Homogeneous Charge Compression Ignition (HCCI) EnginesJoseph Simon Clark

What is an HCCI Engine?HCCI is a form of internal combustion in which the fuel and air are compressed to the point of auto ignition.That means no spark is required to ignite the fuel/air mixtureCreates the same amount of power as a traditional engine, but uses less fuel.Traditional combustion (left) uses a spark to ignite the mixture. HCCI (right) uses piston compression for a more complete ignition.

How Does It Work?A given concentration of fuel and air will spontaneously ignite when it reaches its auto-ignition temperature.The concentration/temperature can be controlled several ways:High compression ratioPreheating of induction gasesForced inductionRetaining or reintroducing exhaust gasesClick here for a nice animation of an HCCI engine in action!

AdvantagesCan achieve up to 15% fuel savingsLower peak temperature leads to cleaner combustion/lower emissionsCan use gasoline, diesel, or most alternative fuels

HCCI automobiles could reduce greenhouse gas emissions

DisadvantagesHigher cylinder peak pressures may damage the engineAuto-ignition is difficult to controlHCCI Engines have a smaller power range

Prototype HCCI car from Saturn

The Future of HCCIThe future of HCCI looks promisingMajor companies such as GM, Mercedes-Benz, Honda, and Volkswagen have invested in HCCI research.Preliminary prototype figures show that HCCI cars can achieve in the area of 43 mpg

Works CitedHomogeneous Charge Compression Ignition http://en.wikipedia.org/wiki/Homogeneous_Charge_Compression_Ignition November, 2008.New HCCI Engine http://videos.howstuffworks.com/multivu/3284-new-hcci-engine-video.htm November, 2008GM Takes New Combustion Technology Out of the Lab and Onto the Road http://www.gm.com/experience/fuel_economy/news/2007/adv_engines/new-combustion-technology-082707.jsp