Browse Publications Technical Papers 2006-01-0222
2006-04-03

A Study of Friction Characteristics of Continuously Variable Valve Event & Lift (VEL) System 2006-01-0222

A continuously variable valve event and lift (VEL) system, actuated by oscillating cams, can provide optimum lift and event angles matching the engine operating conditions, thereby improving fuel economy, exhaust emission performance and power output. The VEL system allows small lift and event angles even in the engine operating region where the required intake air volume is small and the influence of valvetrain friction is substantial, such as during idling. Therefore, the system can reduce friction to lower levels than conventional valvetrains, which works to improve fuel economy.
On the other hand, a distinct feature of oscillating cams is that their sliding velocity is zero at the time of peak lift, which differs from the behavior of conventional rotating cams. For that reason, it is assumed that the friction and lubrication characteristics of oscillating cams may differ from those of conventional cams. This paper describes the friction and lubrication characteristics of the variable valvetrain with oscillating cams, which were made clear on the basis of elastohydrodynamic lubrication (EHL) analyses taking into account mixed lubrication, durability tests and other experiments.

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 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

A Study of a Continuous Variable Valve Event and Lift (VEL) System

2001-01-0243

View Details

TECHNICAL PAPER

A Continuous Variable Valve Event and Lift Control Device (VEL) for Automotive Engines

2001-01-0244

View Details

TECHNICAL PAPER

Liquid LPG Injection System with Variable Fuel Injection Pressure Control

2010-01-0159

View Details

X