New propulsion sytems for ships

Cool post, Brian.

It seems that a lot of the discussion here has been about automobiles, which is cool.

Ships need continuous power because they go long distances without stopping. Flywheels and super capacitors would be of little help to them. They will probably still run on petroleum, coal, then some sort of biofuel because they are already quite efficient.

Cars and trucks, however are very wasteful. Their constant starting and stopping wastes a lot of energy.

The biggest problem is having a decent rate of acceleration.

This is where the energy demand comes in.

The trouble is that this energy has to come from somewhere, and here in the US of A, it comes from mainly coal and oil.

An electric car will either have an engine or it will run off the power grid. The same one that here, in the US of A, is already strained to the breaking point. Imagine plugging in five million electric cars to this system.

It's not so much the price of gasoline that's going to be expensive, but the price of energy, period.

The holy grail of powertrain design is energy recapture. That is when you slow or stop at a traffic light. If the energy that is now turned into waste heat can be put back into the powertrain for the next acceleration, things can be improved immensely.

Electrics, I understand, can do this. But at only about 25% efficiency.

I've thought of two possible systems. And neither one uses batteries. The first uses a flywheel that only turns at about 2,000 RPM.

The other uses compressed air.

The compressed air system seems to be the best because flywheels like to be stationary. They don't like to be tilted as when a car goes up or down a hill or goes around a banked curve.

Whoops! Time for me to go to work.
More on this when I get home.

Bob

 

A couple of years ago, I recall some papers from Ford, in which they discussed a braking energy re-capture system for larger vehicles (the initial concept was for an E-series van, IIRC, but I think they were talking about scaling it to the Class 8 trucks eventually). The system used hydraulic pumps and a pressure vessel containing hydraulic fluid and air (or maybe it was pure nitrogen?), using the hydraulics to transfer energy from the vehicle's deceleration into gas pressure in the tank. The process was reversed to get the vehicle moving again when you pressed the pedal. I haven't heard much about it recently though.

The fact that ships need continuous power, while causing problems in the application of "hybrid" technologies, makes them perfect candidates for fuel cell systems. Among the biggest stumbling blocks (apart from cost) for using fuel cells in a car are:
- Fuel cells like a constant, steady load; cars need a rapidly fluctuating power source that responds instantly to changes in load.
- Fuel cells themselves may be compact, but with all the ancillary equipment to make them work can become quite bulky.
- Using hydrogen as a fuel requires enormous tankage volume; using liquid fuels generally requires you to carry a bulky reformer.
A ship is the complete opposite of the car on these points, especially the first one. It is much, much easier to get large tankage and equipment spaces in a boat than in a car. And the ship wants a constant, steady power source, and doesn't need instantaneous response.

I think we're approaching a point here where, with the next generation of power technologies, motor vehicles and motor vessels are going to take divergent paths. If we are to improve on, or replace, the IC engine, the new technologies will, by necessity, be much more application-specific.

 

I don't want hydrogen on my boat thanks! Remember the "Hindenberg"? I will stick with Coconut Oil. See http://www.pelenaexpress.com/ they use Cummins from new! I assume that includes support & warranty. Have not asked on that point.

At 20 to 250 thousand metric tons & above, - too big for me.

 

This is where the ultra capacitors comes in...very hi-rate of discharge of energy

Note that this Mini QED does NOT plug in. It has a small onboard engine to do its charging. Yet it gets 80 mpg

Have a look at their site. With their motor-in-wheel configuration and the 'space' in the capacitors they are absorbing the regeneration energy from braking on the order of about 85% recapture.

 

If they are getting 85% recapture, that is indeed good news. Forgive me if I'm a wee bit skeptical, but I've heard such incredible stories before.

The system that I was about to propose would get in the order of 40 to 50% recapture which I think is good when you consider friction and other waste heat. Not to mention the fact that there does come a time when you really do have to lay on the brakes because your stopping distance has shrunk to the point of demanding that.

My proposed system would work on pure compressed air with no hydraulics.

There would be an engine, an air pump, a sizable air tank, and an air motor.

The engine would pump air into the tank at a constant rate and the tank would act as an energy buffer. The tank would fill to about 10 atmospheres over pressure, at which point the engine would shut off.

The air motor would have two manifolds.

One would its recapture manifold.

The other would be its drive manifold.

The drive manifold would have a series of spring loaded valves with one cylinder each. As the load on the vehicle decreased, these valves would progressively close until only one was left.

This system, I hope, would eliminate the need for a transmission.

When you step on the brakes, the air motor switches from its drive manifold to its pump manifold and then helps to refill the tank.

I've taken this as far as to estimate how big the tank would have to be to accelerate from a dead stop to 30 meters per second within a distance of 400 meters.

The tank would have to be huge. About 250 liters per ton of vehicle.

despite the big bulky tank, this concept has some merit.

For one, you don't need huge expensive batteries which, by the way, will have to somehow be recycled when they wear out.

If the capacitor system works as good as you say it does, it may be the answer. But I live in Michigan and all this salt mixed with all that high voltage kind of scares me.

I don't think cars have much of a bright future anyway. Energy wise, they are about the least efficient way to move people around ever invented. It takes roughly ten pounds of car to move one hundred pounds of people around. Buses, even with today's technology, do much better. And light rail can improve even on that.

I can imagine that by the second quarter of this century, autos will be well on the way to being relegated to rural transportation as well as being toys of a few rich people.

This is not because cars are bad, they are marvels of engineering garnered over half a century ingenuity and hard trying, but because the realities of the cost of energy will have so drastically changed.

 

You might have a look at this extensive forum posting on using compressed air for driving a vehicle:
http://www.yachtforums.com/forums/technical-discussion/5884-air-electric-drive-system.html

I seriously doubt that. Personal mobility (and autos in some form) will be with us till the end of human kind on this planet. Its just a question of what form it will appear in.

 

Thanks, Brian.
Interesting to read: http://en.wikipedia.org/wiki/Air_engine

Cheers.

 

I agree, Brian. The car will be with us, in some form or another, until the "Star Trek" transporter pad replaces it.
The form will change, though. Already we see in most markets that the SUV is going the way of the dodo (the US and parts of Canada being among the exceptions). In its place we are seeing much lighter vehicles packing similar seating and internal volume in smaller, more streamlined packages. And ignoring for the moment Chrysler's newfound love of the 5.7 L V8, engine size and fuel consumption are finally starting to decline (although the fleet averages for new cars and light trucks are still not much better than they were in the '20s, '30s or '40s, there is progress being made).
Then we see the enormous hype and thousands of people trying to pre-buy the Loremo / Loremo GT and the Volkswagen 1L, even though neither is in production yet. (the Loremo's a 4-seater that gets 1.5-3.5 L/100km depending on engine, the VW is a two-seater that gets about 1 L/100km). Audi's A2 has gone from the Pacific Ocean to the Great Lakes on $90-something of diesel, and is still a fairly roomy vehicle. Even some of the SUVs are caving in - the new GM hybrid SUVs will be getting similar gas mileage to their minivan counterparts, and the new Mercedes diesels can loaf a three-tonne truck along on similar fuel consumption to my eight-year-old Hyundai. So we know we can be more efficient, and stretch our fuel reserves out long enough to develop new solutions. But the market pressure to do so won't be there until fuel prices rise more.
Anyway, back to boats....

 

I am looking for a new propulsion system. Must be capable of running on Coconut Oil (I think Cummins will accept that as within their warranty) but therein lies my problem, why are all these recreational sized engines (i need 2 x 100hp engines) Soooooo HEAVY?

Mercedes "smart" 1400cc diesel placed in recreational aircraft, weighs in at 70kg and produces 100hp (75KW) at 3000 rpm or less when appropriately chipped.

If the price was related to weight I would buy 6 and rotate the engines and service in a comfortable workshop environment. ha ha ha?

I do not think that massive weight can be equated with reliability for the "recreational use" market and it is now big enough to demand something appropriate. Modern performance cruising is usually very weight constrained (particularly in the case of catamarans - but applies everywhere) as the heavier the load to push through the water, the more power needed.

Google "Ramphos" (made in Italy) and I am sure that you will find a local sales outlet for this unique amphibious recreational aircraft. one of the engine options is the Mercedes "smart"! They got it why can't the boaties get it?

 

http://www.ultralightflyer.com/airshow-snf05/19.html scroll down to bottom of page

Turbo Diesel aircraft engine.
Ultralight pilots have used a variety of engines to power their aircraft. Go cart engines, chainsaw engines, snowmobile engines, rotary engines, aircraft engines, and this year Ramphos U.S.A. introduced a turbo diesel engine.

The engine is not new to the market with millions having been installed in the Smart Car, manufactured by Mercedes in Europe and Canada for the past 5 years. The complete unit installed weighs in at 9 lbs less than a Rotax 912, and can put out between 40 and 64 DIESEL horsepower. The power is controlled by the electronics that are installed in the engine package.

The max torque on the engine comes in at 3,000 rpm. and the torque is equal to that of a Rotax 912 at 5800 rpm. Cruise comes in at 3100 rpm! The engine is very quiet and using an astounding 3/4 of a U.S. gallon of fuel per hour. It can run on diesel, jet A mixed with diesel, and on bio diesel.

The first engine installation was on a Zenair which has about 200 hours on it in Europe. In February of 2005 it was decided to do an engine installation on the Ramphos trike. The engine was shipped to Ramphos USA in New York and the installation was completed and the craft flown just prior to Sun N Fun.

The fuel system is totally electronic and compensates for altitude, temperature, density altitude, and fuel temperature. Plus it has a back up on the chip incase of failure that converts the engine over to a low, medium or high power setting. The engine will also be coming with a computer start up check list. When the engine is first started the engine will self diagnose itself and tell you whether it is safe to fly.

TBO is expected to in the 5,000 hour range.

The only problem to date has been that the quality of diesel fuel used in the U.S. is of a lower grade than that used in Europe, which will require the engine to be re-chipped when it gets back to New York.

Delivery times are currently 4 to 6 weeks.
For more information contact:
Ramphos USA
Box 578 Hampton Bays
NY 11946
631-872-2332
gil@ramphosusa.com

Turbo Diesel aircrafSmart Car turbo diesel installed in light sport aircraft Ramphos trike.

 

Piston Speed

Interesting material there Marsalai.

In general light-weight, hi-output engines, be it diesel or gas, are generally higher rev engines...shorter stroke, higher piston speeds. There is the one key element to the longevity of engines between rebuilds, 'piston speed'.

Higher piston speeds mean more and faster wear...shorter time between rebuilds. Aircraft are not concerned with this as generally their regulated rebuilds are timed in short intervals by law, so why worry about this extra wear aspect if you will be rebuilding often anyway.

Another fairly lt-weight diesel utilized in marine applications has to be the Steyr unit from Austria...a mono-block construction without separate heads.

 

Thanks for the reply Brian,
I have looked at Styr, not a significant weight advantage nor fuel burn (mercedes is promoted as 6 litres per hour! almost unbelievable! and 3000 rpm from 1400cc is not very fast as Styr is 3300 revs and 2133cc displacement & 250kg as opposed to 70kg (both at plus gearbox etc).

For my needs too wide as my objective is very narrow hulls (600mm to 750mm) I have only recently accepted the additional beam as engine options are very limited at 100hp to Yanma 5 cyl & Nani/kubota 5 cyl versions)

see my images in members gallery. I am only getting together the concept information inspired by the Chamberlin C10 power cat but with significant range afforded by 2000kg fuel.

 

Those are narrow hulls. Have you considered mounting the engines up over the shafts and driving between the two parallel shafts with a belt arrangement, either chain, kevlar or carbon belt??...gets the engine up in a wider portion of the hull for servicing and gets it out of the bilge bottom?

 

Navy, Alternative Ship Propulsion Technologies

I was just cleaning up some items on my computer and ran across this report.

 

I prefer the weight down low if I can. The engines mentioned will squeeze into the 600mm. widening takes length/beam from 20:1 to about 16:1 which is not really skinny & may let the hull get some lift (and attempt to plane) which I do not want.