[dutchcyclist]

This guy is a genius:
http://en.wikipedia.org/wiki/Crower_six_stroke
http://www.autoweek.com/apps/pbcs.dll/a ... WEEKSISSUE

This technology combined with other efficiency techniques like the LoReMo car and biodiesel could make cars sustainable.

[cipi604]

Cars sustainable... that sounds nice. Only that you don't take into account the oil consumed just to build a car in the first place. A lot of oil! The process of building cars , today, is not sustainable.

[dutchcyclist]

Maybe. but at least Crower's invention doesnt violate any laws of physics like a lot of other 'cars that run on water'.

[cipi604]

This is not the first ICE with improved efficiency. It is still an ICE.

[Tanada]

I prefer the H2O2/Diesel combination engine, a four stroke design with two power strokes. IIRC it was developed by the French to permit their Diesel submarines to operate underwater without needing an independent air supply.

Anyhow it works like this, high test peroxide 95% or higher in purity is pressure injected into the cylender at TDC through a catalyst mesh. The catalyst causes the HTP to decompose into H2O steam and O1, which is extremely reactive chemically. This reaction is very exothermic and expansive, it drives the piston down as a power stroke. At the bottom of the stroke a large portion of the steam O1 mix is vented off by a bottom sidewall exhaust valve. The remaining mixture is highly compressed on the up stroke (#2) and at max compression diesel fuel is injected which combusts in the O1 steam mixture very well, providing power for stroke #3. At the bottom of the third stroke the sidewall valve and again opens releasing most of the exhaust gasses before stroke #4 puts the piston back at TDC for a new cycle of HTP injection. The combination of steam and O1 released in the first power stroke charges the catalytic converter so that any particulates released by the diesel power stroke are consumed completely leaving the exhaust particulate and CO free.

Manufacturing high test peroxide requires energy, but in the widespread plan I read about a long time ago it was intended to use baseload electric power at night for this manufacturing process. HTP is deadly is oyu drink it or get caught in a spill, but Diesel isn't exactly a healthy thing to drink or swim in either and HTP breaks down when exposed to sunlight so any spills soon are eliminated by nature.

[Gerben]

I wasn't too enthousiastic at first, but got more interested the more I thought about the idea. Resulting in a rather long post full of ideas.

A problem appears to be that it uses distilled water (although demineralised water would also work). In a vehicle you have to carry this water with you. Also the water has to be refilled somewhere. Either you refill demiwater, or tap water in which case a small demineraliser should be built into the vehicle. For stationary applications however refilling a demineraliser with tap water is easier than refilling the engine with gasoline.
An important isue then is how much water will be used. I was sceptical at first because it seemed that having an open water cooling system in general would use up way too much water. Open cooling systems are rarely used because of their water consumption. All this water has to be carried along and adds weight and volume to the vehicle.
Water consumption in Crower's system however is reduced compared to a normal open cooling system for two reasons:
1. Reduced fuel consumption (~40% lower fuel consumption) means that less fuel is turned into heat.
2. Higher efficiency also means that less heat has to be cooled away: heat is converted to mechanical energy in the second power stroke.
Crowler estimates that water consumption is about equal to gasoline consumption. That would indicate that without further measures a vehicle would have to carry about 20% more volume and 50% more weight (water is heavier than gasoline) compared to normal when using gasoline.

If we look at the system Crower has developed so far, possible applications can be found in stationary applications, ships and possibly vehicles used for short range such as motorcycles where water is available or it would be less of a problem to refill the water tank regularly.
Water consumption however can be further reduced. I see two options:
1. Supplementary engine cooling
2. Recycling water from the exhaust

1. Supplementary engine cooling
Using supplementary cooling seems a bit strange at first glance as it would not make full use of the potential efficiency gains of the six stroke cycle. For some applications however the elimination of the radiator is far more important than the potential efficiency gains. Further weight reductions can be obtained by consuming as little water for cooling as possible. Supplementary engine cooling can achieve that.
Elimination of the radiator is a topic when designing motorcycles. A motorcycle could normally use air cooling and a 4 stroke cycle and occasionally add a water injection stroke to avoid overheating. Thus water cooled motorcycle performance can be achieved using air cooling. Only a small amount of water would have to be carried along as most of the cooling is done using air cooling.
A six stroke system that uses traditional water cooling but without radiator, combined with water injection cooling could also be designed. Traditional water cooling without a radiator will cause the water to heat up and rise in pressure. At a certain temperature the engine can be switched to 6 stroke cycle and water is injected. Heating water to raise the pressure could eliminate the need for a water injection pump. The water tank can only be refilled when the engine is cold or after venting off steam.

2. Recycling water from the exhaust
The first step to recycle water from the exhaust would be to add a condensor. First of all a choice would have to be made about which stream to use. The combustion gas and steam can be kept seperated to avoid soot, NOx and CO2 being carried back into the engine with the water. These contaminations could require using more advanced materials for some of the parts. The advantage of combining the streams before condensation would be that exhaust emissions could be lower (esp. NOx and soot) as these compounds would be adsorbed by the water and returned to the engine.
Cooling the exhaust stream(s) would allow more water to condense. Cooling only the steam would require less heat to be extracted for a specific amount of recycled water as the combustion stream contains a much smaller water fraction.
When using cold water, it seems wise to cool the exhaust stream with this water before injecting it into the engine. Injecting warmer water allows the same amount of engine heat to produce more steam. The cooling effect of this water would be reduced, but it would also reduce the temperature differences in the engine, thus improving its lifetime. Water that is recycled by condensation is ofcourse already warm. Heat from exhaust cooling can also be used for heating the inside of the vehicle during cold weather. More water can be recycled by adding a radiator or by using an external cooling water source (e.g. on ships). Recycling all the water the engine needs is possible, but the cooling requirement would generally make that impractical. A more likely design would reduce water consumption to only a fraction of the gasoline consumption. Periodical refilling of the water tank would still be required.
Would it be benificial to insulate the engine to increase efficiency even further?
40% lower fuel consumption indicates that the combustion strokes produce 60% of the power, while the steam strokes produce 40% of the power. A steam stroke then produces 2/3rd of the power of a combustion stroke. Over 12 strokes, a six stroke engine would then produce slightly more power than a four stroke engine of the same size.

[Tanada]

I have also spent a few hours thinking about the possible applications of the Crower design and I think the two best applications for it will be Diesel Locomotives and Diesel MV type cargo ships. Both easily support adding a tank of distilled water to feed the cycle, both operate at a steady RPM for long periods of time and they are respectively about the most fuel efficient fossil fueled applications already. I agree that using exhaust heat to pre-heat the water before injection is an excellent idea provided that the temperature is in the proper range to provide adequet cooling for the engine.

One of the competing designs under production in India simply removes the fuel injection on one compression stroke so that the cold intake air can absorb heat from the cylinder and extract some work from it through expansion, that system has the same flushing effect of extracting even more of the combusted exhaust gasses from the system. It also acts as a pre-cooler for the cylinder so that more cool intake air can be drawn in on the first down stroke of the cycle. It goes intake, compress, combust/power, exhaust, intake, compress, expand/power, exhaust, repeat....intake, compress, combust/power...

Strangley enough the Indian system also claims a 40% increase in engine efficiency which seems very unlikely too me, that two active cooling systems to use waste heat provide exactly the same benefit with completley different approaches? The Indian system is much simpler, no extra materials are needed to be carried it simply uses intake air with no fuel in it for the cooling stroke. If the Indian system works as well as is claimed then it will win out. The simplicity of the system makes it adaptable for any ICE with direct fuel injection, you simply tell the computer to not inject fuel on one out of two compression strokes. It would probably work best on a power stroke type diesel where normally every up stroke is a compression stroke instead of half of them being exhaust strokes.

[Gerben]

I also like that Velozeta engine. Had not heared of them before. I'm not sure it will be as good as they claim though. I've seen people tinker with simple two-wheeler engines from SE-Asia before. What I've seen was very primitive. I'd love to see how their idea compares to modern engine technology.
They claim to reduce emissions by over 70%. I have a feeling most of their efficiency gains come from combusting unburnt fuel, not from the expansion of air. You can't get much power from heating up air. Modern car engines don't have that much unburnt fuel. That would also explain why they focus on two-wheelers: two-wheelers generally use more primitive engines.
40% lower fuel consumption seems unlikely. The Statesman article states that there is not 'much reduction in specific power'. Which there wouldn't be at all if they could get that much reduction in fuel consumption (and worked at the same RPM).

[yesplease]

Cars sustainable... that sounds nice. Only that you don't take into account the oil consumed just to build a car in the first place. A lot of oil! The process of building cars , today, is not sustainable.

A tenth of the average vehicle's energy consumption is associated w/ building it, and a quarter of that is oil, so maybe a couple percent of it's overall energy consumption is due to oil during the building process.

[Gerben]

I myself work mostly in the CNG business. For NGVs I had the idea to use CNG expansion as a powersource to supplement the normal combustion energy. This was inspired by that compressed air car idea (which seems unfeasible to me). I think my idea would work, but CNG is already cheap: not a lot of NGV owners would be willing to pay for the added cost and also sacrifice the space required for the little expansion engine. CNG is too cheap to care much about efficiency.
Perhaps CNG expansion could combine well with a six-stroke engine: high pressure CNG is expanded (while being heated with engine heat) and will be stored in a small buffer. The uncompressed CNG can then be used in a few normal 4 stroke cycles, untill the buffer is empty and another 6 stroke cycle is done. The main advantage is ofcourse that you already have high pressure to press down the piston and you don't need to add a water tank, the heat absorption is just an added bonus. A six stroke design would require less hardware than when adding an expansion engine, so is perhaps more feasible.

[Tesnic]

Hi all, i guess i am off topic by now, but has anyone heard if Mr. Crower has done anything since 2006???

i have been looking all over the web for more info´s but unfortunately
the path of informations i found ends in 2006....

another silenced invention or what is going on there???

i´d really appretiate if someone knew what happened to this idea and tell us....

greetz from Berlin

[Tanada]

Hi all, i guess i am off topic by now, but has anyone heard if Mr. Crower has done anything since 2006???

i have been looking all over the web for more info´s but unfortunately
the path of informations i found ends in 2006....

another silenced invention or what is going on there???

i´d really appretiate if someone knew what happened to this idea and tell us....

greetz from Berlin

Overall efficiency, says Crower, could also be boosted into the stratosphere:
“Can you imagine how much fuel goes into radiator losses every day in America? A good spark-ignition engine is about 24 percent efficient; ie., about 24 cents of your gasoline dollar ends up in power. The rest goes out in heat loss through the exhaust or radiator, and in driving the water pump and the fan and other friction losses. A good diesel is about 30 percent efficient, a good turbo diesel about 33 percent. But you still have radiators and heavy components, and fan losses are extremely high on a big diesel truck.”

Crower thinks the six-stroke could reach 40 percent, easy.

So that was all in 2006. What happened to the Crower Six-Stroke? Unfortunately, Crower fell ill and was unable to continue research. According to representatives from Crower Cams, the project is currently on hold.

Hopefully Crower or the engineers at Crower Cams can revive the project. It showed a lot of promise and we’re in dire need of cheaper, high-efficiency engines.

More at http://www.ridelust.com/crower-six-stroke/

The interesting thing about this that caught my attention is increasing from 24% to 40% fuel-wheels efficiency is a 60% increase in energy utilization. You would probably add about 300 pounds/130kg to vehicle mass because of the water plus the tank and plumbing. On the other hand you are removing about 40 pound/18 kg of the factory cooling system between the radiator, fan, water pump and water in the cooling jacket around the block. For best efficiency you would want to run the water supply through the cooling jacket before injection so that it absorbs as much heat as possible before it is exhausted. You might also want to run the engine in dry mode until it get up to operating temperature so that all of the injected water is always converted to steam. Running water into a cylinder where it stays liquid seems like a very bad idea to me, you can get rust and erosion problems that way. Simply turning the water on after say 2 minutes of operation and shutting it off 30 seconds before shutting off the fuel flow should prevent any of it from accumulating in the cylinders.

[timmac]

It appears both links are now gone, this was posted in 2008, anyone have any other updated links..

[dolanbaker]

Only Wikipedia.

[Ulenspiegel]

I prefer the H2O2/Diesel combination engine, a four stroke design with two power strokes. IIRC it was developed by the French to permit their Diesel submarines to operate underwater without needing an independent air supply.

...

Manufacturing high test peroxide requires energy, but in the widespread plan I read about a long time ago it was intended to use baseload electric power at night for this manufacturing process. HTP is deadly is oyu drink it or get caught in a spill, but Diesel isn't exactly a healthy thing to drink or swim in either and HTP breaks down when exposed to sunlight so any spills soon are eliminated by nature.

The first engines using H2O2 were so called Walter engines in German submarines (prototypes) before and during WWII. Some of them were used by the allies after the war.

http://en.wikipedia.org/wiki/Hellmuth_Walter
http://de.wikipedia.org/wiki/Walter-Antrieb

The issue in subs is that the storage of H2O2 in the pressure hull consumes space that is lost after the H2O2 is consumed. Batteries usually make more sense.

The basic problem with H2O2 at high concentrations is that it may decompose ("explode"), this process is catalysed by iron ions and some other heavy metal ions, i.e. working with highly concentrated H2O2 is not a job for laymen.

[Subjectivist]

I knew a guy a few years ago that was big into home modified cars. He and his friends would modify and tune up their cars, then take them to the drag racing track an race each other.

His two biggest modifications were installing NOx on one car an water injection on another. By using household strength Hydrogen Peroxide in the water injection system he got the best of both worlds, the 97% water 2.5% Peroxide mixture both cooled his intake air and boosted the oxygen content of the fuel air mix helping create a cleaner burn.

A water injection system works similarly to a fuel injection system with the difference that it injects water, or a mixture of water and alcohol, instead of fuel. Water injection is not to be confused with water spraying on the inlet air chargecooler's surface, water spraying is much less efficient and far less sophisticated.
A turbocharger essentially compresses the air going into the engine in order to force more air than it would be possible using the atmospheric pressure. More air into the engine means, automatically, that more fuel has to be injected in order to maintain the appropriate stoechiometric value of the air/fuel ratio (around 14:1). More air and fuel into the engine leads to more power. However by compressing the inlet air the turbocharger also heats it. Higher air temperatures lead to thinner air and therefore an altered stoechiometric ratio which results to richer mixtures. Over-heated air intake temperatures can cause detonation.
Detonation, an effect also known as engine knock or pinging, occurs when the air/fuel mixture ignites prematurely or burns incorrectly. In normal engine operation the flame front travels from the spark plug across the cylinder in a predefined pattern. Peak chamber pressure occurs at around 12 degrees after TDC and the piston is pushed down the bore.

More about water injection systems for gasoline engines
http://www.rallycars.com/Cars/WaterInjection.html