A method for monitoring an operation of an internal combustion engine includes the steps of: detecting, during the operation of the internal combustion engine, an acoustic signal, at least partially, during a closing process of a gas exchange valve of the internal combustion engine; evaluating, based on the acoustic signal which is detected, at least one functional state of the internal combustion engine; and selecting the at least one functional state of the internal combustion engine from a group consisting of a state of the gas exchange valve and a state of a structure-borne noise sensor used to detect the acoustic signal.

A reciprocating piston internal combustion engine includes: a sensor system on a gas exchange valve which has a valve head situated at a first end of a valve stem; a lever element which engages at a second end of the valve stem and which is designed to actuate the gas exchange valve by displacing the valve head; a detection element which, upon actuation of the gas exchange valve, is displaced along a displacement path; and a sensor device configured to ascertain a position of the detection element. The sensor device is situated in such a way that the detection element, during a displacement along a portion of the displacement path, moves predominantly in a movement toward the sensor device or away from the same, thereby providing a measurement of valve timing of the gas exchange valve.

A magnetic sensor arrangement for determining a position of an actuator may include a magnetic sensor to determine the position of the actuator, where the actuator may be configured to reciprocate along a longitudinal axis of an actuator housing of the actuator, such that at least a portion of the actuator may cross an end plane of the actuator housing when reciprocating along the longitudinal axis, and the magnetic sensor may sense a set of components of a magnetic field generated by a magnet, and determine, based on the sensed set of components of the magnetic field, a position of the actuator along the longitudinal axis of the actuator housing of the actuator, where the magnet may be connected to or forms part of the actuator, and where the magnetic sensor may be connected to the actuator housing, and where a portion of the magnetic sensor may be positioned at least in a first actuator position beyond the end plane of the actuator housing.

A linear variable differential transformer (LVDT) for monitoring engine valve position is disclosed. The system includes a valve guide having an elongated recess through it. The engine valve has a valve head and a valve stem with two adjacent materials having different magnetic properties meeting at an interface. The valve stem fits and moves linearly within the valve guide, and the valve head closes an engine combustion chamber. It also includes monitoring coils within the valve guide that create a signal related to the position of the interface within the valve guide. An engine control unit (ECU) is coupled to the monitoring coils and receives and analyzes the signal from the monitoring coils to determine operation of the valve.

A valve motion measurement assembly is provided for a cylinder valve of an internal combustion engine provided with a valve stem and with a valve head. The valve motion measurement assembly includes a valve position sensor, a supporting bracket provided with at least one sensor seat for the valve position sensor, and a sensor target element configured to be coupled to the valve stem at a distance from the valve head to follow the motion of the cylinder valve. The valve position sensor interacts with the sensor target element for determining the position of the cylinder valve.

According to a method of detecting a lift amount of a valve, an area-increasing jig is attached to an upper surface of a retainer attached to the valve. The area-increasing jig has a larger width than a width of the upper surface of the retainer. Then a lift amount of the valve is detected by measuring a distance to the area-increasing jig by using a non-contact sensor disposed above the retainer.

An apparatus for measuring at least one of temperature and pressure within a cylinder of an internal combustion engine can include an engine valve and a sensor. The internal combustion engine can include a valvetrain having rocker arm assembly, a camshaft, a valve, and a hydraulic lash adjuster. The engine valve can have a valve head and a valve stem extending from the valve head in an axial direction. The valve head can have a valve face configured to be in pressure communication with an engine cylinder. The valve stem can have an outer surface with a cylindrical portion and a variably-shaped portion. The variably-shaped portion can define a target detectable by the sensor and the sensor can be installed adjacent to the target. Alternatively, the sensor can be positioned to detect a level of force at some point along the valvetrain.

A durable system for controlling variable valve actuation of an engine valve corresponding to a cylinder of an automobile engine. The system includes first and second crowned cams having first and second lift profiles and a rocker arm assembly. The rocker assembly includes a first arm having an end connected to said engine valve, having a high impact roller following the first crowned cam operating the engine valves according to a first lift profile. The rocker arm assembly also includes a second arm having durable slider pads riding on the second crowned cam to operate said engine valve according to a second lift profile. A latch secures the second arm relative to the first arm when in a latched position causing the valve to operate according to a second lift profile. The valve operates according to a first lift profile when the latch is not in the latched position.

A system for selectively deactivating engine valves of a cylinder of an internal combustion engine. The system employs switching rocker assemblies between the valves of the engine and rotating cam lobes. The disclosed design is able to operate using a single cam lobe per valve. The rocker assembly employs a first arm pivotally attached to a second arm at one end. The first arm engages the valve and the second arm has a roller bearing that engages the cam lobe. A latch causes the first and second arm to move in unison following the cam surface when latched. When unlatched, the second arm follows and moves according to the rotating cam surface, but the first arm does not follow and does not actuate the valve, thereby deactivating the cylinder.

Methods and systems are provided for injecting fuel into a combustion chamber of an engine. In one example, a system may include a hollow cone-shaped injector and a control unit to control the injector. The control unit may detect the position of an inlet valve and trigger the injection process, wherein the injector may be configured to spray fuel out of an inlet duct, through an annular gap, and into the combustion chamber of an engine in an injection process.