Abstract: A service-interval display for motor vehicles, which generates a signal when a limiting parameter value is reached. Total fuel consumption serves as the basic parameter instead of the distance travelled, previously employed. Other parameters may serve to modify the generation of the signal to cause an earlier or later warning to be displayed.

Abstract: The signalling device provides a signal indicating the need for a maintainance service when a limit value of a given magnitude is reached. This magnitude is a function of the total number of revolutions of an output shaft or any other rotary part and optionally of one or a plurality of additional operation parameters.

Abstract: A service interval display unit for a motor vehicle for alerting the operator of required maintenance wherein actual distance traveled by the vehicle is monitored, and as a factor in determining the service interval, operating parameters such as engine speed, coolant temperature, oil temperature, and/or fuel consumption rate are taken into consideration on a weighted basis to assert earlier a service signal in the display unit when the engine experiences increased periods of higher loads. The display unit includes a series of indicators which are successively extinguished upon attainment of subintervals during the maintenance cycle and warning lights which are energized after attainment of the service interval. Additional warning lights also are provided for emphasizing the expiration of the service interval when the vehicle is operated successive fixed distance intervals beyond the regular service interval.

Abstract: A test installation for motor vehicle operating elements which change compared to a starting condition and which trigger an indicating device when reaching a limit value; a number of change intervals related to a change-influencing parameter and equal among each other are coordinated to the changes of the operating elements and one indicating device each is coordinated to the intervals of equal value of the operating elements; of the several operating elements, that operating element triggers the indicating device and also a warning indicating device which as the first one reaches the limit of its associated change interval, respectively, its limit for the predetermined overall change.

Abstract: A service-interval display for motor vehicles, delivers a signal after a fixed distance has been traversed, the fixed distance (D) is divided into several fixed service distance intervals (i.sub.d) of equal length, and a plurality of individual signal elements, each of which changes its switch status at the end of successive intervals, is assigned to each of these intervals. The number of signal elements activated is an indication of the incremental approach to arrival at and travel beyond the fixed distance (D).