1998-02-23

Intake Valve Opening Optimization 981028

The timing of the intake valve opening event is generally governed by the opposing requirements of providing enough cam duration to allow the performance-justified maximum valve lift, and the need to minimize valve overlap to attain acceptable idle quality.
The optimal timing of intake opening was studied as an independent variable, by creating a family of cam lobes to be run through the WAVE one-dimensional engine simulation program. This allowed intake opening to be varied without changing the other three valve events or valve lift, for a variety of intake closing timings. The engine simulation results were then experimentally verified with engine dynamometer tests.
The results indicate that the optimal intake valve opening time for maximizing the area under the power curve, is much later than traditionally thought, and this can lead to high specific torque and power engines with exceptional idle quality. Some combustion rate benefits were found for delayed intake opening.

SAE MOBILUS

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

Access SAE MOBILUS »

Members save up to 18% 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

On The Flow Modeling Through The Valve Assembly In Engine Cycle Simulations

2000-01-0570

View Details

TECHNICAL PAPER

Flow Characterization of a High Performance S.I. Engine Intake System - Part 2: Numerical Analysis

2003-01-0632

View Details

TECHNICAL PAPER

Geometric Parameters of Four-Valve Cylinder Heads and Their Relationship to Combustion and Engine Full Load Performance

940205

View Details

X