A process for reducing the amount of CO2 released into the atmosphere with the exhaust gas stream produced by the combustion of a hydrocarbon fuel in an internal combustion engine (ICE) used to power a vehicle by capturing at least a portion of the CO2 in a liquid sorbent on board the vehicle, recovering the CO2 from the sorbent and compressing the CO2 for temporary storage on board the vehicle, where the process is operated as a semi-closed system in which the liquid sorbent that captures the CO2 serves as a working fluid and retains the CO2 during the power generation cycle to produce mechanical energy or work, after which the CO2 is desorbed for densification and recovery as an essentially pure gas stream and the working fluid is recycled for use in the process.