How HCCI Engines Work

HCCI engines have the potential of being highly efficient. HCCI stands for “Homogeneous Charge Compression Ignition”. HCCI uses gasoline in a diesel-like way, allowing compression to auto-ignite the gasoline like a diesel engine would, rather than a spark plug. Along with computer control, HCCI can improve efficiency up to 15%. Here’s an overview:

GM is demonstrating a working version of the technology, and Mercedes is working on its DiesOtto engine of the same design:

A more radical HCCI design uses opposing pistons, as shown here:

Popular Mechanics has an article on the technology here:

In Efficiency Lab, GM Rethinks the Old-School Engine

From the article:

Dismissed as a laboratory curiosity in the 1970s, homogeneous charge-compression ignition (HCCI) has now emerged as a more feasible alternative to alternative fuels—and it’s almost ready to roll out en masse. When used in conjunction with other advanced engine technologies, this combustion process can help deliver a whopping 25- to 30 -percent better fuel economy than today’s spark- or compression-ignited internal combustion engines (ICE). HCCI does all this with near-zero emissions, just like a hybrid—and it won’t have any impact on your driving habits or come at a premium price.

See also: Homogeneous Charge Compression Ignition (HCCI)

For more info see:

- How Car Engines Work

- How Diesel Engines Work