Two-stroke emissions not so bad?

[Badjelly]

One of the threads in the Racing forum has started to morph into a discussion on the reasonableness or otherwise of emissions regulations as applied to 2-stroke motorbikes. Eg see my post

http://www.kiwibiker.co.nz/forums/sh...4&postcount=36

So I've started this new thread with the following challenge:

Because 2-stroke engines burn oil as well as petrol (and I think also because they don't burn the petrol completely) they emit more carbon monoxide, hydrocarbons, and particulate matter than 4-strokes. I don't know exactly how much more, but various fragments I've seen on the WWW suggest much, much more, eg this (which admittedly is more concerned about hydrocarbons in the water than in the air)

http://www.kimointernational.org/Default.aspx?tabid=68

But I admit there are holes in my knowledge about this, so I have a challenge: I've seen many posts on KB dismissing the environmental problems caused by 2-stroke engines, but not one that suggested the poster actually knew the first thing about the subject. If anyone wants to go off and do a bit of reading and come back and argue that the emissions regulations applied to 2-stroke motorbikes are excessive or unreasonable, then please do and we can discuss it.

[bungbung]

Looking at petrol and oil input to kilometres travelled, and using comparable bikes.

My only 2T on road experience is with a 50cc scooter.
It needed 1l of 2T oil per 1000km, in that period it would use 35l petrol.

A 4T 50cc scoot should be more economical, lets try 30l per 1000km.

If oil and petrol are considered equivalent for pollution, and for this exercise the 2T has 20% more emissions than a 4T.

[gijoe1313]

My poor stinky, two stroker smokers! Imagine that, finding a reason to get them off the road

Borrocks to that! Just imagine a future where bikers are bootlegging around on two-strokers evading the Environmental Police!

In the bigger scale of things, I'm sure the mass of used PET bottles for water would rank higher! (But then again, I guess if everyone was riding two strokers it would be a problem then innit? ) There ya go, completely anecdotal and unformed opinionated claptrap .. oh wait

Never mind, let the games begin!

[xwhatsit]

We don't have emissions regs on two-strokes in NZ. Just thought I'd point that out.

[pete376403]

two strokes started to be demonised in California many years ago and what starts in California is usually taken up by the rest of the US soon after. And Japan isn't going to piss off its single biggest market.
I would suggest that the fact that the 2T exhaust "looks" bad, even if it's not, was grounds enough for kneejerk legislation calling for the banning.
(wild unsubstantiated guess follows) The volume of emissions from all the smokers in a year probably doesn't come anywhere near the volume of emissions from diesels in a single day, but by railing against 2T bikes (users of which are a very minor part of the voting mass), politicians can pretend they are trying to save the planet.
Outboard motor users probably don't care whats under the hood, as long as it pushes the boat along

[WRT]

2/'s aren't always terrible polluters, BRP seem to have got their act together with the emissions on their etec Evinrude outboards.

Be nice to see the same technology come across from the outboards to bikes. Clean burning, less pollution than an equivalent four stroke. And it's pretty cool engine management, the whole thing can be controlled by a laptop, turning off and on individual spark plugs or injectors, you can also see the history of the engine, temp, revs, throttle, etc. There's also no running in period, and the maintenance schedule is remarkably long - service once every three years. Wouldn't that be nice on your bike . . .

However, while the etec outboards run very cleanly, I don't think the same could be said of my CR (aka, Puff the Tragic Wagon). And BRP only use 2 stroke on their larger outboards, over 40hp. So perhaps the technology isnt suited to smaller engines. Sorry scooters . . .

I'm sure BRP must have looked at the possibility of transferring the technology from Evinrude to Ski-Doo/Sea-Doo, and to Rotax. Imagine if Rotax were to start producing a large capacity bike engine using the etec system? Now that would be cool.

However, according to the Vatican us current 2/ riders are all doomed to "eternal death" (is there another kind?) and will be going straight to hell.

[WRT]

Actually, another article on the etecs, but talking about automotive use as well:

http://findarticles.com/p/articles/m...5/ai_103990207

Ah, if only . . .

[Badjelly]

We don't have emissions regs on two-strokes in NZ. Just thought I'd point that out.

Fair point, but I understand that the move away from 2-strokes overseas is due to emissions regulations there. (Well, partly due, anyway. I think the move away from 2-strokes is also due to their higher fuel consumption and the fact that many people just don't like them.)

two strokes started to be demonised in California many years ago and what starts in California is usually taken up by the rest of the US soon after. And Japan isn't going to piss off its single biggest market. I would suggest that the fact that the 2T exhaust "looks" bad, even if it's not, was grounds enough for kneejerk legislation calling for the banning. (wild unsubstantiated guess follows) The volume of emissions from all the smokers in a year probably doesn't come anywhere near the volume of emissions from diesels in a single day, but by railing against 2T bikes (users of which are a very minor part of the voting mass), politicians can pretend they are trying to save the planet.
Outboard motor users probably don't care whats under the hood, as long as it pushes the boat along

"Demonised"? "Kneejerk"? Your kneejerk dismissal of the issues and demonising of the politicians isn't going to convince anyone who hasn't turned his brain off.

"The fact that the 2T exhaust "looks" bad, even if it's not"? (Actually, as I understand it, it looks bad and it is bad.)

I'm not sure about your (wild, unsubstantiated ) comparison between diesels and 2-stroke motorbikes. I'm no fan of diesels myself, but they are being subjected to quite tough regulations these days, and about time too.

2/'s aren't always terrible polluters, BRP seem to have got their act together with the emissions on their etec Evinrude outboards.

Be nice to see the same technology come across from the outboards to bikes. Clean burning, less pollution than an equivalent four stroke.

Thanks for that. I suspect that the technology won't come across because there isn't the demand in the market, but I may be wrong.

[Ixion]

Actually, in NZ, two strokes are EXEMPTED from our emission regulations (such as they are). Or (depending on which bit ) have much higher limits.

We do win one sometimes.

[Badjelly]

Actually, in NZ, two strokes are EXEMPTED from our emission regulations (such as they are). Or (depending on which bit) have much higher limits. We do win one sometimes.

Thanks, Ixion. Can you please point me to a source of information on this?

As I understand it, NZ emission regulations basically say that vehicles have to comply with emission regulations in the country of origin. And I understand there has been a change recently that effectively banned used imports more than 5 years old. Am I right?

[Ixion]

Road Rule Vehicle Exhaust Emissions 2007

Says that if a vehicle was built to comply with an emissions standard it must still comply on entry.

And specifies the emission limits for general application (Table 3.1)

Four strokes 1% Co, 300 ppm HC
Two strokes 4.5% 7500 ppm (thats the smoke)

So if a two stroke originally complied with whatever the standard required it still must (fair enough). And if it didn't comply with any standard it is allowed nearly 30 times as much emission as a four stroke. . Woo hoo

Two strokes are also effectively exempted from the WoF visible smoke test (technically, they must not smoke more than they did when new. But who is going to be able to judge that !)

[Badjelly]

To the people who say, "Can my little 2-stoke really be that bad?" I think the answer is, possibly, "Yes!"

Ixion's already told us a 2-stroke is allowed to put out 2000 times as much hydrocarbon as a 4-stroke. How much does that matter? I'm not sure, but I suspect that some of the hydrocarbons in question aren't very nice.

And from this page

http://www.engr.colostate.edu/comm/n...n&cat=8&id=117

we learn

The United Nations Environmental Program has singled out two-stroke engines and diesel engines as primary contributors to the Asian brown cloud, a layer of particulate pollution that is one mile deep and roughly the size of the United States, which now covers South Asia.

"In the developed world, nearly all vehicles are powered by cleaner four-stroke engines. However, in developing nations, two-strokes are favored for personal transportation due to their low cost, durability and high power-to-weight ratio," said Lorenz. "Unfortunately, the simple two-stroke engine has so much pollution that one small tricycle may produce the same amount of pollution as 30 to 50 modern automobiles. The 250,000 tricycles in Manila contribute pollution equivalent to 10 million Honda Accords."

Throughout Asia, two-stroke vehicles create the pollution equivalent of 2 billion to 5 billion Honda Accords.

And here

http://www.pubmedcentral.nih.gov/art...?artid=1247506

it says

Measurements of how much pollution two-wheelers emit are rare, but one study of traffic intersections in Bangkok, Thailand, found that two-wheelers contributed up to 47% of particulates. When the city instituted a stringent inspection program and emissions standards in 2000, two-wheelers made up 96% of the city’s traffic; by March 2004 they made up only 40%, reported Supat Wangwongwatana, deputy director general of Thailand’s Pollution Control Department.

Similarly, when two-stroke baby taxis were phased out of Dhaka, Bangladesh, in 2002, particulate concentrations dropped up to 40%, and carbon monoxide and hydrocarbons fell significantly, reported S.M.A. Bari, director of engineering at the Bangladesh Road Transport Authority.

Now, this may be over-simplifying things, it may even be completely wrong, but I think it's not reasonable to accuse the politicians & bureacrats of a kneejerk reaction to a non-problem.

[Ixion]

But but but (I got the maths wrong BTW, its only 30 times as much. But of course when I fire up Petal that makes up for the rest, Petal leaves an ozone hole trail the way jets leave contrails ). You speak as if two smoker smoke was BAD. It's bewdiful!

Four strokes pollute. Two strokes perfume the air.

[Badjelly]

Looking at petrol and oil input to kilometres travelled, and using comparable bikes.

My only 2T on road experience is with a 50cc scooter.
It needed 1l of 2T oil per 1000km, in that period it would use 35l petrol.

A 4T 50cc scoot should be more economical, lets try 30l per 1000km.

If oil and petrol are considered equivalent for pollution, and for this exercise the 2T has 20% more emissions than a 4T.

Thanks for that. Your calculations relate to total amount of hydrocarbons burned, and hence (roughly) total amount of CO2 emitted. This is relevant for global warming (but let's not get into that here). Compared to 4-strokes, 2-strokes use a bit more fuel and produce a bit more CO2. However they don't burn the fuel efficiently, so they produce a lot more unburned or partially burned hydrocarbons. This is why they have trouble meeting emissions regulations.

[Ixion]

Now, this may be over-simplifying things, it may even be completely wrong, but I think it's not reasonable to accuse the politicians & bureacrats of a kneejerk reaction to a non-problem.

Of course it is. Two strokes are never a problem. They're SPECIAL.