More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.

As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference.

I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR

On 18 Jan 2006 19:03:15 -0800, wrote:

More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.

As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference.

I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR
Opposed Piston ?
Gerry :-)}
London, Canada

wrote in message
ups.com...
More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.

As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference.

I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR

The terminology has changed from time to time. DKW (German) made such an
engine, as did Jawa (Czech, I think) and Vostok (Russian). I have seen them
called "undoubled" engines as well as "twin cylinder."

The old Taylor books from MIT called them "U-chamber" engines, or something
like that.

Which manufacturer were you thinking of?

--
Ed Huntress

" As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference."

I think you have it nailed. I had one of those (about 40 years ago, come to
think of it) in a motorcyhcle. It had 2 cylinders firing simultaneously
under a common head. I remember the definition of that configuration as
being "twin cylinder".

Bob Swinney



wrote in message
ups.com...
More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.


I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR

Robert Swinney wrote:

" As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference."

I think you have it nailed. I had one of those (about 40 years ago, come to
think of it) in a motorcyhcle. It had 2 cylinders firing simultaneously
under a common head. I remember the definition of that configuration as
being "twin cylinder".

Bob Swinney

wrote in message
ups.com...
More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.


I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR


Try a search for "split single" if you want to find all those old DKW
and similar bike engines. I think Villiers was responsible for quite a
few as well.

I could perhaps buy into a definition of "twin cylinder" covering such
bikes as the Triumph or Honda twins where the two cylinders are in one
assembly, as opposed to a BMW where the two cylinders are not attached
to each other.

Cheers
Trevor Jones

The older Puch motorcycles had a twin cylinder arrangement that was
sometimes called a "twingle". Two cylinders and two pistons on a common
crank with a common combustion chamber, they were two strokes and had
the pistons slightly out of phase, one piston about 5deg. ahead of the
other IIRC. I think the idea was to scavenge the fuel/air mixture more
effeciently.
A buddy had one of these (sold by Sears under the Allstate name) and
while not especially fast, it did survive a lot of very rough treatment.

wrote:

More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.

As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference.

I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR

The first you mention, were known as split singles although the German
TWN used a forked connecting rod as the cylinders were side by side
whereas the Puch with cylinders for & aft, used a master rod and slave.
Both were
2 strokes.

Most of the older auto books tend to use the term "twin" when referring
to a vee type engine where both cylinder rods mount to the same throw
in the same plane. e.g They used a fork & knife connecting rod setup,
HD, Indian Vee Twins etc..
Early V12 auto engines were always referred to as "twin" sixes and
they all shared the same conrod layout rather than the side by side
setup prevalent today.
British twin cycle motorcycles that were referred to as "vertical twins"
had engines with 360º crankshafts, so there is a connection of sorts
to the above.

As for "two cylinder", that basically is self-eexplanatory, an engine
with two cylinders, opposed, inline or angularly deposed, with
crankshafts
of either 180º or 360º throws.

Tom

IYears ago Maytag made "twin" cylinder two stroke engine for their
washing machines. Both cylinders fired at the same time. I think it was
more of a gimmick, just like the Aeromotor 8 stroke cycle engine.

Chuck P.

Here is some examples of single cylinder, two piston per cyl.,engines using
one combustion chamber in diesel. First one I saw was in a sub at a naval
park. I said dam, they put this engine in upside down. Little did I know
there was another piston coming up from the bottom too.

http://www.fleetsubmarine.com/propulsion.html
http://www.williamsdistribution.com/...banksmorse.jsp
http://en.wikipedia.org/wiki/Fairbanks-Morse

"Tom" wrote in message
...
pdrahn@coine

As for "two cylinder", that basically is self-eexplanatory, an engine
with two cylinders, opposed, inline or angularly deposed, with
crankshafts
of either 180º or 360º throws.

Tom

Don't forget Tandem

"MOP CAP" wrote in message
news:180120062012058984%Pilgrim6nospam@mindspring. com...
IYears ago Maytag made "twin" cylinder two stroke engine for their
washing machines. Both cylinders fired at the same time. I think it was
more of a gimmick, just like the Aeromotor 8 stroke cycle engine.

Chuck P.

Maytag made about a half-million of those twins from 1937 to 1952.
Very reliable and smooth running. Probably one of the greatest engine
designs of all time.

Ed Huntress wrote:

The terminology has changed from time to time. DKW (German) made such an
engine, as did Jawa (Czech, I think) and Vostok (Russian). I have seen them
called "undoubled" engines as well as "twin cylinder."

I always saw them called "U-cylinder". At least in technical literature.

In reality, they are "bent-over opposed piston engines (with phase
shiftet crank-shafts)".


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

wrote:

As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference.

To add to the confusion here are examples for 2-cylinder-namings:

* 2 cylinder (most generic)
* V-2
* boxer
* twin
* parallel twin
* U-cylinder
* flat V


Explanation:
2 cylinder is generic an must (?) be one of the following:
- V2:
Two cylinders arranged in V-shape. Both rods sit on _one_ cranck pin.
Example: HDs

- boxer
Two cylinders arranged opposed with crank shaft in between. Con rods
have separate crank pins 180deg apart.
Example: BMW

-twin:
Two cylinders parallel. Pistons are 180 degrees out of phase. 4 strokes
get a bit weird sound with this assembly. Example: Yamaha RDs (2 stroke)


-parallel twin
like twin, but the two pistons in phase. Example: almost all classical
Brit-Bikes were of that type

-U cylinder.
Mostly parallel cylinders with the two pistons slightly out of phase (15
deg) and a _single_ crank-pin. Common combustion chamber. Only two
strokes. ExampleKW, Puch

-flat V
looks like a boxer, but the pistons working in the same direction. Not
used on 2 cylinders (they would shake like mad) but on 4 or 6 cylinders
in cars:Example: Alfa Romeo, Citroen

One missing:
V with 2 crank-pins. Example?


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

Mike wrote:

Here is some examples of single cylinder, two piston per cyl.,engines using
one combustion chamber in diesel.

Opposed piston diesel engines. First built by Junkers.
Need something more weird? "The Deltic Engine".


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

Nick Müller wrote:

Mike wrote:

Here is some examples of single cylinder, two piston per cyl.,engines using
one combustion chamber in diesel.

Opposed piston diesel engines. First built by Junkers.
Need something more weird? "The Deltic Engine".

Nick

I thought you may have mentioned something more home
grown, like the Junkers Jumo 223 or 224?
Taking the Napier connection with Junkers, maybe it was
these engines that inspired the Deltic?

Tom

Tom wrote:

I thought you may have mentioned something more home
grown, like the Junkers Jumo 223 or 224?

I have to correct me. I am not sure wether it was Junkers who built the
first opposed piston engines. He was the first one to build aereal
engines of this type.

Yes, all the nice Jumo-engines. Development (by Jumo) was given up when
the jet came.

Fairbanks-Morse came at the end of the 30's, Junkers started at the
beginning of the 30's.

There are others having opposed piston engines: Rolls Royce, Leyland,
Charkow, Stearns, Knudsen. (not out of my head:-))


Taking the Napier connection with Junkers, maybe it was
these engines that inspired the Deltic?

I don't know of that connection. But I guess it was that way. The deltic
being very compact (at least for an opposed piston engine) was a logic
consequence.


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

Such as shown here http://en.wikipedia.org/wiki/Napier_Deltic

Nick Müller wrote:

Mike wrote:

Here is some examples of single cylinder, two piston per cyl.,engines using
one combustion chamber in diesel.


Opposed piston diesel engines. First built by Junkers.
Need something more weird? "The Deltic Engine".


Nick

wrote:
More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.

As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference.

I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR

Is this any help?
http://www.keveney.com/Engines.html

Mike wrote:

Here is some examples of single cylinder, two piston per cyl.,engines using
one combustion chamber in diesel. First one I saw was in a sub at a naval
park. I said dam, they put this engine in upside down. Little did I know
there was another piston coming up from the bottom too.

http://www.fleetsubmarine.com/propulsion.html
http://www.williamsdistribution.com/...banksmorse.jsp
http://en.wikipedia.org/wiki/Fairbanks-Morse

If ya think that's cool, search "Deltic Diesel"

Three banks of cylinders arranged in a triangle, with a crankshaft at
each point and pistons at each end of each cylinder.

Cheers
Trevor Jones

wrote:
More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.

As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference.

I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR


The english language has never had an absolute authority to answer
questions like this. Even general use dictionaries are at odds on some
terminologies. It is very hard to define 'common usage' because various
groups may have different terminologies within their own groups. If SAE
says something about a definition, I'd tend to go with that. Does
anyone know if SAE ever published a 'dictionary of terms'?

As an example of the lengths that these arguments an go to, find a large
group and ask for definition of 'boat' vs 'ship'.

wrote:
More than 40 years ago I had an automotive encyclopedia that gave good
definitions for both two cylinder engins and twin cylinder engines. I
loaned the book and never got it back.

As I remember, a twin cylinder engine had two pistons, rods, and shared
the same combustion chamber, while a two cylinder engine had separate
combustion chambers. I am probably remembering wrong, but know there
was a distinct difference.

I have Googled all the ways I can think of, but cannot find a
definition for a "twin cylinder" engine. Seems like the names have
become interchangable. Does anyone have a documented source for the
definition of the "twin cylinder" engine?

This has been driving me crazy for years.

Thanks,
Paul in Redmond, OR


The english language has never had an absolute authority to answer
questions like this. Even general use dictionaries are at odds on some
terminologies. It is very hard to define 'common usage' because various
groups may have different terminologies within their own groups. If SAE
says something about a definition, I'd tend to go with that. Does
anyone know if SAE ever published a 'dictionary of terms'?

As an example of the lengths that these arguments an go to, find a large
group and ask for definition of 'boat' vs 'ship'.

Ducati?

On Thu, 19 Jan 2006 06:15:27 -0700, Trevor Jones
wrote:

If ya think that's cool, search "Deltic Diesel"

Three banks of cylinders arranged in a triangle, with a crankshaft at
each point and pistons at each end of each cylinder.

That's not cool (and Junkers had already done it)

Realising that if you contra-rotated one shaft then you only needed 3
banks not 4, now _that_ was cool.

Andy Dingley wrote:

On Thu, 19 Jan 2006 06:15:27 -0700, Trevor Jones
wrote:

If ya think that's cool, search "Deltic Diesel"

Three banks of cylinders arranged in a triangle, with a crankshaft at
each point and pistons at each end of each cylinder.

That's not cool (and Junkers had already done it)

Realising that if you contra-rotated one shaft then you only needed 3
banks not 4, now _that_ was cool.

The utilisation of three banks actually mandated the contra-rotation
of one crankshaft.

Tom