Bruce Crower, founder of Crower Cams and Equipment, is now retired but he’s still working in his well equipped home workshop. While thinking of ways to improve the old internal combustion engine, he came up with a method to harness the wasted heat energy by creating steam inside the combustion chamber, and using it to boost the engine’s power output and also to control its temperature.
It has a few rather amazing attributes:
“It’ll run for an hour and you can literally put your hand on it. It’s warm, yeah, but it’s not scorching hot. Any conventional engine running without a water jacket or fins, you couldn’t do that.â€
Indeed, the test unit has no external cooling system—no water jacket, no water pump, no radiator; nothing. It does retain fins because it came with them, but Crower indicates the engine would be more efficient if he took the trouble to grind them off. He has discarded the original cooling fan.
Bruce Crower has quite a history all of his own and if you visit the Crower site you can read all about him. But this engine, if it works as described, could add a whole new chapter to his accomplishments. Very neat.
via Autoweek
C.J. Luke says
No intention of sounding like a know it all…but water injection has been around for a long time, and, with today’s electronic injection technology, it seems to me that a 4 stroke engine with an additional injector could be optimized way beyond what was accomplished in the old P-51 Mustang. Seriously, timing the injection of the water ‘mist’ to coincide with the completion ( or near completion) of the flame front on the combustion stroke would be optimum for utilizing the maximum heat generated to create the most additional power from the conversion from water to steam. It also seems like this method would not require anything near a 50/50 ratio of water to fuel. The down side of water injection would seem to me to be the cooling effect. Over the last 15 years or so, we have learned how to get good power and reasonable emmissions by going to a ‘High temperature’ engine (we used to have 165, 175, and 185 degree thermostats) that are “lean burn” type engines. It seems like water injection would present new hurdles with emmissions. I can see it now, once a month you add injector cleaner to the fuel tank, and a bottle of Lime Away to the water tank 🙂
kneeslider says
I think this is a bit beyond water injection like the old fighter planes used. I didn’t go into great detail in this post because I simply don’t have the details. The original article says he did get a patent, so if we dig that out and take a look we may find out what Bruce was up to. If Lime Away is mentioned, we’re in trouble 🙂
Ian MacLeod says
It does look like he may have come up with a new and unique method of introducing water into the combustion chamber. If he’s able to put a hand on a 13:1 compression ratio engine, I agree, there’s something going on in there!
C.J. Luke says
From what I read in the article, I got the sense that he has introduced an additional ‘power’ cycle after the normal power stroke of a traditional 4 stroke engine thus the ‘6 cycle’ reference. I agree that his approach is much different than the traditional water injection of old and didn’t mean to imply that it was not. But the principle of using heat generated by the power cycle to convert water to steam is still the basic theme. I was just speculating that the possibility exist today to significantly improve on the original concept. Think super charger or turbo charger….you modify the original engine to lower the ‘static’ compression ratio and ‘boost’ the quantity of air-fuel mixture to effectively raise the dynamic compression back up even higher than before and create more explosive force on the power stroke. Well…instead of external blower think water injection timed to allow the maximum heat to be generated before injecting the water mist…it just seems like we could do a much better job now.
todd says
I think its alternating cycles; first the four cycles to get one hot burning fuel air power stroke. Next, shut off the fuel-air supply and inject water into the cylinder just after TDC of the previous cycle’s exhaust stroke. This water will expand to steam and the returning stroke will drive it out the exhaust. -Hence the 1/3 speed camshaft and “6 strokes”.
-todd
hoyt says
very cool, especially if this prolongs the lifespan of air-cooled engines & continues the manufacture of air-cooled bikes
Dodgy says
I wonder how it goes with the very effective superheated steam cleaning effect? Basically it should scrub the cylinder walls of any oil film and end up seizing, or are the rings really that effective?
The same thing was proposed and described about ten years ago in (the sadly defunct) “Midnight Engineering” magazine.
Jason Peck says
Ok, want to have real fun with this? This motor will have the normal intake stroke, compression stroke, power stroke and exhaust stroke. Then it adds a second power stroke by squirting water on to the hot piston around TDC that will create steam and has a second exhaust stroke to push the steam out.
So if you use 12 strokes to get a fair comparison to a 4 stroke you have the following.
4 stroke (over 12 strokes)
3 intake strokes
3 compression strokes
3 power strokes
3 exhaust strokes
6 stroke (over 12 strokes)
2 intake strokes (only for gasoline or diesel strokes combustion strokes)
2 compression strokes (only compressing for fuel power strokes though he is playing around with compression for the water power stroke as well)
4 power strokes (2 using fuel, 2 using water)
4 exhaust strokes (2 from fuel, 2 from water)
So you end up with less air needed, less wasteful compression strokes, more power strokes with only half using fuel and more exhaust strokes but 2 are clean exhaust.
By using the water it reduces the temperature of the engine enough that it does not need to be water or even air cooled. That means no water pump or radiator needed (nor cooling jackets for the water).
Now for the fun part. The best application for this would be in the form of a turbodiesel if you want to achieve maximum efficiency. But with less intake strokes the turbo’s will not be working as hard to meet the demands of the engine. In addition, the extra exhaust strokes will have more power to drive the turbos in the first place. So why not harness that extra turbo capacity?
Attach the alternator directly to turbo shaft. This way it will act like a turbine generator. So with no need for a water pump, no need for a fan and being able to run the alternator off of the exhaust, you can get rid of the whole belt drive system for accessories entirely and avoid the parasitic losses related to them. Use an electrical power-steering assist unit instead of a belt driven one.
This will be even better in a hybrid setup because the extra electricity generated by the exhaust turbine generator can be pumped directly to the batteries/capacitors already used by the hybrid drive system.
Now if you wanted to get even fancier, instead of using distilled water, use hydrogen-peroxide for the steam stroke. Highly concentrated h2o2 when combusted creates steam (h2o) and oxygen (o2). Not only will it create more power than straight water, but you will be pumping o2 through your exhaust which will help clean up the emissions generated by the fuel stroke considerably. It will be similar to the function of smog pumps which were just air pumps that helped dilute exhaust. Normaly h2o2 requires a catalyst (silver, platinum, etc) to react with to combust but the high temperatures of the cylinder should cause it to combust without the need of a catylist.
If you have a h2o2 spill it will evaperate as it naturally splits itself into oxygen and water but you will turn anyone exposed to it into a bleach blonde.
Jason Peck says
Even better, how about making it a variable 2-stroke engine instead?
And what I came up with was a variable stroke engine. Make the engine a 2-stroke direct injection turbo-diesel. Only, have a second water injector and alternate between diesel and water for the power stroke. So in effect it will be a 4-stroke motor that is really two seperate 2-stroke cycles, one for each ‘fuel’.
This has many advantages. 2-stroke engines are inherently more poweful than 4-stroke engines. The traditional negative is poor emissions due to the need to mix oil into the gas for lubrication. However, the water injected steam power stroke solves many problems.
Treat the engine as if it is a water cooled. Only you would not need a radiator. Simply have a 10 or 15 gallon water tank. Run that water through the engines water jackets for cooling and siphon off the water to be injected into the cylinder during the steam stroke. This way the engine will not only be getting cool water to keep the engine at fairly low temperatures, it will also be pre-heating the water so that it will flash boil quicker when injected into the cylinder and making contact with the hot piston. And the water hitting the piston itself will help cool the engine considerably.
By running at much lower temperatures you should be able to jack up the compression without detonation making the diesel power stroke more efficient. Add a turbo since increased back pressure is good for a 2-stroke engine for even more power. But the biggest advantage is being able to use different engine materials due to the much lower temperatures involved.
With the engine being cool, you can use alternative materials for the cylinder liner, piston and most importantly, the rings. Using materials such as ceramics and coating the various parts with permenant lubricant layers you should be able to eliminate the need to mix in oil with the gas for lubrication. This will reduce emissions considerabally.
And with the new low-sulfer diesel fuel and the self-cleaning properties of the steam stroke and the engine should stay cleaner longer. Add in the power advantages of the two stroke and the fuel savings in only having every other power stroke using diesel fuel and you should have a very efficient, powerful, simple and clean running engine.
Now, why did I call it a variable stroke motor? You can switch back and forth between what fuel each stroke is depending on how much power you need. For acceleration run more fuel power strokes in a row. For cruising and braking, run more steam strokes in a row.
MarkM says
Reader CJ Luke may have problem completely covered with his opening comment above. Water injection is actually a very old concept, versions of which occurred on pre-wwII tractors, and is probably as old as the internal combustion engine. Mr. Crower is really “crowing” indeed to suggest 40% improvement in fuel economy, without having run a test and achieve hard numbers. Certainly, we’d all like to figure out how to make waste heat do work, but retarding the exhaust exit actually does work TO the exhaust, increasing the heat loss out the tailpipe.
Yet Mr Crower does have something we’d all dream to have ourselves- a foundry and machine shop at his service. And, like us, he’s obviously an incorrigible tinkerer. As we all hope for the success of tinkerers, perhaps he’s found something after all- IF:
IF water injection is somehow better at absorbing waste heat in todays modern higher compression, higher reving engines.
IF this effect is increased or supplemented due to the newest, most modern fuel injection technologies
IF somehow the major car companies around the world have overlooked and forgotton water injection during the last 20 years of rapidly advancing engine technologies
And If God is really smiling on Mr. Crower
then, he may really have something. So good luck Mr. Crower
RogerH says
Crower certainly looks like he is the man to get even more out if the ICE. If you read other articles on this topic, he is using the existing diesel injector for the water. Weight is saved as there is no coolant, no radiator, no double walled block/cylinder—etc.
Powered strokes go from 25% of crankshaft rotations to 33%. Exhaust is dramatically cooled as far more powered gasses are available to a turbocharger. And please notice that the cooling allows for dramatically higher compression ratios. It would seem reasonable that, on ethanol/methanol, the engine could run the customary 20 to 25:1 ratios.
Even if this goes nowhere relating to auto manufacture, we can bet that Crower could make 1/3 speed camshafts/drives available and fuel intake devices to bolt onto air-cooled diesels that inject water instead of diesel.
The biggest problem is making this idiot proof. Of course, many folks out there can’t keep track of tire inflation, let alone crankcase oil volume. Keeping enough water around and preventing freezing may be just too much for the majority of the driving population.
This is truly a revolutionary development–imagine the efficiencies that can come to electrical generation where large ICE are used!
Please read all other coverage under Crower 6 cycle at your favorite search.
Boby Sebastian says
Because the 2nd power stroke is comparatively very smaller than the actual power stroke, so the flywheel may not accept that 2nd power stroke or a chance of lose of work at flywheel. Your idea will cool the cylinder that will improve the ideal thermal efficiency. But friction lose in the addition two strokes (water injection & steam exhaust strokes) cannot be negligible. So the overall efficiency may be less than actual 4 stroke engine. But your engine may be a pollution free one. If you can reduce the energy loss (in the form of friction) in the 5th and 6th stroke your engine becomes a good one. And the next important challenge is the material selection. Magnitude of second power stroke depend on the pressure developed dew to the formation of steam in normal engine it won’t be enough for developing a power stoke or not even enough for overcome the friction in the cylinder. Designing of cam (&valve timing) is also complicated. Opening of valve in the addition stroke also reduce the output. In my view the only advantage is cylinder cooling……………
Fred says
Wouldnt there be some rpm limitations using steam? Am I correct in believing that steam wont push the piston as fast as normal fossil fuel combustion? I can see this being very beneficial to industrial engines, where throttle response and high horsepower and rpms arent a priority. For now, my opinion is that performance engineering will center around expanding metallurgy in order to handle more of those things that we know increase efficiency ie compression, spark lead and lean mixture, while burning perpetually decreasing grades of fuel and improving reliability. In the street racing circles (check out “pinks” on speedvision) the popular combination seems to be stout chevys (small and big block) that are realtively mild during normal aspiration yet have access to an army of nitrous injectors. I think in a few years time, most car engines will be up around 12.5:1 utilizing stronger blocks, heads and cranks. Maybe detroit will start sprouting up large cryo facilities? How about micro-polishing? Ive been using the process in my race engines and I must say that there is a tangible benefit//
Ed says
CAT tried this in the 60’s or 70’s. One of my college professors actually worked for the company and recalled one day to a few of us students how they actually modified a 3.5 Hp Briggs and Stratton’s cam to include strokes 5 and 6. The engine did run as modified, however they never got around to adding the water injection part due to CAT cancelling the project. It’s a nice idea, but hardly anything “new”. If nothing else it gets people thinking in other directions than “conventional”.
s.singh says
Water injection is not new but was not persued because the computer was not yet invented. Too much water will give hot water and too little will have no effect. Also, the timing is very critical, combined with intermiittent quantities before TDC, depending on load and speed conditions. Resident time is very important to permit heat transfer. At high engine speeds, heat transfer to increase HP is not effective.
The best way to use the heat that is normally wasted in the exhaust and cooling systems is with the hybrid technology.
This tecnology is full explained in US Patent #6,311,651, dated Nov 6,2001, US Patent # 6,51,749, dated June 3,2003 and US Patent # 7,021,272, dated April 4, 2006 all awarded for COMPUTER CONTROLLED SIX STROKE ENGINE. ( Water Injected)
These patents were already awarded while Mr. Bruce Crower was still thinking of building his engine 18 months ago, so he is definitely not the first
Dave Hoffman says
My hat is off to Mr. Crower and anyone else who is working on this great concept 6-stroke engine. I am not an engineer, but do believe the answer in keeping water from freezing could be by using ethanol. Ethanol is 113 octane and unlike MTBE’s half-life of 500 years, ethanol has a half-life of only 24 hours and is of course readily soluble in water.
John C. Randolph says
I just spoke with Mr. Crower, and his design doesn’t require a computer as Mr. Singh’s does. He’s apparently been able to adjust the water injection with a simple thermostat: more heat, more water.
-jcr
Maeghun says
Is the six stroke engine likely to go into production or is it already in production?
And if it is, then is it really feasible??
From what i gather,at a stretch it operates for about an hour.Inspite of the fact that it drastically cuts down on emissions and improves fuel economy,will it prove to be reliable in the long run?
Abner Perney says
This is really a steam /IC hybrid engine concept and it’s brilliant! It makes more sense in many ways than an electric/IC hybrid because of the simplicity, yet would seem to offer just as much net fuel economy. No motor, no regeneration , no special transmission, No extra batteries, just a water tank, and pump, which would have to be insulated and heated for winter use. According to Crower, the water consumption would be about equal to the fuel consumption. Biggest question is whether distilled water is absolutely necessary, because the energy required for distilling would be an additional enviornmental cost and might negate the advantages.
isaac j. tapia says
This soooo cool I want to do this to my lawn-mower, or mabey even my car. he said–“Crower indicates the engine would be more efficient if he took the trouble to grind them off.”.–well here is a solution! Turbo charge it(NOT SUPERCHGARGE).
1. turbo; because of the extra heat! and there won’t be a need for any inter-cooler to cool the air off since you want it hotter, but with more heat=less dense air, so a little less compression. but a turbo compresses the air, so…someone should experiment with this ideal idea.
2. motorcycles already get excelent gas milage(like 44mpg) there gas bill is low, but if you get an old carberated one you can possibley convert it over, to get even better milage.+ the turbo on it. its my theory and im guessing 70mpg+!
Hobbes says
I think the point we’re missing here is that the inherent advantage of this engine is its ability to use the heat created in an engine in a useful way. I’ve read on another website that the amount of water injected via the diesel injector is controlled by a thermostat – Crower’s words, “the more heat, the more water” – so the real advantage is that we can use methods of getting tremendous amounts of power and efficiency (which previously came at the expense of enourmous amounts of heat), and harness it.
To be blunt, running gargantuan compression ratios, say 15 to 1, and stoichiometric mixtures that run incredibly lean would have previously generated unacceptable amounts of heat. Now that eenergy can be harnessed. So if anything, the hydrocarbon strokes could exist simply to create as much heat as possible, and the water strokes could exist to capture it (this by injecting a great deal of water into the cylinder).
Besides the obvious teething problems of any new technology, the real limit would the the integrity of the block and head, which would have to withstand the pressures of huge compression ratios. Additionally, once we see a maturation of direct injection technology, dual injectors could supply fuel and water. The only problem I see unaddressed here is how to capture and segregate the two different types of exhaust, particularly the capturing of steam for cabin heating purposes and condensation. This is, of course, wholly surmountable. Many applicable solutions exist; technologies from steam locomotives, turbines – very little will have to be conjured from scratch.
In short, the advantage we’re seeing here is that heat has now, in this engine design, become a desirable and beneficial characteristic of engines. Running 13, 14 to 1 compression ratios has always been possible, until the engine warms up and pinging begins, but now we’ve found a sustainable way to capture that power under running conditions. Ultra-lean mixtures and super-high compression ratios open new vistas of internal combustion engines.
garimella srikanth says
sir, i want the cyclic representation of the six stroke engine cycle (pv diagram). just like otto and diesel cycle for s.i and c.i engines. i didn`t find it here.
raj jeya-pandian says
I like the steam part of the six stroke engine,if it could go into a old 1979 A12 Mazda rotary, you could experiment on a larger scale
scott says
what about the rapid expansion and contraction of the hot and cold metals inside the engine? what could fix this problem?
scott says
also what benifits could you get from burning hydrogen ?