CNG pump compressor DIY home refueling

[P-hack]

methane stoic ratio by mass: 17.2

air = 0.075 lbs/ft3.
methane = .038 lbs/ft3.

0.6536 lbs air needed for 1ft3 methane.
8.7ft3 air per 1ft3 ch4, "fogging" would be 11.5% of the intake volume at stoic if I figure it right. Probably acceptable losses given the extremely low entry cost and low cost of NG, easy enough to dump ANG methane into a throttle body, don't know about diesel.

[vlad]

The cng diesel fumigation is well known technology and there is no "magic" in it. You simply feed (metered by different devices) cng low pressure into intake before turbo, then cng air mix pushed into cylinder (by turbo). When mix compressed by piston it is "waiting" for ignitor (diesel injection) then this all air/cng/diesel mix "explodes". Cng adds 30-50% extra power, so you simply ease off your gas pedal and as soon as you do this you diesel injection amount lowers.

Diesel engine has no throttle (most of them). Your gas pedal is "attached" to fuel metering device.
In gas vehicle your gas pedal is "attached" to air metering device which in turn "attached" to fuel metering device.

Don't look at cng as an air "thief". It works instead of diesel

Just watch this and see power it gives:

http://www.youtube.com/watch?v=Yem6t6GQrc8

[P-hack]

That video was useless. I'm leaning towards ANG and gas, since the @home compression technology seems feasible and very affordable and tanks already exist, and there are so few diesels in the states. And fogging w/throttle seems quite doable on a gasser without gutting the gasoline system for longer range trips.

[P-hack]

called g-tec, the ng-130 tank holds 1 gal equiv, $590 each, not as bad as I expected. Could handle %90 of my driving needs, adds 150ish lbs to car.

The Refueler is like $3000 (275 psi AC screw compressor), so yah, alternative there please.

[CFECO]

There are high pressure pumps for pre-charged air guns, not high volume but with several running together, overnight it might work. They are for compressing Air not flammable gas so I don't know of any "Issues".

Benjamin Hand Pump, Fits Crosman & Benjamin PCP Guns
Retail: $255.00
Our Price: $179.99
You Save: $75.01 (29%) add to cart

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SKU: PY-A-2222
Availability: Usually ships the next business day



Manufactured by Benjamin
Description
3-stage hand pump
Made specifically for the Crosman/Benjamin PCP pistols & rifles (fits any brand of PCP gun with a male Foster quick-disconnect on its reservoir)
Includes a female Foster quick-disconnect on the end of the pump hose
Goes up to 3600 psi (although some of the guns listed above operate on a max pressure of 2000 or 3,000 psi)
With other hoses, pump can be adapted to other PCPs
Requires less effort than other pumps
Integral air pressure gauge
Moisture filter

[cRiPpLe_rOoStEr]

Originally Posted by P-hack

And fogging w/throttle seems quite doable on a gasser without gutting the gasoline system for longer range trips.

A multipoint setup with one injector per cylinder is better, and also available to aftermarket conversions. And it also doesn't freeze the intake manifold so easily as it can happen with a throttle-body fumigation setup. My country has the 4th largest CNG-powered fleet, only below Pakistan, Argentina and Iran, and I've already driven a few cars with aftermarket CNG setups.

[P-hack]

The only kits around here are for trucks, so no thanks.

[vlad]

Here are some specs from my Copeland HP/AC scroll compressor:
http://s1314.photobucket.com/user/vl...c9d4e.jpg.html

Max operating pressure 27.5 Bar or about 400 Psi
Flow 7.13 m3 or 251 ft3 which is 1.97 GGE

This is a very standard AC/HP compressor 2 ton capacity. They are real work horses.

The first potential problem I can see is overheating because they cool by return vapor. But they have a lot of oil in them 38 oz!!! So to make it's life cooler I can turn some copper tubing around bottom (where all oil sits). Cold water or coolant can be used.

The second problem is oil. All AC compressors are spitting oil I mean they really blow oil out. To solve this problem is easy you need to add refrigerant oil separator just like this one:

http://www.qequality.com/categories/...EPARATORS.aspx

It connects to discharge of the compressor. Oil separates from gas inside but when too much oil it opens valve and oil goes back to compressor. You can't just dump oil in suction line (hydro-lock). I will braze extra tube to compressor can....



I forgot to mention I found it locally on craigslist and paid $200 for it.



So my "1 stage" is kinda getting clear.

[vlad]

Originally Posted by P-hack

The only kits around here are for trucks, so no thanks.

Why????

Check this out:

My CNG Guy | Utah CNG Kits | 801-687-7788 - CHECK OUR ALL OUR NEW TOP OF THE LINE PRODUCTS Archive » My CNG Guy | Utah CNG Kits | 801-687-7788

I am not affiliated with this business.

[cRiPpLe_rOoStEr]

Any of the major players in the CNG kits industry have multipoint injection kits, which we know in my country as "positive pressure" systems.