Mono Energy Engines (Compressed air only)
Ambient air is compressed in the vehicle’s tank (see HP tanks refilling). The air coming from the high pressure tank crosses a pressure reducer (patented by MDI which allows a quasi isothermal transformation). It is then used in a system of expansion with work, consisting of an active chamber and an expansion cylinder. This new thermodynamic cycle consist of:
- The feeding of the charge cylinder (or the active chamber) at constant pressure. This phase is performed at constant pressure and temperature; it produces significant work on the crankshaft. It makes it possible to double the efficiency of a conventional expansion.
- Expansion of the volume of air created by the active chamber in the expansion cylinder.
The mono energy compressed-air engines are totally eco-friendly.
Dual- energy engines (Compressed air + energetic adjuvant)
The engine has the same base as the engine described above. An external combustion chamber (at constant pressure and variable volume), is added. An energetic adjuvant is thus use to heat the compressed air before introducing it into the system of expansion with work. The combustion is continuous and not related to the engine’s cycle; this allows a better control of emissions. The dual-energy engines are totally ‘multi-fuel’, have unprecedented consumption figures and are ‘iso-efficient’ in charge and rev.
Four operating modes:
- Mode 1, mono energy compressed air: below 50km/h, only the compressed air in the tank is used.
- Mode 2, simple dual energy: range extension by using the compressed air in the tank which is heated using an energetic adjuvant for the external combustion chamber before it is introduced in the engine.
- Mode 3, autonomous dual energy: beyond 50 km/h the stored compressed air in the tanks is not used anymore. •A combined air compressor produces compressed air at working pressure which is then heated in the external combustion chamber before being transferred in the active chamber and expanded in the work cylinder.
This operating mode is also used below 50 km/h when the tank is empty.
- Mode 4, Dual energy with recompression of the tanks: an energy sharing occur using part of the produced compressed air (by the combined compressor) to run the vehicle (as in mode 3) and rest is directed towards a booster to refill the tanks.
The use of dual-energy engines allows a similar or better range than in conventional vehicles while:
- running in a totally eco-friendly mode downtown, by using compressed air stored in tanks at high pressure.
- an additional mode of refilling of the tanks.
- an unprecedented consumption: less than 2 liters per hundred kilometers (90 km/h for MiniFlowAIR)
- Very limited emissions on the roads/motorways (Zero Nox, 3 to 4000 times less unburned HC than in a conventional engine, 3 times less CO 2 emission compared to a thermal engine with similar power).