Could a 2 stroke be green?
 

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

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

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.

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

2 stroke wont be green since it "burns" oil

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.

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

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.

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.

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?

Has Orbital done anything since 2003?

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

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

do you have anything to back this up?

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

thank you.

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

I've been using a rechargable electric lawn mower for years. Also electric weed whacker & chainsaw - running a couple hundred feet of extension cord is a lot less hassle than mixing 2-cycle gas, trying to get the damn things to start, etc.

All I need now is to get the electric chain saw to work off DC. Then I've got a spare Insight battery pack that I could charge up and take out to the woods to cut firewood.

Between my dad and myself we've owned Black & Decker corded electric mowers since 1969. You get used to planning for the cord.

I've tried electric snowblowers, but they don't work well in the heavy, wet snow we often get in the late winter.

Screw dragging cords everywhere.....hell all my lawn equipment is gas...1 pull for everything, and they start right up.

As a side note, a couple hundred feet is not the recommended length for corded trimmers and chainsaws. 100Ft Maximum/14 Gauge Minumum, anything else and you run the risk of burning out the tool you're using. Just my $0.02. I used to work at SEARS in the repairs department and you wouldn't believe the number of burnouts we had because people would connect 2 100Ft cords together and roast the motors.

Err... There's this new device called a "snow shovel". Runs on biofuel, so it doesn't need gas or electricity.

If you live on a 40'x80' lot then electric stuff makes alot of sense, it also seems that its hard to find quality electic equipment. I guess I could use a corded mower but then I'd have to mow the lawn 3 times as often just so I wouldn't kill it in tall thick grass...

Jamesqf, Stihl does make a good electric saw, I think they are $300 new but a used one might be found. Also how many kilowatt hours are in an insight battery? When I'm doing firewood I'd use about 1.75 KWH per hour with a 5hp chainsaw, maybe more like 1.5KWH/hour if I have to move around for each cut.

I can't say I'm totally opposed to electric equipment but it always seems like the batteries can't be charged after awhile, batteries overheat easily too if you run things too hard, and cords get cut and tangled. I find for my rougher carpentry projects my small gas chainsaw is handier than a circular saw. Take about the same time to pick and use and it can do cuts that a circular saw can't.

Ian

I've ridden a Bobardier Jet Ski with a Rotax motor that I could have sworn was a 4 stroke.

So much so that I filed the oil tank with Fuel :-( I Fixed the problem before I started it though.

Overall not a bad powerplant Burnt 1/3 the fuel that the smaller, slower 2 stroke Jet ski did. Smells Clean, not that it counts for much.

When I first read the title, first thing to mind.

Old diesels. 2 Stroke diesels for many years were considered to be more powerfull and fuel efficient than the 4 stroke variations. Reason, they are blown so exhaust does not appreciably mix with the clean air, and they still have the higher compression ratios diesels like best. (they were the mainstay from very early on up through the late 70's in buses and semi's)

The military still uses detroit 2 strokes, on one unit called a HET, 23000lbs empty the thing gets 10-12mpg on pavement. Not bad for 8wd all the time, redlines at 46mph though.

I would think if the design for the diesel 2 stroke was applied to the gasoline 2 stroke we would eliminate oil in the fuel, richer than necessary fuel mixtures, and improve compression and combustion.

I believe some snowmobiles have gone this route, at least they alluded to it 10 years ago.

Also of note the car I would most like to have at the moment is a 2 stroke, the Subaru 360 and it gets 50-60mpg easily. But yes it does pollute but probably less than a 2 stroke lawnmower given it has oil injection.

Most of the Jap and Chinese Kei cars are all 2 strokes, some are quite modern and do offer pollution controls. If anyone reads japanese or chinese worth looking into.

I think mine's a Remington, and about $50. The blade's a bit short, but it handles most of what I need to do.

I do mine differently: usually the places I get it have been logged or thinned, so I don't need to do much cutting out in the field - just to trim some of the logs to pickup lengths. Most of the time is spent loading, then I cut them to fireplace size at home with the electric, which is quiet enough that it doesn't bother the neighbors.

As a side note; I own the following in addition to 2 gas chainsaws.

http://www.remingtonchainsaw.com/ima...9-01-large.jpg
Works great; used lots until we got
Amazon.com: Black & Decker 18-Volt Cordless Electric Chain Saw #CCS818: Home Improvement Works nearly as well, no cord!

yeah, my yard is just a 1/4 acre......but with that said, I do yard work on the side, and at my grandmother's house, she has an electric weedeater, her yard is tiny, and I refuse to use the tool....I just bring my own.
Cuts down at least 7-8 minutes of yard work not having to deal with cords.

But to each his own.

I don't know if you go onto some of the chainsaw forums but there's always an ideal saw for a situation, not an ideal saw for everyone. If the remington works well for you then its a good saw for what your doing.
My firewood tends to be big enough that I need to block it to move it all, so electric anything isn't really an option. Some of it I need to split right there to load it even. For my big saw I've got a husky 372 with a 20" bar, it pulls it well even buried in white oak. For my little saw I've got husky 141 with a 16" bar, in softwoods under 16" and smaller hardwoods it work fine and is alot lighter.
I've used an old 2 man buck saw a couple times at a friends cottage and it worked pretty good. I'm tempted to get one at an antique store sometime, just to get more of a workout. I burn 2 or 3 cords a year so it really doesn't take very long to get it done. If I use more than $20 in gas between the atv and the saws I'd be surprised.
Guys do use veggie oil for the bar, regular veggie oil oxidizes leaving "crud" that can gum up the oil pump but there are specialized veggie oils that behave like normal oil. If you can remember to clean out the tank or use your saw frequently (like once a week) you can use normal veggie oil.
Ian
Not my video but here's a stock 372 in action.
YouTube - Stock Husky 372xp Stock Chain

Then I'd like to invite you over this winter to shovel the foot of heavy wet snow from my 150'x12' driveway. :p