ttstansfield
tulsa
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8.1 Van wrote:no_bytes wrote:A simple answer.
There is more energy in Diesel fuel vs. Gasoline.
And the turbo with 4 valves per cyl don't have anything to do with it. 
No the turbo and 4 valves have NOTHING to do with it as these can both be found on a gas engine for the same benifits...therefore they do not make a diesel more efficient than a gas engine.
Diesel fuel has a higher calorific value than gas and so there is more energy to be squeezed (pardon the pun) from each gallon.
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concretecamper
Macungie, PA
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I wonder what a 6.8L V10 would output with direct injection + turbo charging + 4 valves per cylinder. These 3 details help diesels produce the torque they do. Yes diesel fuel has more energy but it is also the technology.
The output numbers of the new EcoBoost engines are impressive for the displacement. Makes one wonder will there be a need for diesels in light duty trucks in the future?
Mike
2004 Excursion Limited 4x4
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8.1 Van
Millstone NJ
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ttstansfield wrote:8.1 Van wrote:no_bytes wrote:A simple answer.
There is more energy in Diesel fuel vs. Gasoline.
And the turbo with 4 valves per cyl don't have anything to do with it.
No the turbo and 4 valves have NOTHING to do with it as these can both be found on a gas engine for the same benifits...therefore they do not make a diesel more efficient than a gas engine.
Diesel fuel has a higher calorific value than gas and so there is more energy to be squeezed (pardon the pun) from each gallon.
BS, put a turbo and 4-valve heads on a gasser and the torque will climb up 50% or take the turbo off a diesel and swap out the 4-valve heads for 2 valve heads and watch the torque drop 50%.
FKA PSDExcursion
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JPhelps
SE of Monkeys Eyebrow & Possum Trot
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The burn characteristics and btu content of diesel fuel vs gasoline is why diesel engines produce more torque than a gasoline engine of the same horsepower. Gasoline will detonate and lose power under the cylinder pressures used in diesels plus it also burns faster than diesel fuel. The faster burn is what makes it good for power in the higher rpm range and not as good as diesel for lower rpm. The slower burn of diesel prevents it from being a high rpm power producer (not enough time in the cycle for it to burn) but the extremely high compression ratio plus the boost pressure plus the higher btu content makes it produce high torque output.
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sack1
Kent, WA
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I don't think there's a diesel made today without a turbocharger. Diesels without them are pretty much dogs out on the road. But they do still produce good low rpm torque but so do the BB gas engines. More energy content in diesel fuel and higher compression are only part of the equation. Without a turbocharger you wouldn't want to tow with a diesel. Not at least as you would expect in today's world. Diesels today use heavily electronically controlled variable vane turbos. They have allowed today's diesels to broaden their torque bands and produce higher HP along with boosting peak torque figures, just as they can do for a gas engine.
Maximum torque figures (non-turbo) are heavily reliant on engine displacement. Take any number of engines with similar displacement and you'll see that their peak torque ratings don't differ very much. Even tuned engines will produce similar peak figures, usually a little higher, but do so at higher rpm thus developing more HP.
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dougger222
Maplewood MN
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The other day was on a retired US Coast Guard ice breaker boat on Lake Michigan on a tour. The 1944 10 cylinder diesel motors are good for 2,000 hp at 850 rpms times six motors. The retired guy giving the tour of the motor room claimed the motors were supercharged. The motors didn't appear to have a supercharger on them but he said the motors brought in cold outside air to cool them which is what he could have thought meant supercharged, who knows. At any rate the motors were very amazing. Each motor was said to burn 100 gallons of unrefined diesel fuel per hour. In 2006 when the boat was put out of commission the price per gallon for the fuel was $1.01. That seems cheap but the tank is 276,000 gallons!!!
Hey Supercharged, did you hear that???
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dougger222
Maplewood MN
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The GLHS in my signature was Dodge's first etempt with intercooling a turbocharged 4 cylinder motor.
101 hp with no turbo (high output NA motor)
146 hp with turbo
175 hp with intercooled turbo
2,350 lbs without driver. 135 mph top speed. 0-60 in 6.5 seconds and ran the quarter in 14.5 seconds. Not bad for an 80's econobox that gets 30 mpg.
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pronstar
The LBC
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If you could control detonation, pumping a gasser with 30+ psi boost will likewise produce some excellent power & torque numbers.
But that's a big "if"...very tough to do under heavy load for long periods of time.
2007 Dodge Ram 2500 CTD 4x4/QC/LB
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marspec
West Virginia
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dougger222 wrote:The other day was on a retired US Coast Guard ice breaker boat on Lake Michigan on a tour. The 1944 10 cylinder diesel motors are good for 2,000 hp at 850 rpms times six motors. The retired guy giving the tour of the motor room claimed the motors were supercharged. The motors didn't appear to have a supercharger on them but he said the motors brought in cold outside air to cool them which is what he could have thought meant supercharged, who knows. At any rate the motors were very amazing. Each motor was said to burn 100 gallons of unrefined diesel fuel per hour. In 2006 when the boat was put out of commission the price per gallon for the fuel was $1.01. That seems cheap but the tank is 276,000 gallons!!!
Hey Supercharged, did you hear that???
They diesels are equipped with blowers which equate to superchargers. They are also 2 cycle opposed piston.
The main engines turned generators to power the two main motors aft and one for the bow screw forward (if used). The diesels were cooled by lake water. The motors by air. Served on Mighty Mac 63-65.
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