Converting an MPV

[nuke11]

This is my idea on how to convert an MPV to fusion. No cutting of the vehicle or changing the general interior space required.

General ideas of how it is done, more specifics can be done if required.

The fuel tank is removed, but that same space can be used for a water tank instead for the crew.

An example of how an MPV might be converted;

- The diesel or gasoline engine, with the muffler, catalytic converter, tailpipe and gas tank are removed.
- A fusion power pack is added.
- The clutch assembly is removed. The existing manual transmission can be left in place, and pinned in second gear or a longer drive shaft is used.
- A new AC or DC electric motor is bolted to the transmission with an adapter plate or directly to the longer drive shaft with an adapter
- An electric controller is added to control the AC or DC motor. Example a 50kW controller uses 300 volts DC and produces 240 volts AC, three-phase.
- Electric motors are added to power things that used to get their power from the engine: the water pump (used to cool the electric motor if water cooled), power steering pump, air conditioner.
- A vacuum pump is added for the power brakes (which used engine vacuum when the vehicle had an engine).
- A small electric water heater is added to provide heat.
- The automatic transmission shifter is used to select forward and reverse. It contains a small switch, which sends a signal to the controller.

Everything else is stock. When you get in, you put the key in the ignition and turn it to the "on" position to turn the vehicle on or push a button to start or stop. You shift into "Drive" with the shifter, push on the accelerator pedal and go. It performs like a normal gasoline car.

When you push on the gas pedal, a cable from the pedal connects to two potentiometers: The potentiometers hook to the gas pedal and send a signal to the controller. The signal from the potentiometers tells the controller how much power to deliver to the electric motor. There are two potentiometers for safety sake. The controller reads both potentiometers and makes sure that their signals are equal. If they are not, then the controller does not operate. This arrangement guards against a situation where a potentiometer fails in the full-on position.

[cosmicfish]

Overall, it is a pretty straightforward process, I just have a couple of comments:

Originally Posted by nuke11

No cutting of the vehicle or changing the general interior space required.

Can't say that without knowing the form factors of the fusion pack and motor - their geometries are not infinitely variable, you may need to cut or rearrange. But neither of those should be a big deal for TMP.

Originally Posted by nuke11

The existing manual transmission can be left in place, and pinned in second gear or a longer drive shaft is used.

Better to remove the transmission and replace it with a long, simple shaft. Even pinned in place, the transmission is extra weight and a more likely failure point. Both are big criteria for MPV's.

Originally Posted by nuke11

- A small electric water heater is added to provide heat.

Is this just for the cabin? I can't imagine that a fusion pack isn't going to produce waste heat already.

Originally Posted by nuke11

The controller reads both potentiometers and makes sure that their signals are equal. If they are not, then the controller does not operate. This arrangement guards against a situation where a potentiometer fails in the full-on position.

Choose the lower signal, whatever it is - you really don't want to stop the vehicle if you can avoid it, and choosing the lower signal avoids a high fail. A low fail is still a problem but assuming that both types of failure are equally likely, this reduces the overall kill rate by 50%.

[nuke11]

Originally Posted by cosmicfish

Is this just for the cabin? I can't imagine that a fusion pack isn't going to produce waste heat already.

The problem lies in the vagueness of the fusion power pack in the 3rd/4th edition, more so in the 3rd. If we go by the description of the portable power pack in the 3rd edition "A man-portable backpack power source.
The reactor works in the same manner as the larger reactor."

Now I'm not sure if it is a good idea to have a man-portable device that gets hot enough that it needs water cooling or anything other than ambient air cooling. So by assumption the larger reactor would be the same as well. All part of the fuzzy science.

Then there is the fusion charge that is next up, by this assumption alone, they are implying the fusion packs are hot fusion, so by extension, the casing should be very hot on the 2 reactors, but that is not what is implied at all.

So for simplicity sake, just adding am electric water heater just takes out the fuzziness of the science, but yes I did think the fusion power source would be used to heat a glycol/water mix.

[cosmicfish]

But fusion is an exothermic reaction, that is the only power it produces - the only question is what percentage of the heat is captured for electricity and what percentage is waste heat. Regardless, if you want heat it should be trivial to vent some heat.

[mmartin798]

Originally Posted by cosmicfish

But fusion is an exothermic reaction, that is the only power it produces - the only question is what percentage of the heat is captured for electricity and what percentage is waste heat. Regardless, if you want heat it should be trivial to vent some heat.

If you go looking at some of the other fusion threads, there are more problems than just heat and more ways to get power than just heat. If we assume the use of the HE3+HE3 reaction, you get a great deal of power from electron capture and some additional from heat. There are also no neutron from this reaction, making shielding requirements much easier. If you use D+D or a D+T reaction, you get some very energetic neutron that would require substantial shielding. HE3 can be produced from a D+D reactor, so my world holds that there is are hidden Morrow D+D reactors along the coasts that generated a lot of power and HE3. If they still function after 150 years, there was a lot of electricity going no place other than the electrolysis cells.

[cosmicfish]

It's still a significantly exothermic reaction. You don't need a separate heater in a vehicle that is constantly generating waste heat. Are there any fusion reactions, viable for power production, that are NOT exothermic?

[ArmySGT.]

Originally Posted by cosmicfish

Overall, it is a pretty straightforward process, I just have a couple of comments:


Can't say that without knowing the form factors of the fusion pack and motor - their geometries are not infinitely variable, you may need to cut or rearrange. But neither of those should be a big deal for TMP.

Gauging off the engine compartment size of the V-150S. That and anything larger is certainly fair game for conversion.

Originally Posted by cosmicfish

Better to remove the transmission and replace it with a long, simple shaft. Even pinned in place, the transmission is extra weight and a more likely failure point. Both are big criteria for MPV's.

Then you render all your vehicles 4x2. With the transmission you gain the low low gearing for climbing and getting through mud, plus the High for highway. Then this transfers power to the transfer case so the front wheels are powered too. I have personally limped a M1025 humvee back to the motor pool without the rear drive shaft in 4x4 powering the front wheels. U joint failed to the rear differential.

Originally Posted by cosmicfish

Is this just for the cabin? I can't imagine that a fusion pack isn't going to produce waste heat already.

Sure, but I am all for having a heated cabin myself.

Originally Posted by cosmicfish

Choose the lower signal, whatever it is - you really don't want to stop the vehicle if you can avoid it, and choosing the lower signal avoids a high fail. A low fail is still a problem but assuming that both types of failure are equally likely, this reduces the overall kill rate by 50%.

Or just cut it out all together..... two signals or none. Seems like a pretty easy part to access and replace in the field.

[kato13]

The fusion side of this is totally theoretical, but if you could have "Cold Fusion" of He3 without magnetic plasma containment (possibly using some type of exotic metal lattice and a "resonate" frequency) you could get a fusion engine that produced much less waste heat than a gasoline engine for the same power output.

You primarily get energy from proton generation (potentially 95% of the reaction can be harnessed directly from this, but current experiments have only gotten 70%).

For any waste heat I imagine the reaction vessel being wrapped in the new polymers which convert a significant portion of that waste heat into additional electricity.

http://sciencenordic.com/plastic-can...at-electricity

The limit of efficiency and the amount of waste heat produced would all depend on the details of the plastics heat to energy conversion. I would assume at low power generation levels the heat lost would be negligible. At higher levels it would be higher depending on whatever limitations there are in the polymer but even at the highest levels it might not exceed 30% of the total energy. Most gasoline engines lose 80% of the reaction energy as waste heat IIRC.

[cosmicfish]

Originally Posted by ArmySGT.

Gauging off the engine compartment size of the V-150S. That and anything larger is certainly fair game for conversion.

Sure, I am just saying that the fusion reactor and electric motor combo might have a different form factor than the components it is replacing. Just because you can get it in there doesn't mean you won't have to take a torch to the frame here and there to make that happen!

Originally Posted by ArmySGT.

Then you render all your vehicles 4x2. With the transmission you gain the low low gearing for climbing and getting through mud, plus the High for highway. Then this transfers power to the transfer case so the front wheels are powered too.

The transmission and the transfer case are two different components - you need the transfer case for all-wheel drive, you don't need the transmission. Electric motors have their maximum torque at 0 RPM's and maintain that torque with little or no drop pretty close to their peak efficiency speed, at which point torque and horsepower both start to drop. It is a completely different arrangement than gas or diesel motors. If you take the lowest crawler gear on a 500HP diesel, you will still have less torque than you will with a 500HP electric motor and no transmission at all. Really, the only potential advantage of a transmission on an electric motor is at the other end - high speed performance, which is not generally going to be worth the increased mechanical components for MPV's.

Originally Posted by ArmySGT.

Sure, but I am all for having a heated cabin myself.

Me too, I just think manipulating the waste heat is going to be an easier, more reliable, and more efficient way of heating the cabin.

Originally Posted by ArmySGT.

Or just cut it out all together..... two signals or none. Seems like a pretty easy part to access and replace in the field.

That works too.