SERIOUS engineering going on here...

[simon]

I stumbled on this page by accident. It's about an engine from a Deltic deisel train (yawn) being rebuilt (yawn)
And you thought your engine was big????
If you follow it on to page two there is the mother of all superchargers there (or is it a turbocharger)

http://www.deltic9000.freeserve.co.uk/pu_rebuild.htm

[simon]

Ecscuze my speeling, it seams I carnt speel deezall.
soree:+

[Trigger]

Thanks for that Simon. Led to other very interesting sites. The Deltic engine was designed in the 1940's and is a tribute to British engineering and design. Seems like it was 18 cyliders with 36 pistons or the same as 3 V12's clagged together. Six and 12 cylinder engines are inherently smooth and vibration-free. Add this to 2-stroke working and 1800-2000 rpm and you have a very smooth engine. It was also very light the crank cases being made from light alloy. Five tons for 2500hp is incredible. Developed for marine use it ended up in British Raiway loco's and gave 20 years service there. I work with 20 cylinder diesel engines, ex-American loco engines (GM!) and they are very big and heavy in comparison with the same 2500hp output. And very inefficient! The Merlin was another great British engine but it did take the Americans to get it into mass production. They took a couple of engines, stripped them, took measurements and made drawings then made them by the thousands for Spitfires, P51's etc and MTB's. Thought you might want to know this.Trigger

[STEVE G]

I do thier plating,used to re tin the inside of the deltic cylinder.Still andodise and chrome rocker covers for Gin Palace ships engines
Steve G
GRAVETTI 427-Rover 281ci.

[MarkT]

This one is only a baby.

We use much bigger ones on the slow speed 2 stroke engines that are used to propel ships.

A medium sized slow speed will have a 900mm bore and a 1200mm stroke with 8 or 9 cylinders producing around 1,000 horsepower per cylinder.

The engine will tick over at 35 RPM and be flat out at around 140 RPM.

Fuel consumption 40 tonnes (9,000 gallons a day)

My big block Chevy seems to use almost as much !!!!

Brgds


Mark

[Trigger]

Far too brutal for me! I like the finesse of the Deltic. I travelled by rail a lot when they were in service with BR and they sounded pretty good too. I also like aluminium engines ... like the RV8. And they! sound good. Your fuel consumption doesn't sound too good. I would guess the Deltic's was. Seems like it has one piston doing the exhaust and the other doing the inlet for each cylinder and with the necessary turbo charger it would get a clean charge everytime with good scavenging. Fuel consuption for diesels is usually in the range of 0.4-0.5 pints/kwh with 2-strokes maybe less efficient because of unburnt fuel carry over. Trigger

[MarkT]

Trigger,

Hate to tell you but the Deltic is a two stroke.

Most of the marine 2 strokes have inlet ports at the bottom of the liner and a poppet type exhaust valve at the top in the cylinder head, allowing for very efficient uniflow scavenging.

The fuel injection and exhaust valve timing are variable, at low speeds an electric blower takes over from the turbocharger to ensure fresh charge air.


Mark

[Trigger]

Hi Mark, I didn't say the Deltic wasn't a 2 stroke ... read the posts! I said 2-stokes are less efficient with fuel than 4-strokes. I'm not sure the Deltic has exhaust valves as with the 2 pistons per cylinder they may not be necessary but may be ported and with the turbo scavenging it could be quite efficient for a 2 stroke. The rule of thumb for fuel consumption applies more to 4-strokes and the bigger the engine the more efficient.

The ones I work with have 2 exhaust valves per cylinder and rack injection. Inlet is by port and the turbo is on a clutch until the exhaust takes it off. They like to run at 80% load. Below that the soon get clogged and the exhaust is half unburnt fuel! Speed is 900 rpm. Trigger

[Trigger]

Nope, no exhaust valves, just ports for intake and exhaust. Trigger.

[STEVE G]

Trigger
As I said earlier I used to re-tin plate Deltic cylinders for Paxmans.
As I understand it the engine had 3 cranksafts at the corners of a triangle with opposing pistons in the three cylinders.(6 pistons per set up)that could be banked together to build bigger engines.No valves just inlet and exhaust post al-la 2 stroke.Is my memory right or is it another "Tennants Momment"
Steve G
GRAVETTI 427-Rover 281ci.