The full form of CCVTI is Controlled Combustion Variable Timing Ignition

Controlled Auto Ignition (CAI) or Homogeneous Charge Compression Ignition (HCCI) is one of the most effective combustion technologies to reduce simultaneously the fuel consumption and NOx emissions from gasoline engines. In this work, CAI combustion was achieved in the 2-stroke operation mode on a 2/4-stroke-switchable poppet valved engine, where the conventional crankcase based 2-stroke scavenging is replaced by the boosted scavenging through poppet valves for standard 4-stroke engines. Because of the flexibility of the electro-hydraulic valvetrain system, the engine could be controlled to achieve CAI operation over a wide range of engine speed and load in the 2-stroke mode. Within the CAI operation range, the effects of spark timing and boost pressure were investigated and are discussed in the paper, together with the fuel consumptions and emissions data.