HCCI: Combining gasoline and diesel combustion
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The New York Times has a nice summary on a form of combustion all major automakers are actively pursuing, called HCCI, short for homogenous charge compression ignition. HCCI was discovered quite some time ago through investigation of so-called "run-on", the continued running of an engine after the ignition was switched off, common with engines of late 1970's vintage. Gasoline engines can be designed for very low emissions, while diesel engines deliver great fuel economy. To make gasoline engines more fuel efficient, and diesel engines cleaner, money needs to be spent on either advanced engine technologies or expensive after-treatment devices. HCCI, which promises low emissions and high efficiency, uses a premixed fuel and air mixture like a gasoline engine, but the mixture is ignited through compression, as in a diesel engine. According to Dr. Uwe Grebe from General Motors, every automaker is working on the HCCI combustion process, since it deals with mileage and emissions challenges inside the engine, which would make it a more cost effective solution. [Source: The New York Times, free subscription required]
Reader Comments (Page 1 of 1)
garrett lumbattis 9:12PM (7/17/2006)
Better late than never.
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Al Schrader 3:46AM (7/18/2006)
They are searching for technologies I already posses and offered it to them for free.
I've been working on practical fuel economy for 29 years.
Alfred Schrader
Industrialist
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Dr. K. Zaidi 1:25AM (8/10/2006)
HCCI has now become a thing of the past because it is nothing but hoax.
It is in fact HMCI (Homogeneously Mixed Compression Ignition), which actually combines Gasoline and Diesel Combustion and does the perfect job. This new technology is essentially useful for all types of Reciprocating/Piston engines. More detail may follow if desired.
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Pao Chi Pien 5:44AM (12/09/2006)
Gas temperature can be increase by compression or chemical kinetics. Because temperature increase by compression can be much easier to control than by chemical kinetics, the compression temperature should be utilized to initial the autoignition of the homogeneous charge. Temperature contribution from chemical kinetics can be greatly reduced by having a two-stroke engine configuration where the time available for chemical kinetics is drastically reduced. Furthermore, HCCI engine power density is greatly increased by double the number of power strokes at same engine rpm. This concept is fully described in Patent No.: US 7,114,485 B2 issued on Oct. 3, 2006.
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Pao Chi Pien 7:56PM (12/08/2006)
Fuel/air mixture temperature can be increase by compression or chemical kinetics. Because temperature increase by compression can be more accurately controlled than by chemical kinetics, the compression temperature should be utilized to initial the autoignition of the homogeneous charge. Temperature contribution from chemical kinetics can be greatly reduced by having a two-stroke engine configuration where the time available for chemical kinetics is drastically reduced. Furthermore, HCCI engine power density is greatly increased by double the number of power strokes at same engine rpm. This concept is fully described in Patent No.: US 7,114,485 B2 issued on Oct. 3, 2006.
A new two-stroke engine to operate on overexpanded two-stroke HCCI cycle may be obtained by contacting me.
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Gerfried 8:30AM (12/09/2006)
Are you sure you want to have the suction losses of the otto engine with future engines? Premixed air-fuel is not the right thing unless its a lean combustion where you may avoid them by having a big air excess at low loads.
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