Clutch Pedal Pulsation and Vibration Tuning by Introducing a Unified Damper (LFF and HFF) in Clutch Release System

In the current automobile era, weight, emission, and fuel efficiency were driving the overall powertrain development without compromising on the performance. Due to light weight and high-performance engines, the increased level of excitations in terms of torsional, axial, and bending frequency on crank shaft during combustion is inevitable. The axial and bending moment exerted from crankshaft during combustion causes vibration of the clutch diaphragm spring, in turn these vibrations are transferred through the hydraulic release system to clutch pedal which induces undesirable pedal pulsation and vibration during clutch pedal operation. The subjective perception on Noise Vibration and Harshness (NVH) becomes more essential in the Vehicle development process of modern high-performance vehicles. The clutch pedal pulsation in Idle rpm at 10% pedal travel with low frequency less than 80Hz and pedal vibration in higher rpm ranging between 1500 to 2500 RPM at 60% to 80% of total pedal travel with high frequency of 160Hz ~ 450Hz. To solve this concern, one Low Frequency Filter (LFF) and one High Frequency Filter (HFF) is a standard approach in automobile industry. However, the custom use of LFF and HFF dampers in clutch release hydraulic system will result in deterioration of the system efficiency thus increasing the gear shift impulse. This paper mainly focuses on integrating the LFF and HFF as a single unit with reduced volumetric expansion, thus addressing the pedal vibration at low and high frequency without affecting the system level efficiency and gear shift impulse.