In this paper presents the external homogeneous charge preparation (EHCP) is an important and best charge preparation technique for reducing oxides of nitrogen and soot emissions. In this method, the injector is to be found at the intake manifold, Hence the fuel travels along with the air owing the suction stroke. Experiments were carried out in a computerized 4-stroke single-cylinder diesel engine that was converted into HCCI mode. In this experiment, we use diesel, bio-diesel plastic oil as fuel mixing blends (WPPO 20% by volume) of biodiesel. The experimental result found that the cylinder peak pressure and heat release rate obtained were 38.18 % and 24.46 % for plastic oil 20. External homogeneous charge preparation plastic oil 20% blend has 37 % higher brake thermal efficiency than early pilot direct injection D100 at full load. On other hand drastically reduction of NOx and smoke opacity by 32.77%, 30.74%.