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 force sensor can include a magnetic field generator, a magnetic flux return, and a magneto-elastic layer. The magnetic flux return can extend along a first portion of at least one pathway of magnetic flux generated by the magnetic field generator. The magneto-elastic layer can be operable to be in contact with a surface subjected to force and thereby strained. The magneto-elastic layer can extend along a second portion of the at least one pathway of magnetic flux distinct from the first portion.

A force sensor can include a magnetic field generator, a magnetic flux return, and a magneto-elastic layer. The magnetic flux return can extend along a first portion of at least one pathway of magnetic flux generated by the magnetic field generator. The magneto-elastic layer can be operable to be in contact with a surface subjected to force and thereby strained. The magneto-elastic layer can extend along a second portion of the at least one pathway of magnetic flux distinct from the first portion.

A pipeline fluid pressure fluctuation sensing device includes a housing, vibrating membrane, fixing ring, pressure balance hole, magnetic element, and magnetic sensing element. The housing includes an open end and closed end opposite to each other, so that no conducting wire is passed through the housing; the open end is used to connect the fluid pipeline. The vibrating membrane is provided inside the housing, and the vibrating membrane is allowed to be displaced due to the pressure change generated from fluid pipeline. The fixing ring is connected between the housing and vibrating membrane. The pressure balance hole is passed through the fixing ring and used to balance pressure at the two opposite sides of the vibrating membrane. The magnetic element and vibrating membrane are linked to each other, where the magnetic element is generated with a displacement change due to the displacement of the vibrating membrane.

A pipeline fluid pressure fluctuation sensing device includes a housing, vibrating membrane, fixing ring, pressure balance hole, magnetic element, and magnetic sensing element. The housing includes an open end and closed end opposite to each other, so that no conducting wire is passed through the housing; the open end is used to connect the fluid pipeline. The vibrating membrane is provided inside the housing, and the vibrating membrane is allowed to be displaced due to the pressure change generated from fluid pipeline. The fixing ring is connected between the housing and vibrating membrane. The pressure balance hole is passed through the fixing ring and used to balance pressure at the two opposite sides of the vibrating membrane. The magnetic element and vibrating membrane are linked to each other, where the magnetic element is generated with a displacement change due to the displacement of the vibrating membrane.

A magnetostrictive film includes rich regions having a mesh pattern in a cross section perpendicular to a film thickness direction of the magnetostrictive film. The rich regions are richer in a specific element contributing to ferromagnetism than surroundings of the rich regions.