Fuel Pump Controller Relay Switching Reduction
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Solution Overview
Problem
Conventional fuel supply systems face issues with frequent relay ON and OFF cycles, leading to operational failures and inefficiencies, especially in vehicles with idle stop functions and hybrid vehicles, where the fuel pump controller's electric power is cut off during engine stops, causing reliability concerns and increased fuel consumption.
Innovation Solution
The system reduces relay ON and OFF cycles by setting a lower limit guard value for the fuel pump's duty ratio based on the engine's operation state, maintaining the relay in an ON state during engine stops and using PI control to manage fuel pressure, allowing the fuel pump to remain operational and reducing unnecessary power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the relay is turned OFF to cut electric power to the fuel pump controller during engine stops, then power consumption is reduced, but the fuel pump controller becomes inoperable and reliability decreases
Solution Approach 1:
The patent replaces the mechanical relay-based power control system with an electronic control system. The ECU controls the fuel pump controller's operation through electronic signals rather than physically cutting power via a relay. This allows the fuel pump controller to remain powered and operational during engine stops, eliminating the reliability issue while maintaining power management capabilities.
2Use of energy by moving object
If the relay is frequently turned ON and OFF to control fuel pump operation, then power consumption is managed, but the relay lifespan decreases and system reliability worsens
Solution Approach 1:
The patent eliminates the mechanical relay from the control system by using electronic control through the ECU. The ECU sends control signals to the fuel pump controller, which then regulates the fuel pump's operation. This substitution removes the mechanical switching component that was subject to wear from frequent ON/OFF cycling, thereby improving system reliability and durability.
3Use of energy by moving object
If the fuel pump is stopped during engine stops to save power, then power consumption is reduced, but fuel pressure may drop below required levels when engine restarts
Solution Approach 1:
The patent implements a feedback control system where the ECU monitors engine stop conditions and communicates with the fuel pump controller. Based on feedback about engine state and fuel pressure requirements, the ECU instructs the fuel pump controller to maintain or adjust fuel pressure even during engine stops. This ensures fuel pressure remains stable and ready for immediate engine restart while still allowing power management.
Solution Approach 2:
The patent uses preliminary action by having the ECU anticipate engine restart requirements. Before the engine actually restarts, the ECU ensures the fuel pump controller is already prepared to maintain appropriate fuel pressure levels. This preliminary preparation prevents fuel pressure drops and ensures immediate availability of fuel when the engine restarts, while still allowing the system to reduce power consumption during extended stop periods.
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
This approach minimizes relay switching, maintains fuel pump operability during engine stops, and reduces power consumption by preventing frequent start-ups and potential leaks, enhancing the reliability and efficiency of the fuel supply system.
Implementation Method 1
the FPC 12 performs PI control and sets a duty ratio of a drive signal
Data Source
AI summary
A fuel supply system includes an electronic control unit that outputs a target fuel pressure for controlling a low-pressure pump and an engine status, and a fuel pump controller (FPC) that generates a drive signal for driving the low-pressure pump based on the target fuel pressure. The FPC is configured to obtain an actual fuel pressure, to set a duty ratio and to perform a feedback control for the actual fuel pressure to follow the target fuel pressure, and to set a lower limit guard value based on the engine status. The lower limit guard setter sets a duty ratio of 0% as the lower limit guard value when the engine status indicates a stop of the engine.