| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cetane number estimation device which can detect the replenishment of a low cetane number fuel on early stage while maintaining high cetane number estimation accuracy of the fuel. <P>SOLUTION: The device executes fuel injection to a diesel engine at a predetermined amount (S202, S203) under a condition that an execution condition is established (S201:YES), and detects rotation fluctuation ΣΔNE during the execution of the fuel injection (S204). An average value AVE (S206) of the rotation fluctuation ΣΔNE in a nearest predetermined period and standard deviation σ (S207) are calculated. If a latest value R of the rotation fluctuation ΣΔNE is smaller than a value that is obtained by subtracting the triple standard deviation σ from the average value AVE (S208:YES), a low cetane number region is selected (S211). If the latest value R is equal to or larger than the value that is obtained by subtracting the triple standard deviation σ from the average value AVE (S208:NO), the cetane number region is identified on the basis of the average value AVE. <P>COPYRIGHT: (C)2013,JPO&INPIT |
