Ever wonder how an engine works?

[Anonymous-0]

<A HREF="http://www.keveney.com/Engines.html">Engines</A>

 

[Anonymous-0]

Been to that site before... fascinating!

 

[Anonymous-0]

Not really.

I do wonder why they won't start or why they stop for no apparent reason. It's so annoying.

 

[Anonymous-0]

I like that site too. Only thing I didn't see was diesel engines. It's only been a year or two now since I learned about two stroke diesels. Apparently they are very efficient. They are used in locomotives and I'm betting ships mostly. Don't know why they don't use them in trucks. Anyone know? I think it's something to do with weight but not sure. I know they need a supercharger, maybe a turbo would work too, but hey that shouldn't be a problem for trucks.

 

[Anonymous-0]

the 2 stroke does not perform as well as a 4 stroke for trucks and most all RR locos now run 4 strokes bacause the are cleaner remember 3 letters EPA

 

[Anonymous-0]

You never heard a "Jimmy" diesel going down the road? GMC and its sister (Detroit Diesel) built millions of 2 strokes starting in the '30s. They were a factory option in all large trucks and some medium sized trucks. Up until the '90s, all transit buses used them. Unforutunatly, 2 strokes are not "green" engines.

I have owned at least a dozen Detroits. I also have a 2 stroke Diesel Field Marshall. It has no "supercharger". turbo, or blower.

 

[Anonymous-0]

Lots of Detroit Diesels are 2 stroke and are used in trucks and busses. I have driven them a couple million miles.

 

[Anonymous-0]

"It has no "supercharger". turbo, or blower."

They all have blowers. It's the turbos that some had and some didn't.

Detroit, or, I mean leaktroit. Man they p*ss more oil out than anything else I know.

 

[Anonymous-0]

Commer trucks (made in England I think) had a 4 or 6 cylinder horizontally opposed 2-stroke diesel. I can remember them howling up the highway near our farm when I was a boy. Years later when doing my trade training, we got shown the bits of one. They were a wild bit of gear.

 

[Anonymous-0]

Detroit Diesel What a gutless wonder (hill sniffer,gimmy screamer,double breasted yamaha ) the laft lane of I-70in CO used to be called the monfort lane since those detroits were the biggest thing on the road at the time. No torque lots of noise and oil.At the time of there inception the 190&220 cummins was the only thing offered so 238HP was lots of power then later the 318 V-8 then turboed was 350 and so on.If you want to go up the hill use a CAT.

 

[Anonymous-0]

Suck, squeeze, bang and blow. Next question?

 

[Anonymous-0]

Check out the Napier Deltic diesel. It was a two stroke 18 cylinder
36 piston marine and locomotive engine.

 

[Anonymous-0]

How do they fit 36 pistons in 18 cylinders? I assume you mean valves?

 

[Anonymous-0]

I didn't see a diesel / fuel injected 2-stroke on that site, did I miss it?

howstuffworks.com

has good engine explainations include detroit diesels. I forget, do detroit diesels have intake (for air) and exhaust valves, or just open ports like typical 2-stroke?

Seems like fuel ingected, 2-stroke engines should be able to have valves incorporated to cut emissions (particularly of unburnt fuel) to similar to 4 stroke.

 

[Anonymous-0]

The answer is (at least according to howstuffworks.com): Detroit diesels have exhaust valves at the top of the cylinders, and turbos to supply preasuried air intake ports near the bottom of the cylinders.

The site also says emmission of unburnt fuel is not a problem with these engines as it is with smaller carb aspirated two-strokes.

I hate to reply to my own post - I wish you edit your own posts, but about everyone here is reluctant to use the new forum.

 

[Anonymous-0]

MD Nut,

That statement re blowers is just plain wrong.

Let me ask you where the blower is on your chainsaw or weed wacker. The Field Marshall tractor works on the same principle. Crankcase pressure and exhaust scavenging make it happen. Google on that English tractor make.

 

[Anonymous-0]

MD Nut,

That statement re blowers is just plain wrong.

Let me ask you where the blower is on your chainsaw or weed wacker. The Field Marshall tractor works on the same principle. Crankcase pressure and exhaust scavenging make it happen. Google on that English tractor make.

 

[Anonymous-0]

Guess that show I was watching, probably on Discovery, was wrong or out of date because I distinctly remember them saying how efficient it was compared to cars and trucks. I also remember that they stated a supercharger was needed and I only mean to say that some form of positive pressure on the intake is required--blower, supercharger or whatever. I'd question if a turbo would work because it would require the engine to be running to produce that pressure so that would seem to be chicken or the egg puzzle as to if it'd work.

Anyway I did some searching and it seem the GE Evolution engine for locomotives is indeed a 4 stroke. It also seems they've been around since 2004 or so and I might have even seen the show before that--time is passing quickly. I also did turn up pages on monster ship engines that are supposed to be 2 stroke.

 

[Anonymous-0]

Ok here is what I'm referring to:
http://auto.howstuffworks.com/diesel-two-stroke1.htm
It mirrors what I saw on that show. Since the fuel is injected in a diesel the intake charge blowing the exhaust out should be ok. It's just extra air going into the exhaust pipe--that's a plus in cars as it lets the catyletic converter finish buring any unburt fuel but that's beside the point. It should be just as efficient as a 4 stroke I'd think. Comments? As folks have noted some vehicle diesels must have been and maybe still are 2 stroke--I'd never known that. Seems having twice as many power strokes would be a good thing so I must be missing a downside.

 

[Anonymous-0]

Check out this engine:
http://www.greencarcongress.com/2006/11/modeling_a_twos.html
It uses 2 opposing pistons pushing back and forth the same connecting rod with magnets attached to it. The cylinder has wire coils and it generates electricity. According to this 2006 article it's being investigated for use with hybrid cars.

 

[Anonymous-0]

Nope. Two pinstons per cylider. They almost meet in the middle
comperssing air between them. Fuel is injected betwwen them and
they push away from each other. The engine has three crankshafts
at the angles of the triangle and cylinders are the sides of the
triangle. Big gear train ties all three cranks together into one
output shaft. 3500 hp. Wikipedia has a good visual.

 

[Anonymous-0]

Sounds cool, I'll have a look.

Thanks.

 

[Anonymous-0]

He was referring to the Detroit diesel engines - they all have superchargers on them. The supercharger does the scavenging on those particular engines.

 

[Anonymous-0]

I had a 2-53 Detroit on my old JD 435D and it had normal poppet exhaust valves but had a slotted cylinder wall that was mechanically supercharged with a Roots blower.

 

[Anonymous-0]

The 2 stroke Detroits were all supercharged so far as I know. Some used turbo's to charge the air into the supercharger.
The basic idea with those engines was that the piston uncovered the intake ports in the cylinder sleeve when the piston neared BDC. The exhaust valves open, intake air forces the exhaust gases out, exhaust valves close, cylinder fills with air, and as the piston rises past the intake ports, it closes off the intake, compresses the air until injection near TDC, then the power stroke.... and it repeats itself again.
I could be wrong, but I'd say emission control on that system would not be great. There's too much happening in too short a period of time, and exhaust scavenging and intake charge are both limited because of this.
The one and only feature those old buggers had was that they could make a lot of power off a relatively small number of cubic inches. I don't think they were particulairly fuel efficient, but they did make a lot of power per cubic inch of physical displacement. The downsides were numerous. Noise, profuse oil leaks, a gutless wonder at best... and a complicated fuel system with those damn unit injectors.... which were somewhat noted to stick, and could lead the engine to "run away" if they stuck at maximum for some reason. The best thing Detroit Diesel ever did was introduce the 60 series engine with DDEC. In that they succeeded in building a good performing, responsive, efficient, reliable engine with electronic controls.... and led the industry in doing it. At the same time they cleaned up the puddles and some of the noise. For the most part I don't think the 71's and 92
s will be missed on the highway, and the B Cummins obliterated the 53 series not long after it's entry onto the market in the mid 80's....

Rod