I'd be curious to know how many of you feel the need to add a cetane booster to the diesel fuel used in your boat? The diesel sold at my marina has a rating of 40, while the stuff I buy from a local gas station, and use in my boat, has a cetane rating of 45.
Cetane Boosters
- Thread starter Warren M
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Cetane
Warren, Never thought about it before - interesting question! I run a Yanmar 2GM20F in a C&C 26. I buy my diesel from a local gas station, but I've no idea what the cetane value is. I don't have any engine problems, but it may be a reason that many people complain of starting problems. I note, from my Yanmar manual, that US diesel standards usually have a cetane value of 40+. I suspect Canadian standards are similar. Next time I fill up, I'll check the cetane value out of interest. Regards, sam
Warren, Never thought about it before - interesting question! I run a Yanmar 2GM20F in a C&C 26. I buy my diesel from a local gas station, but I've no idea what the cetane value is. I don't have any engine problems, but it may be a reason that many people complain of starting problems. I note, from my Yanmar manual, that US diesel standards usually have a cetane value of 40+. I suspect Canadian standards are similar. Next time I fill up, I'll check the cetane value out of interest. Regards, sam
Cetane...
Here is some information about what Cetane, an addative to diesel fuel is and how it affects engine performance. Delayed ignition is a primary cause of high emissions and inferior engine performance, and there is a direct relationship between a diesel fuel’s cetane number and its ignition point. The lower the cetane number, the longer the ignition delay. Fuels with high cetane numbers burn more quickly and more completely, resulting in smoother-running engines with less power lag, lower emissions and easier engine starting.
Here is some information about what Cetane, an addative to diesel fuel is and how it affects engine performance. Delayed ignition is a primary cause of high emissions and inferior engine performance, and there is a direct relationship between a diesel fuel’s cetane number and its ignition point. The lower the cetane number, the longer the ignition delay. Fuels with high cetane numbers burn more quickly and more completely, resulting in smoother-running engines with less power lag, lower emissions and easier engine starting.
Most marinas I've asked have no clue
what the cetane value of their fuel is or even what cetane is a measure of. I used a booster for a short while and found no benefit. I do use a dose of Power Service for winterizing, and I always use the biocideat ever fillup.
what the cetane value of their fuel is or even what cetane is a measure of. I used a booster for a short while and found no benefit. I do use a dose of Power Service for winterizing, and I always use the biocideat ever fillup.
Rich isn't the cetane right there on the fuel pump
just like Octane rating is on the gasoline pump
just like Octane rating is on the gasoline pump
Consult your manual!
The best cetane rated diesel is the lowest that still meets your engine manufacturer's minimum. If your Yanmar manual says use 40 cetane then that's what it was designed for. Using higher cetane than recommended can help a worn engine with bad compression start easier but once the engine heats up, combustion will occur too early in the injection cycle causing severe power loss. Actual diesel quality is measured with the ASTM D975 procedure. Carbon residue, ash, water, bacteria and sulfur increase engine wear and deposit formation. Better quality diesel has lower specs for these. Then there's the problem of additives. Nitrate containing cetane boosters (like alkyl nitrate)should never be used in a fuel tank that is not completely emptied often. (i.e.: sailboat) They break down quickly producing particulates and sludge. Anyone who wants a copy of the ASTM D613 cetane number test procedure or D975 diesel quality test, can order it from ASTM International here: http://www.astm.org/ Both tests require a lot of expensive machinery. In short (Oops, too late!): API gravity (density) is an excellent indicator of heat value, which translates into fuel economy and power. The distillation curve (ASTM D86) reflects the molecular weight distribution, with higher boiling fractions providing better lubrication, higher cetane - and more deposits. Sulfur content is directly related to corrosion; this needs to be as low as possible. Oxidation stability, water, and sediment content affect the storage life of the fuel. For winter use, low cloud point and low temperature filter plugging point are critical to uninterrupted operation. To insure the best quality fuel for your diesel engines, follow the engine manufacturer's specifications for all these characteristics. Sample spec report on related link below. Happy stink-potting ***_/), MArk (former Marathon refinery engineer)
The best cetane rated diesel is the lowest that still meets your engine manufacturer's minimum. If your Yanmar manual says use 40 cetane then that's what it was designed for. Using higher cetane than recommended can help a worn engine with bad compression start easier but once the engine heats up, combustion will occur too early in the injection cycle causing severe power loss. Actual diesel quality is measured with the ASTM D975 procedure. Carbon residue, ash, water, bacteria and sulfur increase engine wear and deposit formation. Better quality diesel has lower specs for these. Then there's the problem of additives. Nitrate containing cetane boosters (like alkyl nitrate)should never be used in a fuel tank that is not completely emptied often. (i.e.: sailboat) They break down quickly producing particulates and sludge. Anyone who wants a copy of the ASTM D613 cetane number test procedure or D975 diesel quality test, can order it from ASTM International here: http://www.astm.org/ Both tests require a lot of expensive machinery. In short (Oops, too late!): API gravity (density) is an excellent indicator of heat value, which translates into fuel economy and power. The distillation curve (ASTM D86) reflects the molecular weight distribution, with higher boiling fractions providing better lubrication, higher cetane - and more deposits. Sulfur content is directly related to corrosion; this needs to be as low as possible. Oxidation stability, water, and sediment content affect the storage life of the fuel. For winter use, low cloud point and low temperature filter plugging point are critical to uninterrupted operation. To insure the best quality fuel for your diesel engines, follow the engine manufacturer's specifications for all these characteristics. Sample spec report on related link below. Happy stink-potting ***_/), MArk (former Marathon refinery engineer)
I think I found the answer to my question
But I'll have to take a look at my local pumps next time. "Diesel at the pump can be found in two CN ranges: 40-46 for regular diesel, and 45-50 for premium. The minimum CN at the pump is 'suppose' to be 45. The legal minimum cetane rating for #1 and #2 diesel is 40. Most diesel fuel leaves the refinery with a CN of around 42. The CN rating depends on the crude oil the fuel was refined from. It varies so much from tanker to tanker that a consistent CN rating is almost impossible. Distilling diesel is a crude process compared with making gasoline. Gasoline is more of a manufactured product with tighter standards so the octane rating is very consistent. So the CN rating at the pump can be anywhere from 42-46. That's why there is almost never a sticker on a diesel fuel pump for CN." http://www.4crawler.com/Diesel/Diesel.shtml and "Cetane numbers apply only to distillate fuels; they are not measured for fuels containing petroleum resid (sic?) (marine fuels). " http://www.chevron.ca/FAQs/FAQsDiesel.htm Here are a few other interesting links on Diesel additives and Cetane ratings. http://www.lubrizol.com/DieselEngines/default.asp http://www.sailnet.com/collections/articles/index.cfm?articleid=woodto044 http://www.tpub.com/content/construction/14264/css/14264_159.htm
But I'll have to take a look at my local pumps next time. "Diesel at the pump can be found in two CN ranges: 40-46 for regular diesel, and 45-50 for premium. The minimum CN at the pump is 'suppose' to be 45. The legal minimum cetane rating for #1 and #2 diesel is 40. Most diesel fuel leaves the refinery with a CN of around 42. The CN rating depends on the crude oil the fuel was refined from. It varies so much from tanker to tanker that a consistent CN rating is almost impossible. Distilling diesel is a crude process compared with making gasoline. Gasoline is more of a manufactured product with tighter standards so the octane rating is very consistent. So the CN rating at the pump can be anywhere from 42-46. That's why there is almost never a sticker on a diesel fuel pump for CN." http://www.4crawler.com/Diesel/Diesel.shtml and "Cetane numbers apply only to distillate fuels; they are not measured for fuels containing petroleum resid (sic?) (marine fuels). " http://www.chevron.ca/FAQs/FAQsDiesel.htm Here are a few other interesting links on Diesel additives and Cetane ratings. http://www.lubrizol.com/DieselEngines/default.asp http://www.sailnet.com/collections/articles/index.cfm?articleid=woodto044 http://www.tpub.com/content/construction/14264/css/14264_159.htm
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