is still nothing to
keep the propane from premature ignition and therefore, efficiency may
suffer.

Vaughn

 

[clare @ snyder.on .ca]

And how do I meter these doses? Or what company sell the metering device?
Sounds promising if the payback time is reasonable.....
ben

The only system I have seen is simple. The propane is regulated by a
valve connected to the throttle, and on a deisel you regulate power by
regulating fuel, not air, so the more "throttle" the more fuel. A
thermostatically controlled solenoid valve prevents "augmentation" or
fogging when the engine is cold.

 

[ben williams]

The only system I have seen is simple. The propane is regulated by a
valve connected to the throttle, and on a deisel you regulate power by
regulating fuel, not air, so the more "throttle" the more fuel. A
thermostatically controlled solenoid valve prevents "augmentation" or
fogging when the engine is cold.

Sounds doable on a local level. Wish I had some numbers to work with
ben