Blazin Si

If 2 stroke engines had begun making their way into the modern day automobile, could you see yourself driving one?

Lately, I've been looking into 2 stroke technology. The only experience I've had with them was in the mid to late 90's. I raced motocross on a Kawasaki when 2 stokes were still the norm. At that time, Cannondale had a 4 stroke bike they were stuggling to develop. Shortly after that the Big 4 released their own 4 strokes. The bikes needed twice the displacement to compete with the 2 strokes. They were heavier, but had a smoother power band and more torque. They were also more friendly to the enviroment. Once they became popular, the only 2 strokes engines used by consumers were limited to lawn mowers.

I was thinking that if a 2 stroke engine were to be as advanced as the modern day 4 stroke, it could certainly be a viable option. After researching it a bit, it looks like Mercury has a 2 stroke boat engine with the same emissions as a 4 stroke. Dry sump oil systems can do away with the low tech gas/oil mix. 2 strokes are lighter, more simple in nature, cheaper to manufacture and make much more power. The Honda J32A could likely make 350-400 HP if it were designed as a 2 stroke with the same displacement.

While searching, I came across this article. In 1997, Chrystler was developing a 2 stroke for the Neon. It looked very promising with it's "Phase 3" design using direct injection. The project was cut when it didn't meet emissions standards. I believe that if automakers could create intrests in the technology, the EPA would make changes to their regulations that would allow the fuel efficient 2 stokes on our roads.

www.allpar.com/neon/stroke.html

Stapler

I would happily drive a saab 96 today, so yes.

chill_dog

Before I even got to the end, "emissions" was running through my head. It will never happen.

Blazin Si

When I think 2 stroke, a cloud of blue smoke does come to mind. If more money was spent on refining the emissions equipment, the 2 stroke could be as friendly as the 4.

fsttyms1

Just the way they are designed and operate im not sure you could ever make them as efficient as a 4, not to mention as smooth or quiet? Also the powerbands would have to be something they really worked on. 2 strokes are like supras with giant turbos.

Me, probably not. Give me a nice big 4 stroke V8 so i can grin at the sound

Legend2TL

Emissions is the main reason for lack of two stroke engines in automotive, motorcycles, and now some more traditional two-stroke markets are being slowly taken over by four strokes (marine and lawncare). Besides the oil/gas mixture issues with the pollutants there's the problem of burning up all the gas in the mixture and getting complete combustion. My neighbor has a 4-stroke Honda weedwacker which has a novel little motor.

Ford back in the 90's had a sophisticated two-stroke engine they were getting ready for European market but could never work out the emissions to meet the upcoming requirements even with all the ECU electronics helping out.

One strange area where I see 2-strokes today is these giant 2-stroke diesel marine engines used for large ships.

Even MotoGP went over to 4-stroke for PC and marketing for the manufacturers.

Blazin Si

I've never seen a 2 stroke engine with more than 2 cylinders. I would think that more cylinders would help smooth out the power delivery. The Yamaha Banshee had 2 cylinders but was high strung like dirtbikes. Idled rough and wasn't very nice at partial throttle.

The lack of low end torque reminds me of the Honda Civic. :P

I have a hard time understanding the emissions problem. It sounds as if the 2 stroke is more fuel efficient, but doesn't have as complete of a fuel burn. Possibly because of the fast combustion cycle? Exhaust gas exiting while the intake change is being pulled into the cylinder.

It almost sounds like NOx pollution is the biggest concern. I believe that's why Honda stopped producing engines like the Civic VX and HX with thier lean burn VTEC technology.

StreetKA

iTrader: (8)

http://en.m.wikipedia.org/wiki/Two-s...edirected=true

Read about germans Wartburg and Trabant. The way its build it never gonna be as clean as the 4 stroke. Same thing with wankel. But mazda did some own upgrades and it does pass emission
but im sure its not worth it.

It (2stroke) burns oil and it is a real guzler

Legend2TL

Now here's a 2-stroke!

http://www.mechanicshub.com/testing/...orld&Itemid=83

Unfortunately two-stroke diesels do not scale with their efficiency.

chill_dog

^They need a Discovery Channel show about that. Maybe an episode on that show about really large machines.

Blazin Si

I'm just curious what a large automotive manufacturer could do to help lessen the emissions. The 2 stroke has really fallen off radar. No one seems to be spending any money on perfecting an engine that can be used by consumers. Even my Troy Built weed eater is a 4 stroke. It's so much heavier than my dad's Featherlite, which does the same this just as well..

For auto racing, a light 2 stroke would be ideal. You could mount it low and behind the front wheels. All it's power is made in the top end where you'd spend most of the time. Seems perfect in theory. Then again, the rotary did too.

That's nuts. "...more than 50% of the energy in the fuel is converted to motion." This is the kind of tech I want to see in a car.

PortlandRL

Ask the people in East Germany who owned a Trabant. Fill the gas tank, add some oil, shake the whole car side to side in order to mix it properly. That right there will reduce the appeal to 99.9% of the population who want to just put gas in their cars and drive. People can't even be trusted to change their oil on time, what makes you think they'll remember to put it in each time it needs gas?

fsttyms1

Im betting not a whole lot just due to the inherent design of the motor and the way it works

Blazin Si

That only applies to very simple 2 stroke engines. The ones used in some modern day boats have a sealed crankcase like the engine in your car. They use an oil injection systems which allow the engine to idle like a 4 stroke and maintain a low RPM without fouling the plugs.

The 2 stroke idea wouldn't be appealing to everyone. It would be a niche market like diesels and rotaries.

The Dougler

iTrader: (1)

I hear the e-tec's are quite nice. But I'd still take my inboard v-8

Legend2TL

One of those shows (Amazing Machines, How'd they do that,...) did a brief 10 minute coverage on these giant diesels. The crankcases and heads are welded together out of large sheets of metal (from one to several inches thick!). The casting of the crank was also pretty amazing. When they assembly the whole engine, it happens in one multi-story building and takes weeks to put it all together.

Legend2TL

My memory is hazy on two-strokes but I know from a mechanical/friction point of view they are less friction and mechanical inertia (no valvetrain). However they have alot of incomplete combustion and on non-DI engines some of the fresh fuel/air gets sucked out the exhaust. And dealing with incomplete combustion is difficult on engines with wide RPM ranges. Those giant two stroke diesels spend most of their operational life usually at the same RPM and it's easier to tune the engine to meet the efficiency for that point. Same goes for large diesel engines for trains.

A friend races motocross in MD and what he misses on his CR250 and he had a CR500 once is the ease of engine repair. He now has a Yamaha four-stroke motocross bike now and he said to remove the head takes alot more time.

TheMirror

1. Incomplete combustion
2. Required oil combustion
3. Peaky powerband
4. Difficult to engineer in multi-cylinder formats

Add it all up and it doesn't make sense for a car company to try and engineer their way around all those problems. Emissions standards are stringent these days and are only going to get moreso. The real problem I see with a 2-stroke is how to clean the emissions from the oil combustion; oil burning results in different post-combustion compounds than gasoline and a whole new form of catalytic converter would have to be developed.

Blazin Si

Those are both good points. The air intake and fuel delivery system appears to be very simple assembly. I haven't seen exactly what type if boat is powered by these motors. From the sound of it, they maintain a fairly constant speed.

I road my bike literally 4 years straight almost every day and raced it from spring through fall. The bike was extremely reliable and I never even had to replace the rings. That's pretty incredible considering the engine spent most of it's life between 7k and 10k RPM. I had friends blow their motors and a bike mechanic could rebuild the thing in a single day if parts were on hand.

I had thought the better fuel economy would make up for the poor emissions. Sort of like diesel engines. I keep hearing more about "clean diesels" so maybe that's no longer the case.