Method and system to avoid piston-valve collision

Method to control actuation of an engine valve operable to control combustion chamber flow, said combustion chamber formed in a cylinder having a reciprocating piston operably attached to a crankshaft, comprising:

• determining a crank angle at which to initiate engine valve opening, comprising:
• determining a desired valve lift, and a duration of valve open time;
• estimating an opening profile for the engine valve, based upon the desired valve lift, and, the duration of valve open time;
• determining a first crank angle, based upon the estimated opening profile for the engine valve, a cylinder diameter, and, a cylinder displacement;
• determining a second crank angle, based upon the first crank angle, a linear position of the piston determined when the crankshaft is at the first crank angle, and, the estimated opening profile for the engine valve;
• and,
• offsetting the second crank angle by a safety margin.

System to control actuation of an engine valve operable to control combustion chamber flow, comprising:

• an internal combustion engine:
• comprising a plurality of cylinders;
• each cylinder having a head, including at least one air intake valve and at least one exhaust valve;
• and, a reciprocating piston;
• each piston operably connected to a rotating crankshaft;
• a crank position sensor;
• a valve actuation system;
• and,
• a controller, signally electrically connected to the crank position sensor, and, operably connected to the valve actuation system;
• the controller operable to determine a crank angle at which to initiate engine valve opening, comprising:
• determine a desired valve lift, and a duration of valve open time,
• estimate an opening profile for the engine valve, based upon the desired valve lift, and, the duration of valve open time,
• determine a first crank angle, based upon the estimated opening profile for the engine valve, and, the duration of valve open time,
• determine a second crank angle, based upon the first crank angle, a linear position of the piston determined when the crankshaft is at the first crank angle, and, the estimated opening profile for the engine valve, and,
• offset the second crank angle by a safety margin;
• and,
• the controller operable to control the valve actuation system based upon the determined crank angle at which to initiate engine valve opening.