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Technical Paper

A Method of Acceleration Order Extraction for Active Engine Mount

2017-03-28
2017-01-1059
The active engine mount (AEM) is developed in automotive industry to improve overall NVH performance. The AEM is designed to reduce major-order signals of engine vibration over a broad frequency range, therefore it is of vital importance to extract major-order signals from vibration before the actuator of the AEM works. This work focuses on a method of real-time extraction of the major-order acceleration signals at the passive side of the AEM. Firstly, the transient engine speed is tracked and calculated, from which the FFT method with a constant sampling rate is used to identify the time-related frequencies as the fundamental frequencies. Then the major-order signals in frequency domain are computed according to the certain multiple relation of the fundamental frequencies. After that, the major-order signals can be reconstructed in time domain, which are proved accurate through offline simulation, compared with the given signals.
Technical Paper

An FxLMS Controller for Active Control Engine Mount with Experimental Secondary Path Identification

2020-04-14
2020-01-0424
Active engine mounts (AEMs) notably contribute to ensuring superior performance of vehicle’s noise, vibration, and harshness. This paper incorporates a filtered-x-least-mean-squares (FxLMS) controller into the active control engine mount system to attenuate the transmitted force to the body. To avoid the error caused by substituting the load cell for acceleration transducer, the FIR model of the secondary path was obtained by experiment. Finally, a hardware-in-the-loop testing system is built to verify the performance of the active engine mount. It can be observed from the test results that the vibration is reduced notably after control, which demonstrates the effectiveness of the active engine mount and the controller in vibration attenuation.
Technical Paper

An Improved PID Controller Based on Particle Swarm Optimization for Active Control Engine Mount

2017-03-28
2017-01-1056
Manufacturers have been encouraged to accommodate advanced downsizing technologies such as the Variable Displacement Engine (VDE) to satisfy commercial demands of comfort and stringent fuel economy. Particularly, Active control engine mounts (ACMs) notably contribute to ensuring superior effectiveness in vibration attenuation. This paper incorporates a PID controller into the active control engine mount system to attenuate the transmitted force to the body. Furthermore, integrated time absolute error (ITAE) of the transmitted force is introduced to serve as the control goal for searching better PID parameters. Then the particle swarm optimization (PSO) algorithm is adopted for the first time to optimize the PID parameters in the ACM system. Simulation results are presented for searching optimal PID parameters. In the end, experimental validation is conducted to verify the optimized PID controller.
Technical Paper

An Optimized Design of Multi-chamber Perforated Resonators to Attenuate Turbocharged Intake System Noise

2021-04-06
2021-01-0669
The turbocharger air intake noise during transient condition like wide open throttle affects the passenger ride comfort. This paper aims to study an optimized design of multi-chamber perforated resonators to attenuate this noise. The noise produced by turbocharger in a test vehicle has been measured to find out the noise spectral characteristics which can be used to design the acoustic targets including the amplitude and frequency range of transmission loss. To meet the acoustic targets, the structural parameters of the resonators are optimized based on the genetic algorithm and two-dimensional prediction theory of the resonator transmission loss. The optimized resonators are installed on the test vehicle to verify the actual noise reduction effect. The results suggest that the broadband noise has been eliminated and subjective feelings are greatly improved.
Technical Paper

Comparison between different modelling methods of secondary path to maximize control effect for active engine mounts

2021-04-06
2021-01-0668
Active engine mount (AEM) is an effective approach which can optimize the noise, vibration and harshness (NVH) performance of vehicles. The filtered-x-least-mean-squares (FxLMS) algorithm is widely applicated for vibration attenuation in AEMs. However, the performance of FxLMS algorithm can be deteriorated without an accurate secondary path estimation. First, this paper models the secondary path using finite impulse response (FIR) model, infinite impulse response (IIR) model and back propagation (BP) neuron network model and the model errors of which are compared to determine the most accurate and robust modeling method. After that, the influence of operation frequency on accuracy of the secondary path model is analyzed through simulation approach. Then, the impact of reference signal mismatch on the control effect is demonstrated to study the robustness of FxLMS algorithm.
Technical Paper

Full Vehicle Dynamic Modeling for Engine Shake with Hydraulic Engine Mount

2017-06-05
2017-01-1908
The statement of the engine shake problem is presented through comparing the quarter vehicle models with the rigid-connected and flexible-connected powertrain which is supported on the body by a rubber mount. Then the model is extended by replacing the rubber mount as a hydraulic engine mount (HEM) with regard to the inertia and resistance of the fluid within the inertia track. Based on these, a full vehicle model with 14 degree of freedoms (DOFs) is proposed to calculate the engine shake, which consists of 6 of the powertrain, 1 of the fluid within the inertia track of the HEM, 3 of the car body and 4 of the unsprung mass. Simulation analysis based on the proposed model is implemented, through which the conclusion is drawn that the HEM has great influence on the body and seat track response subjected to front wheel inputs, compared with the rubber mount.
Technical Paper

Nonlinear modeling and characteristic analysis of engine shake considering air engine mount

2021-04-06
2021-01-0676
Engine shake is referred to the influence on vehicle vibration causing by powertrain mounting system under the excitation of road irregularities. In this paper, a full vehicle nonlinear model considering air engine mount was established to better describe the characteristics of engine shake. The model consists of 14 degrees of freedom(DOFs), namely 6 of the powertrain, 1 of the air in the air engine mount orifice, 3 of the body, and 4 of the unsprung mass. Then, a Jacobian-free Newton-Krylov(JFNK) method for solving nonlinear equations was proposed to better simulate the model mentioned above. The result demonstrates that air engine mount has great influence on the body and seat track response subjected to front wheel inputs. Finally, the influence of air engine mount parameters on the model characteristics is discussed.
Technical Paper

Subjective and Objective Evaluation of APU Start-Stop NVH for a Range-Extended Electric Vehicle

2015-03-10
2015-01-0047
In recent years, electric vehicle and hybrid vehicle are either on the market or under intensive research and development (R&D). Since the concept of auxiliary power unit (APU) was brought into the automotive industry, the range-extended electric vehicle (ReEV) has become the favor of the worldwide manufacturers. Normally, the APU starts and stops more frequently in response to the control strategy compared with traditional vehicles, which will affect the ride comfort of passengers. Thus, APU start-stop NVH refinement is an important aspect of ReEV R&D. In this paper, a subjective evaluation on a ReEV was performed to quickly diagnose NVH issues firstly. Based on subjective results, the NVH experiment in a semi-anechoic room was carried out to troubleshoot these issues. The accelerations of the APU mounts, the seat track and the steering wheel as well as interior noise level were acquired and analyzed.
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