For modern oil management systems in vehicles we developed an innovative combi-sensor. The sensor component is capable of measuring 6 independent oil parameters (viscosity, density, permittivity, conductance, level, temperature) continously during normal engine operation. It comprises an ultrasonic transducer for the oil level detection as well as a Tuning Fork mechanical resonator for the oil condition measurement. Both elements have been realized as small multi-chip modules, which are combined within a mechanical flange. All data is transmitted to an external ECU by a 1-wire digital interface protocol.
In addition to the measurement and signal preconditioning software that is already implemented on the system, an AUTOSAR-conform software module will be provided for the customer. This software evaluates the incoming signals from the sensor and calculates the current oil quality, considering additional information from the engine. The intelligent Oil Condition Algorithm (OCA) detects contaminants and extreme oil conditions at an early stage. In this way oil change intervals can be adapted to the specific car and the individual driving behavior in a more precise way than is possible with existing oil condition monitoring concepts and algorithms.
Since the oil level can be measured even when the engine is stopped, the sensor ensures an overfill detection comparable to a regular dipstick, which is then redundant.