Thinking out loud: M103 + LPG + Turbo - Page 3 - PeachParts Mercedes-Benz Forum

Deni · #31 06-11-2009, 10:18 AM

Quote:

Originally Posted by RBYCC

The M104-24V with HFM has an electronic throttle actuator.

I am not that familiar wiith it, but there is a signal level sent from the pedal to the engine bay actuator.

I'm not sure of the level or type of signal output, but I would assume it is linear...

So the m104 with HFM doesn't have a throttle by wire like the om606, rather a direct link?

400Eric · #32 06-13-2009, 03:54 AM

Quote:

Originally Posted by RBYCC

The only problem I see with a LPG fueled Turbo engine is that the tuning is counter intuitive.

If you run a rich AFR with LPG you end up with detonation as there is no cooling capacity in the LPG vapor /air mixture versus a Gasoline liquid/air mixture.

You are better off with LPG running closer to stoichmetric and getting power by increasing boost.

But increasing boost adds to engine component stress such as pistons, rings and rods.

The LPG will need more intercooling due to the heat properties of the vapor/air mixture.

I'm still a believer in a gasoline engine making more power at less cost and more safety then LPG.

I wasn't a believer in using additional injectors for gasoline AFR enrichment as I was concerned about equal fuel distribution to all cylinders.

Now I would not do a turbo on an older style engine any other way...the additional injectors mounted in line with the throttle body not only enrich the AFR, but act much like a water/alchohol injection as the gasoline mist acts like a cooling charge to the incoming boosted air !!!

Just some thoughts on the subject...comments always appreciated as this is a great learning experience !!!

There's a new way of running propane where instead of being vaporized and then injected it is injected while still a liquid. It then vaporizes in the combustion chamber and the result is the equivalent to about 5 pounds of boost. This vaporizing would also give a cooling effect just like gas does. I want to find out more about this. Regards, Eric

400Eric · #33 06-13-2009, 04:02 AM

Quote:

Originally Posted by Deni

Eric, I don't know where you're located but here in Europe, and as far as I know in Australia as well, LPG is widely used for economical issues, LPG being much cheaper than petrol. In many countries LPG is also being subventioned by governments (both kits and fuel) for being a cleaner burning fuel.

Here you can read something more about different LPG conversions: http://www.go-lpg.co.uk/which_conversion.html

I still didn't get a clear answer if these outputs can be found (or easily added) on the cis-e setup:

Oxygen (Lambda) sensor signal(s) (I think this is already there)

Throttle Position Sensor (TPS) signal (does the cis-e have this output or can I add it somehow?)

RPM (tach) signal (I guess this is already available)

Manifold ambient pressure (MAP) (this looks easy)

I'm leaning more on the m104 3.0 liter engine than a "little bit more complicated" turbo m103.

Thanks for the link.
Here in California, propane has the added advantage of freeing one from having to run all the emissions equipment too because it's cleaner and the state wants to encourage alternative fuel usage. Regards, Eric

400Eric · #34 06-13-2009, 04:12 AM

Quote:

Originally Posted by Deni

So the m104 with HFM doesn't have a throttle by wire like the om606, rather a direct link?

It is direct if the car does not have ASR but if it does have ASR, then it does have that funky hybrid semi throttle by wire system. That's why I avoid ASR cars. Regards, Eric

Deni · #35 06-16-2009, 03:19 AM

Quote:

Originally Posted by 400Eric

There's a new way of running propane where instead of being vaporized and then injected it is injected while still a liquid. It then vaporizes in the combustion chamber and the result is the equivalent to about 5 pounds of boost. This vaporizing would also give a cooling effect just like gas does. I want to find out more about this. Regards, Eric

I think this is called diect gas injection and I've heard that it was used for petrol engines with direct injection. I was told that lpg is injected directly into the piston chamber when the intake valve opens.

Tha system doesn't need a fumigator but it needs a fuel pump like petol engines do.

I don't know if this system can be used on any petrol as the head of the piston in direct injection engines is different to help mix petrol with air.

400Eric · #36 06-16-2009, 03:42 AM

I know that this is even being done on engines that originally came with a carburetor (they showed it on Hot Rod TV) so I know it can be done on our engines. Since there is a lot of propane usage in Europe, I'm thinking that is where most of the people are who have already done this to a Benz. I'm just hoping to learn from the folks who have already done it. Regards, Eric

BAD300 · #37 08-13-2010, 12:37 AM

so...how'd you go Deni!

Thread seems to have dropped off just over a year ago