Originally Posted by mayonaise
what "standard gas engine components" are you talking about??
Here's the bit from C&D that's causing the confusion:
Originally Posted by Car and Driver
For one thing, the engine will only operate in HCCI mode during cruising conditions at less than full power. Furthermore, in HCCI mode, the engine will be running lean, with comparatively little gasoline injected into each cylinder. It will also be running with lots of exhaust-gas recirculation, which not only further dilutes the mixture but also warms it up sufficiently to make compression ignition possible.
To make this all work, the engine must be able to switch from the HCCI mode to conventional spark-ignition mode from one cylinder firing to the next, using radical alterations in valve timing, fuel metering, and spark-plug operation. And the HCCI combustion must be consistent enough to maintain low emissions performance and flexible enough to be used in the majority of the engine's operation.