Propane injection on big cam cummins?

Hydrogen....

First a bit of theory again.

Similar to the octane number for gasoline indicates the knock(detonation) resistance for liquid fuels, there is the Methane Number for gaseous fuels. (Don't know why they invented this, as far as I'm concerned they could have just used the octane-rating scale)
The scales are different, for example methane has a methane number of 100, but octane number of 130,
propane has a methane number of about 36, but octane number of about 110.
(Even the octane numbers are a bit weird, there is RON, MON, and also used is the average of the RON and MON)

The higher the Methane Number the better the resistance against knock/detonation.
The scale is determined by the 100-point and the 0-point, 100 being the knock-resistance of 100% methane (methane is the main component in natural gas).
The 0-point is the knock resistance of 100% Hydrogen (this will already give you a clue)

A fuel with a methane number of 50 has the same knock resistance as a mix of 50%methane-50% hydrogen.
For example propane has a methane number of about 36.
For hydrogen it is 0.


Another thing about hydrogen is the fact that it has a very low energy density.
In gaseous/vapourous form the energy density of 1 scf of methane is only about 40% of propane.
The energy density of hydrogen is about 30% of methane, 12% of propane.

The nice thing about propane is that it has a boiling point (at atmospheric pressure) of about -40 degrees (F or C, at this point they are the same).
Even at low pressures, propane can be easily be stored/transported as a liquid (at ambient temperatures).
The energy density of the liquid propane is about 300 times higher than gaseous propane (at atmosperic pressure), but still only 70% of diesel. The energy in 100 gallon of propane is only 70% of the energy in 100 gallon of diesel.

For methane it is already looking very different. The boiling point at atmospheric pressure is at -160C or -260F.
To store methane on a truck, there 2 options:
1, in gaseous form (CNG), under high pressure (up to 3600 psi is common in North America, 3000 psi in many other areas). The energy density is still a lot lower than for propane, let alone diesel. You need multiple (expensive) high pressure cilinders to get a somewhat reasonable driving range. OK for the garbage truck or city delivery truck that returns to base every night (or few times per day) and can fill up again, but not good enough for long distance trucking.
2, as a liquid in a double wall vacuum-insulated tank. Basically a large thermos flask in which the methane is kept under (relatively) low pressure, but very low temperature (-220 to -180 F)
Energy density is about double compared to CNG, but still only 55-60% of diesel, but for many situations an acceptable range is possible (provided there are filling stations).
Tanks are very expensive (more than 10k $ easily), and many (spark ignited natural gas) trucks need 2 of these to even get an acceptable driving range.

Now hydrogen:
Boiling point at atmospheric pressure is about -420F. Even with a super-insulated tank, storing it as a liquid is not realy feasible or cost-effective on a truck.
Because of the very low gaseous energy density at atmospheric pressure, if you wan to have some range it needs to be stored under much higher than CNG. Typically close to 10k psi.
It takes a special kind of cilinder to do that, expensive/heavy.


So all things considered: hydrogen is not really a suitable fuel to be used as secundary fuel in an existing truck engine in somewhat larger (noticable) quantities, due to it's combustion properties.

In small quantities it may (but I have not seen proof of it) act as a sort of accelerant for the diesel combustion on older engines running with low injection pressures and slow combustion, more or less similar to advancing the injection timing.
The storage of a reasonable quantity of hydrogen on a truck is a big problem.

There are systems that use water and electrolysis to create hydrogen on the truck, but the amount of hydrogen they can produce is very very small. And they draw power from the alternator to create the electricity needed to produce the hydrogen.

I did test one of these systems on a truck (460 hp Euro-5) on a chassis dyno.
We started by running the engine at full torque on diesel, and than switching on the hydrogen system, without changing the diesel fueling.
If the hydrogen would improve the combustion efficiency or if the amount of hydrogen would be noticable as secundary fuel, the torque/power of the engine would have to increase when the system became operational.
We saw exactly.... nothing.
The inventor of the system was disappointed, and wanted to increase the hydrogen flow to the engine, so a second system was installed. Result was the same, no change in power or torque.

In my opinion hydrogen can be a great fuel for a fuel cell, but much less suitable for an internal combustion engine.

Or, as a former colleague used to say: Ir's the fuel of the future......and it always will be.

 

I believe that there was a transit bus fleet somewhere out west, I want to say Vancouver, Canada? that played with powering buses with Cummins natural gas engines with a mix of Hydrogen and CNG. Don't think it worked out, they stuck to regular CNG after the test was over.

 

Yep, recognize both names.. Both Long gone now though

 

A lot of info to digest on a Monday morning, but very interesting and informative, I'm having thoughts of acetylene, any stats on it as an additive?Also straight methane, like is produced at a landfill or a sewerage plant.

 

This is the silliest thread yet. Get a 600 Cat, and be done with it already. You could pull Monteagle loaded with the motors today, sheesh,,

 

interesting conversation, cant see it being too practical though, unless mabye if you are local and have a big propane re-filling station in your yard. even though many gas stations do sell propane i could see it being a big hassle.

iv heard of propane being used as a power adder in smaller diesels as well but power could be added using bigger injectors as well. and not have to have a secondary fuel source.

 

We're not just talking about power, in small quantities it can make your engine run cleaner and more efficient. Chef of the future.

 

so will upgrading your turbo

 

Just talking hypothetically here, although it would give a nice boost to my little pre-egr 12.7, just for them big hills, c'mon.

 

You are right.

As a power added, I would never recommend it.

As a (partial) diesel replacement to save on fuel costs, it only makes sense if propane (or natural gas) is cheap enough compared to diesel, if you burn enough fuel (run enough miles per year), and if the propane/natural gas is readily available where and when you need it, it can work out.


I'm not familiar with fuel prices in USA, so I just took some numbers, they may be all wrong.
Example 1:
Assume a truck doing 90 thousand miles per year, at 6 mpg, and diesel price of $3 per gallon, and propane of $1.50 per gallon.
That means 15000 gallon of diesel, 45000 dollar per year.

If you replace 20% of the diesel by propane, the truck will now use 12000 gallon of diesel and 4200 gallon of propane (about 40% higher than diesel because of lower energy per gallon).
Total fuel cost: 36000 + 6300 = 42300.

Fuel cost lowered by 2700 per year. In my opinion not enough to justify the investment and the hassle.

Example 2:
Same truck, but now 50% of diesel replaced with CNG, at $0.80 per DGE (diesel gallon equivalent, the amount of CNG that has same energy content as 1 gallon of diesel)

Truck will now use 7500 gallon of diesel per year, which costs 22500.
It will also use 7500 DGE of CNG, which costs 6000.
Total fuel costs: $28500, saving of $16500 per year.
And what if the gas company pays for the conversion, like they do in some countries, no upfront investment?

Starts to make sense now, doesn't it? But it all depends on the fuel prices and how the truck is used.