Homogeneous Charge Compression Ignition (HCCI) Engines

1. Homogeneous Charge Compression Ignition (HCCI) Engines Joseph Simon Clark

2. 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 mixture • Creates 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.

3. 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 ratio • Preheating of induction gases • Forced induction • Retaining or reintroducing exhaust gases Click here for a nice animation of an HCCI engine in action!

4. Advantages • Can achieve up to 15% fuel savings • Lower peak temperature leads to cleaner combustion/lower emissions • Can use gasoline, diesel, or most alternative fuels HCCI automobiles could reduce greenhouse gas emissions

5. Disadvantages • Higher cylinder peak pressures may damage the engine • Auto-ignition is difficult to control • HCCI Engines have a smaller power range Prototype HCCI car from Saturn

6. The Future of HCCI • The future of HCCI looks promising • Major 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

7. Works Cited • “Homogeneous 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, 2008 • “GM 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