Fuel supply control device

A fuel supply control device configured to generate an operation amount used for feedback-controlling rotation of a gear pump based on a deviation of a detected flow rate of a fuel with respect to a target flow rate,

• wherein the fuel supply control device generates the operation amount such that a rotation speed of the gear pump is equal to or greater than a lower limit rotation speed Nmin so as to protect a bearing of the gear pump,
• wherein the fuel supply control device comprises:
• a lower limit value calculator configured to calculate the lower limit rotation speed Nmin using a viscosity coefficient of a lubricant of the bearing calculated based on a fuel temperature of the gear pump, a pressure-boosted amount of the gear pump, a shaft diameter and a minimum gap of the bearing, and a Sommerfeld number,
• an operation amount calculator configured to calculate an operating rotation speed N based on the deviation;
• and
• a comparator configured to output larger one of the lower limit rotation speed Nmin and the operating rotation speed N as the operation amount of an actual rotation speed, and
• wherein the lower limit rotation speed Nmin is given by the following Equation (1) constituted by a viscosity coefficient μ of the lubricant of the bearing calculated based on the fuel temperature of the gear pump, the pressure-boosted amount P of the gear pump, a shaft diameter r, the minimum gap of the bearing cmin, and the Sommerfeld number S:
• N
• ⁢
• min
• =
• P
• μ
• ⁢
• S
• [
• c
• ⁢
• min
• r
• ]
• 2
• (
• 1
• )