Paper Title
Experimental Study of Engine Performance With Two Stage Injection in Compression Ignition Engine

Abstract
The fast depleting primary energy resources and upcoming stringent emission regulations have compelled the researchers to explore the cleaner and more efficient combustion concepts. The homogeneous charge compression ignition (HCCI) is an alternative combustion technology for compression ignition engines. The HCCI combustion engine offers significant benefits in terms of its engine thermal efficiency and emissions. The combustion concept called compound HCCI, which is a compromise to full HCCI is the latest area of research. In the present investigation, port injection technique has been used for preparing homogeneous charge. In this approach only a portion of the fuel is premixed and a portion of combustion is still controlled by the direct injection. This approach affects the formation of premixed charge during the delay period which in turn affects engine performance. The concept will be termed as Homogeneous Charge Compression Ignition � Port injection (HCCI-PI) In this paper, the effects of the port injection timings on the performance and the emission characteristics of HCCI-PI combustion mode were investigated on a single cylinder engine. The fuel used for port as well as direct injection is diesel fuel. HC and CO emissions for HCCI-PI mode were found to be comparable, whereas in general the NOx and smoke emissions were found to be lower than those of conventional compression ignition direct injection engines (CIDI). The indicated specific fuel consumption and the brake specific fuel consumption for HCCI-PI mode were higher than those of CIDI mode, whereas the indicated thermal efficiency and the brake thermal efficiency for HCCI-PI mode were lower than those of conventional CIDI mode. Keywords- Combustion, Engine Performance, HCCI, HCCI-DI, emission;