Adjustable valve control spring loading, for camless IC engine, has valve stem end secured in axially adjustable barrel screwed into valve spring seating cup

摘要

The valve is operated not by cam action but by an electromagnetic actuator (12), screwed (44) to the cylinder head (24) and aligned by a spigot (64) with a cylindrical well (26) in the head, accommodating the helical actuator and valve return springs (66,32). These are seated, respectively, on a circular plate (72), fixed on the actuator plunger end (80,57), and a cup-shaped adjuster (40) on the valve stem top (16). The other ends of the springs (34,70) are seated on the well bottom (28) and the spigot. The valve stem and the actuator plunger, passing through their respective springs, slide in guides (20,58) set coaxially with the well in the head and the actuator. Their adjacent ends abut the opposite sides of a spacer disk (85) placed in the cup of the adjuster. The threaded barrel, sewing into the adjuster cup's central aperture, has a tapered bore that fits the conical outer surface of a retaining split shell. Each half-shell has a circumferential inner rib engaging in a peripheral groove in the valve stem. The barrel and cup top rims are notched to fit hollow tubular spanners, fitting one inside the other, immobilizing the cup while the barrel height is varied to alter the overall length of the spring.