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” November, 2008.
“New HCCI Engine” November, 2008
“GM Takes New Combustion Technology Out of the Lab and Onto the Road”