A method for verifying a CVVD location learning result may include performing a learning value verification control by confirming a position of a control shaft connected to a motor with a signal value of an auxiliary cam sensor for a rotation of a camshaft if a controller determines that a learning value acquired in a short duration and a long duration of a CVVD system is desired to be verified.

A method for adaptation of a detected camshaft position of a camshaft in an internal combustion engine with: Detection of an ACTUAL gas signal in a gas space that is associated with the camshaft and is associated with a detected camshaft position; Processing of the gas signal to produce an ACTUAL gas criterion; Modeling of multiple simulated gas criteria, each of which is associated with a target camshaft position; Determination of a simulated gas criterion with the least deviation from the ACTUAL gas criterion; Determination of an ACTUAL camshaft position that corresponds to the simulated gas criterion with the least deviation from the ACTUAL gas criterion; Determination of a camshaft position correction value from the difference between the ACTUAL camshaft position determined and the detected camshaft position; Determination of corrected camshaft positions by correcting the detected camshaft positions with the camshaft position correction value.

A rocker arm grading system can comprise a grading tool. The grading tool can be used with a rocker arm to measure aspects of the rocker arm and determine a resulting valve lift. The grading tool can comprise a rocker arm jig comprising a pivot peg and a valve peg. A cam jig can comprise a cam arm. A cam pin can be mounted in the cam arm. A rocker arm can be removably mounted to the rocker arm jig. The rocker arm can comprise a radius on a bearing surface. A cam edge of the cam pin can press against the bearing surface. At least one measuring device comprising a wavelength emitting device paired with a wavelength detecting device can be configured to measure the radius of the bearing surface with respect to the pivot peg.

Methods and systems are provided for controlling and monitoring intake and exhaust poppet valves of an internal combustion engine. In one example, the methods and system include feedback control that estimates intake and exhaust valve timing based on output of an in cylinder pressure sensor. In another example, the methods and system include compensation for feedforward control of intake and exhaust valves based on output of the in cylinder pressure sensor.

A control device and a control method for variable valve timing mechanism according to the present invention obtains a first measurement of a rotational phase based on a rotational angle of the motor, obtains a second measurement of the rotational phase based on a relative relationship between a rotational angle of the crankshaft and a rotational angle of the camshaft, calibrates the first measurement based on the second measurement, obtains a derivative term proportional to a rate of change in a deviation between the first measurement and a target value, reduces change in derivative term when calibrating the first measurement based on the second measurement, and controls the motor based on a manipulated variable including the derivative term.

A method of continuously variable valve duration (CVVD) location learning may include when a controller determines necessity of position learning for short duration and long duration of a CVVD system, performing conditional application re-learning control in which the position learning is performed in a situation in which validity determination of system environment condition for CVVD hardware and validity determination of vehicle environment condition for engine operation information of an engine are satisfied.

A control strategy includes: after an engine is energized, the continuously variable valve lift mechanism self learning to determine a current position; if the self learning is successful, the continuously variable valve lift mechanism being located at a maximum lift position, preparing for starting the engine, and determining a regulating mode based on a starting temperature, wherein at the time of normal temperature start, regulation is performed from the maximum lift position to a minimum lift position, and at the time of low temperature start, regulation is performed from the maximum lift position to a position where the two valves for the same cylinder have a maximum lift difference; if the self learning fails, entering a preliminary start mode; entering a CVVL control mode based on an operation condition of the engine; and powering off the engine.

A method for adaptation of a detected camshaft position of a camshaft in an internal combustion engine with: Detection of an ACTUAL gas signal in a gas space that is associated with the camshaft and is associated with a detected camshaft position; Processing of the gas signal to produce an ACTUAL gas criterion; Modeling of multiple simulated gas criteria, each of which is associated with a target camshaft position; Determination of a simulated gas criterion with the least deviation from the ACTUAL gas criterion; Determination of an ACTUAL camshaft position that corresponds to the simulated gas criterion with the least deviation from the ACTUAL gas criterion; Determination of a camshaft position correction value from the difference between the ACTUAL camshaft position determined and the detected camshaft position; Determination of corrected camshaft positions by correcting the detected camshaft positions with the camshaft position correction value.

A rocker arm grading system can comprise a grading tool. The grading tool can be used with a rocker arm to measure aspects of the rocker arm and determine a resulting valve lift. The grading tool can comprise a rocker arm jig comprising a pivot peg and a valve peg. A cam jig can comprise a cam arm. A cam pin can be mounted in the cam arm. A rocker arm can be removably mounted to the rocker arm jig. The rocker arm can comprise a radius on a bearing surface. A cam edge of the cam pin can press against the bearing surface. At least one measuring device comprising a wavelength emitting device paired with a wavelength detecting device can be configured to measure the radius of the bearing surface with respect to the pivot peg.

A control strategy includes: after an engine is energized, the continuously variable valve lift mechanism self learning to determine a current position; if the self learning is successful, the continuously variable valve lift mechanism being located at a maximum lift position, preparing for starting the engine, and determining a regulating mode based on a starting temperature, wherein at the time of normal temperature start, regulation is performed from the maximum lift position to a minimum lift position, and at the time of low temperature start, regulation is performed from the maximum lift position to a position where the two valves for the same cylinder have a maximum lift difference; if the self learning fails, entering a preliminary start mode; entering a CVVL control mode based on an operation condition of the engine; and powering off the engine.