SilverSwallow

Hey folks, sorry if this has been posted.

Over the past several months I have just been lurking and searching, and yesterday, I stumbled on the OS Max 140RX FI. I can't figure out much about them, but they appear to have an electronic module for controlling the injection timing.

Would it be possible for somebody like Davis to make a diesel head for these? I recall someone posting a very old, perhaps German 4 stroke diesel which had an injection system, so I figure it's not out of the question to make one.

Sorry if someone has already mentioned this idea, I couldn't find anything related in my searches.

It would be a true diesel, clacking and all.

lildiesel

In the pictures I found that looks a lot like the Throttle Body EFI set up discussed in the "Atomization Pressure" thread in this forum. I'm going to search for an engine review.

Hey, R/Cpullerdude! OS beat you to market. On the other hand, you now know where to get an injector unit.

Okay. First thing I found out is that this engine is a 2 stroke and so I suppose a diesel head could be made by DDD using their current technology. Here's a list of the FI replacement parts:

# 29401100 140 RX FI CRANKCASE

# 29401200 140 RX FI TEMP SENSOR

# 29407200 140 RX FI COVER PLATE/RPM SENSOR

# 29430010 140 RX FI REAR BEARING WAS 29430000

# 29484000 140 RX FI INJECTOR SET

All I can surmise from this (and the pictures) is that the engine uses a temp sensor on the cylinder liner and an RMP sensor on the on the back coverplate taking a reading off the crank pin at BDC. In another picture I found what is obiviously an ECU shown. There appears to be one injector and there could/must be some sort of electronically controlled butterfly in the throttle body.

Very little comes up in google searches for this engine.

SilverSwallow

Yes, it is very much so 2 stroke.

I know I saw a fuel injected 4 stroke motor, I'll edit this post when I find it.


Here she is, all 1 kilogram of her. http://www3.towerhobbies.com/cgi-bin...?&I=LXRTM4&P=7

Sorry about that.

It's got a blower, too

From the descripton, the injection is fully adjustable.

The injector pump would likely be the box on the rear of the cylinder, and the injector is basically right in the head, making it likely that it is direct injection.

If it is direct injection into the cylinder, such as the newer Corvette engines, converting it to diesel is very easy. Basically, it would require the removal of the butterfly valve, and it could be simply throttled through use of the mixture control, just as in a full size diesel. Of course, this is provided the computer will allow on-the-fly mixture adjustment.


This could turn out to be quite fruitful if someone doesn't mind dropping 1.3 grand into an engine, and whatever Davis would charge to make a head for this machine.

Lou Crane

Theo,

In another thread in here, I mentioned another critical consideration: diesel fuel attacks silicone tubing, and silicone tubing is widely used in glow engine stuff.

Perry pumps, for example, come in two versions, one for glow fuels and one for kerosene or gasoline based fuels.

Be sure that what you find is compatible with diesel fuels, if you plan to use them.

SilverSwallow

Thank you, I didn't take that into consideration, despite the fact that I learned it myself, the hard way. ADD for you?

As you can see, http://www2.gpmd.com/image/o/osmg0941.jpg it has silicone tubing, which is going to be an issue.

Oh well, there are some extremely bright minds on here.

Motorboy

It is too early to please..

Fuel/air mix are programmed in the ECU to use with methanol, methanol/nitro fuel. The exhaust temperature are hotter in glowplug engine than in diesel engine. It will be unuseful to run the engine with ECU programmed to use methanol since exhaust temperature are difference in diesel engine. Fuel/air ratio in diesel engine are about 50% less than fuel/air ratio in glowplug engine. All parametre in ECU must be changed to works with the engine running as diesel engine.

Motorboy

The idea are not new, see this link: http://www.rcuniverse.com/forum/fb.asp?m=1513532 , but the history do not tell how the engine ran..

SilverSwallow

That is exactly the one I was thinking of. Thank you.


Injection can't be too hard then

Munin

Hello

An very interesting engine.

Its operated with a solenoid valve system.
Pressure provided by crankcase pressure with a one way check valve to tank.
I know that this can be done better by using a fuel pump with a mini tank with regular compressed
air for highly pressurized fuel to the solenoid valve. Good luck.

Animation: http://www.youtube.com/watch?v=SwqM8zpmAD8
Video guide: http://www.youtube.com/watch?v=e5434dDB-7w

Pick and choose a valve but these are not diesel certified.
http://www.directindustry.com/cat/hy...ids-G-294.html

Most likely box has to be re-coded / hacked for multi engine/fuel usage. Good luck.

/Munin

lildiesel

My 97 Passat VR6 has been "chipped" since just after I took delivery to match the high flow intake and air cleaner parts and the stainless steel exhaust I wanted. I suppose we'll all be spending large to some small hobby outfit that can program custom flash ROMS for us in the future.

Enya 41.4C DIESEL Four Stroke



Steal the OS throttle body EFI and chip it for this!

SilverSwallow

I'm familiar with those sorts of valves, as they are used in Electropneumatic paintball guns.

I'm sure you wouldn't want to pump diesel into them, they have a hard enough time coping with lithium grease as a lubricant, let alone having something corrosive like diesel.

Here is an example of one of my electropneumatic guns. It has a full blown computer with a GUI and LCD screen, and it is capable of cycling the solenoid as fast as you want. The forward and return dwell values can be changed on the fly; these values determine the maximum cyclic rate. http://www.youtube.com/watch?v=JkNveK3HpDU Don't mind the disaster area in the back.

The air is simply atmospheric air compressed to 4500 PSI in a carbon fiber tank, and a regulator on the tank lowers it to ~850 PSI, then a regulator on the gun lowers to under 100 PSI (an extremely low value, mind you) and further, a secondary regulator drops it to less than 10 PSI. the action is so gentile, that I would be more than comfortable sticking my tongue in the breech and cycling it.

There is no way that the solenoids could hand something like diesel without major reworking. The only solenoid that COULD in theory handle this is a secondary gasoline solenoid, which is normally used in conjunction with a second solenoid for nitrous injection on larger engines. However, the rate at which these reciprocate is likely much too slow for a high rpm motor, such as ours.

That was a mouthfull.

SilverSwallow

Throttle body EFI will not work unless it meets the following criteria.

A. The throttle plate never moves

B. The mixture can be adjusted rapidly, and on demand.

Otherwise, you will get a very odd mixture of pops, stalls, and patches of hair missing.

Diesels are throttled by mixture.

The richer the fuel, the higher the RPMs climb. Ever wonder why they spit out black smoke when accelerated hard? Too rich, due to rapid and heavy injection.



In an unrelated note, why is a glow stem sticking out of the cylinder?

R/Cpullerdude

That's just a dummy plug with shims under it to adjust compression. I really don't think that this injection is much of an advancement from carbs on Diesels. For Diesel injection, you need to inject the fuel in the cylinder near TDC. These could be used as a base, but cost too much to go playing with.

SilverSwallow

There should be variable timing, and it appears to be direct injection, making injection at TDC quite possible.

R/Cpullerdude

It looks more to me that fuel is injected right before the intake valve. I'd think that if it where DI, it'd be centered on the head, were a glow plug normally goes. Look how the intake comes in on the same side as the injector.

SilverSwallow

Ah, you're quite right.

I guess it wouldn't be too easy, as if I ever should have expected it would be

Well, it should be possible to "Rube Goldberg" the injector into the dummy plug receptacle, replace the injector hole with a compression lever, and you're all set.

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