1997-10-01

Fluid Flow, Combustion and Efficiency with Early or Late Inlet Valve Closing 972937

This paper is a study of the effects of valve timing and how it influences the in-cylinder fluid flow, the combustion, and the efficiency of the engine. An engine load of 4.0 bar imepnet was achieved by setting the inlet valve closing time early or late to enable unthrottled operation. Inlet valve deactivation was also used and asymmetrical valve timing, i.e. valve timing with the two inlet valves opening and closing at different times. The valve timing was altered by switching cam lobes between the experiments.
The results indicate a longer flame development period but a faster combustion with early inlet valve closing compared to the throttled case. For late inlet valve closing, a variation in the combustion duration results. As expected, the pumping mean effective pressure (PMEP) was greatly reduced with early and late inlet valve closing compared to the throttled case.

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

Knocking Phenomena in a Gasoline Engine with Late-Intake Valve Closing

920381

View Details

TECHNICAL PAPER

Unsteady-Flow Velocity Measurements Around an Intake Valve of a Reciprocating Engine

870593

View Details

TECHNICAL PAPER

Performance Evaluation of a Camless Engine Using Valve Actuators with Programmable Timing

910450

View Details

X