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Modeling and Simulation of Torsional Vibration of the Compliant Sprocket in Balance Chain Drive Systems

SAE International Journal of Fuels and Lubricants

General Motors Corporation-H.Y. Isaac Du, Xiangming Fang, Jia-Shiun Chen
LMS International-Keith D. Moss, William C. Prescott
  • Journal Article
  • 2008-01-1529
Published 2008-06-23 by SAE International in United States
The work presented in this paper outlines the development of a simulation model to aid in the design and development of a compliant sprocket for balancer drives. A design with dual-mass flywheel and a crank-mounted compliant chain sprocket greatly reduces interior noise levels due to chain meshing. However, experimental observations showed the compliant sprocket can enter into resonance and generate excessive vibration energy during startup. Special features are incorporated into the compliant sprocket design to absorb and dissipate this energy. Additional damper spring rate, high hysteresis and large motion angle that overlap the driving range may solve the problem during engine start-up period.This work develops a simulation model to help interpret the measured data and rank the effectiveness of the design alternatives. A Multibody dynamics system (MBS) model of the balancer chain drive has been developed, validated, and used to investigate the chain noise. This model includes a cranktrain system coupled to a full balancer drive system that includes the chain drive, balance shafts, and water pump. The nonlinear stiffness and damping effects of the…
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An Engineering Method for Part-load Engine Simulation

General Motors Corporation-P. Bertrand Hsing, Jia-Shiun Chen, H.Y. Isaac Du
Published 2007-10-29 by SAE International in United States
This work provides an effective engineering method of building a part-load engine simulation model from a wide-open throttle (WOT) engine model and available dynamometer data. It shows how to perform part-load engine simulation using optimizer for targeted manifold absolute air pressure (MAP) on a basic matrix of engine speed and MAP. Key combustion parameters were estimated to cover the entire part-load region based on affordable assumptions and limitations. Engine rubbing friction and pumping friction were combined to compare against the motoring torque. The emission data from GM dynamometer laboratory were used to compare against engine simulation results after attaching the RLT sensor to record emission data in the engine simulation model.
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Bulkhead Loading Calculation of an Aluminum Engine Block Coupled with a Rotating Crankshaft through Elastohydrodynamic Bearings

General Motors Corporation-H.Y. Isaac Du, Fanghui Shi
Published 2007-04-16 by SAE International in United States
During a new engine development program, or the adaptation of an existing engine to new platform architectures, testing is performed to determine the durability characteristics of the basic engine structure. Such testing helps to uncover High Cycle durability-related issues that can occur at the bulkhead walls as well as cap bolt thread areas in an aluminum cylinder block. When this class of issues occurs, an Elastohydrodynamic (EHD) bearing simulation capability is required.In this study, analytical methods and processes are established to calculate the localized distributed load on the bulkhead. The complexity in performing a system analysis is due to the nonlinear coupling between the bearing hydrodynamic pressure distribution and the crankshaft and block deformation. A system approach for studying the crankshaft-block interaction requires a crankshaft flexible body dynamics model, an engine block assembly flexible body dynamics model and a main bearing lubrication model. Such a system model is presented in this paper by employing multi-body dynamic system simulation to capture the dynamic characteristics from the engine durability test set-up. By using a multi-body code, DADS,…
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Vibration Modeling and Correlation of Driveline Boom for TFWD/AWD Crossover Vehicles

General Motors Corporation-H.Y. Isaac Du, Mark Frederiksen
LMS North America-Scott Happel
Published 2003-05-05 by SAE International in United States
Reducing the high cost of hardware testing with analytical methods has been highly accelerated in the automotive industry. This paper discusses an analytical model to simulate the driveline boom test for the transverse engine with all wheel drive configuration on a front-wheel drive base (TFWD/AWD). Driveline boom caused by engine firing frequency that excites the bending mode of the propeller shaft becomes a noise and vibration issue for the design of TFWD/AWD driveline.The major source of vibrations and noise under the investigation in this paper is the dominant 3rd order engine torque pulse disturbance that excites the bending of the propeller shaft, the bending of the powertrain and possible the bending of the rear halfshaft. All other excitation sources in this powertrain for a 60° V6 engine with a pushrod type valvetrain are assessed and NVH issues are also considered in this transient dynamic model. There exist the 2nd order unbalanced rotating couples (yaw and pitch respective to the engine coordinate system) due to the reciprocating mass of the pistons and connecting rods, and the…
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Dynamic Stress Correlation and Modeling of Driveline Bending Integrity for 4WD Sport Utility Vehicles

GM Powertrain-H.Y. Isaac Du, Xiaobo Liu
General Motors Corp.-Wen K. Chang, Richard Salmon
Published 2002-03-04 by SAE International in United States
Reducing the high cost of hardware testing with analytical methods has been highly accelerated in the automotive industry. This paper discusses an analytical model to simulate the driveline bending integrity test for the longitudinal 4WD-driveline configuration. The dynamic stresses produced in the adapter/transfer case and propeller shaft can be predicted analytically using this model. Particularly, when the 4WD powertrain experiences its structural bending during the operation speed and the propeller shaft experiences the critical whirl motion and its structural bending due to the inherent imbalance. For a 4WD-Powertrain application, the dynamic coupling effect of a flexible powertrain with a flexible propeller shaft is significant and demonstrated in this paper.Three major subsystems are modeled in this analytical model, namely the powertrain, the final rear drive, and the propeller shafts. Component and subsystem finite element model correlation with modal test data was first conducted. Then the system finite element model was correlated to the test-rig setup. Inherent imbalance was analytically included in the propeller shaft model and the whirl motion of propeller shaft was induced to simulate…
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Modeling and Correlation of Driveshaft Whirl Dynamics for RWD Sport Utility Vehicles

GM Powertrain-H.Y. Isaac Du, Jeff Morgan
General Motors Corporation-Jason M. Wong, Richard Salmon
Published 2001-04-30 by SAE International in United States
High interest is expressed in using analytical models to eliminate costly driveline tests used to determine the stresses produced in the driveshaft and driveline during resonant operating conditions. This paper discusses an analytical model to simulate the driveline-bending integrity, test procedure. Three major subsystems are modeled in this analytical approach, namely powertrain, rear axle, and driveshaft. Imbalance masses were added on the driveshaft to induce the whirl motion of the driveshaft. The combination of nonlinear Multi-body System Simulation (MSS) and linear Finite Element Analysis (FEA) in the time domain was employed for the evaluation of the dynamic interaction between several parts.
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Dynamic Analysis of a 3D Finger Follower Valve Train System Coupled with Flexible Camshafts

GM Powertrain-H.Y. Isaac Du, Jia-Shiun Chen
Published 2000-03-06 by SAE International in United States
A 3D dynamic model has been developed to investigate the dynamic response of a finger-follower cam system by considering the interaction between valve train and camshaft. The torsional moments being different for each cam cause the torsional vibrations of the camshaft. The resulting speed fluctuations of the cam affect the dynamics of other valve train components including the ultimate valve motion.To better represent the critical parts of the valve train, special attention was given to the cam and follower and to valve springs. The cam and follower are treated as a force contact relation so parts can separate and impact again. The valve springs are now treated as flexible bodies and important mass effects and coil contact events are captured during the simulation. The mass effects are associated with spring surge that occurs at high speed. Coil contact occurs when the individual coil in the spring collides.One bank of a V6 engine with overhead twin cams is modeled in this study. The complete flexible multi-body model of the valve train includes flexible camshafts, valves, springs…
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Simulation of Flexible Rotating Crankshaft with Flexible Engine Block and Hydrodynamic Bearings for a V6 Engine

GM Powertrain-H.Y. Isaac Du
Published 1999-05-17 by SAE International in United States
This paper discusses how the multi-body dynamics approach combined with flexible body effects is being applied to predict the bearing loads, the vibrations of crankshaft, the orbit plots of individual journal, and the performance of bearing (such as minimum film thickness and maximum film pressure) due to structural flexibility. The oil film effects in the journal bearing are implemented using both impedance method and hydrodynamic fluid film with finite element method. An application example of a V6 engine was given in this paper to show this sophisticated simulation model and to predict the dynamic response of the flexible system and loads in the journal bearings.
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