My Supercar Design

I've been kicking around various ideas regarding vehicular propulsion for a while now, and they've finally crystallized into some sort of order. I'm going to try to lay them out below.

Fuel Source / Power / Drivetrain / Steering

For my fuel I have selected biodiesel. This fuel takes approximately a 1/4 to 1/3 of the energy it contains to produce.

This vehicle has only one fuel but contains two engines. One engine is a small compression engine in the style of traditional internal combustion engines. I expect an engine in the 100-500 CC range in size. The difference comes in how this engine is cooled. Instead of being cooled into the environment, the heat is used to power a heat engine, such as a small steam engine or turbine. This raises various issues which I believe that I can answer.

One is that water/steam is not used in the heat engine. It uses an organic compound instead which is circulated in a closed system. There are multiple reasons for this. One is that the selected compound can have different physical characteristics than water. A boiling point of approximately 60'C is good because temperatures are almost always less than that (else we would die) yet it takes little heat to cause it to evaporate. The vapour can then be recycled through a familiar looking radiator to be condensed into a liquid, which then is recycled into the heat engine.

Each of these engines is used to turn a driveshaft. These shafts are not connected to the wheels, however, through any sort of mechanical linkage. Any mechanical attempt to integrate the two would likely result in twisted metal and failure - a good reason it has not been used previously. Instead, these two engines turn generators (an electric motor running in reverse) to convert the mechanical energy to electrical energy at a high efficiency (perhaps 98%). This electrical energy has to be stored in a buffer zone.

This buffer zone could be a bank of super-capacitors. This is an area of research that is filled with activity - and success. Even if our current super-capacitor capability is slightly lacking my proposed use, I belief that we shall soon see super-capacitors suitable to this purpose.

Energy is continually drawn from the super-capacitor bank to drive electric motors individually attached to each wheel. It is possible to build a chassis which has room for an electric motor to be attached to each wheel and to rotate with the wheel as it turns. This allows each tire to have independent suspension, turning, and drive.

My proposed method for steering this versatile vehicle is a pair of joysticks, one for each hand. Simpler methods, or ones which utilize the feet, can be implemented, especially for vehicles which limit drive or steering to two of the four wheels. (Obviously it is not required to have drive or steering on all 4 wheels.)


Discarded Ideas

I have decided against both solar panels and electro-voltaic batteries. The above mentioned vehicle should theoretically be more efficient than both the hybrid cars we have now, and also the car developed at MIT which was covered in solar panels. The reason for this mainly stems from production costs. THe production cost for a Li-ION or Li-Polymer battery can be expressed in terms of energy units. The same goes for solar panels. To my current understanding, solar panels will not return any significant gain in energy over the course of their life beyond the energy cost of making them. In regards to batteries, there is a car, called the Tesla, which currently runs on Li-ion batteries. However the batteries have to be replaced after an estimated 100,000 kms. This is because the batteries are limited to a certain number of charge-discharge cycles before they are dead. Furthermore, Li-ion batteries slowly decrease in the amount of total charge they will hold from the time they are manufactured regardless of use or storage. In contrast to a Li-ion battery 1000 charge/discharge cycles, a super-capacitor can be charged and discharged over 10,000 times, vastly exceeding its energy cost to manufacture. As an aside, Li batteries are explosive and have various problems that are more easily circumvented in capacitors. Both capacitors and electric motors have very long lives that outlast their costs of manufacture.

Fuels

Biodiesel, as mentioned, is a fuel which has a 3:1 ration for energy stored:energy production cost. Biodiesel is different from regular diesel in that it contains little to no sulphur, but contains more nitrogen from the plants. A detailed analysis of this is beyond my scope, but I will briefly remark that Sulphur produces sulphuric acid in the atmosphere and contributes to acid rain. Likewise NOxs are produced from plant sources and contribute to acid rain in the form of nitric acid - small difference. These are long chain organic oils that have a relatively high expansion ratio under combustion.

Ethanol only has a 1.5:1 ratio in regards to energy carried:energy spent. This is obviously not as good as biodiesel. However ethanol has other benefits such as the fact that its combustion products do not contribute to acid rain at all.

C2H5OH + 3O2 -> 2CO2 + 3H2O

You can see the molar ratio here is 5:4 or 1.25.

Methanol is very similar and comes from similar sources:

CH3OH + (3/2)O2 -> CO2 + 2H2O

The molar ratio here is 3:2.5 or 1.2.

Pure Octane is not available as a fuel source but is expressed here for comparison only:

C8H18 + (13.5)O2 -> 8CO2 + 9H2O

The expansion ratio is 17:14.5 or 1.1724

Hydrogen is a highly researched alternative energy carrier because it has no Carbon in it and therefore does not produce carbon dioxide:

2H2 + O2 -> 2H2O

You will notice that the molar ratio is 2:3 here or 0.667... Hydrogen does not explode when combusted but actually implodes. This is not commonly understood. The mechanical expansion during combustion is totally independent of energy release or absorption. The combustion of Hydrogen produces heat and also implodes. The other fuels/energy carriers listed above all produce heat and explode. Hydrogen is an energy carrier totally unsuited to an internal combustion engine.