Seems to me that by operating a Cangfa at 1/3rd to 1/2 rated speed and lightly loading it would greatly extend the service life of such an engine....
I'd be very careful about basing this project on that assumption. I'm no Diesel engineer, but I'm pretty sure that an engine designed for 2200 rpm is going to suffer some degradation when operated at half speed or less. As has already been mentioned, the balance isn't right, I'm sure injection timing would need to be tweeked, and who knows what else...
The flicker problem could be worked, with a decent electronic regulator, but I wouldn't classify that as an easy design problem, either...
As an lifelong advanced tinkerer and DIY'er now graduated to my 50's I have no quams of taking just about anything made and re-evaluating it's potential to be modified or applied in ways not necessarily intended or conceived by the designer. In many cases the over asked question "Will this work?", can only be answered difinitely by actually setting up hardware and applying the power. Sometimes it is even wise to apply the power via a long extension cord. Intuitively knowing the proper length of that cable is where experience really comes into play.
I respect the valid concerns and comments I've received by those who have some good background here, but who haven't actually taken my idea through a full R&D trial. Such a trial might involve a large flywheel directly driven from the crankshaft by a flex coupler (to break potential crankshaft resonance issues) instead of putting a flywheel on the other end of the drive belt as I had suggested on the alternator itself. I could see this perhaps helping smooth the low speed vibration concerns mentioned. Compliance of the coupler would have to be addressed to fine tune the system I'm sure. Dink with injector timing? By all means! Modify the governor to work better at low speed? I expected to have to do this but didn't mention it.
I have a big DC generator, 400 amps continuous at 50 VDC when spun at 1800 RPM. That's 20 kW. It is huge and weighs maybe 850 lbs. The commutator brush gear is impressive. I want to get a diesel engine coupled to it for use as a welder and possibly battery charger once I'm less grid dependant. A 1.6 L VW diesel or the 1.7 L. Nissan diesel I have still in a car would be perfect but I don't have the inclination or time to put such a project together with all the other projects that I need to finish. I spent many months winter before lastr fabricating a 10 kW, 3 phase genset using a 1.5 litre VW Rabbit diesel and that was a LOT of work. George profiled my effort on his Utterpower website. I want a simple solution and purchasing a 1115 Changfa which already has a fuel tank and cooling system and can be plunked down on a simple frame seemed like a possible fairly painless route to welding capability (I don't need more than 10 kW welding current). If I purchase one as proposed I can also experiment with it and see how it likes reduced RPM operation when time permits.
So who will be the first to explore this reasonably in depth?
Jim Mc,
The flicker problem with the VW only happens on incandescent lamps and is not noticeable on newfangled compact fluorescents, BUT is a symptom of the engine not running properly. Right now my VW genset is running flicker free. I used it for several hours last week during a all night long storm outage to keep my house and air conditioner alive. Remember the VW is a hiugh speed engine. It is designed to rev. Torque peaks at 2500 RPM but HP grows to 4000 or so. Using it at 1800 directly driven it consumes less fuel, wears out slower, is quieter, etc. It gets fully respectable fuel consumption numbers near 30% of fuel to electrical output at my 1650 foot ASL elevation. The flywheel is totally inadequate as I mentioned because the engine is not designed to be driven at that low RPM in the car. I think the fact that I can get smooth power at all, especially with a 3-phase alternator, speaks very higly of the VW engine. I have to say I am inpressed. I routinely place a wooden block in the governor linkage and run the plant at 1200 RPM into electrical space heaters and incandescent lamps to heat my shop with co gen coolant and some exhaust heat going into the building. The engine runs really smoothly and quiet at 1200 RPM (40 Hz) but doesn't make a lot of heat. This is my fuel miser mode for that genset which makes heat and light in the shop but not powering any 60 Hz voltage critical loads.