INTRODUCTION Sales of eco-friendly vehicles focused on hybrids are increasing such that automotive makers are aggressively seeking improved ecofriendly technologies. HKMC has developed its own hybrid system called TMED(Transmission Mounted Electric Device)[ 1]; the TMED is equipped in the Sonata, and Optima Hybrids, which are selling steadily in the market. The system shown in Figure 1 is comprised of a propulsion motor, HSG (Hybrid Starter Generator), 6 speed A/T, engine clutch, combustion engine and high-voltage main battery. The primary feature of the system shown in Figure.1 is the inclusion of two motors: one for propulsion and one for generating energy. The engine power can be used for generation or for propulsion via engine clutch control. Figure 1. The power transmission structure of the TMED system The TMED System has no torque converter, unlike the conventional internal combustion engine; and while this allows for minimal power loss, the driveline vibrations cannot be sufficiently attenuated, leading to poor NVH characteristics. Anti-Jerk technology is applied to reduce free vibration jerk in the drivetrain that occurs with the tipping of the pedal either in or out, gear shifting, and engine clutch jointing.[2,3] In addition, the booming noise generated by the excitation force from variations in engine combustion pressure causes the vehicle Active Booming Noise Control for Hybrid Vehicles Hyungsouk Kang and TaeYoung Chung Hyundai Motor Company Hyeongcheol Lee Hanyang Univ Hyungbin Ihm Hyundai Motor Company ABSTRACT Pressure variation during engine combustion generates torque fluctuation that is delivered through the driveline. Torque fluctuation delivered to the tire shakes the vehicle body and causes the body components to vibrate, resulting in booming noise. HKMC (Hyundai Kia Motor Company)’s TMED (Transmission Mounted Electric Device) type generates booming noises due to increased weight from the addition of customized hybrid parts and the absence of a torque converter. Some of the improvements needed to overcome this weakness include reducing the torsion-damper stiffness, adding dynamic dampers, and moving the operation point of the engine from the optimized point. These modifications have some potential negative impacts such as increased cost and sacrificed fuel economy. Here, we introduce a method of reducing lock-up booming noise in an HEV at low engine speed. Generating a torque profile via the propulsion motor, which has the anti-phase profile of the driveline vibration, can therefore suppress driveline fluctuation. Engine vibration extracted from the HSG (Hybrid Starter Generator) is used for the desired input signal. The generated signal, based upon the rotation angle of the driving motor, is used as a reference input for the RLS adaptive filter. The filter updates its coefficients to minimize the phase difference between the reference signal and the desired input signal. Frequency response characteristics of the powertrain driveline components are used to generate the anti-phase vibration profile of the point causing booming. Ef fectiveness was verified with development vehicles under various driving conditions. The results show an 8dB(C) improvement in booming noise, and 9dB and 4dB improvements in floor panel vibration and steering wheel vibration, respectively . CITATION: Kang, H., Chung, T., Lee, H., and Ihm, H., "Active Booming Noise Control for Hybrid Vehicles," SAE Int. J. Passeng. Cars - Mech. Syst. 9(1):2016, doi:10.4271/2016-01-1122.2016-01-1122 Published 04/05/2016 Copyright © 2016 SAE International doi:10.4271/2016-01-1122 saepcmech.saejournals.org 167Downloaded from SAE International by Univ of Nottingham - Kings Meadow Campus, Saturday, August 11, 2018body system to resonate at a particular engine speed. Lowering the torsion damper stiffness, adding dynamic dampers on the resonating body component and moving the engine operation point from the optimized point can reduce this boomi