Common rail upgrade of 2 and 4 stroke engines

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thechase
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Common rail upgrade of 2 and 4 stroke engines

Postby thechase » Wed Jan 05, 2011 1:36 pm

How would one go about doing this? and is it at all possible?

Might be a dumb question but if I'm to learn I'll have to ask.
Last edited by thechase on Fri Jan 07, 2011 8:18 am, edited 1 time in total.
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The Dieselduck
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Re: Common rail upgrade of 2 and 4 stroke engines

Postby The Dieselduck » Thu Jan 06, 2011 1:13 pm

of course, this is quite feasible, well at least on a larger engine. What size are you talking about? I don't think a 0.1-2 mw engine but 2-10mw might be more feasible. It like anything else, its possible, but is it worth it.

If the OEM for your engine does not offer parts then it is considerably more challenging. First of you would have to get a sensor suite installed. Then develop a microprocessor and program for it, then of course you'll need a pressure producer and special electronically controlled injectors. Anything is possible that for sure but its usual not worth it. What are you working on?
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Re: Common rail upgrade of 2 and 4 stroke engines

Postby thechase » Fri Jan 07, 2011 8:42 am

Can't really say I'm working on anything particular at the moment, but my understanding is that a common rail is more efficient in terms of combustion as it allows for electronical control of the injection, thus allowing you to fine tune the amount of fuel needed.

And as most large ships (to my limited knowledge) use engines without common rail systems, i was wondering if upgrading them was possible.

Sizewise I guess we're talking around 45MW, but I've been unsuccessfull in finding information regarding the details/engine types used in the commercial fleet. Perhaps you (or anybody really) can guide me to a useful site.
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Re: Common rail upgrade of 2 and 4 stroke engines

Postby D Winsor » Fri Jan 07, 2011 12:58 pm

The new Sulzer Flex RTA and MAN B&W engines have common rail fuel systems with electronically controlled injection. Even the exhaust valves are controlled electronically This eliminates the requirement for a camshaft.
I believe that Wartsila, the representatives for Sulzer, has developed a conversion kit for the older RTA engines
Some of the larger Wartsila engines has electronically controlled injection as well
You should check the Wartsila web site for more information
Last edited by D Winsor on Sun Jan 09, 2011 5:03 am, edited 1 time in total.
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Re: Common rail upgrade of 2 and 4 stroke engines

Postby Big Pete » Sat Jan 08, 2011 1:45 am

The old Doxford, opposed piston engines used to use a common rail fuel system with a high pressure pump circulating the hot high pressure fuel round to the fuel injectors, (2 or 3 mounted round the circumference of the cylinder) these were each fitted with a mechanically operated valve to control the injection timing.
At the time, Sulzer, B &W, etc insisted that individual fuel pumps and Uniflow scavenging were more efficient.
Once Doxford closed down, the other engine makers adopted poppet valves, to improve scavenging (similar to the upper piston on a Doxford, which acted as an exhaust valve, while the lower piston acted as the inlet valve, later Doxfords had the upper piston "timed" slightly out of phase with the lower piston, rather than being 180 degrees opposed).
They also adopted common rail fuel injection, the "U" turn was remarkable.

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Re: Common rail upgrade of 2 and 4 stroke engines

Postby jimmys » Sat Jan 08, 2011 6:51 am

What you have to remember is in these engines a system of servo oil operates the exhaust valves and the injectors. The fuel is about 1000 bar and the servo oil about 200bar. There is oil rail valves and injector control valves in the system. The electronics operate them.
The Sulzer RTflex is true common rail But not too sure about the Man engine.
A bit complex for me, I like a big pump on each cylinder and hydraulic poppet, very reliable. I am getting a bit old for this I sailed with the Doxford.

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Re: Common rail upgrade of 2 and 4 stroke engines

Postby JK » Sat Jan 08, 2011 7:34 am

I looked at an operating Doxford on YouTube once and went holy crap look at that!
I liked my big steam recips, even though that was 30 years ago.

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Re: Common rail upgrade of 2 and 4 stroke engines

Postby Big Pete » Sat Jan 08, 2011 10:30 am

Going back to the start of the thread, the efficiency increase comes from varying the injection timing according to load, with the most sophisticated systems variations in fuel quality can be corrected (e.g. Ignition Delay, calorific value,).
The engine then develops the same power using less fuel.
But, many years ago I sailed on a ship with Pielstick main engines, that had modified fuel pumps. The traditional Helix cut out of the fuel pump was modified in shape, so that injection timing changed as the load increased, this was supposed to improve fuel efficiency by several %, at part load of course, as all engines are optimised for full load.
I never saw this system again, so I suppose it didn't catch on.
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Re: Common rail upgrade of 2 and 4 stroke engines

Postby jimmys » Sat Jan 08, 2011 11:41 am

I in a past life was the Surveyor for the PS Waverley a paddler. She had big steam recips. You do not see many like that nowadays. Still sailing.
I sailed with the PC4 and I think I will forget about that. Texaco Windsor and Westminster. Holes in the exhaust valves I could walk around. and oil wells for leakage. The wonders of the Merchant Navy.

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Re: Common rail upgrade of 2 and 4 stroke engines

Postby D Winsor » Sun Jan 09, 2011 5:02 am

From what I understand both the newer Sulzer & MAN-B&W Slow Speed Engines now use a similar Air Spring exhaust valve and fuel system technologies so at first glance it is hard to tell the 2 engines apart.
I recently watched a television program where on the cruse ship "Freedom of the Seas" the engineer adjusted the timing of misfiring cylinder with a computer on a large Wartsila, a V16 or V20 4 stroke engine, indicating that the engine most likely has electronic fuel injection system on a common rail fuel system.
Much of this development of electronic fuel injection has given the engine manufacturer the ability to control emissions that comply with the new emission standards for Tier 2 & Tier 3 engines and still burn lower grade fuels. From what I've been told, on the Flex RTA, the system has a fuel cut off technology so, when operating at low loads, the electronics will reduce the number of firing cylinders in order to improve combustion.
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Re: Common rail upgrade of 2 and 4 stroke engines

Postby jimmys » Fri Jan 14, 2011 9:28 am

I investigated an accident medium speed 275 mm bore. The running gear came out the crankcase via a large hole. No deaths.
In order to improve peak pressure and power for sales reasons the engine timing was advanced to 20 degrees. Normally 12 to 15 degrees.
The fracture started in the gudgeon pin oil holes and stress was showing similar to Big Petes pics in the rod. I did a manual calculation and was not satisfied with the stresses in the engine. We were monitoring a sister vessel with Dive Time equipment to get accurate pressures. I said it was overstressed. The engine builder was not happy with the calculation.
Gov UK sanctioned a finite element analysis on the engine. A computer stress analysis using a suite called PAFEC, I carried it out. It takes a long time to run this.
The engine was over stressed. I would always advise further investigation when you see any faults in rods.keeps,pins etc.

You must watch with variable timing it is easy to overstress. Big pumps every cylinder, push rods, big springs, right up my street. A KGF is far too modern.

PS not happy bunnies at the builder. DOT not flavour of the month.

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Re: Common rail upgrade of 2 and 4 stroke engines

Postby The Dieselduck » Fri Jan 14, 2011 10:36 am

Excellent thread actually. Very informative. I like your comments Jimmy, of the overstressed engine. Its not something that would jump to my mind in a hurry.

Also to go back to "thechase" original inquiry, you could have a look in the main site, under "machinery" you will find a page on "common rail" concept, and this article... http://www.dieselduck.ca/machine/01%20p ... Update.pdf

In passing, you mentioned the Freedom of the Seas (but I think it was on the Oasis of the Seas), yes I saw that show too; that's an old "shipmate" of mine at Royal Caribbean doing the calibration, Francois Cantin, first engineer, is his name... that funny. He's been with Royal Caribbean for a long time, starting as third engineer, and moving up the chain steadily - good to see. In the attached article he's pictured on the Oasis of the Seas. Yes I do believe you are correct, the engines are Wartsila 46, V12 x3 and V16 x3 common rail engines. (http://dieselduck.blogspot.com/search/label/STX)

I attached a couple of articles, for interest. Sorry they are in french thought.
Attachments
imq_gens_du_pays_en_mer.pdf
An article featuring some Canadians working in the cruise industry
(732.95 KiB) Downloaded 491 times
imq_ds_le_ventre_du_geant.pdf
Article on Oasis of the Seas and some Canadian engineers on board
(881.98 KiB) Downloaded 424 times
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Re: Common rail upgrade of 2 and 4 stroke engines

Postby Lasse » Thu Mar 03, 2011 11:09 pm

jimmys wrote:I investigated an accident medium speed 275 mm bore. The running gear came out the crankcase via a large hole. No deaths.
In order to improve peak pressure and power for sales reasons the engine timing was advanced to 20 degrees. Normally 12 to 15 degrees.
The fracture started in the gudgeon pin oil holes and stress was showing similar to Big Petes pics in the rod. I did a manual calculation and was not satisfied with the stresses in the engine. We were monitoring a sister vessel with Dive Time equipment to get accurate pressures. I said it was overstressed. The engine builder was not happy with the calculation.
Gov UK sanctioned a finite element analysis on the engine. A computer stress analysis using a suite called PAFEC, I carried it out. It takes a long time to run this.
The engine was over stressed. I would always advise further investigation when you see any faults in rods.keeps,pins etc.

You must watch with variable timing it is easy to overstress. Big pumps every cylinder, push rods, big springs, right up my street. A KGF is far too modern.

PS not happy bunnies at the builder. DOT not flavour of the month.

regards
jimmy

Hello,

What equations did you use to calculate the overstressed condition? Interesting to know. :)

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Re: Common rail upgrade of 2 and 4 stroke engines

Postby JK » Fri Mar 04, 2011 12:59 am

Google finite element analysis.

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Re: Common rail upgrade of 2 and 4 stroke engines

Postby Madzng » Mon Nov 21, 2011 9:03 am

Just want to add a few comments to this thread, and give a description of the Wartsila RT-Flex and MAN ME engines.

The RT-Flex is a common rail engine, fuel pressure is approx 700 bar, these engines are not "camshaftless". The fuel pressure is created by a series of simple jerk pumps operated on a short camshaft section - each cam has three lobes and for a 12 cylinder engine there are eight pumps arranged in a V configuration. Hydraulic power to the air spring exhaust valves comes from a second set of engine driven pumps. Hydraulic power for the control side is provided by electrically driven pumps. At low load, think it is less than 15% MCR one fuel injector is shut off and the remaining two are swapped at 20 minute intervals to prevent thermal stresses. At even lower loads the engine switches to single injector firing, again with the injector in use changing every 20 minutes to prevent thermal stress.
I have not heard of a retrofit package for changing an RTA into an RT-Flex, and whilst everything is possible, I would suspect the cost would be so high, as to negate any fuel savings.

The MAN Diesel ME engine is not a common rail engine, each individual cylinder has its own fuel pump. The difference is that the fuel pumps on the ME engine are driven by hydraulic oil from engine or electrically driven pumps, there is no camshaft. The control of the fuel pumps is so precise, that different injection pattern in the same stroke can be achieved depending upon requirements. When MAN developed the ME engine, a conventional engine was converted and it was done in such a way that the engine could switch between an "MC" type and "ME" type as required for testing. So I guess it is possible that MAN do offer a "upgrade kit" for the MC engine.

The engines do look similar, but for anyone who has sailed with MAN (B&W) Diesel and Wartsila / Sulzer engines both engines have kept enough identity to easily tell them apart.

I cant see much info one the MAN ME engine on Martins website, so will try to remember in the next few days to start a new thread and post some pictures and info of these engines.


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