Abstract: An optical sensor for the monitoring of combustion processes in a combustion chamber comprises a lens system facing the combustion chamber, a waveguide and a sheath surrounding the lens system. The lens system has at least one essentially plano-concave lens and a double concave lens wherein the planar surface of the plano-concave lens is exposed to the combustion chamber. A method for centering one or more lenses and a waveguide in a sheath of an optical sensor for monitoring combustion processes in a combustion chamber is also disclosed that includes filling the gap between the first lens and the sheath with a soldering paste.

Abstract: A spark plug has an optical window for sensing combustion processes in an Otto engine. The optical window is located in the central electrode of the spark plug and has at least one lens exposed to the combustion chamber, as well as at least one flexible optical fiber which can conduct light through the spark plug from the lens to an analysis system.

Abstract: A piezoelectric measuring element (9) consists of at least two piezoelectric crystals (1) showing a transversal effect for the measurement of axially acting forces and/or pressures as well as to a pressure or force sensor comprising said element. The crystals (1) with transversal effect having an opposite polarization (4) to each other are attached to each other by means of a lateral electrode (12). In this manner, if n crystals (1) are attached to each other, a single multi-layer measuring element (9) is obtained with a stability under load which is n-times that of an individual crystal. Preferably, the electrodes extend alternately into the two force-absorbing end faces (3) of the crystals. Such measuring elements can be fabricated from wafers (15) in a cost-effective manner. A compact multi-layer measuring element prepared in this way can be easily mounted in a sensor, particularly a force or pressure sensor, without the risk of inclination.

Abstract: The present invention relates to an optical sensor for the monitoring of combustion processes in a combustion chamber wherein the optical sensor at least comprises a lens system facing the combustion chamber, a waveguide and a sheath surrounding the lens system and one end of the waveguide characterized in that the lens system consists of at least one essentially plano-concave lens and a double concave lens wherein the planar surface of the plano-concave lens is exposed to the combustion chamber. The invention also relates to a method for the manufacture of said sensor.

Abstract: A spark plug has an optical window for sensing combustion processes in an Otto engine. The optical window is located in the central electrode of the spark plug and has at least one lens exposed to the combustion chamber, as well as at least one flexible optical fiber which can conduct light through the spark plug from the lens to an analysis system.

Abstract: A piezoelectric measuring element (9) consists of at least two piezoelectric crystals (1) showing a transversal effect for the measurement of axially acting forces and/or pressures as well as to a pressure or force sensor comprising said element. The crystals (1) with transversal effect having an opposite polarization (4) to each other are attached to each other by means of a lateral electrode (12). In this manner, if n crystals (1) are attached to each other, a single multi-layer measuring element (9) is obtained with a stability under load which is n-times that of an individual crystal. Preferably, the electrodes extend alternately into the two force-absorbing end faces (3) of the crystals. Such measuring elements can be fabricated from wafers (15) in a cost-effective manner. A compact multi-layer measuring element prepared in this way can be easily mounted in a sensor, particularly a force or pressure sensor, without the risk of inclination.

Abstract: A high-pressure sensor specially for monitoring pulsating hydraulic pressure impulses, as for example in injection systems of combustion engines is provided with a pressure space shaped balloon-like before the diaphragm part, enabling optimal measuring signals to be combined simultaneously with significantly reduced mechanical forces in the welded joint. In addition, welding techniques are proposed enabling a gapless internal welding zone to be achieved, so that notch effects and migratory cracks resulting from these and leading to fractures are obviated. As optimal connection between measuring head and threaded body a two-stage welding routine is proposed first an internal weld is performed by electrical upset welding and then external welding by electron beam, inert gas or laser welding.

Abstract: An accelerometer element of the bender having geometrical outside dimensions and relations wherein the height and width are alike and half of the length. The accelerometer element is built from ceramic materials and consists of two half blocks with a piezoelectric bender element clamped in-between. The high part tolerances are overcome by two fastener gaps, being filled with a special material for microcomponents. This method allows tolerance differences to be compensated by the fastener gaps and its fastening layer. The half blocks consist of a ceramic material to be ground in strips and processed with electronic components in well known batch production methods. Both sides of the blocs are protected with cover plates. The connector recess is filled with a watertight sealing material. The accelerometer element, whether with or without integrated electronics, is fully hermetic and watertight, with only the signal wires protruding on the outside.

Abstract: The detector arrangement comprises a measuring rail with a number of individual elements each having a sensor mounted on a bottom rail and include rectangular elements as force introduction flanges, whose length in the direction of travel is a multiple of their width in the axial direction of the rail. The measuring rail is part of a measuring arrangement for detecting the tire pressures of vehicles in motion. The arrangement includes also at least one contact rail placed ahead of the measuring rail in the direction of travel, and a data acquisition facility. The vehicle speed is determined with the help of the contact rail. The measured values from the sensors yield a tire contact surface with an isobar pattern. From these two, the data acquisition can determine underinflation, normal pressure and overinflation of the individual wheels besides axle loads and vehicle weights, whereby underinflation and overinflation at least are displayed as faults.