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Engineers at automakers, including GM and Toyota, are experimenting with a plugless ignition called Homogeneous Charge Compression Ignition (HCCI), which works like a more refined version of diesel's combustion-via-compression model. HCCI, which the engineers say will work in both diesel and gasoline engines, uses a microchip to calculate the heat required for optimum power and adjust exhaust-valve timing to minutely compensate for changes in fuel composition, as well as engine and external temperatures. While HCCI is still a way off, it's predicted that when ready for prime time, the system could add 20% to fuel economy while tossing fewer unburned hydrocarbons out the tailpipe.

Powering a new generation of cars [ZDNet]

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More on the Gas Crunch: Octane Matters [Internal]