Variable lift cylinder valve system for internal combustion engine
AssigneeFord Global Technologies, LLC
InventorsFang Shui, John Edmund Brune, Mark Alan Zagata
Life of this patent
Estimating the term…
Abstract
A variable lift cylinder valve system for an internal combustion engine includes a poppet valve operated by a rocker arm which is articulated about a translational pivot having its placement determined by a control shaft which operates a control arm in contact with the translational pivot such that rotation of the control shaft produces translational motion of the pivot so as to control the lift ratio of the rocker arm.
Claims11
A variable lift cylinder valve system for an internal combustion engine, comprising:
- at least one poppet valve disposed within a cylinder head of the engine, with said poppet valve having a head and a stem adapted for contact by a valve opening member;
- a spring for biasing the poppet valve into a closed position;
- at least one valve operating camshaft carrying at least one cam lobe;
- a rocker arm in contact with said at least one cam lobe and said valve stem;
- a translational pivot, in articulated contact with the rocker arm, for converting a linear component of motion of said at least one cam lobe into rotational motion of the rocker arm and a corresponding linear motion of said poppet valve;
- a control shaft extending along an axis generally parallel to the axis of said camshaft, with said control shaft being mounted for pure rotation about said control shaft axis;
- and
- a control arm, mounted upon said control shaft and operatively connected with said translational pivot, for converting rotational motion of said control shaft into translational motion of said pivot, so as to control the lift ratio of said rocker arm.
A method for calibrating the minimum lift of position of a variable lift cylinder valve system of an internal combustion engine having a camshaft;
- a rocker arm driven by the camshaft;
- a rotatable valve lift control shaft;
- and a control arm, positioned by the control shaft, for adjusting the rocker arm pivot ratio, with said method comprising the steps of:
- placing the camshaft in a predetermined rotational position;
- placing the cylinder valve in a predetermined position;
- and locking the control arm to the control shaft when the camshaft and the cylinder valve are in said predetermined positions.
A method for adjusting the lift of camshaft driven poppet valves of a reciprocating internal combustion engine, comprising the steps of:
- sampling a plurality of engine operating parameters;
- determining a desired valve lift value from the values of the sampled parameters;
- extracting a rotary lift position value from a lookup table by using said desired lift value as an input variable;
- converting the rotary lift position value into a lift position signal;
- and
- providing the lift position signal to a valve lift control shaft rotary actuator, so as to position a valve control arm rigidly attached to the control shaft.
Dependencies are inferred from the claim text.