Genset of the future?

Read this, sounds like its got a lot of potential for genset. Any fuel and weight is about 130lbs......

Toyota developing free piston engine linear generator for hybrid cars | Fox News

swampu said:

Read this, sounds like its got a lot of potential for genset. Any fuel and weight is about 130lbs......

Toyota developing free piston engine linear generator for hybrid cars | Fox News

Click to expand...

Very Cool - TY!

Video mentions 125 lbs / 40 hp. Wonder what fuel consumption rate is used to create said hp. Physics holds certain prerogatives regarding "potential" power (energy) inherent inside any volume of any type of fuel source. Therefore... seems to me that although many reasons this could be a beneficial new alternative to generating battery charging electricity... same age-old limits still exist.

IMHO, what is needed to be developed is a completely new fuel source that holds these increments:

1. 100% recyclable
2. Cleaner Burning
3. Affordable
4. High Potential and Kinetic Energy per Unit Volume

It’s on the horizon... we’re just not quite there – YET!

Happy Battery Charging Daze! - Art

The big thing I see here is that a reciprocating force (piston) dosn't need to be changed into a rotating force. Much is lost in the piston to crankshaft transfer of energy.

But instead of using a "gas spring chamber" perhaps an opposing combustion chamber would work better. Must be advantages to the "gas spring". I see that the return stroke power is created w the piston compressing the gas and then using the gas pressure to power the return stroke presumably generating electrical power. But the frictional losses could be considerable and the seal critical. Sounds a bit to very much like rotary piston engineering.

However it could fail because of the heavy permanent magnet. Too much reciprocating mass? I'm assuming multi-cylinder as the vibration would be terrible as a single cylinder.

Just because it's future talk dos'nt mean it's better.

I have a flashlight that has a magnet in it and by shaking it back and forth it charges a small capacitor/battery that keeps the 3 LED bulbs burning for about 30 minutes. Same idea and not new. A "magnet "does not have to rotate to generate electricity. I have worked with 18 RPM 28MW motors, but I digress from autos. For autos, anything to reduce size and weight is the name of the game.

The market is huge if size and weight can be reduced from current engines - lookout Tesla and their "technology!" The ability to cost effectively - partially only - charge a battery pack like Tesla uses to provide say 350 miles in the desert with AC on is the goal.

Boat market - unless cost, size and performance effective hard to see it going anywhere soon as the all important conversion factor improvement (if any) from gas/diesel to electricity is yet to be demonstrated.

That thing is going to need an opposing cylinder or the vibes will be intense. Interesting concept, there is some promise there. With modern computers, the field coils can manage piston movement and possibly make it work well. Not sure about the two stroke part, lube oil loss around ports and the emissions associated is what killed DD two strokes. Hard nut to crack, there.

Junkers back in the 30's built a free piston air compressor that ran on diesel, same concept there. I have no idea how that thing worked internally, but there's a youtube shot of one running. So work it does!! Crafty Germans.

I don't know.. The rotary motion of a generator makes a lot of sense. When a coil of wire cuts across the magnetic lines of force, a voltage is generated in that coil. Doing this by rotation is smooth, doesn't cause undo wear or breakage so it is reliable, the clearance between the stator and rotor is easy to control (quality bearings and fitment) and the momentum helps keep output up as load is suddenly increased. The normal generator makes a decent flywheel when it isn't under load.
This thing lacks all of these features. It has combustion very near its coil. The gas spring must stop the movement or it is instantly trashed.
The upside- It is small and has fewer parts.
That's about it. In my opinion it will be a while before these replace the world's ubiquitous generators.

Thanks for posting this, I'd never seen one of these.

While I find this idea fascinating, I am still waiting for manufacturers to figure out that a kerosene burning turbine (basically a jet engine) is a natural for spinning a generator head.

Also, still hoping someone develops a practical ZPM in my lifetime.

MC Escher said:

While I find this idea fascinating, I am still waiting for manufacturers to figure out that a kerosene burning turbine (basically a jet engine) is a natural for spinning a generator head.

Also, still hoping someone develops a practical ZPM in my lifetime.

Click to expand...

You can go out and buy a Capstone microturbine today* as small as 30kw. The engineering company I work for looked at being the vendor rep for Canada many years ago when they were just post startup.

*Well, maybe not today, because it's Saturday.

Northern Spy said:

You can go out and buy a Capstone microturbine today* as small as 30kw.

Click to expand...

I was actually thinking in terms of automotive applications.

A similar technology is already popular in trains and ships; diesel electric.
Change the IC half of the power plant into a turbine which in turn charges a battery/capacitor bank.

Cars and trucks are so terribly inefficient because they need to have a lot of power to accelerate, even though they need very little to cruise at a steady speed. The specific needs for locomotive and marine power are different of course, but the concept is similar enough.

Heck, I would build a POC vehicle myself, out of my own pocket, except I have NO idea how to take it from POC to Production.

Ski in NC said:

Junkers back in the 30's built a free piston air compressor that ran on diesel, same concept there. I have no idea how that thing worked internally, but there's a youtube shot of one running. So work it does!! Crafty Germans.

Click to expand...

There was a company in Vancouver, B.C. working on bringing free piston devices to market in the 70s. I kept an eye on them but as a broke student couldn't afford to invest.

They had a working model of the compressor running for demos. Never saw a working demo of the generator. The compressor had the combustion chamber at one end of the cylinder and used the other end for the compressor. The generator was supposed to have combustion chambers in both ends and the coil in the centre.

No idea when they faded away, but at least they didn't fade away with any of my money.

MC Escher said:

I was actually thinking in terms of automotive applications.

A similar technology is already popular in trains and ships; diesel electric.
Change the IC half of the power plant into a turbine which in turn charges a battery/capacitor bank.

Cars and trucks are so terribly inefficient because they need to have a lot of power to accelerate, even though they need very little to cruise at a steady speed. The specific needs for locomotive and marine power are different of course, but the concept is similar enough.

Heck, I would build a POC vehicle myself, out of my own pocket, except I have NO idea how to take it from POC to Production.

Click to expand...

The killer problem with gas turbines is very poor specific fuel consumtion. Especially small ones. Probably get about half the hp out of turbine per gph compared to diesel. Utility size power plants solve this issue by using a second plant operating on the steam cycle, where the gas turbine exhaust feeds right into a boiler. On those, thermal efficiency has reached 60%, which is dang good.

That heat recovery plant could be used in automotive or marine units, but those plants are complex, heavy, and tricky to start/stop. So then cost shoots through the roof.

On an electric car, a simple cycle gas turbine range extender could make sense due to the low cost and weight, but it would be "emergency use only" as the fuel consumption would be like twice that of a conventional engine.

Ski in NC said:

The killer problem with gas turbines is very poor specific fuel consumption. Especially small ones. Probably get about half the hp out of turbine per gallon compared to diesel.

Click to expand...

The thing is, I wasn't speaking about a variable speed turbine sized at like... 0-150hp.

I was thinking about a constant speed turbine that puts out say, 40hp at a constant RPM. The idea being to have enough to power the vehicle at a steady speed and ALSO to have enough power left over to charge a capacitor/battery bank.

Efficiency should go way up if it can be optimized for a single speed and turbines can burn much crappier fuel than a reciprocating engine; meaning less refining and correspondingly lower operational costs.

I'll bet efficiency is mostly dependent on load. Not rpm.

The problem might be that the car can accept the full power output from the gen as it moves the car AND charges the batts .

On boats folks frequently have noisemakers running at 10% of capacity , never an efficient concept.

So far a LI batt set that could absorb 40HP of juice would cost far too much .

Many folks are unhappy with $1K of batts ,in the bilge,, $6K? , probably less popular .

I would like to see marine diesel versions of Honda Inverter series. RPMs matched to load.

manyboats said:

I'll bet efficiency is mostly dependent on load. Not rpm.

Click to expand...

FF said:

The problem might be that the car can accept the full power output from the gen as it moves the car AND charges the batts .

On boats folks frequently have noisemakers running at 10% of capacity , never an efficient concept.

So far a LI batt set that could absorb 40HP of juice would cost far too much .

Many folks are unhappy with $1K of batts, in the bilge. $6K? Probably less popular.

Click to expand...

As anyone who has taken a long trip on cruise control knows, running your engine at a constant speed instead of continually varying the speed, will result in better mileage; it being requiring less energy to maintain a velocity than to change it.

Keep in mind also that "better efficiency" doesn't automatically translate to "lower cost"; an example being the Gas vs Electic argument in home heating.

Also, I didn't think I needed to specify that this hypothetical power plant would be sized based on the load needing to be served.
(That should not be read as being snarky. It is intended as nothing more than a simple statement of surprise on my part.)


The POINT being that a single internal combustion engine of any type that has sufficient power to meet the high demand side of it's application is going to be hugely oversized for the remaining portion of it's duty cycle. If we size the engine much smaller and add a buffer to accept, hold and then distribute energy that a much smaller engine provides then we can take advantage of the time when power demands are low.


Obviously, or at least I hope it's obvious; this sort of system is best for a machine that has a load variation with both a high frequency and amplitude. For a boat or train that acellerates to a sontant speed and then stays there, it's better to go directly from the engine to power production without a buffer; as in spinning the generator directly off of the IC engine.

manyboats said:

The big thing I see here is that a reciprocating force (piston) dosn't need to be changed into a rotating force.

Click to expand...

manyboats said:

...the vibration would be terrible as a single cylinder.

Click to expand...

I'm not so sure that vibration would be that much of a problem. A lot of the vibration in a "normal" reciprocating engine is a result of that conversion to a rotating force. It comes from the connecting rod going both back and forth as well as around and around, and most of it comes from the "around and around" part.

If your "around and around" is not absolutely perfect (and it is never absolutely perfect) then you get vibration from moving farther on one side than on the other. Indeed, vibrators make deliberate use of this characteristic to create their vibration. Multi-cylinder engines dampen the vibration by having equal and opposite vibrations that cancel each other out.

Without the need for any "around and around," this device won't have to try to create a perfect (and perfectly impossible) circle. The back and forth motion is far less susceptible to vibration to begin with.

In reality, I think it will be much easier to control vibration with this type of generator than with a "normal" one.

denverdOn,
I agree if it was in a 4 cyl configuration.

MC Escher wrote "The POINT being that a single internal combustion engine of any type that has sufficient power to meet the high demand side of it's application is going to be hugely oversized for the remaining portion of it's duty cycle."

That's true w other vehicles and most electrical power generators but w a slow boat if power is kept to a minimum one can operate very near the ideal load basically all the time.

MC Escher said:

As anyone who has taken a long trip on cruise control knows, running your engine at a constant speed instead of continually varying the speed, will result in better mileage; it being requiring less energy to maintain a velocity than to change it.

Click to expand...

No, I don't know this concept.

What I do know is constant RPM and constant velocity can result in radically different fuel burns as we go up and down hills, buck headwinds or have tailwinds. Then throw in gear changes to keep up the velocity. Drive a CVT through the Rockies and watch the fuel burn vary as RPMS vary to maintain velocity.

Or picture a constant speed genset that has very different fuel burns as the load varies, and on and on.

Originally Posted by MC Escher
As anyone who has taken a long trip on cruise control knows, running your engine at a constant speed instead of continually varying the speed, will result in better mileage; it being requiring less energy to maintain a velocity than to change it.

sunchaser said:

No, I don't know this concept.

What I do know is constant RPM and constant velocity can result in radically different fuel burns as we go up and down hills, buck headwinds or have tailwinds. Then throw in gear changes to keep up the velocity. Drive a CVT through the Rockies and watch the fuel burn vary as RPMS vary to maintain velocity.

Or picture a constant speed genset that has very different fuel burns as the load varies, and on and on.

Click to expand...

sun - It appears you prove MC's point... unless I miss your point??

In that, I take MC to mean: With all things being equal (e.g. currents, winds, sea conditions... etc) that cruise control constant speed is more efficient than manually varied speed.

denverd0n said:

I'm not so sure that vibration would be that much of a problem.

Click to expand...

I think it would be a definite problem.
That heavy magnet and piston assembly travel back and forth at reciprocating engine speeds, with no countervailing motion to cancel it out. If it were run as a single cylinder, as in the drawing, it would pound like a jackhammer, gas spring or not. The lighter the entire unit, the worse it would react to these forces.
Look at an engine's crankshaft, there are heavy counterweights designed to cancel out the reciprocating forces of the piston, wrist pin and connecting rod on each crank throw at a chosen RPM. Without them, any engine would hammer itself to pieces.
This device is just an engineering prototype, with no attention paid to this problem at all.
It would require a lot of loc-tite and rubber mounts at least.

I didn't mention it before, but how is the desired frequency obtained? It is easy to govern an engine to run at an RPM that makes generating the desired frequency simple. Maintaining a steady freq output under varying loads, without any flywheel effect means a precision fuel injection and air metering computer has to do the job.
I like the gas turbine idea mentioned earlier, if one can be built to sip fuel.
Now that would be smooth.

Pluto,
I consider you right. Not intended to work as presented. It's like a schematic. Shows the principals and basically how it works but a ready to market item would be very different.

With 4 in-line cylinders w the outboard end cylinders 180 degrees from the other two. Two pistons up .. Two down and no side forces. Looks like perfect balance to me. But a long thing as illustrated w two of them end to end in line each 180 degrees out of phase w eachother would also be perfect balance.

Balance should't be difficult unless you want to make a real small engine like a chain saw. A really large engine would require slower speeds just like other reciprocating engines.

Actually an engine turns heat into mechanical energy but this "thing" turns heat into electrical energy. I think it's still an engine turning heat into reciprocating mechanical energy into electrical energy w a reciprocating alternator. What say all?

It still converts chemical to heat to mechanical to electrical energy. It's just that in going through that process, nothing has to spin. Spinning things have little parasitic loss, so I'm not sure avoiding the "spin" is worth the engineering difficulties this thing presents. Still worth chasing, as with elegant computer controls it could actually work.

And balance would be an issue. It really needs an opposing cylinder. But that can be dealt with after the prototype test with the one-banger. Just bolt it down well to the bench!!

I presume these three diesel engines in a Soviet Foxtrot submarine were reasonably quiet:

A gas turbine genset running in the lazarette would provide a great deal of heat via its exhaust run. Blazing away at 700F to 1100F this exhaust pipe could be passed through a central heating heat exchanger to provide all the cabin heat a small boat would ever need. A long coil from the fresh water tank could make hot water on demand without costing any extra fuel.
I looked up gas turbines and found this on wikipedia-

"Microturbine systems have many claimed advantages over reciprocating engine generators, such as higher power-to-weight ratio, low emissions and few, or just one, moving part. Advantages are that microturbines may be designed with foil bearings and air-cooling operating without lubricating oil, coolants or other hazardous materials. Nevertheless reciprocating engines overall are still cheaper when all factors are considered.[original research?] Microturbines also have a further advantage of having the majority of the waste heat contained in the relatively high temperature exhaust making it simpler to capture, whereas the waste heat of reciprocating engines is split between its exhaust and cooling system.[17]
However, reciprocating engine generators are quicker to respond to changes in output power requirement and are usually slightly more efficient, although the efficiency of microturbines is increasing. Microturbines also lose more efficiency at low power levels than reciprocating engines."


They burn more fuel when unloaded than the good old diesel.




https://en.wikipedia.org/wiki/Gas_turbine

Siemens builds the big stuff-
Power generation ? Sustainable Energy in the U.S. ? Siemens USA

>I would like to see marine diesel versions of Honda Inverter series. RPMs matched to load.<


That would be quite easy to home brew, a coach alt 12v 300A or 24v 300A is very robust and easily found rebuilt .

A welding throttle that simply holds a set voltage and a Trace or similar 4000W inverter would make the package.

For an engine the truck reefer takeouts would be superb , huge oil cap for 10 day operation and with dickering Yanmar or Kubota are 3 for $1000. or less.

All you need is the will , and a couple of grand.

>Keep in mind also that "better efficiency" doesn't automatically translate to "lower cost"; an example being the Gas vs Electic argument in home heating.<

While a toaster wire , resistance heat source is 100% efficient , todasys Mini Splits claim 400% to 500% efficiency as heat sources.

No free lunch , they simply steal heat from an area and bring it inside.