This research presents a lumped-parameter model, distinct from the ones developed until the present time, easily adaptable for its analog/hybrid simulation, and that combines favorably its simplicity and precision to represent appropriately an automotive valve gear system by means of the inclusion of the hydraulic lifter and of the viscous forces produced by its guide. The checking of this new mathematical model has been accomplished by means of a qualitative comparison with other models previously devised. This model will be useful in the design stage to predict the speed at which the valve jump occurs.
This research presents an improved lumpedparameter model that combines favorably its simplicity and precision to represent appropriately an automotive valve-gear system, by means of the inclusion of a fluidic pressure element within the modeling of the hydraulic lifter, and by considering the hysteretic behavior of the pushrod under cyclic loading. Realistic values have been chosen for the parameters of this cam-follower mechanical system, and the checking of this modified mathematical model has been accomplished by means of a qualitative comparison with other models previously conceived, and with previous experimental results obtained from an automobile engine. The digital computer simulation allows the determination of the cam speed for which the valve toss occurs, whose value is of fundamental importance in evaluating the design of automotive cam mechanisms.
This article develops a more efficient technique for the balancing of the overhung rigid rotor, which is a variation of the exact influence coefficient method, that gives directly the correction weights for both balancing planes. During the calibration process, one trial weight is used for the second run and, to reduce the cross effect, only one trial weight to form a couple is used for the third run, improving the field balancing method for maintenance works.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.