Problem to be solved
The best way to reduce carbon dioxide emissions is to burn less fossil fuel by using engines with higher efficiency. Even when we enter the era of biofuels and/or alternative fuels, or hydrogen fuels finally, increasing fuel conversion efficiency and reducing fuel consumption is still a significant strategic solution, because the higher the fuel costs, the higher the engine efficiency is expected. Therefore, a new kind of heat engine, with much higher fuel conversion efficiency, is desired that addresses the immediate and specific needs of reducing fossil fuel consumption, reducing greenhouse gas discharge and reducing combustion exhaust emissions.

Potential benefits
TOHRE is predicted to deliver a 40-50% efficiency gain compared to equivalent conventional engines with a cost reduction of about 30%. This efficiency gain would include a corresponding increase in fuel economy (BSFC ?145 g/kWh) and a decrease in CO2 emissions. The engine is predicted to cost about 30% less due to its mechanical simplicity and compactness in a single piston version. In the case of TOHRE both, the produced energy and the recovered energies are collected as power directly by the engine shaft and all the process is developed in an ultra-compact and simple structure.
If hydrogen is used as fuel the TOHRE efficiency exceed the fuel cell efficiency, offering a low cost alternative.

How it works
TOHRE is build as an opposed piston engine having the combustion chamber in the middle. The engine operates as a conventional opposed two-stroke engine, using a single step supercharging system ensured by an auxiliary supercharging cylinder. A second expansion is assured by the explosion of the vapors converted from the working fluid into another auxiliary cylinder. The working fluid can be water, liquid nitrogen or liquid air and is evaporated by the heat contained in a heat exchanger. The heat exchanger uses the heat of the exhaust gases burned in the combustion chamber.

New engine cycle
The second expansion achieved is able to develop an additional work, compared to the conventional engine cycle. Therefore, the engine will have two expansions during one crankshaft rotation or during each two-stroke cycle.
The rapid expansion caused by the ultra-high compression ratio shortens the high temperature time by about 50%, having the advantage of reducing NOx and limiting the heat exchange.
The high turbulence energy initiated by the high supercharging rate allow to mix the charge effectively, in order to obtain small differences between the burned and unburned gasses temperatures, thus enabling rapid and soot-free combustion.

Manufacturability
Even TOHRE can be considered as revolutionary in terms of performance, as construction point of view can be considered evolutionary, because all the components are similar with those used on the conventional engine.

Market potential
There are several main markets where THORE would be particularly beneficial: as an IC engine for all means of transport having the range between 1 kW to 100.000 kW, as range extender for hybrid vehicles and as Combined Heat and Power energy source.

More info on: http://www.slideshare.net/giurcal/total-heat-recovery-engine