Definition of "multi-fuel"

[Bighurt]

"Only a muilti-fuel as used on our MV's can run both Diesel and Gasoline because of the compression compensator."

I think it is the compression ratio....maybe Cranetruck will chime in?

I actually meant the density compensator and error on my part.

 

[Blood_of_Tyrants]

He claims that a CUCV is mult-fuel. Since it can run off of diesel, jet fuel, kerosene, home heating oil, veggie oil, and motor oil.

Most diesel engine will run on most of those products. Most diesels are not multifuel engines.

 

[m16ty]

The deuce engine was designed as a multi-fuel. The CUCV engine was designed as a diesel. Shoot, my deuce engine even says "multi-fuel" right on the data plate.

I guess technically both engines are diesel. Any compression ignition engine is by definition a diesel engine regardless what fuel it burns. When Rudolf Diesel invented the diesel engine I think it ran off of peanut oil.

 

[Bighurt]

When Rudolf Diesel invented the diesel engine I think it ran off of peanut oil.

That's correct.

 

[merlot566jka]

yup, dear old rudolf hit our veggie oil hippies idea many many years before they did. wonder what our world would be if they were powering the world with peanut oil.

anyway, where is this multi-fuel cucv guy?

 

[velociT]

When Rudolf Diesel invented the diesel engine I think it ran off of peanut oil.

His first design ran off coal dust.

 

[Preacherboy]

Really, I don't think he ever said that his CUCV would run off of gasoline, but he keeps insisting that it is still a multi-fuel...so I said by this definition any IDI or mechanically controlled diesel would be multi-fuel; but they aren't!

The thread in question is on survivalistboards...under the vehicle and transportation section. The thread is titled "my new bug out trailer"...they were speaking about m101a1's and this guy (I'm pretty sure he is a member here) gets on implying how unsafe they are to pull behind a regular vehicle; but he wouldn't give specific reasons...just said "do your own research".

So I called him out and said that he needed to be specific and while I was at it I sort of hi-jacked the thread and told him he was wrong about his CUCV (there are many other threads where he gets on and called his m1009 a multi-fuel too and I was getting tired of it).

Here is another thread where he makes this claim about his CUCV, and if you posted there it wouldn't continue hi-jacking the trailer thread.

If you would like to help stop this guy's nonsense here is a thread about the m1008 and adding comments here wouldn't be a continual derailment of the trailer thread Survivalist Forum - View Single Post - TRUCK, CARGO, TACTICAL, 1-1/4 TON, 4x4, M1008

My post in oposition is #40

 

[JasonS]

If you read the text books on engine design, the ONE factor enabling multifuel-ability is high compression ratio. There have been other multifuel engines which have neither a fuel density compensator nor the MAN combustion chamber design. That said, having really high compression ratio causes the combustion pressure rise fast and high which requires stronger internals (definately not what you will find in the 6.2/6.5).

Another common misconception is that the multifuel's high compression ratio results in high efficiency. ALL of the books that I have read suggest the lowest compression ratio which allows easy starting be used. More specifically, they suggest 18:1 for direct injection and 22:1 for indirect injection which pretty well agrees with what you will find in the field. Further, if you compare the BSFC of the multi to other diesel engines, it is on the poor side.

 

[cranetruck]

......Further, if you compare the BSFC of the multi to other diesel engines, it is on the poor side.

BSFC: "Brake Specific Fuel Consumption", fuel consumption related to the power produced.

Do you have a number for the multifuel?
I calculated my own based on highway speed, weight and fuel consumption some years ago and even if an approximation it was pretty good as I recall.

Part of the reason for the efficiency is the relatively slow combustion rate. The high compression ratio also lets you start the engine without aids at low temperatures.

Remember this is all before the age of the microprocessor.

Microscopic point, but the "Fuel Density Compensator" is a "fuel viscosity compensator" according to operation and original patent. I hooked one up one time and used it to measure viscosity, which changes with temperature, btw...

 

[JasonS]

BSFC: Do you have a number for the multifuel?
I calculated my own based on highway speed, weight and fuel consumption some years ago and even if an approximation it was pretty good as I recall.

Found this with a quick search:

8V92:
0.345 BSFC minimum at 1700 RPM, for an efficiency of roughly 39.8%.
0.355 BSFC at rated horsepower, for an efficiency of roughly 38.7%.

Series-60:
0.311 BSFC minimum at 1550 RPM, for an efficiency of roughly 44.2%.
0.315 BSFC at rated horsepower, for an efficiency of roughly 43.7%.

Using the BSFC from the LDS Troubleshooting manual and calculating efficiency:

LDS-465
0.400 BSFC minimum at 2000 RPM, for an efficiency of 34%
0.430 BSFC at maximum horsepower, for an efficiency of 32%

I'll add the efficiency data for the 5.9 cummins later....

 

[JasonS]

Found this with a quick search:

8V92:
0.345 BSFC minimum at 1700 RPM, for an efficiency of roughly 39.8%.
0.355 BSFC at rated horsepower, for an efficiency of roughly 38.7%.

Series-60:
0.311 BSFC minimum at 1550 RPM, for an efficiency of roughly 44.2%.
0.315 BSFC at rated horsepower, for an efficiency of roughly 43.7%.

Using the BSFC from the LDS Troubleshooting manual and calculating efficiency:

LDS-465
0.400 BSFC minimum at 2000 RPM, for an efficiency of 34%
0.430 BSFC at maximum horsepower, for an efficiency of 32%

5.9 Cummins with VP44
0.334 BSFC minimum at 2000 RPM, for an efficiency of 41.2%
0.365 BSFC at maximum horsepower, for an efficiency of 37.7%

 

[cranetruck]

Thanks for those numbers.

My calculations ended up in the range of 0.36 to 0.40 with MPGs from 8 to 10, right in the ball park...

 

[merlot566jka]

So no numbers on the LDT?

Those are low numbers on the multi. But then again its at a higher RPM than the other motors.

I see room for improvement.

 

[JasonS]

So no numbers on the LDT?

Those are low numbers on the multi. But then again its at a higher RPM than the other motors.

I see room for improvement.

I haven't been able to find numbers for the LDT. I woudl be surprised if they were much different.

The 5.9 cummins is a very fair comparison as the peak torque occurs at the same speed (2000 rpm) and peak horsepower is within 100 rpm.

 

[merlot566jka]

I wish I knew more about the multifuels, like cam specs and timing, and the injection pump timing. I bet we could get the BSFC up with some tweeking.

regardless, this has gone WAYYYY of topic.

 

[cranetruck]

So no numbers on the LDT?

Those are low numbers on the multi. But then again its at a higher RPM than the other motors.

I see room for improvement.

The performance curves from the TM is shown below.

Apparently the BSFC is based on MAX permitted fuel consumption for use during testing and may be lower for an actual motor.

Example: The max fuel consumption for a still acceptable performance is 80 lb/hr producing 180 hp, which is a BSFC of 0.444 (dividing 80 by 180).

Fuel consumption, torque and resulting hp can vary for an actual motor.

Similar numbers for the LDT would be 64lb/hr producing 140 hp or a BSFC of .457.

The LDS465-2 (with numbers from the TMs) 90lb/hr divided by 205 hp for a BSFC of .439.

Again, the MAX permitted fuel consumption (70 lb/hr) is used to figure a BSFC for the LDS465-2 at 2,000 rpm and 440 ft-lb torque (average of 425 to 455 range given) of .420 from the TM.
If a fuel consumption of only 60 lb/hr and the max torque is used, the BSFC becomes 0.344.

In conclusion, I would say the the numbers in the TMs are very conservative, which is military style anyway, to eliminate any surprises.

It would only be fair to see some actual numbers from a real life test when comparing to commercial engines that are, for sales reasons, shown in the best possible light, not the worst possible acceptable results.


Hp =rpm times torque divided by 5250.