The Effects of Natural Aging on Fleet and Durability Vehicle Engine Mounts from a Dynamic Characterization Perspective

2001 ◽  
Author(s):  
Scott Gruenberg ◽  
Jason Blough ◽  
Darin Kowalski ◽  
Jay Pistana
Keyword(s):  
Natural Aging ◽  
Dynamic Characterization ◽  
Engine Mounts ◽  
Vehicle Engine

scholarly journals Fuzzy PID-Based Method for Controlling Piezoelectric Vehicle Engine Mounts

2021 ◽  
Vol 14 (5) ◽  
pp. 143-150
Author(s):  
Hangxu Yang ◽  
Dongmei Liu ◽  
Yongjian Gong
Keyword(s):  
Fuzzy Pid ◽  
Engine Mounts ◽  
Vehicle Engine

scholarly journals Substructuring of a Petrol Engine: Dynamic Characterization and Experimental Validation

2019 ◽  
Vol 9 (22) ◽  
pp. 4969 ◽  
Author(s):  
Enrico Armentani ◽  
Venanzio Giannella ◽  
Roberto Citarella ◽  
Antonio Parente ◽  
Mauro Pirelli
Keyword(s):  
Forced Response ◽  
Operating Conditions ◽  
Petrol Engine ◽  
The Finite Element Method ◽  
Dynamic Characterization ◽  
Fem Model ◽  
Resonant Frequencies ◽  
Engine Mounts ◽  
Engine Dynamic ◽  
The Impact

In this work, the vibration behavior of a 4-cylinder, 4-stroke, petrol engine was simulated by leveraging on the Finite Element Method (FEM). A reduced modelling strategy based on the component mode synthesis (CMS) was adopted to reduce the size of the full FEM model of the engine. Frequency response function (FRF) analyses were used to identify the resonant frequencies and corresponding modes of the different FEM models, and the obtained results were compared with experimental data to get the model validation. Subsequently, modal-based frequency forced response analyses were performed to consider the loads acting during the real operating conditions of the engine. Finally, the impact on vibrations at the mounts, produced by an additional bracket connecting the engine block and gearbox, was also investigated. Both the full and reduced FEM model demonstrated and reproduced with high accuracy the vibration response at the engine mounts, providing a satisfactory agreement with the vibrations measured experimentally. The reduced modelling strategy required significantly shorter runtimes, which decreased from 24 h for the full FEM model to nearly 2 h for the reduced model.

Automotive Vehicle Engine Mounting Systems: A Survey

1999 ◽  
Vol 123 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Yunhe Yu ◽  
Saravanan M. Peelamedu ◽  
Nagi G. Naganathan ◽  
Rao V. Dukkipati
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Frequency Range ◽  
Engine Mounts ◽  
Performance Requirements ◽  
Vehicle Engine ◽  
Engine Mount ◽  
Active Engine ◽  
Stiffness And Damping

This study divided into three portions to provide performance requirements; overview and development of various engine mounts; and the optimization of engine mount systems. The first part provides an insight about the ideal engine mount system that should isolate vibration caused by engine disturbance force in various speed range and prevent engine bounce from shock excitation. This implies that the dynamic stiffness and damping of the engine mount should be frequency and amplitude dependent. Therefore, the development of engine mounting systems has mostly concentrated on improvement of frequency and amplitude dependent properties. The second part starts discussion on the conventional elastomeric mounts that offer a trade-off between static deflection and vibration isolation. The next level, passive hydraulic mounts can provide a better performance than elastomeric mounts especially in the low frequency range. Subsequently, semi-active and active techniques are used to improve performance of hydraulic mounts by making them more tunable. The active engine mounting system can be very stiff at low frequency and be tuned to be very soft at the higher frequency range to isolate the vibration. The final part is about the optimization of engine mounting systems. An overview of the current work on this optimization shows some limitations. Further study is needed to consider the nonlinearities and variations in properties of different types of mounting systems.

scholarly journals Late-Holocene diatom community response to climate driven chemical changes in a small, subarctic lake, Northwest Territories, Canada

The Holocene ◽  
2021 ◽  
pp. 095968362110032
Author(s):  
Paul B Hamilton ◽  
Scott J Hutchinson ◽  
R Timothy Patterson ◽  
Jennifer M Galloway ◽  
Nawaf A Nasser ◽  
...  
Keyword(s):  
Iron Age ◽  
Biological Diversity ◽  
Regional Climate ◽  
Natural Aging ◽  
Community Response ◽  
Warm Period ◽  
Ice Age ◽  
Diatom Assemblages ◽  
Subarctic Lake ◽  
Over Time

The paleolimnological record of diatoms and climate, spanning the last 2800 years, was investigated in a small subarctic lake (Pocket Lake) that from AD 1948 to 2004 was contaminated by gold smelting waste. An age-depth model was constructed using a combination of 210Pb, 14C, and tephra to determine a 2800 year history of lake ontogeny (natural aging), biological diversity, and regional climate variability. Diatoms form six strong paleoecological assemblages over time in response to changes in local hydrological and sedimentological conditions (including metals). Selected environmental variables explained 28.8% of the variance in the diatom assemblages, with Fe, Ca, and sediment end member distribution being important indicators. The diatom assemblages correlated to the Iron Age Cold Epoch (2800–2300 cal BP), Roman Warm Period (2250–1610 cal BP), Dark Age Cold Period (1500–1050 cal BP), Medieval Climate Anomaly (ca. 1100–800 cal BP), and the Little Ice Age (800–200 cal BP). The disappearance of Staurosira venter highlights the change from the Iron Age Cold Epoch to the Roman Warm Period. After deposition of the White River Ash (833–850 CE; 1117–1100 cal BP), transition to circumneutral conditions was followed in tandem by a transition to planktic influenced communities. Ten discrete peaks of Cu, Pb, and Zn were observed and attributed to soluble mobility from catchment soils through enhanced seepage and spring snowmelt. The prominent metal spikes were aligned with increases in Brachysira neoexilis. Downward mobilization of arsenic and antimony from contaminated surficial sediments highlight the problem of post depositional industrial contamination of paleosediments. Results demonstrate that paleoclimatic changes in the region, modulated by solar radiation, impacted temperature and precipitation in the lake catchment, influencing temporal shifts in diatom ecology. Changes in diatom taxa richness provided valuable information on the relative influence of water quality (planktic taxa) and sediment input (benthic taxa). The diatom assemblage succession also provides evidence that natural aging over time has played a role in the ecological evolution of the lake.

Sign in / Sign up

Export Citation Format

Share Document