New (old) Kubota in the stable

[veggie]

I'm Hooked !

My second Z482 is now in the stable.  
I came across a used Kubota Z482 twin which used to power an APU on a Semi-Truck.
The engine is in great shape. Starts instantly and has no blow-by.
This one appears to have the large 6 liter oil sump for extended duration service.

For those who are not familiar, these are very tiny diesels. Only 12" long from the flywheel to the front fan pulley.
Width is only 10 inches.

Pictures below...

I'm looking forward to building some interesting projects with these little beauties.

First project is an auto-start/stop micro-CHP generator, battery charger, space heater.

veggie

[BruceM]

Nice find, Veggie.  What's the rated hp/rpm ? 

[LowGear]

APU?

OK - Auxiliary Power Unit but what kind of power?  Electricity?  How much?  What values?

Casey

[Henry W]

Here you go guys.

http://www.dieselenginemotor.com/kubota/supermini/Z482

I've written more than a few times where these engines should be run. They run best between 2800 to 3000 rpm's. They are ran at 3600 rpm's on many generators but from my personal experience the engine seems stressed at 3600.  I've experimented running a the Z482 engines at 2600 and below. What I found is 2600 about the absolute minimum rpm the Z482 engine should be ran. Anything less than 2600 the engine will start having vibration issues.

Henry

[veggie]

Thanks hwew,

I was wondering what speed to run this one at.
I will design the belt drive at 2600 rpm.
How would you rate the noise levels for these engines?
I have not run mine yet    Other things getting in the way at the moment.

veggie

[Henry W]

When I tested Z482 there are some things I noticed running the engine at 2600 and 2800 rpm's.

Less fuel knock at 2800. Overall the engine seems quieter. If you have a good muffler and air intake silencer these engines are some of the quietest I been around.

Less vibration (shaking) at 2800, engine ran smoother.

At 2600 rpm's the engine would bog down easier than 2800. Happens because once loaded a bit the rpm's drops a bit. This brings the engines torque curve before peak. Running the engine at 2800 and than loading it the engines rpm's would drop slightly but the engines torque curve is slightly after peak. This means the engine can handle greater loads before bogging down. The general rule to properly set up an engine for continuous use to handle loads is to set up the rpm's on an engine to run a couple hundred rpm's after peak torque curve. This will allow the engine to stay slightly after peak torque. This is where the engine will maintain peak efficiency. Once the the rpm's drop to before peak torque curve it's all down hill from there.

If the engine has no load. The engine will use slightly less fuel at 2600 rpm. The amount is so small that most will not be able to measure the difference. These engines like to be loaded. So why run it at 2600? These engines need to be loaded to prevent sooting up. This is why most APU companies set these engines up to run at 2800-3000 rpm. They found out they will run just as long, or longer at these speeds. And they will run much smoother with less shaking.

My opinion about these engines are. The Z482 engine is one of the best engines suited for our applications.


Henry

[veggie]

Thanks Henry,

based on that explanation I am more inclined to run the unit at 2800.

veggie

[Thob]

Veggie,

SCORE!!!!!!

Casey,

The APU on big-rig trucks is a response to the EPA not wanting them to idle the engine all night while the driver sleeps in the sleeper cab.  The units typically consist of a small diesel engine, AC generator, 12 or 24 volt alternator, air conditioner, and heater.  They can run and provide heat or air conditioning for the sleeper cab, a nominal amount of (typically 120V) AC (usually around 1KW +/-), and charge the truck's batteries (hence the 24 volt systems on some).  Features vary a lot, as I'm sure the prices did.  They are usually mounted to the truck's frame rails on the right side just behind the fuel tank in a small box that encloses everything.  Once you see a truck with one on it, you'll know what to look for.

Sounds like the perfect starting place for a CHP system.

I see them for sale on craigslist from time to time.

[LowGear]

Thanks Thob,

Those stats and the previous dimensions really do get the unbridled imagination into high gear quickly. 

Casey

[dkeav]

Where do you find these wonderful toys!  Working on acquiring a stationary detroit 2-53 that needs rebuilt for a backup (20kw or so) genset.

[Henry W]

It's not as easy as it used to be. A few years ago years ago it was fairly easy finding surplus engines.
Those days are gone. You have to look on line every day.

[Thob]

When I'm not looking for one I see them all the time.  When I want to buy one, nothing is available!

Search craigslist for local deals, have patience, engines will show up!  I'm not sure what to look for outside the USA, but there are similar sites around the world.

[dkeav]

Don't think I can swing it right now with buying another engine already.

I found this one on craigslist not all that far from me, but if someone is in the midwest it might be a decent deal.

http://stlouis.craigslist.org/pts/5086551129.html

[veggie]

dkeav,

That is an excellent price ! ($750)
I have seen fresh rebuilds listed for $2500.
If anyone here is interested in these tiny power plants and lives in that area of that advert, the price is right.

veggie

[veggie]

Here is an update on the Z485 project.
A base was fabricated and a Voltmaster 4kw head was mounted on a motor slide base for belt tension adjustment.
The belt drive ratio is 2:1 so that the generator will spin at 3600 rpm when the engine is running at 1800 rpm.
Next is to pipe a heat exchanger to the cooling system so that waste energy can be exchanged with any system that needs heat.

< click the picture to enlarge>

Veggie