"Cross Flow Fan" The more the number of samples to test the data more reliable, at least three. 2000,3000,5000,10000,18000 hour test time can be used as specification. That is the test time point i is 1,2, ... .n, because there is a five-point test point, so n = 5, I = 1,2,3,4,5 a total of five points. Suppose a fan of existing products to the axis of fuel consumption to 50% deemed bad, because fuel consumption to 50% for a long time, it is necessary to seek outside its time difference method. If oil loss curve approaches linearity, fuel consumption formula can be written as Y = Ax + b.