A bit off topic. Way back in the day (mid 90's) I had a 1991 Dodge Dakota 2wd with the 318 engine. 12 m.p.g. Did everything under the sun to improve on it, with little to no improvement.
Fuel economy, why has it not improved more?
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Because cars weigh 500 billion pounds while being expected to pollute the same as a Maple tree, that's why.
I really wish they made a truck that got 32+ mpg. I wouldn't mind if it was the size of the old toyota trucks.
Nox emissions, that's why.
Originally Posted By: TheKracken
I really wish they made a truck that got 32+ mpg. I wouldn't mind if it was the size of the old toyota trucks.
I'd like to see a small turbo diesel pickup. Should do 35+ mpg unloaded easy, and be able to tow/haul quite a bit.
Originally Posted By: TheKracken
I really wish they made a truck that got 32+ mpg. I wouldn't mind if it was the size of the old toyota trucks.
I'd like to see a small turbo diesel pickup. Should do 35+ mpg unloaded easy, and be able to tow/haul quite a bit.
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Originally Posted By: sleddriver
Originally Posted By: Rat407
Food for thought but with today's technology one would thing we would be a lot farther along with fuel economy than we are.....Just seems odd that we are no farther along than we are when it comes to economy.
Surprising that only one guy mentioned the key ingredient: GAS.
Not only are gas formulations different (lead vs. no-lead), but today most burn gasohol! For every 10ga you buy, a gallon of it is ethanol.
If you want to see your fuel economy improve, along with performance, fill up with 100% gas.
Whatever happened to the gasahol craze in the 70s? You'd constantly hear about it and then one day it disappeared.
Originally Posted By: Rat407
Food for thought but with today's technology one would thing we would be a lot farther along with fuel economy than we are.....Just seems odd that we are no farther along than we are when it comes to economy.
Surprising that only one guy mentioned the key ingredient: GAS.
Not only are gas formulations different (lead vs. no-lead), but today most burn gasohol! For every 10ga you buy, a gallon of it is ethanol.
If you want to see your fuel economy improve, along with performance, fill up with 100% gas.
Whatever happened to the gasahol craze in the 70s? You'd constantly hear about it and then one day it disappeared.
Originally Posted By: TheKracken
I really wish they made a truck that got 32+ mpg. I wouldn't mind if it was the size of the old toyota trucks.
There are owners of Ram EcoDiesel trucks who are getting that on the highway.
I really wish they made a truck that got 32+ mpg. I wouldn't mind if it was the size of the old toyota trucks.
There are owners of Ram EcoDiesel trucks who are getting that on the highway.
Originally Posted By: aquariuscsm
Originally Posted By: sleddriver
Originally Posted By: Rat407
Food for thought but with today's technology one would thing we would be a lot farther along with fuel economy than we are.....Just seems odd that we are no farther along than we are when it comes to economy.
Surprising that only one guy mentioned the key ingredient: GAS.
Not only are gas formulations different (lead vs. no-lead), but today most burn gasohol! For every 10ga you buy, a gallon of it is ethanol.
If you want to see your fuel economy improve, along with performance, fill up with 100% gas.
Whatever happened to the gasahol craze in the 70s? You'd constantly hear about it and then one day it disappeared.
Probably didn't make any sense given that gasoline was cheap. However, there was the benefit of "octane giveaway". It would boost the octane rating 2 or 3 points, but then they used a base fuel that met the requirements. So if you had 87 octane on the pump, it might have been closer to 90 if ethanol was added.
What ended up happening in the 90s was that oxygenates were more or less mandated for emissions reasons, and MTBE turned out to be a disaster. I think that's when E10 became far more common, once MTBE was pulled.
Originally Posted By: sleddriver
Originally Posted By: Rat407
Food for thought but with today's technology one would thing we would be a lot farther along with fuel economy than we are.....Just seems odd that we are no farther along than we are when it comes to economy.
Surprising that only one guy mentioned the key ingredient: GAS.
Not only are gas formulations different (lead vs. no-lead), but today most burn gasohol! For every 10ga you buy, a gallon of it is ethanol.
If you want to see your fuel economy improve, along with performance, fill up with 100% gas.
Whatever happened to the gasahol craze in the 70s? You'd constantly hear about it and then one day it disappeared.
Probably didn't make any sense given that gasoline was cheap. However, there was the benefit of "octane giveaway". It would boost the octane rating 2 or 3 points, but then they used a base fuel that met the requirements. So if you had 87 octane on the pump, it might have been closer to 90 if ethanol was added.
What ended up happening in the 90s was that oxygenates were more or less mandated for emissions reasons, and MTBE turned out to be a disaster. I think that's when E10 became far more common, once MTBE was pulled.
Originally Posted By: sleddriver
Originally Posted By: Rat407
Food for thought but with today's technology one would thing we would be a lot farther along with fuel economy than we are.....Just seems odd that we are no farther along than we are when it comes to economy.
Surprising that only one guy mentioned the key ingredient: GAS.
Not only are gas formulations different (lead vs. no-lead), but today most burn gasohol! For every 10ga you buy, a gallon of it is ethanol.
If you want to see your fuel economy improve, along with performance, fill up with 100% gas.
Only makes a difference of about 2%. Most people have a larger variance between tanks than that normally.
The biggest increase in fuel economy was the switch to unibody cars. The next big increase will be when Freevalve engines come out. But I have a feeling we will all be driving electrics soon anyways. So it is kinda a moot point.
Originally Posted By: Rat407
Food for thought but with today's technology one would thing we would be a lot farther along with fuel economy than we are.....Just seems odd that we are no farther along than we are when it comes to economy.
Surprising that only one guy mentioned the key ingredient: GAS.
Not only are gas formulations different (lead vs. no-lead), but today most burn gasohol! For every 10ga you buy, a gallon of it is ethanol.
If you want to see your fuel economy improve, along with performance, fill up with 100% gas.
Only makes a difference of about 2%. Most people have a larger variance between tanks than that normally.
The biggest increase in fuel economy was the switch to unibody cars. The next big increase will be when Freevalve engines come out. But I have a feeling we will all be driving electrics soon anyways. So it is kinda a moot point.
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Originally Posted By: aquariuscsm
Whatever happened to the gasahol craze in the 70s? You'd constantly hear about it and then one day it disappeared.
I believe Gasahol is your E10 to E85. Just not a lot of demand for E85 although many manufacturers made flex fuel cars. Turns out that it's not easy to transport via pipeline and tanker trucks cost more money so outside of the corn belt, it just didn't make any sense and the only reason we have E10 everywhere is due to EPA mandates.
Whatever happened to the gasahol craze in the 70s? You'd constantly hear about it and then one day it disappeared.
I believe Gasahol is your E10 to E85. Just not a lot of demand for E85 although many manufacturers made flex fuel cars. Turns out that it's not easy to transport via pipeline and tanker trucks cost more money so outside of the corn belt, it just didn't make any sense and the only reason we have E10 everywhere is due to EPA mandates.
The major reason is that Joe Sixpac requires a larger engine for quick acceleration. So a small engine won't do.
Larger engines use less than 50% of their max power 95% of the time. Make the engine half as big and run it at 85% of its max power 70% of the time and gas mileage would be up at least 25%. WOT has less restriction on the intake stroke.
Just like home engine/generator units get 21% at WOT (95%load) and 16% at half load. Do the math. Its not rocket scienc
My little Chevy Spark gets 45+ mpg at 65 mph and probably uses 70%b of full load (105 HP). If the engine only put out 80Hp (max HP) at 65 mph it would use the same HP but would be running at almost 90% of its max power. It would get at least 57mpg. And honestly I could deal with that.
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Larger engines use less than 50% of their max power 95% of the time. Make the engine half as big and run it at 85% of its max power 70% of the time and gas mileage would be up at least 25%. WOT has less restriction on the intake stroke.
Just like home engine/generator units get 21% at WOT (95%load) and 16% at half load. Do the math. Its not rocket scienc
My little Chevy Spark gets 45+ mpg at 65 mph and probably uses 70%b of full load (105 HP). If the engine only put out 80Hp (max HP) at 65 mph it would use the same HP but would be running at almost 90% of its max power. It would get at least 57mpg. And honestly I could deal with that.
[/end thread]
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Would there be longevity concerns with a tiny engine that has to run flat-out all the time?
Originally Posted By: Anduril
Would there be longevity concerns with a tiny engine that has to run flat-out all the time?
Well at 65 mph it would only be probably70+ percent of load. This would occurr at highway speeds only ..and highway miles are easy. I doubt it would be an issue. And if it were they would develop an engine that would be happy runninbg at 85% of load most of the time. That would be very easy to do. Lower the rpms a bit and size the bearings a bit larger..at the most. Maybe nothing would be required.
Would there be longevity concerns with a tiny engine that has to run flat-out all the time?
Well at 65 mph it would only be probably70+ percent of load. This would occurr at highway speeds only ..and highway miles are easy. I doubt it would be an issue. And if it were they would develop an engine that would be happy runninbg at 85% of load most of the time. That would be very easy to do. Lower the rpms a bit and size the bearings a bit larger..at the most. Maybe nothing would be required.
Bigger engines and/or turbos, bigger and heavier cars, and bigger and heavier tires. and tighter emissions standards
Originally Posted By: Al
laws of thermodynamics. The Otto Cycle gas efficiency has limits. There is the more efficient Diesel Cycle. Those are the only practical power cycles for cars.
Efficiency has come a long way. Equivalent engine efficiencies have risen 1/3 since the 70s
Actually, theoretically the Otto cycle is more efficient than the diesel cycle.
laws of thermodynamics. The Otto Cycle gas efficiency has limits. There is the more efficient Diesel Cycle. Those are the only practical power cycles for cars.
Efficiency has come a long way. Equivalent engine efficiencies have risen 1/3 since the 70s
Actually, theoretically the Otto cycle is more efficient than the diesel cycle.
Finally, someone who understands it takes a certain amount of fuel to do a certain amount of work. BSFC numbers have improved somewhat over the last 50 years, in most cases. But not all.
I regularly post that the Lycoming engine in my 1971 Cessna has a BSFC of 0.38 lb fuel per HP Hour. Exactly the same as the 2017 Prius engine.
Short of hybrid vehicles that recover kinetic energy and can utilize atkinson cycle engines, there is no magic bullet that will allow additional great leaps.
I regularly post that the Lycoming engine in my 1971 Cessna has a BSFC of 0.38 lb fuel per HP Hour. Exactly the same as the 2017 Prius engine.
Short of hybrid vehicles that recover kinetic energy and can utilize atkinson cycle engines, there is no magic bullet that will allow additional great leaps.
Originally Posted By: DriveHard
Actually, theoretically the Otto cycle is more efficient than the diesel cycle.
But that is kinda irrelevant bc the OTTO cycle can't function with those paramaters using gasoline. There are around a dozen heat engine cycles. Only a couple can be used in transportation as a prctical matter.
Actually, theoretically the Otto cycle is more efficient than the diesel cycle.
But that is kinda irrelevant bc the OTTO cycle can't function with those paramaters using gasoline. There are around a dozen heat engine cycles. Only a couple can be used in transportation as a prctical matter.
Originally Posted By: Al
Originally Posted By: DriveHard
Actually, theoretically the Otto cycle is more efficient than the diesel cycle.
But that is kinda irrelevant bc the OTTO cycle can't function with those paramaters using gasoline. There are around a dozen heat engine cycles. Only a couple can be used in transportation as a prctical matter.
Don't forget that diesel fuel both weighs more and contains more energy per gallon. So using MPG as a defining factor is not directly related to efficiency (which is generally measured by mass of fuel consumed per unit of work) . The new Prius engine is 41% thermally efficient. But still consumes more fuel by gallon per HP produced than a typical diesel.
Originally Posted By: DriveHard
Actually, theoretically the Otto cycle is more efficient than the diesel cycle.
But that is kinda irrelevant bc the OTTO cycle can't function with those paramaters using gasoline. There are around a dozen heat engine cycles. Only a couple can be used in transportation as a prctical matter.
Don't forget that diesel fuel both weighs more and contains more energy per gallon. So using MPG as a defining factor is not directly related to efficiency (which is generally measured by mass of fuel consumed per unit of work) . The new Prius engine is 41% thermally efficient. But still consumes more fuel by gallon per HP produced than a typical diesel.
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Originally Posted By: Cujet
Don't forget that diesel fuel both weighs more and contains more energy per gallon. So using MPG as a defining factor is not directly related to efficiency (which is generally measured by mass of fuel consumed per unit of work) . The new Prius engine is 41% thermally efficient. But still consumes more fuel by gallon per HP produced than a typical diesel.
Effficiency is BtU's [in]/Work [out]..never by fuel mass.
Don't forget that diesel fuel both weighs more and contains more energy per gallon. So using MPG as a defining factor is not directly related to efficiency (which is generally measured by mass of fuel consumed per unit of work) . The new Prius engine is 41% thermally efficient. But still consumes more fuel by gallon per HP produced than a typical diesel.
Effficiency is BtU's [in]/Work [out]..never by fuel mass.
Originally Posted By: Al
Originally Posted By: Cujet
Don't forget that diesel fuel both weighs more and contains more energy per gallon. So using MPG as a defining factor is not directly related to efficiency (which is generally measured by mass of fuel consumed per unit of work) . The new Prius engine is 41% thermally efficient. But still consumes more fuel by gallon per HP produced than a typical diesel.
Effficiency is BtU's [in]/Work [out]..never by fuel mass.
Yeah, it's always the btu content of the fuel. That's why E10 gets better mileage than E85, less BTU's per gallon in E85 although technically they both have gas in it.
Originally Posted By: Cujet
Don't forget that diesel fuel both weighs more and contains more energy per gallon. So using MPG as a defining factor is not directly related to efficiency (which is generally measured by mass of fuel consumed per unit of work) . The new Prius engine is 41% thermally efficient. But still consumes more fuel by gallon per HP produced than a typical diesel.
Effficiency is BtU's [in]/Work [out]..never by fuel mass.
Yeah, it's always the btu content of the fuel. That's why E10 gets better mileage than E85, less BTU's per gallon in E85 although technically they both have gas in it.
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