Biodiesel, Cetane, and Quadzilla Timing

[Scarecrow]

Well, after a lot of reading and a conversation with Mike, more timing should lower EGT and engine load, however when I added timing my load and EGTs went up. Before I got to the numbers he thought would work, engine started to buck, sign of over advance. When I backed off the timing both across the RPM band and cruise things got better. 

This led me to a thread Mike wrote about in the winter he pulled timing out due to higher cetane numbers in winter fuel. This makes sense, but got me thinking about the fuel our trucks were designed to run with, which was not ultra low sulfer biodiesel fuel, so I started digging.

 

Per NDSU AE 1240

No. 2 diesel fuel usually has a cetane rating between 45 and 50 while vegetable oil is 35 to 45. Biodiesel is usually 50 to 60. The ignition quality affects engine performance, cold starting, warm up and engine combustion roughness. Cetane rating is related to the volatility of the fuel where more volatile fuels have higher ratings. A high cetane fuel also may lead to incomplete combustion and smoke if the fuel ignites too soon by not allowing enough time for the fuel to mix with air for complete combustion. The energy content of the fuels also vary. No. 2 diesel fuel typically contains about 140,000 BTU's per gallon while vegetable oil and biodiesel contain about 130,000 BTU/gal.

 

Fuels with a high heat of combustion will usually produce more power per pound of fuel than fuels with lower energy. As a result, an engine using a lower energy fuel will require more fuel to produce the same power as diesel fuel. As a result of the lower energy content, biodiesel will require about 1.1 gallons of fuel to do the same work as a gallon of diesel fuel.

 

So biodiesel has more cetane and less BTUs (energy), doesn't seem to be a problem with the newer trucks, but our trucks aren't  new.

Here in the land of 10,000 taxes we are mandated B20 in the warmer months and B5 in the winter.  While it is easy to add cetane, my question to the group is it possible to lower the cetane rating?

 

Mark

 

Edited May 1 by Scarecrow

[Mopar1973Man]

Give me some time. I'm releasing an article in the standard database as a guide to proper temperatures for the Quadzilla Adrenaline tuner for efficiency purposes. I'm just in the middle of writing it now and trying to proof read and still adding more information as my brain is tickled with different topics of temperature. Onwe I just finished up was talking about fuel temperature and flash point of fuel.

[Mopar1973Man]

Here you go. This should help. I've been working on efficiency and attempting to keep my costs low with all my medical appointments in Boise ID from here which is 180 miles away. I've now got it down to 1/4 tank to do that one way even with interstate travel at 80 MPH.

[Scarecrow]

After our talk last month I started to watch my oil temp and load closer, and that's when I figured out I was too advanced for the fuel I'm using.  One of the problems is unless I go to ND and find non bio, I'm stuck with a higher cetane fuel that will limit my advance/MPG. MN mandates B20 from 15 Apr to 30 Sep, which according to the interweb is a wonderful thing. Of course the interweb also thinks higher cetane is better for diesels and the environment.

 

Mark

[Mopar1973Man]

Quote

There is no benefit to using a higher cetane number fuel than is specified by the engine's manufacturer. The ASTM Standard Specification for Diesel Fuel Oils (D-975) states, "The cetane number requirements depend on engine design, size, nature of speed and load variations, and on starting and atmospheric conditions. Increase in cetane number over values actually required does not materially improve engine performance. Accordingly, the cetane number specified should be as low as possible to insure maximum fuel availability." This quote underscores the importance of matching engine cetane requirements with fuel cetane number!!!

 

As quoted from the ASTM Labs manual for diesel fuel cetane.

 

High cetane means lower BTU's per gallon and lower MPG's. The lower the cetane the higher the BTUs per gallon and the more work is capable of performing with better MPG's.Dark green 43 cetane summer fuel, Light green nearly 55 cetane and winterized fuel.

 

Edited May 2 by Mopar1973Man

[Scarecrow]

Yup, that's the joke.  However, per the internet:

 

Why do cetane numbers matter? The higher a fuel's cetane number, the quicker it ignites — and that carries a variety of benefits for diesel equipment. From increased fuel economy to fewer emissions to better power output, fast combustion is key to a diesel engine's performance.Apr 20, 2021

And:

Since diesels rely on compression ignition, the fuel must be able to readily auto-ignite and quicker is better. 

A higher cetane number, indicating a shorter ignition delay time, usually means more complete combustion of the fuel.  This translates into: 

Quicker starting

Quieter operation with less diesel chatter 

Improved fuel efficiency 

A reduction of harmful emissions  

Less wear and tear on the starter and batteries   

Quicker pumping of protective lubricating fluids throughout the system  

 

It's got to be true because it's on the internet! You can see what you're up against, with this kind of "information" out there.  I'll give them the quicker starting, but thats about it.

 

Mark

 

Edited May 2 by Scarecrow

[Mopar1973Man]

Sadly that is all a lie. 

 

As cetane goes up, lubricity gets worse because of the solvents to increase cetane. Then BTUs go down as seen in my previous post. Emissions go up being you have to burn more fuel to travel the same distance. Louder knock because cetane rose and sudden hammering effect of the rapid burn fuel which enhances wear. 

 

 

Edited May 3 by Mopar1973Man

[Mopar1973Man]

Ok. Now little trick look up MSDS for your favorite cetane products and look at the chemicals used to make said products. 

 

Now take a sample of said product and put small amount in a small open container and leave it exposed. Ex: Power Service will change to a tarry sticky product if exposed. Just remember leave any oil exposed it will still be oil. (Lubricity is poor).

 

Now back to MSDS sheet look up the BTUs of said chemicals you find they are much lower than the diesel fuel. There is no way to add a low BTU chemical to diesel fuel and have it increase the BTUs which is impossible. Ex: Biodiesel is lower BTUs vs Petroleum Diesel (lower cetane).

 

Now go out on YouTube there is a video of home test of a guy burning Power Service and it was very smokey and sooty and then he adds 2 Cycle Oil and it cleans up the mess of Power Service. 

 

No, I don't don't support the Climate Change nor do I believe EPA systems are cleaning up the air. If we cared we all have high efficiency Diesels up above 60 MPG which produces the least amount of emissions but here we are.

[Scarecrow]

So back to the bio question, is there any way (besides diluting with DF2) to bring down the cetane of bio diesel?

 

Mark

[Mopar1973Man]

First off, the best off would be to look for petroleum diesel. 

 

My only solution would be to dilute with 2-cycle oil which is a natural cetane reducer.