CM, under the best of conditions all that the engine would do would be to accelerate the vehicle. That is the type of driving that I amin favor of, which is to say that the traffic would roll right along. This is far more than what is being touted, which is only stopping the engine fo long delaiys, typically traffic lights. There would not be much savings over open road conditions, but in the city traffic at it's worst it could add value.
Ethanol as an automotive fuel is simply a stupid idea. Aside form the inefficient use of resources already presented, it also takes food away from folks and bids up the price of corn. In addition it provides a means for our gasoline fuel to have water added, since ethanol will allow gasoline and water to mix quite well, up to almost 10%. AM I THE ONLY ONE TO KNOW ABOUT THAT?
Is it purely because of the quality ? I think they do it just to make sure that you have things for each and every market. Maybe certain differentiations in quality but not in a major way, especially like the Chinese copies of all these smart phone
It's interesting to compare corn ethanol subsidies with solar PV tax credits. I have a modest PV array that consumes less than 1/100th of an acre (33' by about 10'). Even if you ignore the noted energy inputs that go into producing ethanol, and the fact that a 0.01 acre PV array can use no net land at all by residing on the roof of a house, it's instructional to compare the energy produced.
1 acre of corn yields around 1 gallon of ethanol per day (330-424 gal/acre annually, Wikipedia). That's with arable land, as well as after the energy inputs noted earlier, labor, fertilizers, pesticides, a distillery, etc. Yet my tiny PV array produces an average daily output of about 6kWh, which is approximately equal to the energy of 1/4 gallon of ethanol.
So 4 of my little PV arrays can reside on less than 0.04 acres, but will produce the same energy as 1 acre of corn! And PV is virtually autonomous. Set it and forget it.
Why do we continue the craziness of biofuel subsidies and why aren't so-called fiscal conservatives as hostile toward them as they generally are toward solar energy that produces electricity directly?
Yes, instantaneous MPG can seem to be "eye opening" during acceleration, but if you look at the physics, it does not really matter how quickly you get a mass moving it still has the same kinetic energy (1/2mv^2). The issue is the efficiency of the engine (or battery motor system) when accelerating hard vs. easy. Gasoline engines are actually most efficient at wide open throttle with no fuel enrichment (IE running at stoichiometric) but at low RPM's, typically around 1000 for a V8, 1500 for a V6 and 2000 for a L4. That allows a manual transmission driver to mash the throttle most of the way (not to hit the fuel enrichment of WOT), and short shift the engine and get excellent fuel economy. For electric vehicles, it's mostly the resistive losses (I^2R in the motor, controller, and effective in the battery) that dictates the efficiency. Thus for pure EV's, a reasonable acceleration at say 1/3 maximum current yields most all the possible benefit, since the resistive loses would be roughly 1/10 that of full current, thus in the noise for MJ/mile.
Not sure I agree with the relative contributions of regen vs. smaller engines, but we're on the same page and you make a great point. Let the high torque, instantaneous throttle, efficient motor (electric) work mostly during the low duty cycle periods when so much power is required. Then the big engine can be much smaller and tuned for better efficiency (Atkinson).
Still, unless the vehicle plugs in, the power to that electric motor comes solely from the ICE, only it's time/duty shifted. That means a storage device (battery).
Also, to my original point, for cars that can display instantaneous MPG, monitoring it during acceleration can be an eye-opening experience.
They must not understand what actually happens with government subsidies. The government has heavily subsidized "big oil" for many decades and they still do. The government is heavily subsidizing corn ethanol, yet it has a EROEI (energy return on energy investment) of about 1:1 (less or more depending on who's numbers you use). But when the government subsidizes PV solar and EV's that not OK; it's just baffling!
Hybrids get some mileage improvement with regenerative braking, but they get much more improvement by having a much smaller ICE than a comparable non-hybrid car. Most non-hybrid cars have roughly 10 times as much horse power as they need for cruising (constant speed on level terrain on the freeway). That huge engine has a lot of waste that is there all the time. GM and others cut cylinders which helps some, but there is still all the friction of reciprocating pistons, crank bearings, and air pumping. Also larger gasoline engine cruise at high manifold vacuums levels which is inherently inefficient. Diesel engine have no throttle, so they are superior in thermodynamic efficiency at lighter loads, and they are better overall because of the higher compression ratios. Basically the modern 300 HP family sedan is a race car in disguise. Lots of fun when driven hard, but seriously compromised in the MPG department. Fuel efficient cross country semi-tractor trucks have only 300 HP turbo diesel and they get across the country with a total weight of 80,000 lbs. How much power do you really need?
Although plastics make up only about 11% of all US municipal solid waste, many are actually more energy-dense than coal. Converting these non-recycled plastics into energy with existing technologies could reduce US coal consumption, as well as boost domestic energy reserves, says a new study.
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