How it works Our engines have attracted much curiosity and prompted many questions. For various reasons, one of which is industrial secrecy, we haven´t published all technical details on this site. However, over the coming months, just before we begin serial production, we´ve decided to reproduce an unprecedented amount of information and data on the famous "MDI Air Car". After ten years of research and development of pollution-free engines and cars powered by compressed air, MDI is proud to present: Compressed Air Technology systems © : C.A.T's ©(*). An exclusive technology for truly clean vehicles: Engines A range of pollution-free vehicles Innovative industrialization and commercialization concepts Zero-pollution urban transportation concept Power generation sets Co-energy generation Marine engines The basic principles of the CAT´s 34 Engine This engine was developed between the end of 2001 and the beginning of 2002. It uses an innovative system to control the movement of the 2nd generation pistons and one single crankshaft. The pistons work in two stages: one motor stage and one intermediate stage of compression/expansion. The engine has 4 two-stage pistons, i.e. 8 compression and/or expansion chambers. They have two functions: to compress ambient air and refill the storage tanks; and to make successive expansions (reheating air with ambient thermal energy) thereby approaching isothermic expansion. Its steering-wheel is equipped with a 5kW electric moto-alternator. This motor is simultaneously: the motor to compress air the starting motor the alternator for recharging the battery an electric moderator/brake a temporary power supply (e.g. for parking) No clutch is necessary. The engine is idle when the car is stationary and the vehicle is started by the magnetic plate which re-engages the compressed air. Parking manoeuvres are powered by the electric motor. The CAT´s 34 P04 engine is equipped with patented variable-volume butts and a dynamic variable-volume volumetric reducer. The dual energy system The Series 34 CAT´s engines can be equipped with and run on dual energies - fossil fuels and compressed air - and incorporate a reheating mechanism (a continuous combustion system, easily controlled to minimize pollution) between the storage tank and the engine. This mechanism allows the engine to run exclusively on fossil fuel which permits compatible autonomy on the road. While the car is running on fossil fuel, the compressor refills the compressed air tanks. The control system maintains a zero-pollution emission in the city at speeds up to 60 km/h. Articulated con-rod The MDI con-rod system allows the piston to be held at Top Dead Centre for 70º of the cycle. This way, enough time is given to create the pressure in the cylinder. The torque is also better so the force exerted on the crankshaft is less substantial than in a classic system. Gear box Gear changes are automatic, powered by an electronic system developed by MDI. A computer which controls the speed of the car is effectively continuously changing gears . The latest of many previous versions, this gearbox achieves the objective of seamless changes and mimimal energy consumption. Moto-alternator The moto-alternator connects the engine to the gearbox. It has many functions: It supports the CAT´s motor to allow the tanks to be refilled. As an alternator it produces brake power It starts the vehicle and provides extra power when necessary. mileage and general running Much has been said and written about the mileage of our vehicles and there has generally been a lot of unfounded speculation about the use of compressed air. We have never claimed that the thermodynamic graphs of our engines would be adiabatic (nor are they isothermic). Mileage presents no problem - the volume and pressure of air in the car can be increased considerably. (by changing the tank size or the air pressure). The data published at this link, should help to re-establish the truth and give definitive information on these two points. Distribution and valves To ensure smooth running and to opitimize energy efficiency, our engines use a simple electromagnetic distribution system which controls the flow of air into the engine. This system runs on very little energy and alters neither the valve phase nor its rise. Click for more info and here.