jcb EcoMAX - IPU Mounting and Noise Reduction

JCB EcoMAX Engine Installation Manual
© JCB Power Systems Ltd. 320/A9164-1 Page 25 of 64
8. IPU Mounting and Noise Reduction
W WARNING!
Poor engine mount design may lead to excessive operator environment noise and vibration
levels resulting in personal injury.
C NOTICE! Poor engine or powertrain mount design may cause engine
damage.
The purpose of the engine mount system is to locate the engine whilst reducing the vibration
transmitted into the equipment structure. The engine installer should take care to ensure that
vibrations transmitted to the equipment operator and other people are minimised; vibration is
uncomfortable and can be damaging to health. It is important to ensure that rigid body
modes of vibration of the powertrain do not coincide with sources of vibration input, such as
engine firing frequency or modes of the whole equipment.
The largest single factor affecting vibration isolation, are the bump stops. The engine
installer should take care to ensure adequate clearance of the bump stops and that there are
no fouls between the engine or its associated pipes and hoses, and the chassis / body. It is
very important that the engine mounts provide physical restraints that prevent engine
movement becoming large enough to allow clashes between engine components and the
body work or chassis. Care should also be taken with clearance between the fan tip and
radiator shroud.
The industrial Power Unit comes fitted complete with legs to allow the unit to be mounted
into the equipment using Anti Vibrational Mounts. In specifying the mounts consideration
should also be given not only to the static stiffness but also to the damping provided by the
mounts. Excessive damping can result in poor isolation and problems with mount durability.
If the Aftertreatment system is not sufficiently isolated from machine borne and engine borne
vibration, premature failure of components may occur. As outlined above, care must be
taken when specifying Anti Vibration Mounts.
Any additional brackets which attach to the engine also need careful consideration. They
should be free of resonances up to 150 Hz.
The engine mount system requires testing to ensure that performance requirements (see
Section 1), for stationary bending moment applied to the flywheel housing, resonant bending
frequencies of the powertrain, control of engine movement, control of rigid body modes of
vibration and isolation of engine vibration are met.
Off-Highway equipment must generally meet noise legislation appropriate to the territory of
operation. In order to achieve legislated limits on noise emissions it may be necessary to
apply noise shields around the engine. The engine installer should take care to ensure that
adequate airflow is maintained. Note: Cooling fans are one of the most significant sources of
noise on Off-Highway equipment.
Consideration should be given for the design of bump stop clearances, mistake-proofing of
mounts, mount positions relative to the engine centre of gravity, mount positions relative to
the equipment, protection of the mounts and noise shields.