Abstract
Boosting power by turbocharger is one of the best solutions to improve the engine performance. It is necessary to have some appropriate adjustments to achieve the optimum performance for the diesel engine after boosting. There are several factors impacting strongly on engine performance that related to fuel supply system: the amount of fuel is supplied for an engine cycle and characteristic of fuel supply... Diesel engine boosted by low pressure ratios can have no alterations to the high pump. It is necessary to feed more fuel per engine cycle for the boosting. If it still uses the original cam profile, supplied period would increase, therefore the tail period of time increases and the fuel economy does not improve. This paper presents a method to design an advanced cam profile that it results in a faster follower velocity, this changes the characteristic of fuel supply, increases spray velocity, and as a result the supplied period is reduced. By means of calculating hydro dynamical processes in fuel supply system and surface stress between cam and follower, reasonable geometric parameters of cam used on boost engine can be selected. In addition, this paper compares fuel injection characteristics and engine performance under various cam profiles.
Keywords: diesel engine, turbocharging, cam profile, fuel injection system, fuel injection characteristic.