Could a 2 stroke be green?

[Formula413]

I was hacking away with a string trimmer at work recently, and it got me thinking. With sufficiently advanced technology and engine management, would it be possible to make a 2 stroke engine that could match the efficiency and emissions standards of conventional 4 cycle ICE's? Obviously a 2 cycle engine has a large advantage in power/weight ratio, since the cylinder is firing twice as much. Reducing weight is huge when it comes to improving efficiency.

The idea of 2 cycle engines in cars is not new. Back in the early-mid nineties Jeep had a concept vehicle called the Ecco which was powered by a 1.5L 3 cylinder direct injection 2 cycle engine.

Jeep ECCO Concept - Mojeepin.com

[SVOboy]

I doubt it, but by 2011 the EPA is requiring cats on all lawn equipment and such.

[Peter7307]

Given enough development money and a suitable incentive I think ring dings could be made to be green.
Direct fuel injection and a separate oil system is certainly a starting point but then who would be willing to pay for that on a lawn trimmer or leaf blower?

Pete.

[Formula413]

Just to clarify, I was talking about using 2 cycle engines in cars.

[achang1]

2 stroke wont be green since it "burns" oil

[SVOboy]

2 cycles in cars? What's to gain really? Even if you could the issues with increased wear I think would reduce the value there.

[IndyIan]

2 strokes in cars eh? I remember reading in an old dirtbike magazine that they converted a CR500 engine to run on alcohol and they used vegetable oil for lubrication. It also made some rediculous amount of hp and the top speed near 130mph was traction limited...
It also drained the 1.5 gallon tank in 10 minutes... The emissions were quite "green" but the amount of fuel used makes it impractical.

Probably the most advanced 2 stroke engines available now are in snowmobiles and some are getting nearly the same mileage as 4 stroke sleds, within 10-15%. Total cost of ownership is still probably in the 2-strokes favor as they are far cheaper to buy initially and a rebuild is much cheaper but still required more often. An 800cc 2 stroke snowmobile drivetrain would make a Geo metro into quite the performance machine but I doubt it would get much better than 35 mpg.
Ian

[Big Dave]

I doubt a two-stroke would ever meet even mid-70s emissions standards.

The two-stroke's big edge is it lack of a valve train. But that means port induction/exhaust. So a port uncovers with the combustion event still going on. Unburned hydrocarbons (VOC) are emitted.

A lot of smart cookies tried to save the two-stroker but the last of them died out before Jimmy Carter was out of office.

Like everything else, engineering has a history.

[Frank Lee]

Orbital Corporation Limited - Wikipedia, the free encyclopedia

[Ryland]

my Tomos scooter has a 2 stroke engine, oil injection and a catolitic converter and because of that has very dry exhaust, unlike the old ones that had greasy exhaust.
I've also ran 10% veggie oil in 4 stroke gas engines with great luck, had it burn completely and read about people running it in 2 stroke chain saws with good luck and no ill effects.

[almightybmw]

Check out what Bombardier Ski Doo is doing with their 600cc snowmachine (mobile for you slow folk) motor. The average for it is 17mpg, compared to previous gen 2-stroke that was at best 9-10mpg.

[SuperTrooper]

Originally Posted by almightybmw

Check out what Bombardier Ski Doo is doing with their 600cc snowmachine (mobile for you slow folk) motor. The average for it is 17mpg, compared to previous gen 2-stroke that was at best 9-10mpg.

How does it compare in weight and acceleration?

[Big Dave]

Has Orbital done anything since 2003?

[meemooer]

my truck could be considered 2stroke. It smokes like one on start up, and heavy acceleration. and burns 5qts of oil to 45 gal of gas

[IndyIan]

Originally Posted by SuperTrooper

How does it compare in weight and acceleration?

I just went to the website andl ski-doo is claiming better mileage with the 2 strokes than competitors 4 strokes. Everyones major complaint about the 4 strokes is that they are heavier than the 2 stroke motors. This weight is up front and an extra 20-30lbs on a 450-500lb machine in the wrong spot is very noticable in performance.
I didn't reseach the exact number but a 600cc 2 stroke probably puts out around 100hp, a 600cc 4 stroke puts out 75-80hp. Doesn't sound like a big deal but for most sledders performance trumps FE by quite a bit. There would be lots of guys happy with 5 mpg if it meant they could beat their buddies across the lake everytime....
Ian

[95badbird]

Originally Posted by SVOboy

I doubt it, but by 2011 the EPA is requiring cats on all lawn equipment and such.

do you have anything to back this up?

[dcb]

2011 EPA lawnmower catalytic - Google Search

[metroschultz]

I don't believe the EPA can get catalytic converters on lawn equipment.
No one is going to pay $500 USD for a No-Name WallyWorld lawn-mower that you can get today for the rollback price of just $98.77 USD.
Ain't Happenin
Besides, cats are heavy, where would you mount it? How would you secure it from those night time cat thieves?
Just my $.02
S.
edit;
I already use an electric mower.
Perhaps this will spur the sale of more electrics so they (the gassers) don't have to be strangled with a catalytic concerter.
Hmm

[95badbird]

Originally Posted by dcb

2011 EPA lawnmower catalytic - Google Search

thank you.

[IndyIan]

Originally Posted by metroschultz

I don't believe the EPA can get catalytic converters on lawn equipment.
No one is going to pay $500 USD for a No-Name WallyWorld lawn-mower that you can get today for the rollback price of just $98.77 USD.
Ain't Happenin
Besides, cats are heavy, where would you mount it? How would you secure it from those night time cat thieves?
Just my $.02
S.
edit;
I already use an electric mower.
Perhaps this will spur the sale of more electrics so they (the gassers) don't have to be strangled with a catalytic concerter.
Hmm

I guess cat technology has been brought forward quite a bit lately, many homeowner level chainsaws have had cats on them for a couple years. I have one and the little epa sticker rates it 2 out of 10 (1 is best) on their pollution scale. The muffler/cat is slightly bigger than a regular muffler and gets a bit hotter. It did clean up the exhaust noticably compared to my pro saw. The emmissions system also had a time rating of 50 hours and I'm probably at 60 and it is failing rapidly. The saw seems to be losing power so I thinking of just drilling a couple of 3/8 holes through the whole thing to open it up and see if the lost horsepower is from the cat being clogged.

I've been told there are a few nasty metals/chemicals in the cat itself so I should be careful about the dust from drilling.

I'd like to see an analysis of which is worse, releasing a few litres of unburnt fuel with out a cat, or dealing with nasty compounds in a throw away item?
I guess I could price out a new cat/muffler, I imagine they make it just enough to justify buying a new saw...
Ian