Datsun 240z becomes Electric/Diesel Hybrid

[Daox]

Turbochargers are more efficient than superchargers. I'd go that way.

[AmpEater]

Originally Posted by Daox

Turbochargers are more efficient than superchargers. I'd go that way.

Any idea on where I might find a turbocharger appropriate for a .4L engine?

The smallest turbo I can think of would be the 3cyl 1L metro turbo. Since I'm running the engine at 100% perhaps I could get away with a turbo designed to provide boost at 1/2 power on an engine twice the size. I'm probably only looking for 4-6 psi.

[AmpEater]

"Ford has also announced plans to offer turbocharged engines. Ford’s “EcoBoost” technology—a combination of direct injection and turbocharging—yields as much as a 20 percent increase in fuel economy, and is slated to appear on as many as a half-million vehicles during the next five years."

"Turbocharging, The New Hybrid?"

Very interesting.....

[RH77]

Originally Posted by AmpEater

Any idea on where I might find a turbocharger appropriate for a .4L engine?

The smallest turbo I can think of would be the 3cyl 1L metro turbo. Since I'm running the engine at 100% perhaps I could get away with a turbo designed to provide boost at 1/2 power on an engine twice the size. I'm probably only looking for 4-6 psi.

The first thing I though of was the "Kei Cars" from Japan -- essentially ~660cc mini cars.

Some were produced with turbos (running around 6 psi max boost) -- which is where I might start looking...

RH77

[roflwaffle]

Originally Posted by AmpEater

I really only intend to use the generator for perhaps 30min a day, split into 2 sessions. And then occasionally for 2-3hours. And I don't really expect to use it to "charge the batteries" so much as I want the generator to augment their output just as much as is necessary to get me where I'm going at a reasonable dod. I plan to recharge at school, and work, in addition to home and therefore still be running the car on 80% recharged stored electrons and 20% diesel electrons at any given time.

The reason why I've shied away from similar in the past has been that a diesel generator tends to only weigh a hundred pounds or so less than a small diesel engine and transmission and puts out far less peak power with similar or less efficiency. That being said, since ya got it already, am efficiency hit really won't matter much on WVO.

Originally Posted by AmpEater

Converting a gasoline engine to run of propane is not too complex it seems, with the possiblity of even leaving the gasoline equipment functional should it be necessary. Since I expect the generator to be running at constant speed, constant load finding the optimal amount of propane to inject for a good burn should be simple with a wideband O2 sensor (which I happen to have). I will have to explore this option.

I think this would be your best bet IMO from the POV of emissions.

Originally Posted by AmpEater

Any ideas on how the emissions of a propane injected diesel compare? If the presence of lpg in the combustion chamber really creates a faster, more effecient burn with drastically reduced particulate emissions then I suspect a diesel may be comparably "green". I will have to find a way to test this.

I know on straight propane they're pretty good, something like 1g/hp-hr for NOx+NMHC, which is similar to what gasoline passenger cars are at AFAIK. This is w/o any emissions systems that I know of. Since most emissions for a gasoline powered vehicle are during startup when cold, I imagine a LPG/CNG diesel or gasoline engine would be cleaner if tuned properly. As for propane injection, if it's anything like Hydrogen injection it's supposed to result in a larger drop in emissions, although I don't think it would be better than just LPG/CNG.

[diesel_john]

propane is about 91,000 Btu per gallon so its not less expensive esp. if you add road tax.

Does your generator have to run at a certain frequency?

Turbo gets more power from smaller engine but is only more efficient if you can use most of that power.
What is the compression ratio of your engine? And are the pistons oil cooled?

diesel_john

[AmpEater]

Originally Posted by roflwaffle

The reason why I've shied away from similar in the past has been that a diesel generator tends to only weigh a hundred pounds or so less than a small diesel engine and transmission and puts out far less peak power with similar or less efficiency. That being said, since ya got it already, am efficiency hit really won't matter much on WVO. I think this would be your best bet IMO from the POV of emissions.I know on straight propane they're pretty good, something like 1g/hp-hr for NOx+NMHC, which is similar to what gasoline passenger cars are at AFAIK. This is w/o any emissions systems that I know of. Since most emissions for a gasoline powered vehicle are during startup when cold, I imagine a LPG/CNG diesel or gasoline engine would be cleaner if tuned properly. As for propane injection, if it's anything like Hydrogen injection it's supposed to result in a larger drop in emissions, although I don't think it would be better than just LPG/CNG.

All good points. I was amazed to find that the 100+hp VW TDI engine only weighed twice the 10hp diesel. Perhaps that would be the ultimate system, a small lightweight turbocharged diesel coupled to the transmission, with an electric motor assist and idle stop. You cut out the generator ineffeciency and weight, and reduce the peak requirements of the electrical system saving even more weight. Maybe next time.

"propane is about 91,000 Btu per gallon so its not less expensive esp. if you add road tax.

Does your generator have to run at a certain frequency?

Turbo gets more power from smaller engine but is only more efficient if you can use most of that power. What is the compression ratio of your engine? And are the pistons oil cooled?"

I guess in this situation I'm trading price for the ability to get away with little/no emissions system and still have a relatively clean exhaust. Hopefully I will only be using <1gal / 100 miles so I'm still doing much better than the 30mpg of gasoline I burn currently.

Frequency is totally unimportant for me, each pulse is just getting dumped into the buffer of the battery bank before being consumed by the motor. I guess higher frequency may be slightly more efficient, but pretty negligable.

I bought a generator head rated to make use of ~20hp engine, so every hp over the stock 10 I can make will be capable of becomming more watts for propulsion. I tried to find the compression ratio but I don't see it listed anywhere, perhaps the documentation I get with the engine will be more detailed. From looking at similar engines I would guess between 20:1 and 23:1

[diesel_john]

Above 20 to 1 you are at the point of diminsihing returns. About all there is to gain is taking off your muffler and using the turbo as a muffler. Even with a modest boost of 6 or 7 psi. Your cylinder pressures will be up in the considerably reduced reliability range. What happens is without oil cooled pistons increase intake temperatures reduce the strength the pistons and the increase pressure pushes a hole in the center of the piston. Turbo'd engines have a feed back loop to the injector pump to provide more fuel as more air is delivered so the power gain is not free. A cold air intake at a high pressure area for the intake and the cooling air would be worth while. Also exit the exhaust and heated air to a low pressure area. Propane injection has the effect of advancing the timing and also raises peak pressure. There are undeniable safety concerns with propane on board. You can produce this same effect somewhat by advancing the timing, but with more NOx. Biodiesel burns enough cleaner that just 10% reduces noticeable smoke from my 1983 engine. The only problems that i have encountered with vegetable oils is low temperature waxing and it tends to soften rubber seals in the fuel system. Biodiesel and vegetable oils are two different fuels, biodeisel is engineered to use in diesels, vegetable oils could be anything from bees wax to olive oil.

The reason i asked about frequency is the torque peak of most high speed diesels is below the 60 Hz required for house current. The diesel does not lose efficiency as fast as a gas engine does at rpm's below the torque peak. So you could have the advantage of being able to reduce the engine rpm down below the torque peak or even lower if the cooling fan will provide enough air. This is huge. This like having an infinitely variable transmission, this is very good. You can reduce "rack" and still fully load. Anyway, because diesels have a comparatively long stroke, piston speeds at high rpm's tend to reduce the life expectancy.

[AmpEater]

Originally Posted by diesel_john

Above 20 to 1 you are at the point of diminsihing returns. About all there is to gain is taking off your muffler and using the turbo as a muffler. Even with a modest boost of 6 or 7 psi. Your cylinder pressures will be up in the considerably reduced reliability range. What happens is without oil cooled pistons increase intake temperatures reduce the strength the pistons and the increase pressure pushes a hole in the center of the piston.

First of all I'd like to thank you for some very good information diesel_john! Sounds like you've got about 100,000x better understanding of the technical aspects of diesels than me.

Would an intercooler make a significant difference in this regard? It should lower the intake temperatures to close to ambient. The cylinder pressures would still be increased over designed operating conditions however.

Originally Posted by diesel_john

Propane injection has the effect of advancing the timing and also raises peak pressure. There are undeniable safety concerns with propane on board. You can produce this same effect somewhat by advancing the timing.

I'm a little curious as to how one advances the timing on a diesel? My understanding is that timing refers to the point at which the spark ignites the fuel mixture, but seeing that diesels have no spark I would assume that timing is fixed. Do you instead adjust when the fuel is injected instead?

Originally Posted by diesel_john

Biodiesel burns enough cleaner that just 10% almost eliminates any noticeable smoke from my 1983 engine. The only problems that i have encountered with vegetable oils is low temperature waxing and it tends to soften rubber seals in the fuel system.

I had no idea biodiesel actually burned any cleaner, I thought its sole appeal was better lubrication and being "renewable". This is very interesting, perhaps I can eliminate the need for propane if this is the case. Is your experience with fossil diesel/biodiesel blend, or would this apply to a biodiesel/WVO blend as well?

Originally Posted by diesel_john

The reason i asked about frequency is the torque peak of most high speed diesels is below the 60 Hz required for house current. The diesel does not lose efficiency as fast as a gas engine does at rpm's below the torque peak. So you could have the advantage of being able to reduce the engine rpm down to the torque peak or even lower if the cooling fan will provide enough air. This is huge. This like having an infinitely variable transmission, this is very good. You can reduce "rack" and still fully load. Anyway, because diesels have a comparatively long stroke, piston speeds at high rpm's tend to reduce the life expectancy.

Again, very interesting. Because the generator will be belt driven I could set the ratio at whatever engine speed is ideal. If I could get close to full power with a reduced engine speed and significantly increase the life expectancy I would be very happy. I assume the 60hz tidbit applies to direct drive generators? I'm glad you mentioned the cooling fan. My plans did not include one. It seems like an electric radiator fan should provide more than enough airflow, while still allowing me to turn it off at highway speeds and just allow the passing air to do this work.

[AmpEater]

Its been a busy few days. The engine arrived. I'm suprised at how compact it is. Its also looks very simple, I'm eager to modify it. I wont really touch it until the generator also arrives, but my real focus is on the electric drivetrain. I made a template out of plywood to verify my hole spacing and to be used as a guide for the real deal. I also was able to do a rough fit of the motor to transmission just to help my visualize the finished product and avoid any stupid errors.