[hheynow]

[ QUOTE ]
The Effects of Biodiesel Properties on Diesel Injection Timing, M. Tat* 1 ,J. Van Gerpen 1 ,1 Iowa State University, United States.

Biodiesel is defined as an alternative diesel fuel comprised of mono alkyl esters of long chain fatty acids derived from vegetable oils or animal fats. Biodiesel is completely soluble in petroleum-based diesel fuel, so biodiesel can be used as a blend with petroleum-based diesel fuel. However, biodiesel has different physical properties that affect the diesel fuel injection system and the diesel engine emissions. Biodiesel has a higher speed of sound, isentropic bulk modulus, density, and viscosity that change the fuel injection timing and engine emissions. The objective in this study was to investigate the effect of biodiesel's speed of sound, isentropic bulk modulus, density, and viscosity on diesel injection timing. A John Deere 4045 T diesel engine was used for this research and three different distributor type fuel injection pumps were tested.It was found that the properties of biodiesel affects the fuel injection system and advances the fuel injection timing. These changes were found to be dependent on the specific fuel injection pump used and this was attributed to variations in factory tolerances. It was observed that the start of injection timing of biodiesel was advanced about 0.68 to 1.38 crank angle compared with petroleum-based diesel fuel. When comparing the different fuel injection pumps it was found that from half to all of the advancement was due to the increase in the fuel delivery needed to overcome the power loss that results from biodiesel's lower energy content. As much as half of the advancement was due to the higher speed of sound and isentropic bulk modulus of biodiesel fuel. It was also found that at the same temperature, the fuel delivery of biodiesel was higher than for petroleum-based diesel fuel because of the higher viscosity of biodiesel. At the same viscosity level, it was found that the fuel delivery of petroleum-based diesel fuel was still higher than biodiesel. This was judged to be a result of the orifices in the fuel injection pumps restricting the amount of fuel flow for more dense fuels and the reduction in the amount of fuel delivery affects the fuel injection timing.It was concluded that the different fuel properties of biodiesel have a significant effect on the injection timing. Increasing fuel delivery advances the fuel injection timing following the design characteristics of the pump. The higher speed of sound and the isentropic bulk modulus of biodiesel also advance the fuel injection timing. Additional timing effects were identified as resulting from density and viscosity changes. However, these effects vary for each fuel injection system and in some cases may cancel. It was also concluded that the effects of some properties are coupled and cannot be separately identified by changing one without changing the other, such as density and viscosity.

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from: HERE


If bioD is so good for an engine, how good is it to change the injection timing? /ubbthreads/images/graemlins/shrug.gif I've noticed a big difference between running #2 and then B99 or WVO. My acceleration and max boost readings are always slower and lower on bio fuels. /ubbthreads/images/graemlins/confused.gif

 

[DR435rider]

Biodiesel has less BTU per pound that diesel. But, as I understand it, WVO and biodiesel both burn at a different rate than diesel. The idea is to optimize the burn rate to make the most power out of each fuel. You could very well tune an engine to make more power out of biodiesel than you are currently getting out of diesel. However, our industry hasn't done that much yet on engine performance optimization on biofuels.

It seems folks are either into saving money or making power. Few are into both. Jason at Vegistroke is one who seems invested in making big power while doing it on 'free' fuel.

Todd

 

[Spencnaz]

The reason for the timing advancement in the fuel pump is that biodiesel has a higher cetane rating than regular diesel fuel.

If memory serves RME (rapeseed methyl ester) has a cetane rating hovering in the high 50's range.

Dr. Van Gerpen is now at the University of Idaho (not far from my hometown of Lewiston). They have done extensive tests on the affects of biodiesel on diesel engines that are common to light duty and heavy trucks. In fact they were one of the pioneers of the subject.

 

[JOAT]

IIRC Elsbett used to retard timing slightly on thier conversions, but later were rumored to have stopped doing that. I've advanced the timing experimentally with the EOT mod but it doesn't have the same improvement in performance with VO or Bio like it does on #2 petro. Be interesting to research on a dyno.

 

[Halitosis]

[ QUOTE ]
Dr. Van Gerpen is now at the University of Idaho (not far from my hometown of Lewiston). They have done extensive tests on the affects of biodiesel on diesel engines that are common to light duty and heavy trucks. In fact they were one of the pioneers of the subject.

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That name doesn't sound familiar, but the U of I just got a $X million dollar grant (can't remember the actual number, but I thought it was like 20-30 Million) to do more extensive studies on Biodiesel. IIRC, the primary purpose of the project was to see if they could come up with some sort of a hybrid crop that would allow BioDiesel to be used in (extreme?) colder weather.... essentially busting through "Biodiesel's Kryptonite".

I took my WVO truck over to their research lab about 5 months ago... shook hands with Joe (Thompson? Thomas? can't remember now... he was on the way out to greener pastures, anyway). It was obvious that the crew over there didn't have much of an interest in the mechanical conversion on the WVO side, only the BioDiesel side. (I personally think that attitude is a shame... while WVO and BioDiesel folks have slightly different philosophies, I think we are cut from the same stock).

My .02

Halitosis

 

[RickHredf250]

So how does this effect a Powerstroke that does not have an injection pump?
B50 with #2 I still turn low 15's in the 1/4 mile so no complaints from me.

Van Gerpen is very well known with in the Biodiesel movement, never met him but see him name everywherre I go to do with Biodiesel production.
Rick H...

 

[macmaniac1]

I went to a renewable energy conferance and they said that a 10% blend of alcohol would make biodiesel equal to the energy content of regular diesel as well act as an oxidizer. I wonder how this would fit into the injection timing and performance of biodiesel.?

 

[OMCUSNR]

[ QUOTE ]
I went to a renewable energy conferance and they said that a 10% blend of alcohol would make biodiesel equal to the energy content of regular diesel as well act as an oxidizer. I wonder how this would fit into the injection timing and performance of biodiesel.?

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This might be OK for an older IDI system, but you don't want ANY alcohol near a newer high pressure injection system. The alcohol is hydroscopic, and will bond water to it, bypassing the water seperator in the system. Once this water hits the injectors, it flashes into high pressure steam, and will tear your injectors apart in very short order.

Keep any & all alcohol away from a 6.0, or 6.4, otherwise the repair bill is going to be VERY costly.

 

[hheynow]

[ QUOTE ]

Keep any & all alcohol away from a 6.0, or 6.4, otherwise the repair bill is going to be VERY costly.

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I'd extend it to first and second generation 7.3L Powerstrokes too.

 

[Swellmel]

Three Hundred Seventy Five Million in Federal Funding...
If they don't come up with a save the planet fuel do they have to give the money back?
Give up on gas already
Diesel
Diesel
Diesel
Diesel
...........


http://www.energy.gov/news/5172.htm