Method to operate filter unit for diesel fuel for vehicle engine; involves generating maintenance signal, when fuel temperature and pressure on input side of filter are above specified thresholds

摘要

The method involves using a filter and a unit to display a maintenance signal when the filter is to dirty. The maintenance signal is generated according to the fuel state on the input side of the filter, when both the fuel temperature and pressure are above specified threshold values. A heating unit (1) may be connected to the input side of the filter, when the fuel temperature is below the threshold but the fuel pressure is above the threshold. Independent claims are included for a filter unit and for a unit with a heater for the vehicle engine.