Influence of Clutch Tribodynamics on Drivetrain Noise, Vibration and Harshness, (NVH), Phenomena

Abstract

Limiting problematic Noise, Vibration and Harshness (NVH) phenomena in the modern automotive drivetrain is a task of critical importance. The result of such phenomena is the aggravation of the driver, which results in a reduced perception of vehicle quality. Each phenomenon can be characterized by a distinct frequency range. The aim of the current study is to assess the influence of the interfacial frictional behavior of the dry friction clutch components on the drivetrain dynamic behavior. The dynamics of the system (in terms of its stability) are studied. Surface data from the clutch components are critical to understanding the complex engagement process. The coefficient of friction was measured using a rotary tribometer at representative slip speeds and contact pressures. To aid the analysis infinite focus microscopy was used to measure the geometric properties of the constituent components of the drivetrain. The current approach allows for improved understanding of the drivetrain's dynamic behavior. The improved understanding of the coupling between tribological characteristics and drivetrain system dynamics can lead to the mitigation of future NVH issues.

Noise, vibration and harshness during dry clutch engagement oscillations

“…The structural damping ratio is selected as 0.05% at a natural frequency of 380 Hz. 30 Using proportional damping, at higher natural frequencies there is higher damping content and vice versa for lower natural frequencies than 380 Hz. The eigenproblem for the undamped clutch system was solved…”

“…19,33 The pin-on-disc rig uses a 0.1 m diameter disc, which is an actual replica of the pressure plate. 30 The samples were extracted from the facings of a clutch disc exhibiting aggressive NVH behaviour. The extraction area included the effective radius of the clutch disc.…”

“…For consistency, the dynamic friction coefficient was determined for the same sliding distance (150 m) for each sample (ASTM G115-10). 30 This distance was selected in order to limit any bulk temperature rise as a result of frictional energy dissipation within the contact. 34 Each test was conducted at room temperature with the temperature of the disc measured before and after each test.…”

“…The static coefficient of friction, st , for the system under investigation is taken as 0.4. 30 Figure 7 presents the results of the laboratory experimental measurements of the dynamic friction coefficient variation simulating dry clutch engagement/disengagement conditions.…”

Nonlinear Dynamics of a Power-Split Transmission Unit with a Planetary Gear Train and Selectable One-Way Clutches

“…Friction clutches, as common executive mechanisms, are widely used in vehicle transmissions. Features of the friction engagement governed by diaphragm springs in general, and problems such as friction, wear, temperature, sliding speed, and contact pressure [1][2][3] in particular, have rendered high energy consumption, control complexity, and slow response speed that prevent the existing vehicle transmissions from upgrading.…”