Method to calculate fuel DI number from a measured curve

A system for calculating a fuel driveability (DI) value on-board a vehicle having a fuel tank and an engine controller, the system comprising:

• means for holding a known volume of fuel from the fuel tank in a sensor, said sensor in communication with a flow of fuel from the fuel tank;
• means for heating the sensor and the volume of fuel therein;
• means for measuring temperatures of the sensor relative to the volume of fuel remaining in the sensor as the sensor is heated, and
• means for calculating a DI value from measured T10, T50 and T90 values and predetermined correlation equations for matching the measured temperatures with measured values from a standardized method of ASTM D86, wherein T10 is the temperature when 10% of the fuel in the sensor has been distilled, T50 is the temperature when 50% of the fuel in the sensor has been distilled, and T90 is the temperature when 90% of the fuel in the sensor has been distilled.

A system for calculating a fuel driveability (DI) value for a vehicle having a fuel tank, the system comprising:

• means for calculating a DI value from a standard test and a first sensor having a known volume of fuel therein by measuring the volume of fuel versus temperature as the fuel is heated;
• a related sensor having the capacity for storing another sample of the same known volume of fuel as the first sensor wherein said related sensor is located in the vehicle and in fluid communication with fuel flow from the fuel tank;
• means for heating the related sensor and the volume of fuel therein;
• means for measuring the volume of fuel in the related sensor versus the temperature of the sample fuel;
• and
• means for correlating the measured temperature and volume of fuel in the related sensor with the measured temperature and volume of fuel in the first sensor to provide correlation equations for calculating the DI value from the related sensor.