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Old & Slow

Texas

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Joined: 07/25/2007

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Posted: 10/07/07 04:26pm Link  |  Quote  |  Print  |  Notify Moderator

Professor95:

Your BLACK box inspires a old man, pretty nice any way you look at IT. Look I did. At the carb.[emoticon] Innovation at it's best! However, there must be something in your pocket? Will wait for more to come.

Floyd
O&S

blkfe

Nebraska

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Joined: 10/11/2006

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Posted: 10/07/07 06:29pm Link  |  Quote  |  Print  |  Notify Moderator

professor95 wrote:

blkfe wrote:

Could you share how you get correct head tep readings with a H2O temp gauge?
Brad


Think about your question for a moment, Brad (this is the teacher in me talking).

If you take a thermometer and place it in a refrigerator what do you measure?

If you place the thermometer in an oven, what do you measure?

If you place it in a glass of water, what do you measure?






The mechanical water temperature gauge is nothing but a thermometer. It is going to measure the temperature of whatever environment it is in as long as the temperature of the environment is in the range the thermometer is capable of measuring. The fact that the front of the gauge says "water" is irrelevant.


Thus, if the thermometer probe is placed next to a fin on the engine cylinder, it will give you a temperature reading for that particular point - even if there is no water.

Under heavy load, the gauge will record 260 degrees F. Just idling or with a light load, it barely hits 180. Of course, moving the probe to another place may give a different temp.

Now that I know that 260 degrees on this gauge is pretty darn hot and relates to a cabinet air temp of 165 degrees I can quickly see if the air in the box is getting over the limits I consider safe (around 180 is the max). If the gauge goes over 260 I either need to open the lid on the box or reduce my load.

I once used two accessory water temp gauges to measure engine oil and transmission fluid temperature on a Dodge van that was a former tow vehicle of mine. Why? Because they were 1/2 the price of the same gauge that said "OIL TEMP".


professor95,

I could go on and on about the assumptions and such I was making but in the end it is as simple as "I failed to think it through..... "

Thanks!
Brad

professor95

Mechanicsville, VA

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Posted: 10/07/07 08:10pm Link  |  Quote  |  Print  |  Notify Moderator

TKMJ wrote:

At this point I will assume that you are at least semi retired if not retired. I can't wait for the days when I can check out of work and enjoy the leasure time.

I was not looking for any type of arguement. I think your idea was fantastic. I wish I could dedacate the time to come up with the stuff that you do. Maybe someday.


You know, I am not really sure what I am. I did take early retirement from the Virginia Department of Education in 1999 after 32 years in various levels of educational adminstration and teaching. Then, I started teaching at a local college, supposedly part-time. Five years later I was Dean of Academic Affairs. The job proved to be a monster that possessed my life. I woke up one morning thinking I had never seen a Brink's Truck follow a Hurst. Life was too short as it was without working yourself to death. I cleaned out my office, typed up a resignation, said goodbye and went home. That's where I have been since May.

I am committed to teach at least two electrical engineering courses next quarter at another college. That gives me until early December.

So, I guess semi-retired is a nicer term than temporarily unemployed.

What is this about an argument?


Professor Randy T. Agee & Nancy Agee. Also Oscar, the totally ruined Dachshund.
2009 Cedar Creek 5th Wheel - 2004 Volvo VNL670 class 8 MotorHome conversion as toter.
Turbocharged, 12L, 465 HP and 1,800 ft. Lbs. of torque.


professor95

Mechanicsville, VA

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Posted: 10/07/07 08:18pm Link  |  Quote  |  Print  |  Notify Moderator

blkfe wrote:

could go on and on about the assumptions and such I was making but in the end it is as simple as "I failed to think it through..... "

Thanks!
Brad


I know. That is why I gave you the smart a** teacher approach. Probally in bad taste and totally inexcusable. It was a mood thing I was in at the time. Frequently, I make my students give answers to their own questions when I can see that the lights are on dim. Nothing personal - it is just me.

professor95

Mechanicsville, VA

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Posted: 10/07/07 09:03pm Link  |  Quote  |  Print  |  Notify Moderator

I promised I would talk about propane conversion.

Sitting under a big oak tree on Loft Mountain Saturday, a margerita on the table next to me and my dog at my feet, I decided to pull out the laptop and put together some words.

As I began to write, it occured to me that I should put a disclaimer at the beginning of the article and do the whole thing as a first person story of how I did the conversion(s) rather than creating a "how to" article. Thus, please keep in mind that this is how I completed MY project. It is not really intended as a plan on how to create yours.

The disclaimer:

The following article describes the author’s method of converting a 6.5 HP gasoline engine to run on propane (LPG). The methods in this article do not in any way imply compliance of the engine with EPA or CARB regulations after conversion. The author cannot and does not warranty the safety, durability or success of the conversion. This article is intended ONLY to serve as a description of the author’s steps to make a conversion on his personally owned equipment and IS NOT intended as a step-by-step construction method for others to follow.

An any and all alteration that may be performed to equipment owned by individuals reading this article is strictly performed at their own risk with no liability associated with the author.

The Story:

The common Chinese genset produces around 3,000 watts from a gasoline fueled engine that is basically identical to the popular Honda GX200. Gasoline carburetors used on the entire crop of Chinese gensets built around this engine are similar or the same in design.
I am of the opinion that all of these engines are easily and inexpensively capable of being converted to run on LPG and still produce the same horsepower and wattage as they did on gasoline.

For those who want a “turn key” system, US Carburetion, http://www.uscarb.com/, offers both low and high pressure kits to completely accomplish the conversion.

I was not afraid to do a little work myself and reused some cast off parts from an old burned out gas Bar-B-Q grill. By doing so I cut my cost over purchasing a complete conversion kit by as much as 75%.

I believe a little understanding of LPG is needed to safely accomplish the conversion.

LPG is commonly stored in metal cylinders under pressure. Since LPG (propane) turns from a liquid to a gas at 44 degrees below zero (boiling temperature) the pressure in the tank is necessary to keep the gas in liquid form.

The pressure right out of a propane cylinder will vary between 25 psi and 180 psi depending on ambient temperature. Some gas appliances are called “high pressure”.
These may include portable propane camp stoves, ovens, grills lanterns and the common propane torch used to solder and heat metals. These systems do not use a regulator between the propane tank and appliance.

Recreational vehicles use a low pressure propane system. To accomplish this pressure in the propane tanks is lowered via a regulator, usually attached at the tank, to no more than 10 psi. This pressure is consistent no matter what the outside temperature is. I had previously determined that since this pressure is consistently low, for my personal purposes, high pressure LPG rated rubber hose was not necessary. I felt that hoses at or beyond the regulator should be at a minimum of rubber automotive fuel line designed for unleaded fuel and alcohol in fuel injected vehicles. This hose is available at automotive supply stores by the foot. I did not feel that a substitute of rubber vacuum hose or vinyl fuel hose of a lesser quality, material or pressure rating would be safe. All connections should be made to barbed fittings with well secured gear hose clamps. A leak test must be performed after hose make-up. Do not construe this statement to mean that the uses of hoses other than those rated for LPG usage are acceptable or safe.

Internal combustion engines such as the ones on the Chinese gensets need an even lower LPG pressure system supplying around ½ psi. These engines also need a variable volume of fuel and air, depending on the speed and load of the engine. To control this variable load, a vacuum demand regulator is required between the system’s low pressure regulator and the engine. These regulators are available from sources such as US Carburetion for around $60 in US funds. The low pressure regulator from a defunct LPG grill may be recycled, or the gas line currently on the RV may be tapped for the low pressure source of fuel. If the RV gas supply is tapped, a cut-off valve between the supply and the demand regulator is needed.

The OEM gasoline carburetor on the engine needed to be converted, or drilled, to work with LPG. While dual fuel methods are possible, the simplest method is to just simply adapt the current carburetor. I decided to acquire a second carburetor to accomplish the conversion, leaving the original intact should I ever want to restore the engine to the original fuel. The second carburetor need not be from the same type of engine so long as the carburetor will fit the mounting studs.

To accomplish the evolution from gasoline carburetor to propane mixer, the float bowl, float and needle are removed. The main jet in the center of the carburetor is also removed. These parts are discarded.

I found a piece of ¼” OD copper tubing about 3” long left over from installing a water line to a refrigerator ice maker. I cut one end of the tubing at a 45 degree angle with a hacksaw and cleaned up the remaining burrs with a file. A ¼” drill bit (make sure the bit is the same size as the tubing OD) and a regular electric or hand drill was used to drill up through the center of the carburetor where the main jet once resided until the bit came out in the middle of the carburetor opening. The copper tube was inserted so that the taller end of the 45 degree cut was facing the choke end and the lower part of the 45 degree cut was facing the engine end. Using JB Quick Weld epoxy (RTV is also OK), I glued and sealed the bottom of the copper tube to the carburetor. The exposed piece of copper tubing became the feed point for the LPG. I left 1” of copper tubing for attachment of a hose. I later decided to cut the tubing flush with the carburetor and push a ¼” NPT brass ell over the tube and attach a barbed hose fitting on the other end of the ell as the hose fed. It is important to seal the brass ell to the carburetor with JB Quick Weld or RTV.

Again, using JB Weld (or RTV), I found, removed and sealed all remaining jets and openings in the OEM carburetor.

My conversion from a gasoline carburetor to a LPG mixer was complete.

I now needed to make what is known as a “load block”. This is nothing more than a valve between the output of the demand regulator and the mixer. The load block may be a regular gas ball valve (about $8 for a 3/8” gas rated brass ball valve at Home Depot) or a home made adjustable restrictor using a brass “T”. Stay away from valves made for water. Water valves can easily leak a gas like propane. I selected to make the adjustable restrictor with a brass “T”.

So far, this is what I have: A propane tank, a low pressure regulator attached to the propane tank (or the RV’s low pressure gas source), a “demand” regulator after the low pressure regulator. An adjustable “load block” coming out of the demand regulator which attaches via a hose to the input to the mixer. I started with the load block about ½ open.

Now, time to adjust and test.

With all connections complete, I slowly turned on the propane tank (turn on too fast and the OPD valve will shut down).

I then spraed all connections with a 50/50 solution of Dawn dish washing liquid and water to see if there are any bubbles. Bubbles will indicate a leak that must be fixed! Since there were NO bubbles, I set the choke and pulled the engine starter rope.

The engine started, but run roughly. I needed to adjust the load block valve until the engine ran smoothly.

That’s all there is to it. My genset is now converted to run on safe, clean, non-spoiling or gumming LPG! Since I was resourceful with re-purposing previously cast off LPG components and adapting the gasoline carburetor to a LPG mixer, my only out-of-pocket cost was the demand regulator.

To turn off the genset, I close the valve on the propane tank or from the low pressure line on the RV. I do not turn off the engine with the normal kill switch.

Photo Links:

http://i21.photobucket.com/albums/b298/professor95/carbparts.jpg

http://i21.photobucket.com/albums/b298/professor95/drilling.jpg

http://i21.photobucket.com/albums/b298/professor95/inserttube.jpg

http://i21.photobucket.com/albums/b298/professor95/seal.jpg


http://i21.photobucket.com/albums/b298/professor95/insidetube.jpg


http://i21.photobucket.com/albums/b298/professor95/lowspeedremoved.jpg

http://i21.photobucket.com/albums/b298/professor95/loadblock.jpg

http://i21.photobucket.com/albums/b298/professor95/demandregmixer.jpg

http://i21.photobucket.com/albums/b298/professor95/regmodel.jpg

http://i21.photobucket.com/albums/b298/professor95/primer.jpg

http://i21.photobucket.com/albums/b298/professor95/system.jpg

http://i21.photobucket.com/albums/b298/professor95/mixerinstalled1.jpg

http://i21.photobucket.com/albums/b298/professor95/brassell.jpg

http://i21.photobucket.com/albums/b298/professor95/alternateconnection.jpg

TKMJ

Ohio

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Posted: 10/08/07 01:56am Link  |  Quote  |  Print  |  Notify Moderator

professor95 wrote:



What is this about an argument?


Professor95, Never mind. I assumed. Sorry!

Ken

professor95

Mechanicsville, VA

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Posted: 10/08/07 07:17am Link  |  Quote  |  Print  |  Notify Moderator

Sound Abatement Enclosure Details and Photos
Copyright Professor Randy T. Agee, E.ED., October 15, 2007


This is not the first enclosure I have built. But, it is the most thought out and successful enclosure to date. Before building this enclosure I spent several months doing research on noise abatement and transfer of thermal energy. Not that I really needed to, it was more of an exercise in confirming the ideas I had previously developed.

My goals were simple:

1. Cool the engine. Keep the cabinet temperature under
170 degrees F in the most severe operating situation.

2. Cool the AVR and alternator. Ideally, keep these
components under 140 degrees F.

3. Achieve a noise level equal to (or better than) the
Honda 3000 Inverter model. This would be 59dB[A]
at 21 feet away under no to moderate loads and
62-63 dB[A] under full load at the same distance.

4. Keep the size and weight as close as possible to the original genset.

5. Allow easy access for service or repair, especially spark plug and oil changes.

6. Keep it safe. Gasoline in a closed compartment disturbed me greatly.
I could not come up with a method of achieving this that would let me sleep
comfortably at night.

7. The cabinet needed to be weather resistant.

8. Cost was also a factor. I set a limit of $200 for the entire unit.
Anything over that was out of the question.

9. And, lastly, re-purpose as many materials and components as possible.
This reduces trash in our environment (or at least delays it) and lowers
construction/materials cost.

I had done some experiments earlier with fuel pumps and remotely mounted gas tanks. The carburetor on the GX200 engine was not designed for a pressurized fuel system. The close as I could get to something that worked was a 2.5 psi electric pump designed to work on 12 VDC, but run on 6VDC. At 12 VDC gas would seep out around the float needle valve. While a system of relays and voltage reducers could make the pump safer and shut it down automatically when the engine stopped, I was still uncomfortable with the design.

Gravity feed was an option. But the tank would mount over the top of the enclosure, making access problematic. I just did not like the idea of using gasoline with an enclosure. I began to research LPG options and discovered the conversion was extremely simple, and surprisingly inexpensive. In fact, I could convert to LPG for a comparable cost of a remote electric fuel pump. LPG became a no-brainer.

Effectively getting rid of excess heat was a major consideration. Much of the heat from the genset comes from the muffler. It is a giant heat capturing device and radiator. Again, it was a no-brainer that the muffler needed to be relocated outside of the enclosure.
The next issue was the volume and path of cooling air. On the Chinese gensets there are two major cooling paths. One is into the grill around the recoil starter and across the cylinder head fins. The other was the movement of air into the alternator grill (on the end) and out the bottom of the alternator near the engine. Simply sucking or blowing air into a box would only serve to recycle lot of hot air. Brute force systems using several large fans might work, but efficiency would be really low. My research had shown that what was needed was a small enclosure that would allow evacuation of air rapidly, a directed airflow into the engine cooling side and an additional cooling intake for the alternator and AVR.

My design included a 6” diameter, 12 VDC, 300 CFM exhaust fan, a shroud over the engine intake around the recoil starter to direct air flow, and complete isolation of the air intake on the end of the alternator from hot air in the cabinet.
Just for good measure, I added a small 50 CFM fan to the end of the alternator to force cooler outside air across the AVR and alternator coils. This airflow design has proven to work extremely well keeping cabinet temperatures well within the desired maximums.

There are many methods to reduce the transfer of sound. The cheapest and perhaps most effective, especially for low frequency reduction, is a small cabinet with very thick open cell material to capture sound pressure. To meet this requirement, I selected a full 2” thick foam insulating board made by Dow Corning. It is available at most home stores in 4x8 foot sheets for less than $25.00 (one brand is pink, another brand is green). The foam board is easily cut with a common saw and really smooth edges can be accomplished on a table saw using a fine tooth blade and slow feed. Openings are cut with a fine tooth saber saw set on a low speed. Once sized, the foam board can be painted with a latex paint “as-is” or laminated. I chose to laminate mine with Filon, a 1/8” thick fiberglass board similar to the material used on the outside of many campers. It is available at home stores for less than $30 for a 4x8 foot sheet. It can be trimmed with a router using a laminate bit. Just be sure to use a latex contact adhesive. Other adhesives may dissolve the foam board.

I had previously made a new frame for the genset from surplus angle iron re-purposed from discarded bed rails. This made it easy to attach the foam panels since the surface was flat and square. If one lacks welding equipment, I am of the opinion a similar frame could be made of hardwood 2”x2” lumber.

The foam panels were attached with Velcro. I used the industrial variety. It doesn’t take much to securely hold the foam board in place and it is not affected by the heat in the box. Open gaps between foam board and angle iron faces caused by the pieces of Velcro were filled with 1/8” thick rubber gasket material used to seal camper caps to the bed of pickup trucks.

The stock front genset panel was retained. A piece of ¾” thick, Formica laminated outdoor grade plywood was cut to fit the contour of the stock panel and then covered with Filon. I used plywood here since I needed a rigid panel to mount accessories. Cutting this piece on the bandsaw was scary – it was the same saw I severed my left little finger on last May 14th. This was the first time I had used it since the accident. I did need to use spacers under the OEM genset panel to get the right offset for a flush fit to the plywood.

Both cooling fans were 12 VDC. The genset was electric start, so a relay was needed to energize the 12 volts to the fans. I had a surplus 120 VAC single pole, single throw relay in my junk box. I connected the coil of this relay to the output of the generator. When the generator started, it would pull in the relay and supply 12 VDC to the fans. If there had been no battery, I could have just direct connected the fans to the 12 VDC out of the genset.

I needed good venture vacuum to prime the engine so it would start or an electric solenoid that could push the primer on the demand regulator. US Carb does sell an electric primer solenoid as part of their RSK kit, but that was more money to spend. To get the vacuum, I had to retain the choke. So that a remote start system could be implemented, the choke needed to be electric. I borrowed a 12 VDC solenoid from an old surplus computer disk drive. The solenoid was configured to pull in the choke on start. Other solenoids such as those used on automotive door locks should work equally as well.


I found two surplus automotive gauges in my junk box. One was an automotive water temperature gauge, the other a DC voltmeter. I placed the probe for the water temperature gauge against the cylinder head fins on the engine. I now have a head temperature gauge.

As an added safety feature, I exchanged the 120 volt, 20 amp outlet for a GFCI outlet. I changed the wiring behind the control panel so that the cooling fans were before the GFCI outlet. This was done to be sure a GFCI trip would not stop cooling. I added a new circuit breaker for the inside outlet used to fed the 120 volt relay for the cooling fans.

Changing oil could be a problem with an enclosure. I ran a tube from thbe engine's oil drain plug to outside of the front panel to make this service a whole lot easier.


I had previously purchased a "hatch" from West Marine for use on my boat, and then decided not to use it. While not necessary since the top of the enclosure is removable, I felt like I should use the hatch somewhere and decided what better place than the top of the box for quick and easy access.

Were all of my objectives met? You bet they were! 58dB[A] at 21 feet with low to moderate load. 62dB[A] with the air conditioner compressor locked in on the camper.
This system is as quite as, if not quieter than the Honda Inverter. It beats any installed motor home genset hands down. Temperatures inside the box all fell within my established limits, even on a hot 90 degree October afternoon..

My total cost was also well under the $200 limit I had established.

This is one quite and cool puppy!

(Additional Photo Links)


21 foot view

view with top off

150 VAC full scale meter to replace 300 VAC full scale meter

only front panel on - sides off

bringing starter rope to front panel

added HR meter to keep track of service due intervals

generator end

engine panel showing 6" to 8" ductwork transition used as fan shroud

real-time air temp reading inside cabinet

* This post was edited 10/08/07 07:24am by professor95 *

Old & Slow

Texas

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Posted: 10/08/07 07:58am Link  |  Quote  |  Print  |  Notify Moderator

Professor95:

I made a previous comment about the picture of the carb., that something must be in your pocket, thanks for a better picture[emoticon]. I now see the copper wire connecting the solenoid to the choke. Next step please, the remote control.Great work in innovation! Your grade, A+

JaySki

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Posted: 10/08/07 11:49am Link  |  Quote  |  Print  |  Notify Moderator

Amazing.. Simply amazing.. I look forward to having the time to 'tinker' with stuff like this. Unfortunately.. I think it'll be about 30 years till then....

Thanks for all the time and GREAT info you have put up here.

blkfe

Nebraska

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Posted: 10/08/07 04:12pm Link  |  Quote  |  Print  |  Notify Moderator

Awsome job Professor95!
Is the frame size of the electric start Champion the same as previous models?
Also, any combination of 12VDC fans I look at which provide cfm flows as great or greater than what you used draw more current than the 12VDC output of the Champion is rated to put out. Have you measured DC current draw of your fans?
Brad

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