is 2 cycle engine that harmful to environment?

Question

I heard that EPA has banned importing 2cycle engines from other countries to try to get rid of 2cycle engine uses.
I wonder what is so bad about 2 cycle engines.
it the pollution made from 2 cyce engines that harmful?

Answer 1

Geeze. So much poor and mis-information out there...

Two stroke engines have not been banned by the epa, nor are they illegal. Several years ago the EPA told the motorcycle industry that they would be moving towards an emission standard simular to the C.A.R.B. (California Air Resourse Board) standard in 2007. The thing is, they left a huge loop hole in the requirements stating that competition or closed course use only machine would be EXEMPT from any and all requirments. Therefore, now, and for the foreseeable future, if the machine is delivered from the factory/dealer without working lights, a spark arrestor, and/or delivered with a sticker proclaiming the machine is for "CLOSED COURSE USE ONLY" it is as EPA legal as any other bike built and sold. Period. End of story.

These same EPA/CARB standards also effect the on-road market. As we speak the aftermarket industry is reeling as they try to get changes made in legislation and scramble for new technology because these standards basically make it illegal to replace or modify stock exhaust systems. That will have a HUGE impact on the crusier and sport bike markets, which re-main curiously quiet about all of this...

But back to the off road issues...

The factories, in a classic knee jerk reaction, began work on new generation R.F.S. (Racing Four Stroke) engines to see if they could/would be compliant and if he market would accept them. They found out two things. The RFS engine DOES NOT meet EPA/CARB standards and the average buyer (especially the wanna be MX crowd) will buy anything that the factory race teams put thier highly touted and paid superstars on. I.E. if Ricky, Bubba and Chad started riding Tomos Mopeds there would be a huge influx of mopeds on the starting lines of local MX tracks all over the US.

Take a look at what is available for the "off-road" market. The WR series from Yamaha, XC/XC-W from KTM and the CRF-X's from Honda. The Yamaha's are delivered with throttle blocks, ignition retarders, and highly restrictive snorkles in place. Why? Because they won't meet the EPA/CARB standards for noise and emissions uncorked. However, they are 'legal' for use 'off-road'. KTM decided to switch rather than fight, and last year redesignated thier off-road line up as XC's and XC-W's (as opposed to the EXC) and no longer deliver the bikes with lights or spark arresters and put the mighty "CLOSED COURSE USE ONLY" sticker on it. The EXC line is now basically a dual sport primarily targeted for the european markets. Honda's X line retains the lights and spark arrestor, but proudly wears the CCUO sticker and skirts the standards.

This has been discussed here many many times, but the hard facts are this. AS DELIVERED an RFS produces a little less hydrocarbons and pollutants than a two stroke engine. However, the overwhelming majority of riders and racers change exhaust systems, jetting and open up the air intakes to make them perform better. Once that is done, they are just as 'dirty' as any two stroke, and a make a lot more noise. Remember, rich is fast on a four stroke, but lean is mean on a two stroke...

As mentioned, the factories have already figured out that they can sell these bikes to the buying public, and now the motivation to do some comes from the fact that they have created a cash cow. The RFS engines are NOT what the average consumer considers them to be. They require more upkeep and maintaince than a comparitive two stroke, they have more moving parts and therefore more wear items that need to be replaced. $$$$$. I've read where Honda recommends changing the piston and rings on the 250/450 RFS at the same interval as the oil.

As for the old 6V, 8V and 12V series of Detroit Diesel engines, they were basically phased out of over the road truck use 25 years ago. But it had nothing to do with emissions standards. The cam and valve style two stroke diesel engine was basically a piss poor design that had out lived it's usefulness. To be honest, it's main selling point was that it was cheap to buy. Detroit Diesel worked with Roger Penske and designed the Series 60 engine, which is a four stroke in-line 6 engine that is remarkably simular to a 3406 Cat. But that's another story.

What ultimately killed the 2 stroke Detroit's was that they were all 'leakers'. The damn things leaked oil worse than an AMF Harley! In fact, in the late 70's Detroit Diesel ran a huge advertising campaign as a last ditch effort to salvage the engine in which they showed an 8V92TT "Silver OO" engine and proudly proclaimed "We've made over 75 changes to help keep oil INSIDE our engines." It didn't work, the damage to thier market was already done, and work began on the Series 60 engine.

I believe they are still producing the 6V and 8V engines in limited numbers for the marine market, but I'm pretty sure the 12V engine is gone. The V-12's last market was the railroad and I don't believe that market is strong enough to justify producing that engine soley for it. Besides, it was a horribly ineffecient engine that sucked fuel like nobodies business. But it sure would make an over the road truck fly!

Answer 2

Yes and No... most Current 2-strokes (not 2 cylinders as mentioned above, 2-strokes can have any number of cylinders) are fed by carburators. Due to the nature of the 2-stroke beast, they draw in more fuel than they can use, and some of that fuel passes straight through to the exhaust without ever burning. Were someone willing to devote the resources needed to develope a GOOD, working direct injection EFI system, then they wouldn't have to be so bad.

Bimota actually did this with the V-Due 500, but the fuel injection system had lots of flaws out of the factory. Even so, it passed EPA regulations and was legal in 49 states (California being the exception, always the odd state out). So it Can be done.

Another interesting fact is that Detroit Diesel engines (semi-trucks) run 2-stroke Diesel motors and turn millions of miles on the roads in this country each year.

So it's not that anyone's trying to get rid of 2-strokes, it's just that they're Really hard to clean up to meet ever tightening emissions regulations ~ 4-strokes are much easier in that regard.

Answer 3

It does not do near the harm, that all the Chemical Plants in Texas do to the environment. Most all of the Pollutants, come from the Chemical Industries, which are 10 billon times greater than all the 2 cycle engines in the world could make.

It's what you can't see, that's harmful to the environment.

Answer 4

Conventional 2 stroke motorcycle engines are poor on emissions for two reasons - one that they have unburnt lubricating oil in the exhaust, but also because the valve timing allows unburnt fuel/air mixture to exit the exhaust port before it closes on the compression stroke.

Direct injection 2 stroke motors have none of these problems. They have been used extensively on trucks and rail locomotives for years. The complication is that fuel injection has to occur under very high pressure (unlike 4 stroke injection) directly into the compressed air as the piston nears the top of the compression stroke to work properly.

A number of small capacity direct injection 2 strokes are around in small motorcycles using technology patented by the Orbital Engine Company.

Answer 5

Yes, they are bad.
You have to mix oil with the gas for the 2 strokes (a.k.a. 2 cylinder engine) to run. So you're constantly burning oil, which is no good. I'm sure there's more to it, but that's what I know for sure. If you go to the Dominican Republic there's soooo much smog and crap in the air from all of the 2 stroke scooters around there. Almost everyone has one that they travel on, the air quality is horrible.

Answer 6

Because two cycle engines have lubricating oil mixed with the gasoline, the fuel burns less efficiently and produces more hydrocarbons in the exhaust than four cycle engines which only burn straight gasoline.

Answer 7

I think any engine of cumbustion outputs chemicals that are harmful to the atmosphere. I don't think it will be our demise though. We will have to come up with a fuel source alternative when fossi fuels are depleated. I am guessin solar energy.

Answer 8

yes and no yes= if it isnt tuned properly no=so much fun it will be illegal to sell buy a 2 stroke in dealerships in 08-09 becouse of those nosey tree huggersthey dont want to hurt the flowers

Answer 9

Yes, any internal combustion engine is bad for the environment to some extent.