JakeRobb

This is pretty interesting. I'm surprised nobody has posted it here yet: AutoWeek article

SUCK-SQUISH-BANG-BLOW is no more.

In its place, we get:
SUCK-SQUISH-BANG-SQUISH-BOIL-BLOW

Threxx

That sounds really interesting but I have to say I'm waiting on at least 10 technologies I've heard about in the last 5 years that were supposed to flat out obsolete some current modern day technology, and instead I've heard absolutely nothing.

I'm starting to learn to not get excited about something until it actually starts moving into the mass market.

Zeroshift anyone?

JakeRobb

Yeah, good point. I'm still waiting for Caroll Shelby to make good on his OX2 engine...

Still, this is pretty cool stuff, and it seems like the changes to an existing four stroke engine are a lot less drastic than a lot of those other technologies.

rlchv70

Some potential problems with it:

1. You couldn't use any water. It would need to be distilled with some type of anti-freeze.
2. There is a risk of oil contamination.
3. You wouldn't want to start/stop an engine on the water injection stroke.
4. Increased vehicle weight to carry around the water.

These can be overcome, though...

Randy

detltu

Cool stuff. I hadn't seen the OX2 engine either. Don't really have time to read the whole OX2 site but I'll get to it later.

JakeRobb

1. Crower already said it would need to be distilled water. There's no reason gas stations couldn't start carrying distilled water, possibly even something with an anti-freeze compound in it.

2. True, but I don't think this risk is much greater than it is now. As long as your piston ring seals hold, you're fine.

3. True, I hadn't thought of that. The computer responsible for triggering the water injection would need to know not to inject the water until the engine was running. That's not too difficult.

4. This should be counteracted by the weight saved in the removal of the existing cooling system (fan, radiator, coolant, coolant reservoir). In addition, since we're increasing miles per gallon of gasoline by so much, we don't need the gas tank to be as big.

I don't mean to come off as a cheerleader for this technology or anything, but I think it has some pretty huge potential.

number77

cliff notes, how does it work?

JakeRobb

1. Standard intake stroke - piston moving down.
2. Standard compression stroke - piston moving up.
3. Standard power stroke - piston moving down.
4. All valves remain closed. Inject water (distilled, from a tank, warm from engine heat but not yet at the boiling point) and compress - piston moving up.
5. Valves still closed. Cylinder heat and compression causes water to boil, creating another power stroke - piston moving down.
6. Standard exhaust stroke expels exhaust from both power strokes - piston moving up.

Repeat!

Like I said before: suck, squish, bang, squish, boil, blow.

number77

Thanks.

Even though this is published by editors, I still think that compressing water will be very bad for the engine. (have you guys looked into hydro lock?)
and the heat required to heat the gas, will have to come from another cylinder and would result in a net loss when the steam is released.

...if too much gas gets in your engine, you might get some backfiring...if too much water gets in...you will need a new engine.

Maybe this guys gain in fuel economy is because he doesn't inject fuel into the cylinder 1/8th of the time....I think someone else does this without water (displacement on demand?)

JakeRobb

I think this sort of technology will have a lot more potential once we have computer-controlled electromechanical valve actuation (instead of pure mechanical via a camshaft). That way, the engine could run in regular four-stroke mode until it got warm enough for the water to boil, and then it could seamlessly switch over to six-stroke mode. This would eliminate the problem of starting on a water injection stroke, too.

The heat of the engine in four-stroke mode could be used to defrost the water tank and lines, and once everything was defrosted, there would be no problem switching to six-stroke mode.

The water tank might have to be right in the engine bay in order to maximize the thaw rate. Or the exhaust could be routed deliberately near the water lines in order to thaw everything.

I think the biggest issue would be the fact that water expands when it freezes... that could break stuff. The engine would have to purge itself of all water or something.

JakeRobb

He's compressing exhaust with a little tiny bit of water in it. No hydro lock.

There's a loss of horsepower with DOD. Crower was seeing pretty much the same power output in six-stroke mode. Imagine what a six-stroke DOD motor could do...

morb|d

Just imagine:

A hybrid-electric, bio-diesel, direct-injection, displacement-on-demand, six-stroke, multi-valve, variable-intake, infinite variable valve lift and timing, turbo-charged, intercooled, internal combustion V8.

Angelis83LT

nothing like having to have a high compression engine if you wanted al that stuff in it.. Although turbo charging such a system might be a litle more complicated with the extra 2 strokes...


As far as the overall 6 stroke idea.. it would be a good idea.. as long as the power was there with the same displacement as a 4 cycle. another thing that people have not thought about would be you would not only lose all the coolant stuff, but also all the supports and brackets for it, along with being able to make the car shorter in front of the engine which would reduce frame weight, body panel weight and such. Not saying having a shorter car was be good (the things these days are to short for my tastes anyhow.) but a compact car could really be compact, or for the older car that would do a swap, you could get rid of alot of extra in the front of the car. and replace with lightweight material

rlchv70

There's always some blowby due to ring end gap, and tolerance between the rings and the piston. It doesn't take long for it to contaminate to oil.

Randy

5thgen69camaro

I was thinking the same thing. And if your rings or Valve seals go bad... Maybe something other than water could be used to boil. It certainly sounds cool.