Full Description

Note: Nothing in the specification supersedes applicable laws andregulations unless specificexemption has been obtained.

Note: In the event of conflict between the English and domesticlanguage, the English languageshall take precedence.

Purpose. Determination of hydraulic power steering system noise.

Forward. This procedure describes the noise measurement of thehydraulic-assisted power steeringsystem.

Applicability. The test is applicable to passenger vehicles withhydraulic-assisted power steeringsystem. Specific noise covered in this procedure includes:

1. Hydraulic Power Steering Pump Noise

2. Hydraulic Power Steering Gear Noise

This test procedure includes quantification of typical hydraulic powersteering gear noises, suchas hiss, squawk, and whistle. The frequency range for hiss is 1-4 kHzfor structure borne noise and4-12.5 kHz for airborne noise. Squawk, a type of closed loopinstability, has a frequency range of100-350 Hz. The frequency range for whistle is 4-9 kHz.

Definitions.

LFRE: left front seat, right ear (left hand drive vehicle, driver'sseat occupied)

RF: right front (seat vacant, microphone placed in center of seatposition)

RFLE: right front seat, left ear (right hand drive vehicle, driver'sseat occupied)

LF: left front (seat vacant, microphone placed in center of seatposition)