Gm Global Technolgoy Operations, Inc.

Christopher M De Minco

Mark James Spath

Scott H Nather

Michael James Fox

Timothy Wilton Kunz

Wayne S Harris

Michael Thomas Faville

John J Krieg

Daniel B O'Connell

Ivan R Samalot

Timothy J Peterson

Steven F Lowe

Small engine control is provided in which a manual selection of an engine operating level, such as from a positioning of a movable selector between a discrete number of selection settings is used to reference open-loop fuel, air, and ignition timing commands for application to respective actuators in accord with simple yet accurate and flexible engine control. Control precision, sensitivity, and stability are enhanced through engine parameter feedback control, wherein any of the open-loop air, fuel and ignition timing commands may be adjusted in accord with a difference between a feedback signal and a target value.

Integrated small engine control

A low mass two-step valve lifter has concentric inner and outer cylindrical cam followers engagable by radially disposed axially aligned lock pins in the outer high lift follower. Both inner and outer followers have cylindrically crowned cam engaging surfaces for high lift capability and low load eccentricity. The lock pins are positioned on the lifter thrust axis normal to the direction of the engine camshaft axis and the skirt has upward seal extensions and downward extending skirt portions adjacent the lock pin openings to maintain seal area. Other skirt portions are cut away to reduce weight. Vent holes in the lock pins discharge collected oil that might interfere with fast pin engagement. A separate passage is provided to feed oil to a hydraulic lash adjuster disposed in the inner follower cylinder. A single guide pin aligns the dual followers with the external bore oil ports and the camshaft cams. Additional features are also disclosed.

Low mass two-step valve lifter

Compact valve lifters are disclosed for overhead camshaft engines with direct acting valve gear and for engines with indirect acting valve actuation such as push rod actuated overhead valves. Two step variable lift and non-variable lift valve lifters are included as are roller and non-roller follower types with various features in common.

Compact valve lifters

Low mass hydraulic and mechanical valve lifters are shown and described. The lifters are of oblong configuration for reduced mass, with straight or narrowed sides connecting longitudinally spaced ends having depending semi-cylindrical end walls that are received in similarly shaped end portions of lifter gallery openings to absorb all longitudinal and lateral side loads. The lifters are preferably made by investment casting of steel alloys. The investment casting permits the use of thin semi-cylindrical walls at each end of the valve lifters which also have internal reinforcing ribs extending on their undersides.

Low mass valve lifters

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Honeoye Falls, NY, United States of America

Christopher M De Minco