basis of consumption values of urea solution measured in the past arithmetic unit 1 forecasts the amount of time that engine 8 can continue to run until the urea supply in tank 25 has been depleted this time is compared to the time remaining until the next filter regeneration which was calculated as described with reference to the first embodiment and the lesser of the two times is displayed as a numeral 11 for the remaining operating time on the basis of said remaining operating time the remaining harvesting quantity and the remaining territory of numerals 13 14 are calculated it can be provided that a text message or a special icon is displayed on display screen 5 to signal to the driver whether the factor limiting the remaining operating capacity is the filter capacity or the urea supply it is also feasible however to display sections that indicate the need to replenish a resource in the work plan of bar diagram 15 such as section 21 which indicates filter regeneration in different colors depending on which resource needs to be replenished it will be understood that each of the elements described above or two or more together may also find a useful application in other types of constructions differing from the types described above while the invention has been illustrated and described as embodied in a monitoring device for an internal combustion engine it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention without further analysis the foregoing will so fully reveal the.