A system for monitoring operation of an internal combustion engine having a rocker arm assembly for actuating an engine valve is disclosed. The rocker arm assembly includes a first arm with a first end, a second arm also having a first end pivotally connected near the first end of the first arm along a pivot axle, at least one torsion spring coiled around an end of the pivot axle, a latch that when latched secures the first arm relative to the second arm in a latched mode, and when unlatched allows the first arm to move relative to the second arm in an unlatched mode. The system also employs a sensor attached to one of the first and second arms that can detect when the arms are moving relative to each other, and adapted to provide a signal indicating the sensed movement.

A system for monitoring operation of an internal combustion engine having a rocker arm assembly for actuating an engine valve is disclosed. The rocker arm assembly includes a first arm with a first end and a second end, at least one slider pad connected to the first arm near the second end of the first arm, a second arm also having a first end pivotally connected near the first end of the first arm along a pivot axle, a latch that when latched secures the first arm relative to the second arm in a latched mode, and when unlatched allows the first arm to move relative to the second arm in an unlatched mode. The system also employs a sensor attached to one of the arms that can detect when the arms are moving relative to each other, and adapted to provide a signal indicating the detected movement.

A system for monitoring operation of an internal combustion engine having a rocker arm assembly for actuating an engine valve is disclosed. The rocker arm assembly includes a first arm with a first end, a second arm also having a first end pivotally connected near the first end of the first arm, a latch that when latched secures the first arm relative to the second arm in a latched mode, and when unlatched allows the first arm to move relative to the second arm in an unlatched mode. The system also employing a sensor attached to one of the first and second arms that can detect when the arms are moving relative to each other, and adapted to provide a signal indicating the sensed movement.

Various embodiments include a method for checking a variable valve lift control of an internal combustion engine comprising: during operation of the internal combustion engine, detecting a rotational speed of the internal combustion engine; and measuring an intake pressure in the intake tract of the internal combustion engine corresponding to the detected rotational speed. The method further includes: defining a reference frequency dependent on the rotational speed of the internal combustion engine; defining a comparison frequency as a non-integral multiple of the reference frequency; determining amplitudes of oscillations of the intake pressure at the reference frequency and amplitudes of oscillations of the intake pressure at the comparison frequency; and evaluating a ratio of the determined amplitudes and the respective absolute values.

A system for monitoring operation of an internal combustion engine having a rocker arm assembly for actuating an engine valve is disclosed. The rocker arm assembly includes a first arm with a first end, a second arm also having a first end pivotally connected near the first end of the first arm, a latch that when latched secures the first arm relative to the second arm in a latched mode, and when unlatched allows the first arm to move relative to the second arm in an unlatched mode. The system also employing a sensor attached to one of the first and second arms that can detect when the arms are moving relative to each other, and adapted to provide a signal indicating the sensed movement.

A system for monitoring operation of an internal combustion engine having a rocker arm assembly for actuating an engine valve is disclosed. The rocker arm assembly includes a first arm with a first end, a second arm also having a first end pivotally connected near the first end of the first arm along a pivot axle, at least one torsion spring coiled around an end of the pivot axle, a latch that when latched secures the first arm relative to the second arm in a latched mode, and when unlatched allows the first arm to move relative to the second arm in an unlatched mode. The system also employs a sensor attached to one of the first and second arms that can detect when the arms are moving relative to each other, and adapted to provide a signal indicating the sensed movement.

Various embodiments include a method for checking a variable valve lift control of an internal combustion engine comprising: during operation of the internal combustion engine, detecting a rotational speed of the internal combustion engine; and measuring an intake pressure in the intake tract of the internal combustion engine corresponding to the detected rotational speed. The method further includes: defining a reference frequency dependent on the rotational speed of the internal combustion engine; defining a comparison frequency as a non-integral multiple of the reference frequency; determining amplitudes of oscillations of the intake pressure at the reference frequency and amplitudes of oscillations of the intake pressure at the comparison frequency; and evaluating a ratio of the determined amplitudes and the respective absolute values.

A method and apparatus for continually and rapidly adjusting the output torque of an engine according to a torque demand uses an active tappet to vary the instant air charge in a combustion chamber. The invention allows substantially efficient combustion throughout the engine operating map. Various methods of changing the charge of air are disclosed.

A system for monitoring operation of an internal combustion engine having a rocker arm assembly for actuating an engine valve is disclosed. The rocker arm assembly includes a first arm with a first end, a second arm also having a first end pivotally connected near the first end of the first arm, a latch that when latched secures the first arm relative to the second arm in a latched mode, and when unlatched allows the first arm to move relative to the second arm in an unlatched mode. The system also employing a sensor attached to one of the first and second arms that can detect when the arms are moving relative to each other, and adapted to provide a signal indicating the sensed movement.