1993-03-01

A Study of Vehicle Equipped with Non-Throttling S.I. Engine with Early Intake Valve Closing Mechanism 930820

To enable non-throttling operation of gasoline S.I. engine, we have manufactured engines equipped with a newly developed Hydraulic Variable-valve Train (HVT), which can vary its intake-valve closing-timing freely. The air-intake control ability of HVT engine is equivalent to conventional throttling engines. Combustion becomes unstable, however, under non-throttling operation at idling. For the countermeasure, newly designed combustion chamber has been developed. The reduction of pumping loss by the HVT depends on engine speed rather than load, and amounts to about 80 % maximum.
A conventional engine-management system is not applicable for non-throttling operation. Therefore, new management system has been developed for load control. The vehicle equipped with the HVT engine proved an equivalent driveability to the vehicle with conventional engine, particularly, it satisfied EPA emission standards in the U.S. and proved about 7% improvement of fuel consumption in EPA Urban Dynamometer Driving Schedule.

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

Effects of intake-Valve Closing Timing on Spark-Ignition Engine Combustion

850074

View Details

TECHNICAL PAPER

The HCCI Concept and Control, Performed with MultiAir Technology on Gasoline Engines

2011-24-0026

View Details

TECHNICAL PAPER

Reducing Part Load Pumping Loss and Improving Thermal Efficiency through High Compression Ratio Over-Expanded Cycle

2013-01-1744

View Details

X