Abstract: A simplified lost motion valve control system and method for engines combines a cam, having a seating ramp located between lift and return profiles of the cam lobe, with a simplified hydraulic actuator having follower and actuator pistons and a fluid discharge passage that is internally cut off by the actuator piston when the valve is close to its seated position. After opening of the valve by the cam through the actuator to a desired valve opening, the valve is closed by opening a solenoid valve to discharge fluid from the actuator until the valve closes to near its seated position. The valve is then seated by the actuator following the cam seating ramp. The actuator is refilled upon return of the follower piston along the cam return profile to the base circle. Exemplary embodiments of hydraulic actuators are disclosed as is a system including control of dual actuators, driven by out of phase cams, through a single solenoid valve alternately isolated by the discharge port closure of the actuator pistons.

Abstract: A structure for mounting electronic valve timing control system components wherein any bubbles or other air carrying obstructions are purged from the system. The inlet and outlet passageways (14, 18) to and from the actuator (16) are displaced either a predetermined vertical distance ("H") or are in-line and inclined along the same passageway axis.

Abstract: In an internal combustion engine control system, an electronic circuit accepts a non-linear analog signal from a Mass Air Flow (MAF) sensor and converts it to a digital signal by means of a linear or non-linear analog to digital (A/D) converter. The digital signal is then processed by a two-dimensional look-up table which includes corrections for the MAF sensor non-linearity and additional corrections for non-linearity of the A/D converter. This linearized MAF signal is then integrated or averaged to provide air mass per engine event or average mass air flow during an event. This circuit is useful in obtaining better accuracy in fuel management systems that use MAF sensors, particularly if variable valve control is included as part of the control system. The look up table and integrator can be easily implemented in a digital signal processor or microcontroller.

Abstract: A variable camshaft timing system for an internal combustion engine varies the relative angular position between the intake camshaft and the exhaust camshaft by controlling the path of the timing belt means. A first belt means is interconnected at one end of the engine between the crankshaft and the exhaust camshaft. At the other end of the engine the intake camshaft and the exhaust camshaft are connected by a second belt means for rotating the intake camshaft from the rotational drive supplied via exhaust camshaft. Idler arms are positioned for controlling the path and tension in the second belt means for varying the timing of the intake camshaft relative to the exhaust camshaft. A motor means operates to position the idler arms through a positioning cam means.