Never seen this before. Not sure what the benefits are...
Hillman Car Club of South Australia – Commer TS3 Two Stroke Diesel Engine
Hillman Car Club of South Australia – Commer TS3 Two Stroke Diesel Engine
Interesting engine - Commer Knocker...
- Thread starter OC_
- Start date
I know there's something with exhaust scavenging with opposed piston designs...
here it is running:
https://www.youtube.com/watch?v=JrAoj5Cuu68
here it is running:
https://www.youtube.com/watch?v=JrAoj5Cuu68
Jim Rosenthal
Supporter
What advantage would this design have over a regular two-stroke diesel? Better balance, maybe? The frictional losses would be substantial. Of course you don't have valve gear to service etc so it makes some of the lost power back in that respect.
"Uniflow air scavenging" is an advantage to the opposed piston design. The intake ports are opened on one side of the cylinder and the exhaust on the other. So, the charge has straight shot into the cylinder and can fill it effectively.
I'm not an expert on the fluid dynamics of engines, but I don't think scavenging can ever be this efficient on a poppet valve engine since the intake/exhaust valves are relatively close to each other and also because of their position on the top of the cylinder. There's a limit to how much a poppet valve head can scavenge before the intake air/charge goes out the exhaust - so, in effect, the opposed piston engine can have way more "valve" overlap than a poppet valve engine.
I'm not an expert on the fluid dynamics of engines, but I don't think scavenging can ever be this efficient on a poppet valve engine since the intake/exhaust valves are relatively close to each other and also because of their position on the top of the cylinder. There's a limit to how much a poppet valve head can scavenge before the intake air/charge goes out the exhaust - so, in effect, the opposed piston engine can have way more "valve" overlap than a poppet valve engine.
Jim Rosenthal
Supporter
Sounds reasonable. I wonder about the power/weight ratio of this design if built in modern materials. Back then diesels didn't have a lot of aluminum in them, but they do now.
Two-strokes do have emissions issues, but there is a lot of technology having to do with making diesels cleaner. Maybe someone out there is working on this design yet today.
Two-strokes do have emissions issues, but there is a lot of technology having to do with making diesels cleaner. Maybe someone out there is working on this design yet today.
Dave Wood
Lifetime Supporter
I remember seeing this engine many years ago, at least the design, never saw a running one. I would guess there are no advantages/benefits. The frictional loss was mentioned, but the manufacturing/development costs had to out weigh any potential advantage. The knowledge that it was dropped by Chrysler at the early point in emmissions standards might also suggest that could be another yet to be resolved issue.
I watched as some mechanics wrestled with such new things as FI and overhead cams, I'd love to have seen some of those dullards attempt to repair one of these
.
I watched as some mechanics wrestled with such new things as FI and overhead cams, I'd love to have seen some of those dullards attempt to repair one of these
.I remember working on some of the Detroit Diesels in the early 70's and there was a general consensus that they would not be long for this world because of tightening emissions standards, they always leaked oil, and were probably one of the noisiest motors available. The 2 strokes were considered naturally aspirated with the roots type blower, which is a necessity for scavenging on these motors, and it just adds more to break.
We used to run 4 stroke diesels like Mack and Cummins with turbos and no muffler as they were that quiet with an up-pipe.
The biggest development to come out of the high cost of fuel was the high torque rise/slow speed engines being used now that run about 1300 to 1400 rpm at highway speeds, and require 5 speed transmissions not 13 or 15 speed, many are automatics now.
The rotating mass is much lighter, goes slower, and has to turn less shafts and gears so the efficiency is way up. Electronic fuel injection just ices the cake and virtually everything is now drive-by-wire throttle.
I still would love to hear that little two stroke at full song.
Cheers
Phil
We used to run 4 stroke diesels like Mack and Cummins with turbos and no muffler as they were that quiet with an up-pipe.
The biggest development to come out of the high cost of fuel was the high torque rise/slow speed engines being used now that run about 1300 to 1400 rpm at highway speeds, and require 5 speed transmissions not 13 or 15 speed, many are automatics now.
The rotating mass is much lighter, goes slower, and has to turn less shafts and gears so the efficiency is way up. Electronic fuel injection just ices the cake and virtually everything is now drive-by-wire throttle.
I still would love to hear that little two stroke at full song.
Cheers
Phil
I was told that this engine was designed for tax reasons.
Road tax was paid on engine capacity.
Jim
Road tax was paid on engine capacity.
Jim
I remember those from the '50's and '60's very powerfull, very quiet, sort of a whistle but terrible fuel consumption. Even at five bob a gallon, diesel was actually cheaper than petrol then, meant that they soon filtered down to the lower end of the transport mob, where poor or no maintenance resulted in lots of TS3s spread all over the, then, new motorways.
Most got replaced by the more frugal, and boring engines like the old Gardners. Used to see loads of TS3 motors in the scrap yards.
Mike
Most got replaced by the more frugal, and boring engines like the old Gardners. Used to see loads of TS3 motors in the scrap yards.
Mike
Here is an interesting video on EPA compliant Detroit Diesel two strokes, and part of what
it discusses is indeed exhaust valve timing, along with modified air intake
ports, to change the combustion process timing to get a more complete burn and
reduce emissions.
Detroit Diesel 71 and 92 Series EPA Tier II Compliant Upgrade Kits - YouTube
Dave Wood
Lifetime Supporter
I remembered that so many technical advancements are sometimes decades and longer to become viable, for many reasons. While 4 valve heads seem so modern they have been around since the early development of engines, metallurgy was not at the same level of development and so they became interesting "oddities" until metallurgy and machining were up to the task, many things come to mind like that. Rotary engines, desmo valvetrain and the recently "mainstream" stratified injection(direct) system. I like to pick up old magazines when I locate them, if they have interesting tech articles. I have a 196os Popular Science that has an article on Ford's work with a stratified system. It was being tested on a 430 Lincoln and was being touted as a way to get better mileage( I guess losing a few tons didn't occur at the time). Now it is being used in a whole line of small engines to get better mileage while making EPA standards easily. Regular FI went through some of the same issues as it was refined. So who knows, maybe in another 25-50 years it could be viable.
Tim:
Interesting video, thanks for that.
I remember the best we could get with the 6 cylinder inline (6-71) engines which were fondly called "238 Detroit" referencing the horsepower rating was about 3 mpg.. It sounds terrible but fuel was 28 cents a gallon then. The four stroke diesels were already over 3 1/2 and 4 mpg which sounds insignificant until you go 100,000 miles a year or more and the numbers really make a difference.
I have a friend that has a 48 foot boat with two 92 series V-8 engines and it can really crank but its a heavy drinker.
Sorry guys for the thread drift...
That Commer Knocker reminds me of a Deutz Diesel I once saw on a spray rig, I think its still in use.
Cheers
Phil
Interesting video, thanks for that.
I remember the best we could get with the 6 cylinder inline (6-71) engines which were fondly called "238 Detroit" referencing the horsepower rating was about 3 mpg.. It sounds terrible but fuel was 28 cents a gallon then. The four stroke diesels were already over 3 1/2 and 4 mpg which sounds insignificant until you go 100,000 miles a year or more and the numbers really make a difference.
I have a friend that has a 48 foot boat with two 92 series V-8 engines and it can really crank but its a heavy drinker.
Sorry guys for the thread drift...
That Commer Knocker reminds me of a Deutz Diesel I once saw on a spray rig, I think its still in use.
Cheers
Phil
Jim Rosenthal
Supporter
Honda had stratified-charge technology in Civics in the seventies- called CVCC. Worked very well. I don't know when they gave it up, but they sold a lot of them until they did.
I have had boats for decades including two with 2-cycle Detroit diesels- one set of 6v-53s and one set of 6-71s, both naturals. There was a period of time when there weren't a lot of other marine diesels made and DD was pretty much the only game around. There were some independent DD marine engine builders like J&T and Covington who sold DDs with ridiculous horsepower ratings, achieved by using turbochargers, intercoolers, aftercoolers, bypasses, etc. These engines were getting better than a hp per cubic inch, but they had very short life expectancies. And they were heavy, since the basic DD design was rather robust.
All of that changed when other manufacturers got into the marine diesel business. Today Detroit/MTU has very little of the marine market. They don't make 2-stroke diesels anymore although a lot of their old engines are out there trucking along. Most of the marine market is Cummins and Cat, and Cummins common-rail diesels are making way better than a horse per cubic inch- and they are reliable. A Cummins marine diesel that makes nearly 500 hp weighs about 1300 pounds- a far cry from the DD that made 485 and weighed two tons......and lasted a thousand hours or less between rebuilds.
I have had boats for decades including two with 2-cycle Detroit diesels- one set of 6v-53s and one set of 6-71s, both naturals. There was a period of time when there weren't a lot of other marine diesels made and DD was pretty much the only game around. There were some independent DD marine engine builders like J&T and Covington who sold DDs with ridiculous horsepower ratings, achieved by using turbochargers, intercoolers, aftercoolers, bypasses, etc. These engines were getting better than a hp per cubic inch, but they had very short life expectancies. And they were heavy, since the basic DD design was rather robust.
All of that changed when other manufacturers got into the marine diesel business. Today Detroit/MTU has very little of the marine market. They don't make 2-stroke diesels anymore although a lot of their old engines are out there trucking along. Most of the marine market is Cummins and Cat, and Cummins common-rail diesels are making way better than a horse per cubic inch- and they are reliable. A Cummins marine diesel that makes nearly 500 hp weighs about 1300 pounds- a far cry from the DD that made 485 and weighed two tons......and lasted a thousand hours or less between rebuilds.
Dave Wood
Lifetime Supporter
One thing with the old knocker, lb for lb it could out pull anything in its class, when I first got my truck licence I worked for the biggest trucking company in NZ at the time Freightways, and we had the contract to haul sugar out of the refinery over the shore, big deal you say, well the grade from the front gate to the top of the hill was bloody steep and you couldn't get a run at it, 466 Bedfords could make it just, in low gear and low diff [ 2 speed diffs back then] Leyland with either the 360 or the Gardiner, we had both, also low low but the ole Commer knocker 2nd hi and hold it flat, and that was with 14 ton of sugar on a tandem flatbed, mind you most drivers went deaf in a short space of time, they were noisier than the 653 jimmy.
but in the other extreme they were a fantastic marine engine , with a wet exhaust they were whisper quiet and vibration free, and could be made very economical with the right prop. I grew up on them both driving and rebuilding, still have a soft spot for the ole girls, very easy to overhaul, I could re ring one in under an hr, try that with one of your new fangled common rail thingy me bobs today.
cheers John
but in the other extreme they were a fantastic marine engine , with a wet exhaust they were whisper quiet and vibration free, and could be made very economical with the right prop. I grew up on them both driving and rebuilding, still have a soft spot for the ole girls, very easy to overhaul, I could re ring one in under an hr, try that with one of your new fangled common rail thingy me bobs today.
cheers John
I have worked on them. The early ones used to break the rocker rods but they sorted them on the mk2 version. They used to howl and you could here them coming from miles away. A lot of them were fitted in the then british rail artic units . The upside of the design was there were no cylinder heads so no gaskets to blow but they were not popular and were good at eating the exhaust system. Does any one remember the junkas jumo two stroke aero engine ?
http://en.wikipedia.org/wiki/Junkers_Jumo_205
Bob
http://en.wikipedia.org/wiki/Junkers_Jumo_205
Bob