Uses for a small Kubota diesel?

[Gasoline Fumes]

Originally Posted by Christ

Why such high expectations? What do you have that even comes close to rivaling that now?

I have a moped that does 30 MPH and should get around 100 MPG. And I'm working on a '94 Metro that will hopefully get 60+ MPG.

Your speed limitation isn't really all that realistic, either, I think. How many days do you really HAVE to go 50 MPH? Could you not suffice with 35-40 MPH?

I thought 50 MPH was slow. In the rural area I live in, it would take forever to get anywhere at 35 MPH.

Beyond that, there are many things you can do to increase the power output once you've built the project and gotten it working. Later on, you can streamline it, change gear ratios, increase output and efficiency with a small turbo, etc.

From what I understand, turbos don't work too well with single cylinder engines. I'm sure there's some extra power in the engine if I increase the governed speed and turn up the fuel, but I wouldn't expect a lot more output from it.

Build it, then worry about the details. Very few peopele actually stick to all of their goals when building something one-off. Compromise is necessary until the thing can be considered "tangible".

I still want to build it, but it's not really a priority right now.

[Gasoline Fumes]

If it made more power, I'd be very tempted to try making a pusher trailer with maybe a hydrostatic mower transmission. Make it radio-controlled so it would work in any vehicle.

And no trailer registration in NY if it's a "generator" that doesn't haul anything.

[Piwoslaw]

Today I was thinking about a small 3-5HP pusher.
Say you have FWD car and you could add a small pusher to the rear wheels which you turn on when cruising. It probably wouldn't have enough power to sustain your speed, but add P&G and EOC with the main drivetrain and you've got one loooooong coast, plus a faster pulse.

[Christ]

Originally Posted by Gasoline Fumes

If it made more power, I'd be very tempted to try making a pusher trailer with maybe a hydrostatic mower transmission. Make it radio-controlled so it would work in any vehicle.

And no trailer registration in NY if it's a "generator" that doesn't haul anything.

That would be pretty pimp.

Turbos do work with single cylinder engines, but not very well. Guys put them on lawn mowers all the time, but they really prefer to have several exhaust pulses rather than just expanding gasses. I had assumed it was a 2 cylinder 2 cycle. If you had mentioned otherwise, my apologies.

I live in a rural area of PA not far from you... It takes me about 4 minutes longer to get to my dad's house if I drive 45 versus 55. The difference is that if I drive 45, I get to "see" things better. Sure, it's the same route every weekend (9.9 miles). But I get to pay attention to all the little changes that nature has this way of making you notice and appreciate when you take the time to look and recognize. Maybe you're not interested in that, but I surely am.

Beyond the pusher trailer, I'm not really sure what to use it for, honestly. You could do an EV and use it for a genset, which it's obviously equipped for.

That'll be another issue if you use it for motive duty... you'll have to figure out the governor, because it won't like to rev up and down without smoking. It'll want to stay at a specific pre-determined RPM for best output and efficiency. GenSet should be the key, even on a pusher trailer, as a range extender.

[dcb]

It would keep a small aerodynamic trike moving along at a good clip too, with the motorcycle tires.

Gotta get the gearing right too.

[Gasoline Fumes]

Originally Posted by Christ

I live in a rural area of PA not far from you... It takes me about 4 minutes longer to get to my dad's house if I drive 45 versus 55. The difference is that if I drive 45, I get to "see" things better. Sure, it's the same route every weekend (9.9 miles). But I get to pay attention to all the little changes that nature has this way of making you notice and appreciate when you take the time to look and recognize. Maybe you're not interested in that, but I surely am.

I am definitely interested in nature, but I can ride a bicycle or moped if I want to look around more. Or take a walk in the woods.

It's about 4 miles to town from my house, which is fine at lower speeds. But most other places worth going to are 30-50 miles away. And my parents are about 70 miles away.

4 minutes each way every weekend? You're "wasting" almost 7 hours a year!

That'll be another issue if you use it for motive duty... you'll have to figure out the governor, because it won't like to rev up and down without smoking. It'll want to stay at a specific pre-determined RPM for best output and efficiency. GenSet should be the key, even on a pusher trailer, as a range extender.

I was thinking I could just shift through the gears at a fixed RPM since it's a governor, not a throttle. Just leave it at maybe 1500-2000 RPM and adjust it once up to cruising speed. I'm assuming this would work at the low RPM of this engine.

I have no idea what to do for a clutch. Right now it just has a pulley driving a 12v alternator.

[Gasoline Fumes]

[Christ]

RE: Clutch - Visit a Tractor Supply Co. store, they have centrifugal clutches. If you just want somthing simple to drive, that will do it, and they have them for like $30 that can handle 10 HP, IIRC.

You could use the governor, but engine speed control is much more likely to get you a desirable result. If you have enough gears, of course, or a CVT pulley, that will net you better results than even a throttle control would, as you could run CVT into a normal gearbox, which gives you basically Infinitely Variable ratios. (IVT).

If you don't mind using belts, and you are any good at fabrication, you can make a CVT pulley with V-belts and pulley cogs. If you want to see one, go to any place that sells MTD tractor parts, and ask them for a "transmission pulley" or CVT pulley. They call it both.

It's a double cone that slides in the middle of a wide standard pulley, which changes the open diameter on either side of the double cone. If one side is input, and the other is output, you have variable drive ratios. It's a simple "hydrostatic" transmission setup that MTD and Craftsman used to use, and may still be using.

[dcb]

Drive the wheels with a belt, and lever to control the tension on the belt will get you started too, via idler pully. That is how my 3.5 hp snowblower worked.

[RobertSmalls]

Oh, I love data.

Originally Posted by Gasoline Fumes

That is a super-flat BSFC curve. I guess that should be expected from this sort of diesel, though.

The tragedy here is that the BSFC is consistently underwhelming. 210g/HP*hr is the same as 282g/KWh for the diesels you'll find here, or 277g/KWh for the gassers. Bottom line, at 27.8% efficiency, this Kubota is about as efficient as a garden-variety engine with fuel economy gearing, but much less efficient than any of the special engines out there - TDI, lean burn, Prius.

I like the idea of an underpowered, efficient small diesel for cruising, plus a large gas engine for accelerating, hill climbing, etc. However, this is not the correct engine.