Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Centurion 128-mpg ... and smaller engines

sgtlethargic · 01-16-2012, 01:41 PM

128-mpg Diesel-Powered Sports Car

This text rings true to me:
"The technology used to produce Centurion's high fuel economy is very straightforward. An internal combustion engine runs most efficiently when it is operating at 60% to 90% of maximum output. In contrast, when an engine is throttled so it develops only a small portion of its power output capability, fuel economy plummets. Automobiles operate most of the time with the engine throttled to 5% or less of full power, such as when cruising at low speeds in urban traffic. Even on the highway, the average family sedan can cruise at 55 mph on a little as 8 to 10 hp, which is only a fraction of the power capability of the engine. An engine throttled into fractional power regions can use double or triple the fuel per unit of power output. It's as simple as that."

What do you think?

Do you think this had reasonable acceleration?

And this text:
"Turbocharging the engine would increase maximum power and performance, and improve fuel economy as well."

I'm thinking turbocharging is key. Could you say turbocharging allows for two powerbands, and two "BSFCs"? How would a gas engine kept in the sweet spot compare to a diesel in efficiency? In other words, what percentage of a diesel's efficiency is due to no throttling?

So, it looks like one needs a non-car/motorcycle engine to achieve 100 mpg with an ICE and no driving tricks.

What might be good sources for used gas and diesel engines of ~20 hp with an appropriate powerband?

Or, if you could get the gear ratios numerically-high enough to have something like a Honda 175 motorcycle engine in its sweet spot (Wiki says "20 bhp @ 10,000 rpm"). That might be more fun- having something that'd rev versus a sewing machine engine.

01-16-2012, 01:41 PM	#1 (permalink)
sgtlethargic Master EcoModder Join Date: Jun 2011 Location: Earth Posts: 632 Thanks: 28 Thanked 148 Times in 116 Posts	Centurion 128-mpg ... and smaller engines 128-mpg Diesel-Powered Sports Car This text rings true to me: "The technology used to produce Centurion's high fuel economy is very straightforward. An internal combustion engine runs most efficiently when it is operating at 60% to 90% of maximum output. In contrast, when an engine is throttled so it develops only a small portion of its power output capability, fuel economy plummets. Automobiles operate most of the time with the engine throttled to 5% or less of full power, such as when cruising at low speeds in urban traffic. Even on the highway, the average family sedan can cruise at 55 mph on a little as 8 to 10 hp, which is only a fraction of the power capability of the engine. An engine throttled into fractional power regions can use double or triple the fuel per unit of power output. It's as simple as that." What do you think? Do you think this had reasonable acceleration? And this text: "Turbocharging the engine would increase maximum power and performance, and improve fuel economy as well." I'm thinking turbocharging is key. Could you say turbocharging allows for two powerbands, and two "BSFCs"? How would a gas engine kept in the sweet spot compare to a diesel in efficiency? In other words, what percentage of a diesel's efficiency is due to no throttling? So, it looks like one needs a non-car/motorcycle engine to achieve 100 mpg with an ICE and no driving tricks. What might be good sources for used gas and diesel engines of ~20 hp with an appropriate powerband? Or, if you could get the gear ratios numerically-high enough to have something like a Honda 175 motorcycle engine in its sweet spot (Wiki says "20 bhp @ 10,000 rpm"). That might be more fun- having something that'd rev versus a sewing machine engine.