thoughts on Crower 6-stroke?
 

Article on Crower (of Crower Cams) 6-stroke engine

Anybody have any thoughts on this? Leave it up to an old fart with a machine shop to beat the pants off of millions of dollars in research into new engines. Sounds like a regular engine, minus the cooling equipment, plus a water injector and modified 1/3-speed cams.

suck - squish - bang - blow/squirt - steam - puff?

I wonder how this would work in a rotary?

Could work with a custom rotary with a three lobed epitrochoid. Edit, though it won't be putting any cooling on the hot section, oops.

http://upload.wikimedia.org/wikipedi...rochoidIn3.gif

Though I'm not yet convinced that the crower is more efficient than a really well designed water injection system. I haven't researched it much yet though.

The idea of water injection is just to fog the intake so there is already moisture in the combustion?

Hi,

As I understand it, the idea is to use some of the heat energy, that would otherwise be lost.

yeah, the crower squirts water in after the "blow" stroke (does that sound dirty?) and that generates another power stroke (due to steam). The steam carries away all that cylinder wall heat with it and the process starts over. Sounds phenominal to me. Not to mention, this engine could live in an air-tight engine bay with 0 openings to create drag.

If you can squirt (perhaps direct inject) some water in right after combustion begins then you could also get more work out of the fuel input, and with less engine revolutions, maybe.

I wish I had the time, skill and money to do these things... oh well. Drive slow and wait for the big corporations to release the next generation of cars...

News of this came out back in Feb '06, I was initially excited, but with 'no time on the dyno' and not having seen any updates since (Other than re-prints and re-posts of the same article, I searched again today and nothing) I am not real optimistic, but I hope this goes somewhere.

Guys like Bruce have this... something about them. I've never met him, but I have been fortunate enough to work for, with or just spend some time with several guys like him. Very inspiring to say the least.

In one way it's neat, but in another it seems pretty pointless. Why tinker with raising the efficiency of an IC engine, when a Stirling engine is thermodynamically even better? All you need to do is marry it to the proper hybrid system.

two words... existing technology. Two more... existing infrastructure. how about existing markets...

The point is, it isn't a huge stretch. You could take any motor production line, change the head design (add the water injectors), change the cam and pullies, add a water tank and you now have +40% efficiency. You're not trying to reinvent the car, you're just aking it work better. I see it as being even easier to do than electric hybrid, nevermind stirling, and it stays helpful at high rpms and high speeds, unlike electric.

Good question though. Someone who knows something about those should start a thread on it.

When somebody like Bruce Crower talks, I listen, but I am a bit puzzled he hasn’t put this baby on a dyno yet. Normally when somebody like Crower or his type can get the engine to idle, they want to put it under load and see what she’ll do.

I suspect he’s got injection problems. Ideally, he should have two injectors – one for fuel, the other for water. That’s why he started out with a carbureted gas engine – so he could use the injector for water. But for a man of Bruce Crower’s savvy and means even a one-off special hear and camshaft drive, so he must have a severe problem somewhere. Maybe he is having problems with the injector. Water has very low viscosity and friction in the injector may be giving him fits. Maybe he is having problems getting the water to flash to steam fast enough. Maybe the water/steam is causing lubrication problems.

Presuming he can overcome his mechanical problems, this engine should be an elegant means of improving thermal efficiency and even power in a given size. Always compounding (that’s sorta what this is) has used a separate “engine” (such as a turbocharger or the turbocompounding engines used in the mid 1940s) but crower uses the same piston and crankcase.

If he can recover and use half the rejected jacket heat, he could be looking at a 10-15% improvement in thermal efficiency. That is huge. Maximum thermal efficiency has not moved in over a half-century since the Napier Sabre and R-3360.

Back in the 70s Cummins tried a different approach. They used a ceramic liner to take the heat of an uncooled jacket and recovered the power in a better turbo. My understanding is that they had lubrication problems.

BTW, the big drawback to a Stirling engine is the size and complexity of the machinery required for a given amount of power. To make the power of a chainsaw engine, a Stirling would have to be the size of a big US V-8 SUV engine. The size and cost have up til now always overwhelmed the efficiency. Other than the little toy engine kits you can buy, I doubt there are a half-dozen Stirlings on the planet.

Thanks for your insite, Dave. I think that the water injection would not be problem. It is very common in industry to have water sprayers and foggers that survive all sorts of extreme conditions. Any manufacturing magazine will have ads for such nozles. Your idea of lubrication issues is definately valid. I imagine that the concept of lubricating this engine would have to be a complete re-think because of different operating temperatures and such.

Do you suspect that maybe the complete lack of news aside from the intro article is due to success, and not failure? Getting an engine like this to work flawlessly is not a 6-month endeavor. Getting it to industry is more like a 5-year endeavor.

And what about the ECU side of things? There has never been study on how to efficiently do the water injection timing/duratoin because it has never been done. Bruce can't ride on the backs of a hundred years of engineers on this one. Again, not a 6-month endeavor.

I have some faith in this one... but what's the difference between a clever idea and a good idea? Good ideas sell.

Not so. In fact, if you do some searching, you'll find that Ford & others had them working in cars back in the '70s. The basic problem with the Stirling engine isn't size (that's only when you have a low temperature difference between hot & cold sides), it's that it takes a while to start up, and doesn't easily change speed. Those are obvious drawbacks for a car's sole powerplant.

If instead you have a Volt-like system where the primary drive is electric, and the combustion engine only comes on to add range, then the startup time doesn't matter. The Stirling engine (or gas turbines, fuel cells, etc) become much better alternatives for this sort of system.

Are you just bored? Or was that a comment on his design in some obscure way? :p

the six stroke idea is interesting but i'm leaning towards converting a normal ICE to a Miller cycle.

Have sent out a few emails about getting a custom cam ground for my Z1 engine but haven't had any replies yet.

Imagine taking that same 6 stroke concept and adding electronic valves, eliminating the need to use cams, and oiling valves, etc ... plus it would make it infinately easier to tune.

Bruce patented the 6 stroke engine in 1981.

<http://www.google.com/patents?id=gP02AAAAEBAJ&printsec=abstract&zoom=4&d q=Crower+stroke#PPA3,M1>

IF you are ADD and/or sleepy - DO NOT ATTEMPT to read this patent.

ABSTRACT
An internal combustion engine having at least one cylinder, the at least one cylinder having intake and exhaust ports, the engine comprising: a slidably and rotatably disposed camshaft; a cam and follower arrangement including cam lobes disposed on the camshaft, for controlling the intake and exhaust ports, each of the cam lobes having multiple lift surfaces which are shaped to provide at least two different periods of time during which the intake and exhaust ports are open; and, apparatus for axially displacing the camshaft during operation of the engine, whereby the different periods of time may be selected in accordance with engine or vehicle speed. :eek:

...and this is just the opening paragraph. Counting drawings it is 12 pages L O N G.

In aviation past the J-79 jet engine on the KC-135 used demineralized water injection for 120 seconds/6000 gallons on takeoff to increase thrust. Demineralized to prevent mineral deposits. IMHO the water was converted into noise. :)

My experience is to not send emails to performance shops... most of the so called 'performance shops' that are email savy are actually virtual manufacturers who make nothing, they are just drop ship businesses run by some guy(s) with computers out of a small office. You want someone who will take on a project for custom cam work.

The guy who grinds my race cams (Dema Elgin) doesn't have time for email. I need to take time off work and go see him in person, bring my own blank and tell him what I'm looking for... and we've done so oddball grinds and he does know his stuff.

Webcam (closer to you) also has great technical support (phone), and has ground a custom cam for me.

Why not just do direct injection of water instead? Would be great for high output race engines where heat/detonation is a problem.

For normal use, I'll take variable intake valves (Atkinson cycle).

i googled this a few times and also found some info on wiki, i know some don't trust but there have been others that have used a six stroke design but instead of injecting water for the last two strokes then just injected compressed air i got almost the same effect. any thoughts on that being a lot less complicated then water since there are alot of other systems that are needed to work with the water system.

BDC... ever heard of a steam engine? make something hot and when water hits it, it will turn to steam and evaporate and expand. I think that stuff's been around for a while... even longer than the duece coupe, for that matter. And its has proven reliable...

Nobody is trying to get something for nothing here. Pumping heat out your rad is just getting nothing for something! Take that heat, make it into steam, use that steam to keep pushing the car. Its not magic.

Some people break down the H2 and the O and burn it. But not cost effectively. Ignore all discussions and modifications that involve this.

Water can be useful for piston/valve cooling and in some cases, good for turning some of this heat into pressure. But ecomodders are all running their engines at low outputs anyway - so excess heat isn't such a problem.

excess heat is ALWAYS a problem. Any time your thermostat opens, you are just using hard-earned gas money to heat up your engine bay. Any way that you can use that heat to push your car forward is good!

water is good

add a little meth and its even better

:)

Ok, as the piston moves down on the power stroke and cylinder pressure decreases, direct inject some water to flash into steam and add some more pressure.

I'm not smart enough to tell you if the expanding steam pressure is enough to offset the cooling/contraction of the existing combustion gases.

I had an idea for a two-stroke engine that was two-strokes IC, then two strokes steam. It was inspired by the Crower process, but the idea was to use a half-speed cam like a four-stroke, which would operate two sets of valves, first set for the combustion process, the second set to exhaust steam after the steam expansion cycle.

Another idea is to have the conrod rigidly attached to the cylinder and project through a solid bottom in the cylinder, and the top be IC and the bottom is steam. That may be difficult to lube though - how did they do it with the old steam engines?

Because it can take heat energy and transform it to kinetic energy without anything more than a change of state. Once it leaves your exhaust, it cools and condenses on the nearest pretty little flower to keep the hippie's garden growing.

BDC, you seem like a reasonably intellegent dude and you yourself proclaimed your ultimate status as researcher king of the world in a different thread. Go read up on it and you'll understand why this engine isn't totally bogus. It may not yet have been engineered to perfection, but the idea is quite sound and aluminum-hat-free.

Good point about the 2-stroke. I wonder if a TBI 2-stroke could simply choose when to spray water or gas based on cyl wall temps. Engine is too cold, run as normal. Reach operating temp and do 1 water cyclefor every 9 gas cycles, then, 2/8, then 3/7 till a temperature equalibrium is met... interesting.

I think this idea is even more practical than the original 6 cycle setup. The bottom steam engine cylinder could be engineered as a regular steam engine with the exception that it would generate its own steam when water was injected. The two cylinders would be constructed so that the heat from IC engine could be used by steam cylinder.
A temperature monitor would determine when the water would be utilized, the rest of the time it would just idle.

My first post, nice forum!

Rolf

I'm not holding my breath. No progress after two decades...he's hit a rock.

I think the use of steam to capture energy from waste engine heat is absolutely fascinating.

For the fun of it, Google "steam engines", "stanley steamer", or whatever just to see the torque figures of the old time steam engines.

Makes one wonder why every heavy duty truck and train engine mfr hasn't been researching the heck out of ways to incorporate steam into their systems for the incredible pulling power they could attain.

Maybe a tribrid engine Diesel-Electric-Steam or say a Westport Natural Gas(diesel)-Electric-Steam would be an unbeatable combination for power and efficiency.

I'm always amazed at the number of people who are stuck on torque being such an important engine parameter. It's HP that gets the job done (ie, moves or accelerates a vehicle) and RPM can be traded for torque (with gears).

I agree that a engine that generates a good amount of HP over a wide RPM range (vs a peak at a single RPM) can be important. But give me the HP and RPM specs and torque doesn't matter.

Actually, from an efficiency standpoint, an engine with higher torque and lower rpms can be a good thing (if not done in the usual excesses). This was the mechanical approach used by Matsu Matsuzawa in his 470mpg run. He stroked a one cylinder 125 up to 185cc and probably put a tiny sprocket on the back (plus aeromods, etc)

1985 Matsu talks

Hp can generate high SPEEDS, but if you need to move something, it's torque that does the job. Why do you think trucks use big, slow turning engines? They often make more torque than HP. (See "diesels")

Well, to jonrs point, an M1 tank uses a turbine that produces very little torque for its power rating (like 262 FTLbs), but creates 1500 hp @ 30000 RPM. The torque to move the tank is obtained through reduction. But an M1 is not a model of fuel efficiency either.

Back on the engine waste heat being used for steam generation concept... what if the vehicle's downpipes went through a drum containing water (supplied by a water tank elsewhere). The engine heats up, the exhaust is quite hot and starts heating the drum of water. The drum of water could then to used to power a couple extra pistons that were previously just spinning with open valves. Once it is up to temp, the steam starts driving the piston and the valves operate accordingly...

Now this may be silly... the exhaust could bubble through the water for maximum heat transfer and reduction in airborne contaminants (like smoke through a bong)

First of all, if the exhaust went through the water there would be no way to collect the resulting pressure from the steam. It would go out with the exhaust.

Second, unless you could keep the steam circuit closed (with a condenser) you'd have to carry a significant amount of water to make this work. Water is heavier than gasoline.

Yes, i realized your first point immediately after posting :p

I would expect that the downpipes would travel through a small vessel containing a small amount of water so it isn't heating a huge amount at a time. Another tank of water would have to be in the car, yes. I think we've established that weight has a relatively small effect on FE and if we could get SOME return on the efficiency by capturing heat and changing it into power, it may work out fine. The engine could still run without water, too, just with less power and less efficiency.

Matt, at lunch I ran this thread by my facility's steam/HVAC expert. He came up with several thoughts:

1. Just running a pipe through the water wouldn't transfer enough heat. You would need a heat exchanger because you need to create HIGH PRESSURE steam to drive a piston. Then, if you were able to tranfer enough heat to make steam there might not be enough heat left to fire off the catalytic converter. Add in the restriction in the exhaust you'd be creating and it would be very tricky.

2. You'd have to carefully control the steam flow to balance engine speed. Meaning, if you are using too much steam to drive that part of the engine the IC side will use less fuel, which will make less heat = less steam.

3. High pressure steam is dangerous! A piping leak or vessel rupture can burn or kill. People are certified to run steam boilers and other similar systems for a reason.

4. The crankcase for the steam portion of the engine would need to be isolated from the IC crankcase, otherwise the steam/water that WILL get past the piston rings will condense and ruin the oil.

He was intrigued enough by the idea to agree that a parallel hybrid design using exhaust powered steam to drive a separate steam engine could occassionally add power for hills and acceleration, but the wieght of such a system would be a genuine concern.

It would seem that a more useable approach would be to use the waste heat of an IC engine to power a sterling engine. A sterling engine can be designed to run on a very wide range of temperature differentials.