Upload
dinhkiet
View
218
Download
0
Embed Size (px)
Citation preview
NVH vs. Vehicle Fuel Economy Trade-off
Mario Felice, Jack Liu, Imad Khan Ford Motor Company
Jonathan Zeman, Llorenc Gomez Gamma Technologies
Wulong Sun MSC Software
Michael Platten Romax Technology
2015 North American GT Conference, Nov. 9th
Introduction • Study of the fuel economy vs. NVH (Noise Vibration and Harshness) trade-off of
a 4 cylinder AWD vehicle with a 6 speed automatic transmission integrating technology from 3 partner software suppliers – Gamma Technologies for Engine and Torsional Damper – MSC Adams for 3D Driveline and Chassis – RomaxDESIGNER for Transmission and PTU (Power Take-off Unit)
• Four main aims: – Predictively quantify fuel economy penalty for slipping TCC (Torque
Convertor Clutch) – Predictively quantify transmission torsional vibration and seat track
acceleration amplitudes for locked and slipping TCC – Predictively quantify drivetrain lugging and rattle NVH responses under
damper designs and slipping TCC – Evaluate other damper technologies as an alternative to TCC slip – Understand details and benefits of software co-simulation and model
reduction
Engine Behavior
Predictive GT-POWER engine gives physically accurate engine torque and fuel consumption output as a function of engine rpm and load request
GT-Suite Damper Models • Models of three common used damping technologies to
reduce the oscillatory characteristic of the engine torque – Conventional Damper
• Controlled slip from 0-60RPM in 10RPM increments – Series Double Damper – Centrifugal Pendulum Absorber (CPA)
• Modeled with 1D+2D planar components
Conventional Damper
Series Double Damper
Pendulum Absorber
6F35 with PTU in RomaxDESIGNER
Dynamic FUSION discretizes and exports a time-domain 1D/3D MBD model
Visualization of Adams format of Romax model
Dynamic FUSION Workflow Dynamic FUSION can export a native 3D Adams file, or generic XML file, which can be read by GT-SUITE to create a 1D torsional-only model
Model Setup and Co-simulation • Merged chassis, transmission and driveline models
• Dynamic engine speed sweep from 800-3000 RPM at full load with Rear Differential Unit (RDU) clutch locked
• GT-SUITE co-simulates with Adams, exchange transmission input shaft speed and torque data
Adams Vehicle Model Romax Trans/PTU Model
Adams Drivetrain Model
GT Engine Model Romax/Adams Model
Co-simulation
• Transmission Output Shaft RMS Speed Amplitudes – Conventional Damper with Slip
Co-Simulation Results: TCC Slip
Driveline resonance
Co-Simulation Results: Seat Track Vibration
Seat Track Acceleration: TCC Slip with Conventional Damper
Seat Track Acceleration: Damper Design
Co-Simulation Results: Seat Track Vibration 2nd Order Cut
Seat Track Acceleration: Damper Design
*Shift of 2nd order response due to torque converter slip is due to increasing engine starting speed with increased amounts of slip
Seat Track Acceleration: TCC Slip with Conventional Damper
— 0RPM Slip ― 20RPM Slip — 40RPM Slip — 60RPM Slip
Baseline (0 TC slip)
Co-Simulation Results: PTU Rattle
RDU Open (7Nm constant drag) Gear Lash in Driveshaft: 2 Degree Full Throttle, 5th gear position Various TCC Slip (0 – 60 rpm)
Vehicle Model Setup Model Outputs PTU rattle torque Drivetrain torsional vibration Drivetrain torsional modes Seat track vibration
Relative Gear Displacement Torque on Gear
Rattle Rattle Rattle Rattle
Driveshaft Torsional Mode at Rattle ~59Hz
Co-Simulation Results: PTU Rattle Baseline (0 TCC slip) Linear Mode Animation
59 Hz
Frequency domain
Time domain + FFT Rattle
Rattle Peak
TCC Slip reduces PTU rattle response Relative Gear Displacement
Torque on Gear
Co-Simulation Results: PTU Rattle
0 rpm 30 rpm 60 rpm
0 rpm 30 rpm 60 rpm
Co-Simulation Results: PTU Rattle Comparison of damper design vs. TCC slip
Relative Gear Displacement
Torque on Gear
0 rpm 40 rpm Double CPA
0 rpm 40 rpm Double CPA
Co-Simulation Results: Fuel Economy • TCC slip has negative impact on fuel economy
– Damper design has negligible effect on fuel economy
Conclusions • This paper performs the FE evaluation based on special
driving maneuvers – Lugging results show a high fuel economy penalty for TCC slip – However, a complete certification driving cycle will not exhibit the
same penalty • Compare baseline TCC slip map (40 rpm max) with a more
aggressive lockup map, which could be realized with a different damper
FTP75 HFET US06 NEDC
Modified Slip Map 1.5% 0.22% 1.4% 0.30%
Fuel Economy Penalty vs. Driving Cycle
Conclusions
• This paper demonstrates a powerful method in evaluating predictive tradeoff of fuel economy and NVH – An optimal design best balancing fuel economy and NVH can be
analytically determined before prototypes are built
• This method is also applicable for predicting tradeoff of cost
vs. performance, and fuel economy