Partially premixed combustion (PPC), also known as PPCI (partially-premixed compression ignition) or GDCI (gasoline direct-injection compression-ignition)
is a modern combustion process intended to be used in
internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal c ...
s of automobiles and other motorized vehicles in the future. Its high
specific power, high
fuel efficiency and low exhaust pollution have made it a promising technology. As a compression-ignition engine, the fuel mixture ignites due to the increase in temperature that occurs with compression rather than a spark from a spark plug. A PPC engine injects and premixes a charge during the compression stroke. This premixed charge is too lean to ignite during the compression stroke – the charge will ignite after the last fuel injection ends near
TDC. The fuel efficiency and working principle of a PPC engine resemble those of
Diesel engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-ca ...
, but the PPC engine can be run with a variety of fuels. Also, the partially premixed charge burns clean.
Challenges with using gasoline in a PPC engine arise due to the low
lubricity
Lubricity is the measure of the reduction in friction and/or wear by a lubricant. The study of lubrication and wear mechanisms is called tribology.
Measurement of lubricity
The lubricity of a substance is not a material property, and cannot be me ...
of gasoline and the low
cetane
Hexadecane (also called cetane) is an alkane hydrocarbon with the chemical formula C16H34. Hexadecane consists of a chain of 16 carbon atoms, with three hydrogen atoms bonded to the two end carbon atoms, and two hydrogens bonded to each of the 14 ...
value of gasoline. Use of fuel additives or gasoline-diesel or gasoline-
biodiesel
Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat ( tallow), soybean oil, or some other vegetable oil ...
blends can mitigate the various problems with gasoline.
See also
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Reactivity controlled compression ignition
Reactivity controlled compression ignition (RCCI) is a form of internal combustion developed at the Engine Research Center, University of Wisconsin–Madison, by the research group of Wisconsin Distinguished Professor Rolf Reitz.
During RCCI combu ...
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Diesel engine
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-ca ...
References
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Notes
{{Automobile configuration
Internal combustion piston engines