This has got to be snake oil
This has got to be snake oil
(OP)
Researcher claims 5%-20% (!!!!) improvement in efficiency by using an electric field to reduce the fuel viscosity and hence droplet size in a diesel engine.
http://pub s.acs.org/ cgi-bin/sa mple.cgi/e nfuem/asap /html/ef80 04898.html
http://pub s.acs.org/ cgi-bin/sa mple.cgi/e nfuem/asap /html/ef80 04898.html
This makes very little sense to me, I wasn't aware that the burn time of the droplets was a significant cause of inefficiency.
http://pub
http://pub
This makes very little sense to me, I wasn't aware that the burn time of the droplets was a significant cause of inefficiency.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.





RE: This has got to be snake oil
- Steve
RE: This has got to be snake oil
RE: This has got to be snake oil
Luck is a difficult thing to verify and therefore should be tested often. - Me
RE: This has got to be snake oil
I'm no diesel expert, but what would happen if you simply altered the fuel viscosity?
Rod
RE: This has got to be snake oil
If this really does allow much better atomization of fuel at a lower working pressure, then it could certainly improve pump life and/or reduce input torque requirements. Fuel economy and low emissions seem to be pretty closely tied to atomization (via ever higher pressures, typically).
RE: This has got to be snake oil
Is this even relevant on a ~10-15 year-old diesel engine anyway?
RE: This has got to be snake oil
In the end, I'd have to see the energy inputs and I'd have to see this on a high pressure application before I would say it's a realizable success in an application. I'm very dubious of the size of the claimed efficiency improvements, either the 12-18% or the 20.4%.
RE: This has got to be snake oil
Most viscosifier adjustments (like chemical additives) cause incompatibilities, cause emissions impact, cause lubricity problems, or are just too expensive.
Heating the fuel can require signficant energy input, I'm guessing there is a reason this is not done beyond the extent of heating above "cold." There is a diminishing return with higher temperatures, with viscosity gains decreasing and heat losses to the environment increasing.
RE: This has got to be snake oil
RE: This has got to be snake oil
Large diesel engines (Residual fuelled) have an inline viscometer which is used to control the fuel heater so that the viscosity is optimised.
If the fuel viscosity is too low then a fine non-dispersive mist is formed which does not fully mix with the air flow; the fuel burns incompletely and in the region of the injectors.
If the viscosity is too high the large drops formed project too far across the burning zone, again do not mix well with the air flow and incomplete combustion results, and in the wrong place.
In either case optimising the viscosity makes the engine more fuel efficient and less polluting.
Theoretically, the same situation could apply to smaller diesels burning commercial diesel or turbines burning aviation fuel.
BUT:
How variable is fuel quality?
Commercial diesel of a the approved grade for the engine shouldn't exhibit that much viscosity variation nor should it vary much over the normal range of fuel temperatures with the engine operating normally.
Hence I would have expected that the engine design would be that at normal working conditions of temperature etc. the viscosity ought to be pretty much optimum or is this wrong? How significantly does diesel viscosity vary according to source, garde and fuel temperature?
At what point does viscosity control become desirable? I'd certainly like to know.
Am I right in thinking that simply reducing the viscosity isn't automatically a good idea?
JMW
www.ViscoAnalyser.com
RE: This has got to be snake oil
RE: This has got to be snake oil
From this US Patent (http://www.freepatentsonline.com/EP0387857.html):
An electroviscous fluid comprising an electrically insulating liquid and solid electrolyte particles dispersed therein.
And we learn bout the primary electro viscous nature of some salt solutions and, apparently, some observed effect in polystyrene. But a significant effect in fuel oils or even diesel? That takes some getting used to.
There are some viscometers that depend on magnets in some way; some use strong magnetic fields to self centre the rotating element and thus also do away with bearings (and bearing drag) e.g. the Levimetrix (http://www.levimetrix.com/). More relevant is the Stabinger SVM 3000 (htt
This is approved to ASTM D7042 and is of equivalent precision to the capillary viscometer ASTM D445. It also makes use of magentic levitation of the rotating element. The primary application for this viscometer is fuels, and lubricants. So how can you employ magnets without affecting the performance of the viscometer?
Yet here we have it:
The article is in the references:
http://
and the authors are: R. Tao and X. Xu, and R. Tao is one of the authors of this report so it is a natural progression from discovering the principal to looking at applications.
OK they talk about pulsed electromagnetic fields and our viscometers presumably rely on stable magnetic fields.... but I'll need to think about it some more.
JMW
www.ViscoAnalyser.com
RE: This has got to be snake oil
RE: This has got to be snake oil
JMW
www.ViscoAnalyser.com
RE: This has got to be snake oil
"The typical laboratory test result of the Mercedes-Benz with a dynamometer is shown in Figure 7, At a fixed fuel consumption rate close to 500 g/h, the dynamometer measured the engine output. When the device was turned off, the average power output was 0.3677 hp. It increased to 0.4428 hp after the device was turned on. This indicates that the power output was improved by about 20.4% at the same fuel consumption rate. In other words, if the engine on the road is under the same condition as our laboratory test with the dynamometer, the fuel mileage will be increased by 20.4%. The laboratory test was repeated for 3 h and had an error within 5%.
"
The engine they are testing has a rated bhp of several hundred horsepower (hp), and probably uses at least 25-50 hp in normal driving at low speeds...so why test it on a dyno at ~1/50th of its expected minimum operating output power? (I have trouble even imagining the engine maintaining a steady rpm with that low of an output power). Irregardless of the signal-to-noise problem with a dyno operating near its zero, pointed out by others, how can they make any meaningful statements about fuel mileage at any reasonable speed/operating power level based on tests at 0.4 hp output?
The stated mileage numbers are dubious for all the usual reasons (small sample size, uncontrolled drive cycle, etc. etc.).
RE: This has got to be snake oil
RE: This has got to be snake oil
500g/h and only 0.4hp?
That is gallons per hour is it or is it grams per hour?
Road tests: well now, I have found my fuel consumption varies according to the amount of attention I pay to the on-board computer.
If this were a car to which the device were attached without the user's knowledge and was switched on on alternate days or there was some way to conduct a double blind test, we might be getting somewhere. As it is One has to wonder if we are actually measuring device effect or operator effect (Deren Brown is pretty good reading on ouija boards and how they work..something the same could be working here. Then again, it could all be pucker gen................couldn't it?
JMW
www.ViscoAnalyser.com
RE: This has got to be snake oil
RE: This has got to be snake oil
So, how is this method different, assuming it works in the first place?
RE: This has got to be snake oil
RE: This has got to be snake oil
RE: This has got to be snake oil
RE: This has got to be snake oil
ht
Er, isn't the idea that petrol will vaporise and mix with air while diesels and heavier fuels are atomised?
Anyway, it seems the expert opinion is not that favourable either.
By the way: "Temple University has applied for a patent on Tao's work and has licensed the technology to California-based Save The World Air Inc."
Now there's a nice company name designed to play on the Californian conscience.
JMW
www.ViscoAnalyser.com
RE: This has got to be snake oil
a visit to the STWA website (http://www.stwa.com/product.htm) is a bit frightening with claims like this:
Why do terms like "certified laboratory testing" make me feel someone is about to try and pick my pocket?
JMW
www.ViscoAnalyser.com
RE: This has got to be snake oil
ht
JMW
www.ViscoAnalyser.com