Engine performance validation of the optimal design of experiment valvetrain parameters

Abstract

Early stage of engine valvetrain noise improvement involves the implementation of Design of Experiment (DOE) specifically the Taguchi methodology to identify the optimum valvetrain parameters which resulted in significant noise improvement. The parameters are consist of seven controlled factors such as cylinder head tappet bore diameter, mechanical tappet diameter, valve spring load, camshaft exhaust and intake waviness together with tappet exhaust and intake clearance. The confirmation run which was previously completed yields the valvetrain noise level at 67.07db SPL by 1 meter distance in completed vehicle during idling condition. In order to satisfy the final quality of the optimal valvetrain, a test is carried out to validate the performance curve on a dynamometer according to benchmark specification. The objective of the test is to validate the optimal valvetrain based on the experimental result which minimum manufacturing target shall be achieved to indicate that the engine is operated within its intended design. The performance test was conducted at the manufacturing plant on an eddy current dynamometer which runs for 11 hours. As results, the performance are within the standard with approximate increased by 6.9% as compared with baseline valvetrain and confirmed by several follow-up tests made on the improved valvetrain. In order to verify and address the main engine output of the optimal valvetrain, brake specific fuel consumption (BSFC) and emissions test results are then presented at the end of this paper.