|Does energy saving take us back to the steam engine?|
The steam engine is the precursor of today's engine with internal combustion, yet has never really asserted itself in the construction of vehicles. The steam engine is maybe re-activated after more than 100 years, because we are in search of the "lost" energy of today's engines. The energy is "lost" in the sense that it is not transformed into movement, but blown out as cooling or exhaust gas heat. It might be up to 50%, so it is definitely worthwhile trying to recapture it.
|Condensing technology for vehicles|
The heating engineers have demonstrated how to use energy more efficient using the condensing technology. They kept on adding heat exchangers, until the exhaust gas left the chimney colder than when it was sucked into the heating. They claim more than 100% efficiency. Applied to vehicles you would not even have their humidity problems in the chimney when the vapor becomes liquid by lowering the temperature under the dew point. In a vehicle exhaust system the humidity would not matter.
|Expansion machine drives crankshaft with exhaust gas heat.|
However, it is not possible to use the accumulated heat directly; it must be transformed into movement first. For this a medium is needed which becomes gaseous by the heat. For the high temperature cycle this medium is water which is pumped through the cooling system heat exchanger (8) and both exhaust gas heat exchangers (3, 4). The enlargement in terms of volume while vaporizing is used in an expansion machine (6), driving directly the crankshaft. This machine resembles, in principle, the steam engine. It is also possible to drive several auxiliary systems directly.
|Residual heat may provide additional kinetic energy.|
If you want to recover even more energy, you need a second cycle, e.g., with Ethanol which becomes gaseous at a clearly lower temperature level than water. The residual heat from the cooling circuit (7) and the final silencer (4) is pumped into a second expansion machine (5). On the test bench there was a torque/performance gain of approx. 15%. Of course, the question remains what the total energy balance looks like in the vehicle. It is fairly easy to integrate the above mentioned ideas into available constructions, but on the downside might be the extra weight... 05/07