1995-10-01

Unsteady Intake Valve Gap Flows 952477

The performance of engine intake ports is traditionally characterized by pressure drop and in-cylinder swirl or tumble ill steady flow at discrete valve lifts. These characteristics are often complemented by velocity profiles in the cylinder and the valve gap, but the influence of valve and piston motion cannot be represented.
In this work the intake stroke simulation was improved with a moving piston, although the valve remained motionless. A simple port geometry was chosen, since it was not the intention to optimize the port design for a particular engine. Measurements of three mean velocity components and the corresponding turbulence intensities around the intake valve showed complex flow patterns, including separation from the valve seat and sealing faces and back-flow into the intake port near the cylinder wall.
Assuming quasi-steady flow conditions, i.e. a constant flow coefficient, flow velocities should scale with the instantaneous piston speed. It is demonstrated that normalized distributions of mean axial and radial velocity across the valve gap do indeed fit a single distribution at each azimuthal location at all crankangles. This normalization does not, however, eliminate engine speed dependence for the tangential mean velocity and all turbulence intensity components.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

High Speed Laser Tomography Analysis of Flame Propagation in a Simulated Internal Combustion Engine - Applications to Nonuniform Mixture

941990

View Details

TECHNICAL PAPER

Effects of Pulsating Flow on Exhaust Port Flow Coefficients

1999-01-0214

View Details

TECHNICAL PAPER

Modeling the Dynamics and Lubrication of Three Piece Oil Control Rings in Internal Combustion Engines

982657

View Details

X