Project 8: AUSA Study Dumpers&Forklifts
In 2000, AUSA, a manufacturer of compact industrial vehicles for the movement of goods and road maintenance, which operates in the global market, contacted ICR to carry out various acoustic studies of two of its vehicles: a C150H model forklift and a D350AHG dump truck.
Among the undertaken studies, there were the analysis of noise and vibration transmission paths between the engine and various positions around the vehicle, which was applied in both vehicle models, and the vibrational characterization of the engine and the design of an acoustic silencer for the exhaust pipe of the C150H model.
The technology used for the analysis of vibro-acoustic transmission paths was the ATPA method, developed by ICR, this method allowed us to differentiate structure-borne noise from airborne noise coming from the engine, in the driver positions and around the vehicle. This study made possible to determine the necessary modifications to the vehicle in order to reduce the noise levels emitted.
For the vibratory characterization of the motor, the method of mobilities and the source descriptor were applied. The application of the mobility method allowed to know the vibratory power transmitted by the engine to the vehicle, through the engine-body attachment points. On the other hand, the so-called source descriptor method allowed us to study how the power of the engine transmitted to the car body through the elastic mounts was modified when the latter were changed. The study also provided the ability to predict what would be the vibratory power that the engine would transmit, together with the elastic mounts, to a different receiver, that is, in a different car body. The study was carried out on a C150H vehicle, which exhibited excessive vibration levels when idling, when the hydraulic pump that moves the forks, turned on. When the pump turned on a reduction of the engine turns happened, resulting in an increase on the car body vibration. By applying the method of mobilities and the Source Descriptor, a solution was found to reduce the vibration levels.
The design of a new acoustic silencer for the vehicle’s exhaust pipe also contributed to the reduction of the emitted noise.