A fully hydraulic variable valve system（FHVVS） driven by cam for a compression ignition engine was proposed. By establishing the simulation calculation model with AMESim

the influence of the start and end time of the oil drain

the flow area

etc. on the intake valve movement was researched

and the oil drain throttling scheme of the FHVVS plunger oil control device was optimized. On this basis

a type of FHVVS for a 6 cylinder diesel engine was developed

and corresponding test study and simulation calculations were carried out. The research results show that the hydraulic fluctuation amplitude in high-pressure system of FHVVS increases significantly with the increase of engine speed

and the throttling action of the plunger oil control device has the influence of “shaving peaks and filling valleys” on the hydraulic pressure fluctuations. Stepless and continuous change of the maximum valve lift

opening duration and valve timing can be achieved in FHVVS with good valve cycle stability and valve dynamics performance.