Patent ID: 7788905

Claim:
A fuel fractionation method for an internal combustion engine comprising the steps of: applying an operation for promoting a fractionation of a fuel of the internal combustion engine to a fractionation passage while making the fuel flow to the fractionation passage, thereby fractionating the fuel into a gas phase fuel and a liquid phase fuel within the fractionation passage; conducting the fractionated gas phase fuel and the fractionated liquid phase fuel to a branch point of the fractionation passage; separating the gas phase fuel and the liquid phase fuel to an upper branch passage and a lower branch passage, respectively due to gravity; applying a heat operation to the fractionation passage by utilizing exhaust heat wasted from the internal combustion engine from the operation for promoting the fractionation of the fuel; adjusting a flow rate of the fuel conducted to the fractionation passage with a temperature adjusting device so that the temperature of the branch point of the fractionation passage is maintained at a predetermined target temperature; accumulating the fuel conducted from the upper branch passage in a distillation fuel container; detecting an accumulation volume of the distillation fuel container with an accumulation volume detecting device; and lowering the target temperature in relation to the detected accumulation volume when the detected accumulation volume is increasing.