The document discusses recent trends in vehicle engines and technologies including air assisted combustion, homogeneous charge compression ignition engines, variable geometry turbochargers, common rail direct injection systems, hybrid electric vehicles, NOx adsorbers, and onboard diagnostics. It describes homogeneous charge compression ignition engines which auto-ignite compressed fuel and air, common rail direct injection systems, and the three types of hybrid electric vehicle systems: series, parallel, and series-parallel.