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Old 15th December 2005, 07:23   #1
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Why did Two stroke engines became obsolete? I think the only problem they had was the fuel efficiency problem. Now, if we use a fuel injector instead of a carb, it should give fantastic fuel efficiency because of better scavenging. Use a turbocharger, more better efficiency?
i have'nt read about it anywhere, but it came into my thoughts n i dont know whether they are in some text books; are they?)

the turbocharging could also increase the thermal efficiency,... add a catalytic converter, you will get rid of all the NOXs....

SO, WHY NOT TWO STROKES???

Last edited by Domnic : 15th December 2005 at 09:55.
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Old 15th December 2005, 09:42   #2
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burning the lube oil causes hydrocarbon emissions

Fuel injector + cat is expensive...at that point 4 stroke is cheaper.
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Old 15th December 2005, 12:03   #3
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Not neccesrly, for example if a conventional 4 stroke were "turned into" a 2stroke as in my thread it would have the lube system your using now. They do the lube mix to save cost because most 2stroke's are designed for that sort of job.
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Old 15th December 2005, 14:34   #4
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2 stroke engines are mainly used in two wheelers.

http://www.deepscience.com/articles/engines.html
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Old 15th December 2005, 15:01   #5
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Every time you put in fuel-air mixture, part of it leaks out in exaust stroke. So lower efficiency. Also the life of a 2 stroke engine is shorter. Therefore they are used mostly in 2 wheelers where the running is lower.

Two stroke engines have lower efficiency, need oil with the fuel which is polluting, waste fuel and last less, Enough said!
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Old 15th December 2005, 15:11   #6
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Emmision is also higher in the 2 stroke.... I may be wrong but as far as i know the fuel-air mix is richer, leading to more smoke.... that means incomplete combustion of fuel.....
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Old 15th December 2005, 17:30   #7
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WRONG, two-strokes engines were primarily used in two wheelers, due to the low production cost.
Orbital corp of Australia, is extensively researching on two-stroke engines for being employed in cars. Ford Motor Co., General Motors Corp. and Fiat SpA are some of the licensees of Orbital Corp.
Some time back OverDrive had an article on a 2000cc car from some European car maker which had a two stroke engine, anybody recall reading this, I will search it out from huge
OD mags I have stocked.
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Old 15th December 2005, 17:32   #8
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Hmmm - you have a point there, mate.

One of the best 2-strokers in India were the RX-series Yamaha - especially the RX-100.
Fun to drive - very flickable - good thrust power - and very very low maintainence - could last on for years and years.

Guess they lost out when guys like Pulsar came out providing the same power at much higher FE - great bike all round though not as fun to drive as a yam-rx
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Old 16th December 2005, 00:20   #9
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because of the emissions
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Old 16th December 2005, 01:46   #10
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Quote:
Originally Posted by goldie_malhotra
Hmmm - you have a point there, mate.

One of the best 2-strokers in India were the RX-series Yamaha - especially the RX-100.
Fun to drive - very flickable - good thrust power - and very very low maintainence - could last on for years and years.

Guess they lost out when guys like Pulsar came out providing the same power at much higher FE - great bike all round though not as fun to drive as a yam-rx

I think you should be reconsidering your words now. Its not the "RX" but "RD" That was the greatest two stroke bike in India.


2-stroke is not an obosolete technology. Its just that it lost out to R&D against 4-strokes.

I still love the way two-stroke run.

Kawasaki has introduced a new mini ninja motorcycle that is 2-stroke and based on new technology and also meets emission norms. I guess its on sale in malaysia and thailand.
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Old 16th December 2005, 02:09   #11
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i learnt to ride a bike on a yamaha Rx 100.just love the way that bike handles.obiously it cant be compared to pulsars n unicorns but in its time it was a great bike to ride as well as modify !!hell when i go to goa i prefer renting out rx 100's rather than pulsars to remind me of ol' times...


Rev
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Old 16th December 2005, 03:38   #12
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ok this is coming from a pulsar 180 ex-owner. I first had an LML adreno, a 4-stroke bike. Then came the decision to buy another one and I was deciding on the RX-Z 14bhp version.

The blow came just because Setalvad BRos or Kanwal Automobiles the dealers for Yamaha were not interested in Selling rx-z at all.

Pulsar 180 which is equallu good and better in some respects came as an obvious choice.


my neighbour on the left has a yamaha Rx-135 5-speed and my neighbour in the front had and rx-z. Poos soul sold his rx-z the day Fuel prices sky rocket and got a Hero Honda for FE.
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Old 16th December 2005, 11:55   #13
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Quote:
Originally Posted by Mpower
burning the lube oil causes hydrocarbon emissions

.
what if we use something like pressurised lube system (anything except the petroil system). is it possible, if not why?
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Old 16th December 2005, 12:01   #14
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Quote:
Originally Posted by tsk1979
Every time you put in fuel-air mixture, part of it leaks out in exaust stroke. So lower efficiency. Also the life of a 2 stroke engine is shorter. Therefore they are used mostly in 2 wheelers where the running is lower.

Two stroke engines have lower efficiency, need oil with the fuel which is polluting, waste fuel and last less, Enough said!
there are many ways to improve scavenging efficiency....like using reed valves (a project done at my college on 2S engine, using reed valve proved to be very successful)...
using turbo/super charging might also help (i am not so sure about that, well that was one of my thought experiment product), and also redesigning engine.... plz do reply
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Old 16th December 2005, 14:28   #15
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Well i remember toyota filled a (US) patent once for new 2 stroke engines that (they claim) is atleast equal to current 4 stroke engines.Also prateesh the lube/oil mix was done not as neccesity but to save costs and a conventional lube system like a 4 stroke would work (like in the toyota patent). I will try to look for it but meanwhile try: www.uspat.org for Us patents and ofcourse google.
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