A blended CFD/multi-body analysis method for elastohydrodynamics of plastic oil pan

Area of Science:

• Automotive Engineering
• Mechanical Engineering
• Acoustics

Background:

• Noise, vibration, and harshness (NVH) are critical factors influencing vehicle durability, comfort, and regulatory compliance.
• Thin-walled engine components, such as oil pans, significantly impact overall NVH performance.
• Existing methods may not fully capture the complex hydrodynamic and structural interactions affecting engine NVH.

Purpose of the Study:

• To propose and validate a novel computational fluid dynamics (CFD) and finite element multi-body analysis (FEA) blending method for assessing engine oil pan NVH.
• To analyze the dynamic characteristics of plastic oil pans and identify hydrodynamic and structural factors influencing camshaft speed fluctuations.
• To compare the NVH performance of plastic oil pans against traditional metal oil pans.

Main Methods:

• A hybrid approach combining CFD for simulating oil-air two-phase flow and FEA for structural and multi-body dynamics was employed.
• CFD simulations depicted oil flow evolution in plastic oil pans under gravitational load.
• Fluid viscosity effects and multi-body interactions of solid surfaces were coupled to evaluate NVH.

Main Results:

• Plastic oil pans demonstrated a 31.20%–42.04% increase in modal frequency compared to metal oil pans.
• A sound power level reduction of 2.9–7.2 dB was observed for plastic oil pans.
• The proposed method accurately simulates elastohydrodynamics and identifies key NVH factors.

Conclusions:

• The integrated CFD-FEA method effectively analyzes NVH characteristics of plastic oil pans.
• Plastic oil pans offer superior NVH performance, including higher modal frequencies and reduced sound power levels.
• This research provides crucial insights for designing modern diesel engines with enhanced NVH properties.