lyeinyoureye

Who said anything about increases in compression and rpm range? Granted, the EPA test used a TDI engine, but that's only because it's the only stock/cheap engine with a VNT and EGR cooler iirc. So, when running high rates of EGR, they didn't have to make many modifications to the engine, only run SAFI (Stand Alone Fuel Injection). The point of the paper was that higher octane fuels allow for more EGR, which fills up the cylinder and minimizes low load pumping losses. This can be done with lower compression engines, all that's needed is turbocharging/EGR cooling. The same system was mentioned in a Uni of Wisconsin paper. In fact, the engine would probably last longer because it's more efficient. It won't have to inject extra gas just to overcome the pressure difference between the cylinder and crankcase on the intake stroke.
Hardly. If this were the case we wouldn't have drive by wire, VVT-whatever, or anything else. The only thing needed for this would be a turbocharger, EGR cooler, and associated hardware. I bet a reasonable approximation could be done w/o turbocharging via internal EGR.

pedex

any significant gains in efficiency, and I mean real significant gains taking advantage of the octane levels of ethanol mean increases in compression, and better machining to increase the volumetric efficiency, which in trun means more power per cubic inch

there are NO MAGIC BULLETS HERE, engine tech is a very very mature well known discipline, one Im familiar with

turbocharging in effect increases the dynamic compression in the cylinders, this is also well known and understood, typically turbo'd engines run very very low compression, reason being cylinder filling with a dense charge raises the effective compression ratio, they also suffer all the things that go with it, like short lifespans

your not gonna BS your way out of this one

lyeinyoureye

You can't be this...

O.k. The only way you will raise the maximum effective compression ratio is if you make more power. This system is not about making more power, it's about minimizing pumping losses. If I have a NA engine that makes 100hp@6k rpm, and I turbo-charge the engine but make the same amount of peak power at the same rpm, there is no change in effective maximum compression ratio. It brings in X amount of air, to react with Y amount of fuel. The turbo just allows the system to use the energy of the exhaust, and the exhaust itself, to increase low load efficiency. Any car these days uses EGR in order to reduce NOx emissions and help out with fuel economy.
The limit for EGR helping out BSFC is octane, and a homogeneous intake charge to a certain extent. An auto manf can't dump more EGR in the cylinder if the fuel auto ignites on the compression stroke because of too much heat. That's why E85 allows much higher low load efficiencies... More EGR can be run without causing the fuel to autoignite, which reduces pumping losses, giving diesel like efficiency. So, if, according to the EPA, something like a diesel Jetta gets 50% better mileage than a gasoline version, this technology would allow the gasoline version to approach that level of thermal efficiency at low load. What you are referring to is high load engine efficiency, which can be increased via higher CR. But that doesn't matter for most people because they usually don't have the pedal to the metal all the time.

For instance, a Camry built a decade and a half ago has ~33% peak BTE iirc, which isn't a big difference between the peak BTE of the Prius. But on the highway, the Prius gets well over twice the mileage. Why? Because the Prius has good low load efficiency, something like a minimum of 28% BTE, but the Camry drops down to maybe 12% BTE because the Camry suffers from lots of low load pumping losses. The Prius doesn't because of the Atkinson cycle, which is another way to minimize pumping losses. The downside of the Atkinson cycle is that torque is limited because a portion of the air drawn into the cylinder has to be pushed back out... So we have an engine that isn't "suitable" for the average driver. By supplementing it with an electric motor, peak power is increased, and other fuel saving features can be used. The use of EGR/VGTs with high octane fuel allows good mixing (something that's also need for lean burn systems) and high EGR at low load, which reduces pumping losses, and can result in a more efficient engine at the same power output w/o the need for a hybrid system. Most manufacturers aren't going to roll out these systems until E85 is established, so current engines aren't designed to run on them, and won't be unless E85 sticks around, not to mention the two to four years needed for development. VVT has been around for almost half a century, but it only penetrated the market within the last decade...
So there are delays when bringing any new device to the market. Now, if we have consistent, sizable E85 output in a decade, then I'm guessing we'll see these engines. But going back to what I said, I don't think we will because electric tech has been pushed back for too long. The Tesla Roadster is indicative of this.

*sigh*

pedex

classic case of reading tech and not understanding whats going on behind it

when you slide the powerband of an engine lower thru whatever means while maintaining the same max power output relative to any rpm without changing the displacement what happens? what kinds of things are you going to see with the engine....like manifold pressure, cylinder pressure, combustion chamber temperature for example? In other words, take a look at BSFC vs power vs rpm vs torque. It will bear out what Im getting at.

and on top of all this, you and your articles are avoiding one of the easier methods for increasing engine efficiency, and thats making use of all the unused heat which gets sent out the tailpipe and radiator, however, just like anything else its a tradeoff, there are no magic bullets here, never have been

smokey yunich(I think thats how his name is spelled) played with some of the combos you mentioned above about 30 years ago, also built some semi-adiabatic engines, results were good, until you get into practicality and longevity

all the technology in the world isnt going to make enough of a difference with ethanol im afraid, it has too many other problems besides what is involved with actually running it in an engine

oh ya, while im here, go ahead and post a reply, it wont be followed up on, Ive tried to have a decent discussion with you, the cute little eek smilies and sighs mean you arent interested anyway

maybe you should put your $$ where your mouth is, Ive built a few engines, ante up yourself and have at it, it isnt all that difficult, ive built two engines completely from scratch already, everything is a tradeoff

lyeinyoureye

The only changes in the power band happen because of reduced pumping losses. I mean, you can increase peak power/cylinder pressure, but nothing about this system makes this a requirement. The increase in torque at less than peak load happens because the pressure difference between the cylinder on the intake stroke and crankcase is minimized. So, less parasitic drag. This is because the cylinder is allowed to "fill up", like a diesel, and this translates into an efficiency gain. The advantage is an engine would operate very much like a diesel, more power at lower engine speeds per CI, better efficiency, but with emissions closer to that of a gasoline vehicle. Another approach to pumping losses is MDS, which can result in up to a 30% increase in efficiency, kill some cylinders, reduce pumping losses, increase efficiency, yadda... And sure, a few companies are developing exhaust based alternators, so there are efficiency gains to be made in plenty of areas.

You can say, or not say, what you like. But telling me that changing the peak cylinder pressure/power/engine speed is going to influence reliability, when this system doesn't change peak cylinder pressure/power/engine speed, just efficiency. Is, uh, I dunno... Odd? Pumping losses make the engine burn more fuel to make the same amount of power compared to an engine that doesn't suffer from them. More fuel usually means more wear, so, a system that minimizes pumping losses, and increases efficiency would mean that the engine doesn't have burn as much fuel to make the same amount of power, and will probably last longer, all things being equal.

gwd

I've never heard of "non discretionary side of the economy". What is that? Do you mean only use money when necessary? By eliminate debt and conserve I assume you mean personally since you were answering a question.

A huge interconnected beast can be very stable and robust, if the connections support each other. One of the buzz phrases I learned in an ecosystems course was "diversity breeds stability" meaning that an ecosystem with many ecological niches can remain stable and productive in the face of an disruption. If something happens to a part of the system it tends to heal itself. Maybe our ecosystem just needs a few years to adjust to some of the energy production being siphoned from nutritional needs to transportational needs.

Just in time systems work when the everything in the supply chain is predictable, the inventory should be some measure of uncertainty in the supply chain. So if uncertainty increases more quickly than inventory space can be created and filled, you get problems. I think what you're worried about is that businesses quickly dumped warehouse space when their supply chains became more reliable through information technology. But they can't build warehouses as quickly as they dumped them so if the supply chain suddenly becomew unreliable for whatever reason they'll have problems until they can recover the reliablilty or inventory space.

JeffS

Your first one is pretty key for the average person. At some point, the price of suburban homes is going to plummet, and large sectors of jobs - like everything housing related - is going to go away. You can imagine what happens to a person who can't make their mortgage payment and can't sell their house for enough money to cover the principal.


Anyway... I'm surprised to hear about the corn prices. I guess my head is still pretty far in the sand. From strictly an environmental standpoint my biggest concern is over some of the other agricultural crops that can be used to produce fuels - specifically the ones that grow especially well in South America. The rain forests are at a huge risk to big-agriculture. If they go, the effect on the planet could be horrific.

wheel

Someday we will be like the rest of the 33 nations who grow Hemp.
Then we can use it for paper, fuel, etc.

lyeinyoureye

I wish... That stuff is so handy. CA is cracking down on small WVO users and installers... Things don't seem to be getting more reasonable.

Cyclepath

Karl Marx described how capitalism would self-destruct long before it became obvious. But of course since "communism is dead" we don't think we can learn from that or could gain from reading Marx (note that communism & Stalinism have always been two entirely different things, the two marketed by our bosses as synonymous & promoted as the Evil Empire in spite of the fact that US industry [& to some extent British, with a few others] actually created the early Soviet industrial infrastructure. Sounds unbelievable based on what we've been taught by the official sources, but see the massively well-documented book WESTERN TECHNOLOGY & SOVIET ECONOMIC DEVELOPMENT Vol 1. by A. Sutton, probably the ultimate piece of suppressed history in our time, & judge for yourself).

kc9eog

A quick aside regarding the two arguing about increasing power in combustion engines; really we don't need an equivalent of the automobile we have now, we need something like an enclosed go cart with maybe five horsepower to move people around with along with bicycle's and public transit. If the future is a Tahoe with some alternative fueled engine(ethanol, hydrogen), I would be truly stunned.