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user removed · 05-12-2011, 11:01 PM

The new Mazda skyactive system uses 14 to 1 compression with fuel injected directly into the combustion chamber in stages at very high pressures. Fuel is initially introduced to get ignition, then fuel is added during combustion to eliminate the shock wave of pre ignition.

Ultra high pressure (like 2800+ PSI) actually exceeds combustion pressure. Direct injection allows the fuel to absorb heat directly from the combustion chamber, and the multiple injections prevent pre ignition by not allowing a sufficient quantity of fuel to preignite in the first place.

All of these developments are in the direction of the goal of true HCCI combustion (homogeneous charge compression ignition) where mixture ratios of 25 to 1 can be ignited without knock since the fuel air charge would be completely homogeneous at the point of combustion.

It may actually be done, and when it is with whatever combination actually gets the results, we may see IC engines that get 60% fuel conversion efficiency. Argonne labs is already working on that premise, and when it is done and capacitive storage and application of energy are combined, you will see 2000 pound 5 passenger sedans regularly getting over 100 MPG in normal operation, up to speeds of 70 + MPH as long as the aero is good enough to keep power requirements low at higher speeds.

regards
Mech

05-12-2011, 11:01 PM	#14 (permalink)
user removed Master EcoModder Join Date: Sep 2009 Posts: 5,927 Thanks: 877 Thanked 2,024 Times in 1,304 Posts	The new Mazda skyactive system uses 14 to 1 compression with fuel injected directly into the combustion chamber in stages at very high pressures. Fuel is initially introduced to get ignition, then fuel is added during combustion to eliminate the shock wave of pre ignition. Ultra high pressure (like 2800+ PSI) actually exceeds combustion pressure. Direct injection allows the fuel to absorb heat directly from the combustion chamber, and the multiple injections prevent pre ignition by not allowing a sufficient quantity of fuel to preignite in the first place. All of these developments are in the direction of the goal of true HCCI combustion (homogeneous charge compression ignition) where mixture ratios of 25 to 1 can be ignited without knock since the fuel air charge would be completely homogeneous at the point of combustion. It may actually be done, and when it is with whatever combination actually gets the results, we may see IC engines that get 60% fuel conversion efficiency. Argonne labs is already working on that premise, and when it is done and capacitive storage and application of energy are combined, you will see 2000 pound 5 passenger sedans regularly getting over 100 MPG in normal operation, up to speeds of 70 + MPH as long as the aero is good enough to keep power requirements low at higher speeds. regards Mech Last edited by user removed; 05-12-2011 at 11:16 PM..