Electric Supercharger

[Frank Lee]

If you're not hard on the gas enough to get into boost the thing could always act as a genset and not a supercharger thus the battery capacity would be a moot point.

[dremd]

Originally Posted by Frank Lee

If you're not hard on the gas enough to get into boost the thing could always act as a genset and not a supercharger thus the battery capacity would be a moot point.

I'm with Frank; Especially if there was a little VGT action going on to replicate a throttle plate!

[Christ]

Mech - Please, don't think I was attacking you personally. If you've come up with a way to use a generator in the intake stream, please, by all means, go for it.

As with any new technology, there will be nay sayers. In this case, I'm one of them. Mathematically, there just isn't that much energy to be extracted from the intake's volume at ANY RPM, let alone at idle, as I calculated.

There is another formula that I can use to show you exactly how much energy a given cross section of wind contains:

P = 0.5 x rho x A x V3: Power in the area swept by the wind turbine rotor: (This doesn't necessarily imply that you're using a wind turbine, it's just the power contained in the cross section of flow.)

Once again, we'll assume as many ideal circumstances as we can, to give the best possible chance for a good result. We're also going to use the influx of an 8.0 liter engine at 6,000 RPM, assuming 100% VE, for exaggeration's sake:

P = 0.5*1.225 kg/m3*0.008 m2*0.4 m3/s (847.552 CFM)

0.00196W - This is the total amount of energy contained in the volume of air that is necessary for that engine at the quoted RPM and displacement.

For simple comparison, a 10 foot blade span (20 foot diameter swept area), using the same CFM figure, contains:

P= 0.5*1.225 kg/m3*29.2 m2*0.4 m3/s

P= 143.08W, or 0.2 HP.

Remember - air is a constant in science, and wind is a battery. Air holds potential energy, wind contains kinetic energy - kinetic energy had to be given to the wind by something else, so the wind is a battery of energy which can be extracted. Air is not very dense, thus, requires very little energy to move a given mass at a given speed. Per Conservation of Energy, when very little energy is passed into an object, very little energy can be extracted from it.

According to Albert Betz, no more than 59.3% of the energy in the wind can be extracted by means which require the energy of the wind to move an object to convert energy. If no conversion can successfully be more than 60% efficient, of the 143W in the second example (20 foot diameter), you can only successfully get ~57W. On top of that, there are generation losses from heat and friction, further reducing the amount of energy that can be extracted.

Adding to all that - If you extract the Betz Limit of energy from 800 CFM, you're only left with a flow rate of approx 320 CFM, which is much less than the requirement to keep the 8 liter engine at 6,000 RPM and 100%VE.

While the project in question would be able to operate as an engine brake by extracting energy from the intake stream, very little power would be generated by it, and almost none that would be useful over a short period of time.

Keep in mind - I'm not saying that you can't use a positive displacement pump to charge the intake air, thereby creating forced induction - I'm just saying that the process won't work in reverse, according to currently understood physics and fluid dynamics.

[Bicycle Bob]

Without reading this whole thread, I'll just say I like the idea a lot. With a positive displacement reversible pump, such as a rootes blower, we are not limited to windmill efficiencies when extracting energy from the incoming air by replacing the throttle plate. With the pump in place, supercharging can be used to overcome the restriction of a milder, more efficient cam. Since we usually run engines at less than half power, most people would be taking a load off the generator.

[user removed]

Christ and every one else. I worked on customers cars for 14 years as an owner operator of my own business, so my skin is almost the consistency of titanium, if you know what I mean.

I was fascinated by the number of Engineers who come to this site regularly.
To me that represents a desire to address the inefficiencies of current automotive designs.

Sometimes my own lack of formal education makes me a little gun shy when it comes to debates where that weakness may be exploited to my disadvantage, but then practical experience and demonstrations of a concept have their own validity. Remember the Wright brothers had very little education.

I am not trying to argue any of your most valid points my friend. I just see potential. On of my demonstration tools is a simple cylinder, with a steel rod of about 4 inches in length. I turned the rod on my little lathe so the rod was a very close fit in the cylinder. Placing my thumb on one end of the cylinder I was surprised to see that if I put the rod in the cylinder and banged one hand against the other the vacuum created was strong enough to keep the solid steel rod from exiting the end of the cylinder.

Some photos of my small demo model of my design.

This is a piston in cylinder positive displacement pump.
It is also variable displacement.
It does not reciprocate.
The outer portion, outside the black highlighted part, is the rotating portion.
Notice the lack of connecting rods, a large frictional loss in a conventional recip engine or pump.

The inlet and outlet ports are located in the adjustable journal, where the red highlighted cylinders meet. Adjusting that journal accomplished a change in the stroke position. One photo shows the neutral or no stroke position, while the rest show a stroke position and several positions of the outer rim in that same stroke position.

Consider this as a hydraulic in wheel drive for vehicles, where this pump motor replaces your conventional brakes, and eliminates the necessity of all the rest of your power train components. The pump-motors are driven by a hydraulic accumulator. The engine, motor, or whatever stored energy consuming power source can now be cycled to replenish the charge level in the accumulator, but all power to the wheels comes from the accumulator itself.

Virginia Tech has looked at it for a year as a Senior Engineering project, and the same design was published in the August edition of the AMSE journal.

A super lightweight much simpler power train that could be incorporated into a very inexpensive hydraulic hybrid vehicle that could sell for less than anything on the market today.

The patent has passed the initial review and the test of novelty, it should be issued within a few months.

It might have a function in the electric compressor application, although that was not my conceptual pathway.

Christ, it just seems to me that there is something wrong with an electric supercharger that requires 200 amps to blow one atmosphere but can only extract such a low amount of power working for the opposite purpose.

I wont try to contradict your valid points, because I am sure of your ability, due to looking at your many posts here.

It just seems to me that such a wide disparity in the power required versus the power that could be potentially extracted would indicate that there was something wrong with the basic design of the system in this thread.

It may just be my ignorance, but remember ignorance is curable, stupidity is not.

I think my design demonstrates the I am not stupid, but lets let the reader make that determination. The ability to be self critical is a key component in my persona, mistakes are the pathway to success.

regards
Mech

[pgfpro]

WOW!!! Cool design nice work

[Christ]

Mech - I'm not sure of the formulae necessary to consider losses due to compressing air, but I do know that it's a very inefficient process in most cases, given how long it takes piston pumps to provide X volume of compressed air.

I do know that if you want to measure the mass of a tank of compressed air, you consider:
Volume of vessel*intake CFM*compressor efficiency/time empty to full

You end up with:

M = V*I*Ce/T as a formula for calculating the mass of air inside a vessel, when you don't know the pressure. (Obviously, if you knew the pressure, it's a much easier process.)

Mech - Never let anyone take advantage of your "lack of formal education" either. I quit school in 10th grade, 1st semester. Just make sure you never stop learning, and you'll be fine.

I'm can't say much about your design, because I'm not all to familiar with the design or theory of operation. I'd like to read whatever writings you have on it, though. (After the Patent, of course.)

[user removed]

There is a reasonable amount of information on the web if you Google using advanced search.

"Rotational Inertial Dampening Engine"

Its very loosely based on the WW1 era rotary aircraft engine with significant modifications.

I understand the limitations of any compressed air system, at least to a certain extent. Most of the issues are with the "spring effect" of compressed gasses.

That is why the design would be using a liquid versus a gas.

I appreciate your candor in revealing your formal education limitations.

Frankly based on the considerable amount of information I see you have contributed to this forum, I was surprised top see you had not graduated from MIT with a Doctorate in Engineering.

As one of 4 sons of a Civil Servant the finances for higher education were limited in my case. I did start at Virginia Tech with an intent in graduating with a degree in Nuclear Physics, but I left after 6 months, went home and got a job, and spent 30 years in the auto repair industry.

I read a couple of months ago, think it was Green Car Congress, that Argonne Labs is working on improving IC efficiency with a goal of 60%. My design was originally for an engine that could, by stoke position adjustment, transform itself from an engine to a flywheel for short term storage of energy. No valve train, with compression ratios as high as 50 atmospheres, in a compression ignition configuration. Multi fuel capabilities.

I have been attacked for my belief that in order to fix the real problem with automotive inefficiency you need to fix the system, not the people. My father (still living at 88) hypermiled his 4 engine bomber over Europe to conserve fuel in order to give him more of a chance to get back to his home base.

Hypermiling goes back to WW2 era gas rationing. How far could you get on 2 gallons a week?

I see in my conceptual visions, vehicles that are capable of 100+MPG while carrying 5 passengers in comfort. Hypermilers are the pioneers in that pursuit, but we also have to alter our driving styles to compensate for the basic design deficiencies in current vehicles.

While I would love to see my efforts bear financial returns, the more important point is that the global demand for energy needs to be addressed with the prime objective of better utilization of every energy source.

The term "free energy" drives engineers crazy. Maybe a better definition would be available sources of energy that do not involve the expenditure of capital.

regards
Mech

[Bicycle Bob]

Hydraulic accumulators still use an air spring. Compressing that air raises its temperature, and that heat is very hard to contain, and when it escapes, you loose pressure and energy.

[user removed]

According to the EPA and Eaton, accumulators are 96-99% efficient. They are referring to the bladder type. The spring piston type can handle higher pressures but are much heavier. There are also inert gas piston types, as well as many others that are not very commonly encountered.

The bladder is precharged to several hundred PSI, pumping the fluid into the containment vessel outside the bladder collapses the bladder and increases the pressure.

The heat rises as the gas in the bladder (usually Nitrogen) is compressed. That increase in temperature increases the effective pressure necessary to push more fluid into the liquid portion of the accumulator.

Heat losses are minimal. If that was not true the efficiency calculations would be lower. When the charge in the accumulator is released the temperature of the gas falls off to the same temperature that existed before the charge cycle began.

Few energy storage sources can compete with hydraulic accumulators. The closest competitor is a flywheel battery, but you are talking about 150,000 RPM, magnetic bearings, in a perfect vacuum vessel.

That NASA developed flywheel battery can store 10 KWH in a vessel the size of a gallon gas can, but it cost several hundred thousand dollars.

Accumulators do not use air for a spring generally speaking. This is because if you used any gas containing oxygen, that allowed the combination of a volatile liquid and that same oxygen at pressures above the compression pressure of a Diesel engine, you could have spontaneous combustion.

Conceptually speaking that phenomena could potentially be exploited as a form of an engine, creating spontaneous combustion intentionally to increase pressure significantly with a single combustion event.

regards
Mech