Browse Publications Technical Papers 820408
1982-02-01

Controlling Engine Load by Means of Early Intake-Valve Closing 820408

Early closing of the intake valve was examined as a means for controlling the load of a homogeneous-charge, spark-ignition engine. The engine was operated unthrottled, with load controlled by closing the intake valve during the intake stroke of the engine after the required amount of charge had been inducted into the cylinder. The concept was examined both experimentally, using intake cams giving reduced intake-valve lift and opening duration, and analytically, using an engine simulation.
Comparisons to a conventional throttled engine operating at part load show the early intake-valve-closing engine to have lower pumping loss, lower specific fuel consumption, lower cylinder-gas temperatures, lower heat transfer, lower NOx emissions, similar combustion duration and cyclic variability, and somewhat higher HC emissions. However, the fuel economy benefit offered by this load-control concept would be diminished by the frictional losses of a control mechanism and by the current trends toward lower vehicular power/weight ratios and broader-range transmissions.

SAE MOBILUS

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

Access SAE MOBILUS »

Preview Document Add to Cart
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

Controlling Engine Load by Means of Late Intake-Valve Closing

800794

View Details

TECHNICAL PAPER

A Hydraulic Valve Control System and its Application to Turbocharged Diesel Engines

880603

View Details

TECHNICAL PAPER

Development of a Variable Valve Timed Engine to Eliminate the Pumping Losses Associated with Throttled Operation

860537

View Details

X