Two Stroke Emissions

T

Tinker1980

Guest
I was looking for information on the emissions of 2 stroke engines, I just can't get my head around the idea that my bitty little 67cc one lunger pollutes a whole lot more per mile than my fullsize chevrolet truck, which for the record has a 350 V8. (Which is 5736.5cc)

I found some info at this site: http://www.bajajusa.com/emissions.htm there they mentioned a 150cc Bajaj scooter that was a 2 stroke, and said it gave off 660-1540 pounds of hydrocarbons per 10,000 miles.

I got to thinking about those numbers, and they don't add up. Lets assume our Bajaj Chetak 150 cc scooter gets only 80 MPG. (I know someone who has one of the 2 strokers, and she gets right at 100 out of it) Assuming that, we could say it burns 1/80th gallon per mile, or about 1.2 ounces by weight per mile. That adds up to 750 pounds of gas to go 10,000 miles. So... How... are we getting 660-1540 pounds of hydrocarbons per 10k miles? That would mean that, on average, the entire mass of gasoline used is emitted in unburned hydrocarbons, so, how is the silly thing even running since you're in effect pouring the gas out on the ground?

Or, more likely... Who's math is wrong? Is this a case of panicky sky-is-falling environmentalism, or are my math skills at 1:48 post meridian (Early morning for me) not up to snuff yet?

-Mark
 
I think you've made an error when you equated "fluid ounces" with ounces of weight.

Let me do some figuring. I'll be back if I can figure out whether the difference will work in favor of your suspicion or against it.
 
No - I figured out the 1.2 ounces per mile from the six pounds that a gallon of gas weighs, not the 128 fluid ounces in a gallon.

-Mark
 
You also have not taken into account the weight of the oxygen that is burned at over 10 times the amount of the fuel and is compounded with the fuel during the combustion process to become a component in the so-called greenhouse gases.
 
You also have not taken into account the weight of the oxygen that is burned at over 10 times the amount of the fuel and is compounded with the fuel during the combustion process to become a component in the so-called greenhouse gases.

Actually, yes I have. I'm just talking about Unburned Hydrocarbons. They haven't been burned, so there is no oxygen from the air present. As far as "greenhouse gases", the amount of CO2 produced is directly proportional to how much fuel you burn, so in that case, a little 2 stroke is far cleaner than a car.

-Mark
 
This might help some understand http://www.fueleconomy.gov/Feg/co2.shtml louis

No... I'm only talking about *unburned hydrocarbons*. They are unburned. And hydrocarbons. They are only hydrogen and carbon. They are the bits of gasoline and oil that went through the combustion process without combusting, therefore have not gained any mass from added oxygen. I understand that getting CO2 and CO adds mass because of the added oxygen, but I'm not talking about CO2 or CO.

-Mark
 
Okay, we're talking about nothing but the fuel and oil that passes through unburnt.
And as a matter of fact, that is what you said in the original post.

At the moment I'm a bit too tired to work with figures without screwing it up.

But I can make one comment; two strokes are on the dirty side but two stroke haters can exaggerate to the point of being kinda dirty themselves.
 
Ok here is some numbers,
1gal.=6.3lb
1lb=453.6grams
Now to get close to the numbers the site stats your 2 stroke would be 66% efficient.
So 30grams per mile x 3 =90, 2857.7grams per gal.gas\ 90=31.7 mpg.
Just plane stupid!
And 70grams per mile? louis

P.S. I'm tired of people bashing 2 strokes
 
I wrote an email asking them what was the deal with their math, once I woke up all the way. They haven't responded but it's the weekend, and I imagine they will try the "Oxygen adds mass" argument, which is of course invalid in this case.

On a related note, how big a deal would it be to make a homebuilt catalytic converter? Seems that you could hit up a junkyard, find a honeycomb type catalyst, core it with a pipe and run your exhaust through it.

-Mark
 
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