Patent ID: 8950245
Filing Date: 2015-02-10
Classification: F02D,Y02T

Abstract:
1. A fuel quality determining method for determining quality of fuel based on a combustion state of the fuel by injecting the fuel into a combustion chamber and burning the fuel, comprising providing a coordinate plane which has a coordinate axis which indicates a value of ignition delay which is a time from fuel injection to fuel ignition and a coordinate axis which indicates a value of a flame spread rate which is an increase rate of a flame from a point of time immediately after fuel is ignited with respect to a plurality of fuels whose quality is determined to be good or bad based on the presence or the non-presence of a combustion failure as a result of an actual use of the fuels are already known, defining a first range which is at least either one of a range where a value of the ignition delay is smaller than a predetermined value with respect to the ignition delay and a range where the value of ignition delay is larger than a second predetermined value which is larger than the predetermined value with respect to the ignition delay, the first range being a range where whether quality of fuel is good or bad is unequivocally decided based on the value of ignition delay, and defining a second range which is a range between the predetermined value and the second predetermined value and in which whether the quality of fuel is good or bad is not unequivocally decided based on the value of the ignition delay, the second range being defined based on the distribution of the respective values on the coordinate plane, providing a determination reference which defines a range of values of the flame spread rate indicative of good products corresponding to the values of the ignition delay on the coordinate plane with respect to the flame spread rate within a range which includes the second range based on the distribution with respect to the plurality of materials, and measuring the value of ignition delay and the value of flame spread rate with respect to fuel which is an object to be determined, wherein the quality of the fuel which is an object to be determined is determined to be good when the measured value of the ignition delay falls within a range smaller than the predetermined value within the first range, and the quality of the fuel which is an object to be determined is determined to be bad when the measured value of the ignition delay falls within a range larger than the second predetermined value within the first range, and wherein whether quality of the fuel is good or bad which is an object to be determined is determined based on whether or not the measured value of the flame spread rate falls within the good product range in accordance with the determination reference when the measured value of the ignition delay falls within the second range.