Sennadar Forums

There is indeed research in using waste heat from the engine to generate electricity - if you can do that efficiently enough, then you can replace the alternator that normally tops up your battery - and eats about 5% of the power of the engine.

And solar cells are unfortunately too expensive - yet. But I am working on it

Cool. Thanks for the link

There is an even more efficient hybrid here. One of the ways it accomplishes the feat is an astounding aerodynamic coefficient, 0.011 if my memory is working correctly. It is a serial hybrid, and the company is in California. Initial sales will be to California residents only, because they don't have a dealer/service network yet. But they are gearing up now for production, and they plan to begin production this year.

I want one. BADLY. But it will be at least two or three years before they get to this part of the country.

There's a good bit of info on the site. Enjoy.

Nicolai

I've been thinking about the thermoelectric power generation used by deep space probes. Many space probes that go beyond earth orbit use a form of nuclear power plant that uses the heat released by a small nuclear pile to create electricity. This is done because the mass of a small pile plus shielding, plus the thermocouples weighs less than a solar array or other power plant rated for the same electrical output. Perhaps we can harness that technology - not the nuclear part - to develop a low-mass thermoelectric plant. One component of gasoline engines that is Very hot is the exhaust system. The catalytic converters in most cars today must reach several hundred degrees simply to function . . . we could strap a bunch of thermocouples to/inside of the exhaust manifold and collect that heat. It should be noted that efficiency of these systems is Very low - 10% at best. However, if we consider the mass added, the potential gains are tremendous. The power plant on the Cassini probe weighs 55.5 kg and generates 300W. This includes the Pu238 core and shielding, etc. http://en.wikipedia.org/wiki/Radioisoto ... _generator

Could be interesting.

miraborn wrote:I've been thinking about the thermoelectric power generation used by deep space probes. Many space probes that go beyond earth orbit use a form of nuclear power plant that uses the heat released by a small nuclear pile to create electricity. This is done because the mass of a small pile plus shielding, plus the thermocouples weighs less than a solar array or other power plant rated for the same electrical output. Perhaps we can harness that technology - not the nuclear part - to develop a low-mass thermoelectric plant. One component of gasoline engines that is Very hot is the exhaust system. The catalytic converters in most cars today must reach several hundred degrees simply to function . . . we could strap a bunch of thermocouples to/inside of the exhaust manifold and collect that heat. It should be noted that efficiency of these systems is Very low - 10% at best. However, if we consider the mass added, the potential gains are tremendous. The power plant on the Cassini probe weighs 55.5 kg and generates 300W. This includes the Pu238 core and shielding, etc. http://en.wikipedia.org/wiki/Radioisoto ... _generator

Could be interesting.

The problem with using that system is that you need to use that nuclear part. How it works is the decay of the nuclear isotope which generates heat. Remember that PU238 is a waste product from a nuclear reactor, which means its highly radioactive. The other problem is that of Half life, Pu238's is 87.7 years and it alpha decays into Urainium 234 which is still radioactive with a half life of 105 years. So that is not a very good item to use in an urban enviroment. What we really need is to find a high temp superconductor. Once that is in place you can use less dangerous fuels, maybe some type of recombinant system, and be able to generate power without much loss.

boballab wrote:The problem with using that system is that you need to use that nuclear part. How it works is the decay of the nuclear isotope which generates heat.

I'm not suggesting use of the nuclear part - rather the thermoelectric part. How much heat does the isotope of plutonium generate? At what temperature is the Pu core in an RTG? I did a quick search and it seems that the temperature is something on the order of 400 degrees C. Automobile engines don't usually get Quite that hot, but it could be something useful to augment the existing power systems.

Space is way different then the surroundings or insides of a car.
If you just one thing as temperatures it is a wast difference.
Then comes dust and vibrations and so on, and air.

And don't sneeze at that 55+ kilos of added weight too.

Don't get me wrong, if something could be made to get something somewhat efficient i am all for it.

One thing that could be mentioned, is having 55 kilos of solar cells may be better in some way, but i think that deep space probably is a bit dark for it to be efficient and that is why they had that system.
Or it being in a shadow for a longer time, (think jovian planet)
But nowadays solar cells are both low weight and way more efficient then they used to be.
Cost is one factor still, but that is getting better too.

furry_wolf2001b wrote:Space is way different then the surroundings or insides of a car.
If you just one thing as temperatures it is a wast difference.
Then comes dust and vibrations and so on, and air.

And don't sneeze at that 55+ kilos of added weight too.

Don't get me wrong, if something could be made to get something somewhat efficient i am all for it.

One thing that could be mentioned, is having 55 kilos of solar cells may be better in some way, but i think that deep space probably is a bit dark for it to be efficient and that is why they had that system.
Or it being in a shadow for a longer time, (think jovian planet)
But nowadays solar cells are both low weight and way more efficient then they used to be.
Cost is one factor still, but that is getting better too.

A major factor of efficient travel in urban areas is actually the weight of the vehicle itself. I've been told that every one hundred pounds of excess weight you can save is something like 1% fuel savings.

Realistically speaking, if you have followed this thread this far, you should know that you can eke out another twenty to thirty miles to the tank by merely shaving a few pounds out of the trunk (ie not having a sand bag in the trunk for summer driving), making sure your tires are properly inflated, and most importantly, giving yourself plenty of time to travel back and forth. Those jack rabbit starts off the green light, and hard braking stops can change your fuel economy by as much as 7% according to some studies.

That being said, I just bought a Toyota Prius and I'll have the car paid for in 12 years, assuming the cost of fuel rises by only 3 cents a year.

Sancria wrote:That being said, I just bought a Toyota Prius and I'll have the car paid for in 12 years, assuming the cost of fuel rises by only 3 cents a year.

umm... is that supposed to be a joke? i realyy hope you aren't serious about the financing or the price of gas.

I think he means that the car will pay for itself in 12 years due to savings on gas.

Sancria wrote:That being said, I just bought a Toyota Prius and I'll have the car paid for in 12 years, assuming the cost of fuel rises by only 3 cents a year.

I wish it were only 3 cents a year in Australia! You may very well need to recalculate for yourself at some point.

DigitalMaestro wrote:

Sancria wrote:That being said, I just bought a Toyota Prius and I'll have the car paid for in 12 years, assuming the cost of fuel rises by only 3 cents a year.

umm... is that supposed to be a joke? i realyy hope you aren't serious about the financing or the price of gas.

Actually I was perhaps a bit too happy with my purchase to explain.

Assuming I drive 25,000 km per year (the average per year in the area I live is something like 33,000km) and the average person spends about $120-300 a month on gas (lots of trucks and SUV's where I live), my car is something like oh 38 bucks a month.

I will save about $82-260 a month, or about on average $171 a month. 12 months in a year and I'm saving $2052 a year.

My brand new car only cost me about 30K or so after the nice government kick back, so i can have it paid off in 14.5 years assuming gas doesn't get more expensive.

Sancria wrote:My brand new car only cost me about 30K or so after the nice government kick back, so i can have it paid off in 14.5 years assuming gas doesn't get more expensive.

The Prius has gotten better stats since the last time i looked at it.

But you're assuming that gas doesn't get more expensive. Here, in Florida, gas has increased about $1/gal/yr. I expect that rate will slow down after a while, but many analysts expect the crest to be ~$7/gal. I would hope that you have figured for the realistic prices of gas in your planning.... not to mention: how many people do you know who keep their cars for 15yrs?

I've got plans to attend the Detroit Auto Show this year. My understanding is that the new prius will be the first plug-in model. If so, I'll leave the auto show having bought my prius there.

Elsh wrote:I've got plans to attend the Detroit Auto Show this year. My understanding is that the new prius will be the first plug-in model. If so, I'll leave the auto show having bought my prius there.

I have two questions about that:

1. what is the life expectancy of the battery?

2. what is the cost of a replacement battery?

Those two things would determine your actual savings.