VWDiesel.net The IDI, TDI, and mTDI source.
General Information => General => Topic started by: malone on February 15, 2007, 01:26:02 pm
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For years, the 2 cycle diesel engine powered everything from small industrial equipment to locomotives to large ships. 2 cycle diesel engines powered tanks and boats that helped the allies go on to win WW2. 2 cycle diesel engines powered the Greyhound buses that carried freedom riders throughout the south. Many hospital backup generators use 2 cycle diesel engines.
The lowdown on the 2 stroke diesel
Like a gasoline 2 cycle engine, the diesel 2 cycle has, obviously, 2 cycles; the compression cycle and the power cycle. But unlike a 2 cycle gasoline engine, the 2 cycle diesel has a conventional wet sump lubrication system. Since the power cycle isn't used to pressurize the air/fuel mixture in the sump as is done in a 2 cycle gasoline engine, the 2 cycle diesel needs another method of pressurizing the intake air. An engine driven supercharger (usually a Roots) takes care of this. However unlike a performance engine supercharger, the supercharger on a 2 cycle diesel only needs to pressurize the air a few PSI above ambient pressure.
The compression and power cycles of a 2 cycle diesel are pretty much the same as those in a 4 cycle diesel: air is compressed and fuel is injected. At the end of the power cycle, when the piston uncovers the intake ports, it creates a swirling effect that pushes the exhaust out valves in the cylinder head. This is a process called scavenging.
(http://www.steamengine.com.au/ic/engines/simple_engine/pics/diesel-2-stroke-bdc.gif)
Basic design of a 2 cycle diesel.
One of the benefits of the 2 cycle diesel is the wide power band it provides. They will produce useable power up to it's governed RPM and will run like that all day, while in most 4 cycle diesels, the power drops sharply before it reaches it's governed RPM. For example, a typical 4 cycle diesel in a semi truck's "sweet spot" (where it produces the power most efficiently) is between 1200 and 1700 rpm despite it having a governed RPM at 2100 rpm. OTOH, in a 2 cycle, it might be between 1200 and 2100 rpm. A 2 cycle diesel can run all day at it's maximum RPM without missing a beat. Thats why 2 cycle engines in buses ran so well with 4 and 5 speed transmissions, the wide gear steps didn't cause it to run out of it's power band, unlike in a 4 cycle, which would need at least 6 gears to run efficiently.
2 cycle diesels can also be turbocharged. The turbocharger feeds into the supercharger. These are known in trucking circles as "huffer and puffer engines. Often a jacket water aftercooler is mounted between the supercharger and intake ports.
2 cycle diesel engines are also able to produce more power for their size compared to similarly sized 4 cycle diesels. For example: a 750 cubic inch turbocharged 2 cycle diesel can produce the same power as a turbocharged 850 cubic inch 4 cycle diesel
There are a few drawbacks. 2 cycle diesels aren't able to produce as clean emissions as their 4 cycle brothers. They also tend to consume larger amounts of oil. This is due to the design of the 2 cycle engine. Since the intake ports are in the sides of the cylinder, the rings of the piston go past them. This allows engine oil to be consumed at a higher rate than a 4 cycle engine. Consequently, this prohibits cleaner emissions. This also requires the use of a low sulfated ash lubricating oil in the sump. Using an oil with a high level of sulfated ash can leave deposits in the exhaust ports. Usually SAE 30 and 40 single weight oils are specified, though newer "mixed fleet" 15W40 multigrade oils are also sufficient for use in 2 cycle diesels.
Detroit Diesel: The King of 2 cycle diesels
One engine company has a name that's synonimous with 2 cycle diesel technology: Detroit Diesel. Detroit Diesel's history dates back to 1938 when it was formed as GM diesel division.
One of the first engines they produced was a 426 cubic inc inline 6 cylinder engine. It would later be known as the 6-71. 6 being the number of cylinders and 71 being the displacement (in cubic inches) of each cylinder. It would also gain the nickname of "238", referring to the advertised HP rating. The 6-71 engine was quite popular in the marine industry since it was lightweight and powerful for it's size at the time. The 6-71 engine would also find use in military applications, such as in the Sherman tank.
(http://www.sellabus.com/busbuilder_engine.jpg)
A GM 6-71 diesel. Note the supercharger on the side of the engine.
GM diesel also offered giant EMD series 2 cycle diesel engines for use in the first diesel locomotives, some with over 700 cubic inches per cylinder.
(http://www.lolkebijlsma.com/di3/di3_film2.jpg)
An EMD equipped diesel locomotive.
GM diesel would expand it's 2 cycle lineup with the smaller "53" series that powered everything from large forklifts to city buses. (The 4-53 diesel has been known to repower former gasoline pickup trucks) In the late 1950's, GM diesel introduced the "318" (as in 318 horsepower) or 8V71, it's first V8 diesel. Later they released a V6 version of the 6 cylinder engine. The 6, 6V and 8V comprised the "71 series" family, which well known in the road transportation industry.
(http://www.oilfield.com/images1/27-59.jpg)
An industrial 8V71 engine.
In 1965, GM diesel changed their name to Detroit Diesel. By 1974, they introduced the "92 series", which had everything from a V6 to a V16. Quite a few semi-trucks were equipped with 12V71 engines. The 12V71 and the larger 92 series engines required 2 superchargers mounted nose to tail.
(http://www.dslspec.com/images/client/16V92MarineLarge.jpg)
A marine 16V92 engine.
By the 1980's, Detroit Diesel offered the 53, 71, 92 and 149 series 2 cycle diesels, the larger V12 and V16 92 series and the 149 series being built for off-road industrial uses only. 8V71 and 6V92 engines were very popular in the motorcoach industry. Many firetrucks sport 8V92 engines.
(http://www.northpolefire.org/DSCN0057.JPG)
A firetruck equipped with an 8V92 engine.
One remarkable feature of the Detroit Diesel 2 cycles was the interchangability of parts throughout a series. For example, the 6-71 originally came with a 2 valve head. A better breathing 4 valve head is found on the 12V71. A cylinder head off a 12V71 fits on a 6-71 with no problem.
(http://www.evolutioncustomcoach.com/forsale/87-102a3-04/87102a30412.jpg)
An MCI 102A3 motorcoach engine compartment with an 8V71 engine.
Turbocharged versions of Detroits 2 cycles have either a "T" for turbo, or "TA" for turbo and aftercooled in the name (6V71T, 8V92TA), non turbo models have an "NA" in the name, for naturally aspirated (8V71NA).
(http://www.findconstructionequipment.com/images/IndustrialEngineImages/Detroit-8V92-TAB-sm.gif)
A Detroit Diesel 8V92TA engine.
In the late 1980's the 71 series was phased out of production due to emissions control issues around the same time that Detroit Diesel introduced the Series 50 and 60 engines, Detroits venture into the commercial truck 4 cycle engine market. Detroit Diesel later added electronic controls to the remaining 2 cycle engine offerings but by the early 90's, it became clear that the 2 cycle diesel just couldn't match the newer 4 cycle engines in terms of fuel economy and clean operation even with sophisticated electronic controlls and they were subsequently dropped from on-road use.
By 2000 Detroit Diesel became part of DaimlerChrysler.
Source: RatRedux
Coming next:
- Cummins: A man with a mission. (http://www.agencyfaqs.com/community/quiz/grfx/q111_01.jpg)
During his 1931 cross country trip to promote diesel engines in trucks, Clessie and his crew almost died during a descent down Cajon Pass on old US66 in California. Their brakes overheated and failed and the truck ended up nearly crashing. Here's a teaser quote written by Cummins on how he was inspired to create the Compression Brake, an essential feature that's still used in diesel trucking today:
The brakes wouldn’t hold. Now running in third gear, I tried desperately to get into a lower speed. Nothing doing. I saw I would just have to ride it out. Well down the long grade by now,I suddenly saw something moving across the road ahead. There was along dark shadow and then a red glow flared in the sky. I realized with new alarm that a freight train was cutting across our path. The truck roared on. Dave and Ford screamed bloody murder in the compartment behind me. And I clung to that steer-ring wheel like a madman. [remaining quote removed] -- Clessie Cummins
- Soviet tank raised from bottom of lake for 56 years...still RUNS!!
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Teaser picture of the Soviet tank being pulled from the bottom of the lake after 56 years:
(http://i154.photobucket.com/albums/s268/malonetdi/tank.jpg)
During battles in the summer of 1944, the tank was captured from the Soviet army and used by the German army. (This is the reason that there are German markings painted on the tank's exterior.) On 19 September 1944, German troops began an organised retreat along the Narva front. It is suspected that the tank was then purposefully driven into the lake, abandoning it when its captors left the area.
There's video proof of its engine running as well.
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:D Awesome write-up, thank you.
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Most if not all Shermans used a Lycomming radial aircraft engine, not the 6-71. On the other hand, just about all the standard'six-by' six wheel drive transports did use the 6-71 and there are loads of stories out there about them being able to run on pretty much anything stronger than water,...
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They still use 2 strokes in marine applications. Most of all the big container ships use slow speed 2 stroke engines. I use to work at a power plant that had 2 emd apu gen sets off of trains. I use to love running them 16 cylinders 750 rpm screaming through 4 6 inch stacks. They were a little loud.
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Cummins has a record at the indy 500 that will never be broken or matched, in the 50s they entered a diesel that ran the whole race without refueling. But they didn't win.
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Cummins has a record at the indy 500 that will never be broken or matched, in the 50s they entered a diesel that ran the whole race without refueling. But they didn't win.
Why won't it get beaten? I'm sure soon enough someone will do it but actually win, or maybe place at least
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Teaser picture of the Soviet tank being pulled from the bottom of the lake after 56 years:
(http://i154.photobucket.com/albums/s268/malonetdi/tank.jpg)
During battles in the summer of 1944, the tank was captured from the Soviet army and used by the German army. (This is the reason that there are German markings painted on the tank's exterior.) On 19 September 1944, German troops began an organised retreat along the Narva front. It is suspected that the tank was then purposefully driven into the lake, abandoning it when its captors left the area.
There's video proof of its engine running as well.
Just goes to show you the germans can build a good diesel.
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I thought it was a russian tank.
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I would like to know more about this tank at the bottom of the lake..... where's a website on it?
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LOL ... nm. All it took was a search.
http://www.englishrussia.com/?p=299
More pics here too. 8)
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Cummins has a record at the indy 500 that will never be broken or matched, in the 50s they entered a diesel that ran the whole race without refueling. But they didn't win.
Why won't it get beaten? I'm sure soon enough someone will do it but actually win, or maybe place at least
Well, under race conditions the Audi R10 gets 7-8 MPG compared to ~6 for the gassers, IIRC. At 7.5 MPG they'd need to carry almost 70 gallons of fuel to go 500 miles, and I think they can only carry 40 according tot he rules.
I thought it was a russian tank.
It is a russian tank, but it was captured by the germans.
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I thought it was a russian tank.
If you read the caption is was a german tank that was captured by the russians. The tank also has german markings. The germans had the best tanks of ww2.
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The Soviet-built T34/76A tank had been resting at the bottom of the lake for 56 years.
soviet built tank. soviet engine. Probably built from stolen plans, possibly german. :)
I've always liked those old 2 stroke diesels! Smokeydub and I took a diesel overhaul course recently, and they had a city bus 6-71 turbo in the test cell. I really wanted to crank that thing up, but it wasn't part of the course, sadly!
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Anyone who loves detroit diesels has never been trapped in a 10' x 10' equipment room with a 16V-71 on a genset at full honk. Gawd what a sound, I'm not sure that I'm still able to father children after that experience... The drool is something else as well, they leak profusely from every joint, hence the nickname "green leaker". 4-53's and 4-71's are often found on aircraft ground power units, the slime blows back on any and all attached equipment (my department). They are impossible to work on without becoming completely filthy. I wish they would all die...
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When I worked for a GM Diesel dealer, we serviced some odd stuff. We had 12V149 boat engines, 6-110 engines that were flat on their sides for rail coaches (had centrifugal blowers) and all aluminum 6V53 engines from Army APCs that were usually always melted because someone had bypassed the governor. A friend has one in a pull truck that he's turned to 6800 RPM. It's a thing of beauty to the ears :D :D :D
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got any videos of that?
One of the best automotive exhaust sounds I've ever heard came from an old, 1950-something aircraft fueling truck. Detroit 4 banger.
If you could make a vw diesel sound like that (without transplanting a 'Green Leaker') you'd scare off all the competition before having a chance to race 'em! It was a deadly, put-up-your-dukes-and-fight racket. The dictionary definition of sheep in wolf's clothing! :lol:
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Here's a classic 2-stroke video. I think the truck has twin 8V92T engines.
http://smg.photobucket.com/albums/v648/stewardc/?action=view¤t=Truckburnout.flv
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http://www.englishrussia.com/?p=299
More pics here too. 8)
Nice find! The site I found did not have English translation.
Here's the video of the tank's engine running:
http://www.diving.ee/video.php?f=t34.AVI
A few more pictures:
(http://www.diving.ee/articles/images/a035p10.jpg)
(http://www.diving.ee/articles/images/a030p11.jpg)
(http://www.diving.ee/articles/images/a035p11.jpg)
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my polish mechanic said that they had these russian trucks that were meant to run on gas, but would run on diesel fuel... you first start it up on gas and then switch over to diesel... pretty neat! great to see that they got that motor working... what an accomplishment (must have been hell cleaning it out!!!)
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http://www.englishrussia.com/?p=299
More pics here too. 8)
Nice find! The site I found did not have English translation.
Here's the video of the tank's engine running:
http://www.diving.ee/video.php?f=t34.AVI
A few more pictures:
(http://www.diving.ee/articles/images/a035p11.jpg)
Why are they showing a Soviet built T-34 then?
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..because that happens to be the tank they pulled out of a lake. Who said it isn't a Soviet built T34?