Fuel Supply Control Device Switching Feedback for Pressure Stability
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Solution Overview
Problem
The existing fuel supply apparatus experiences unstable differential pressure in high flow-rate ranges, making stable fuel supply control challenging when the pressurizing valve is opened.
Innovation Solution
A fuel supply control device that uses a combination of a differential pressure-fuel supply amount conversion table, a rotation speed-fuel supply amount conversion table, a leakage amount estimation unit, and a switching logic circuit to generate control amounts for the electric motor, allowing for stable fuel supply control by switching between different control strategies based on flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pressurizing valve is opened to increase fuel flow rate, then the fuel supply amount increases, but the front-rear differential pressure becomes unstable
Solution Approach 1:
The control method changes the parameter used for feedback control based on the operating condition. When the pressurizing valve is closed, differential pressure is used as the feedback parameter. When the pressurizing valve is opened, the control switches to using pump rotation speed as the feedback parameter instead, thereby maintaining stable control across different flow rate ranges despite the instability of differential pressure at high flow rates
Solution Approach 2:
The control system dynamically switches between two different control strategies based on the opening state of the pressurizing valve. This dynamic adaptation allows the system to optimize its control approach for each operating condition, ensuring stable fuel supply control whether the valve is closed (low flow rate) or open (high flow rate)
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables stable and accurate fuel supply control in both low and high flow-rate ranges by using the appropriate control amounts, ensuring the fuel supply meets the control target values effectively.
Implementation Method 1
a front-rear differential pressure across the fixed orifice, that is, the pressurizing valve, which is detected by a differential pressure gauge
Implementation Method 2
a fuel tank, a centrifugal pump, a gear pump
Implementation Method 3
a fuel tank, a centrifugal pump, a gear pump
Data Source
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AI summary
A fuel supply control device (8) is configured to control a fuel supply pump (3) on the basis of a front-rear differential pressure across a metering valve for a fuel supply amount, which is detected by a differential pressure gauge (7), using parallel flow passages of an orifice (6) and a pressurizing valve (5) as the metering valve. The fuel supply control device (8) includes a first control amount generation unit (8a) that is configured to generate a first control amount (S1) on the basis of the front-rear differential pressure, a second control amount generation unit (8b, 8c, and 8d) that is configured to generate a second control amount (S2) on the basis of the rotation speed of the fuel supply pump (3), a control amount selection unit (8f) that is configured to alternatively select the first control amount (S1) or the second control amount (S2) on the basis of the rotation speed, a subtractor (8g) that is configured to calculate a deviation of the output of the control amount selection unit (8f) from a control target value, and a control calculation unit (8h) that is configured to calculate an operation amount of the fuel supply pump (3) on the basis of the output of the subtractor (8g). The control amount selection unit (8f) is configured to select the first control amount (S1) in a case where the rotation speed is equal to or lower than a predetermined threshold and select the second control amount (S2) instead of the first control amount (S1) in a case where the rotation speed exceeds the threshold.