Abstract: A spark plug for use in an internal combustion engine and comprising a movement sensor located in the region of the upsetting and heat-shrink area of the spark plug housing for sensing movement resulting from movement of movable parts of the engine such as pistons, valves, etc.

Abstract: A servocylinder (1, 3, 4) with an electric piston end position transmitter is suggested. It is constructed as a piezoelectric converter (17 and 18). By means of applying voltage to the piezoelectric converter (17 and 18) the latter becomes a regulating element which overcomes a force holding the piston (2) in its stroke end position and removes the piston (2) from its position in which the feed line (7 and 8) of the pressure medium is sealed.

Abstract: A piezoelectric control block, particularly for controlling a fuel injection device for a combustion engine, preferably diesel engine, with a distributor injecting pipe, has an adjustable fuel quantity adjusting member, and a longitudinally extending mechanical movement converter which is formed so that under longitudinal load it deforms transversely to its longitudinal expansion and has a part which performs an overproportional movement under the longitudinal load and is connected with the feed quantity adjusting member.

Abstract: A piezoelectric device for measuring the pressure of a gas like medium comprises two oscillators disposed opposite to each other in a substantially closed system by intermediate introduction of the gas to be measured. The measuring is performed by defining a transfer factor from the first piezoelectric oscillator to the second piezoelectric oscillator, whereby the first piezoelectric oscillator is definitely excited and the measuring signal is picked up by the second piezoelectric oscillator.

Abstract: To determine if a pulsed beam system, typically an ultrasonic pulsed beam system, which is located externally of a motor vehicle is in operative condition, a transmitter (14) projects a beam to a fixed reflector (16) located on the vehicle, and one (19) of a group of timing stages (18; 19, 20, 21) evaluates the transit time to the reflector. If the transit time to the reflector is slightly less than a predetermined time interval (Tc), so that the threshold timing level (Tc) is passed, a first indication, for example a frequency at a first tone (f1), generated by an acoustic tone generator (30) is reproduced in a loudspeaker; if, then, an obstruction is sensed by the beam, and the distance between the transmitter (14) and the obstruction (17) which forms a reflecting object drops below a first predetermined distance represented by a time period (T2), a second one of the transit time stages responds, and, through logic gates (22-24, 28, 29) provides a second discrete output frequency (f2) in the loudspeaker.