Fuel Pump Control Unit Duty Ratio Adjustment
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Solution Overview
Problem
Existing fuel suppliers for automobiles experience a time delay in increasing the number of revolutions of the fuel pump when the accelerator is pressed, leading to a decrease in fuel pressure below the target pressure, which affects acceleration performance.
Innovation Solution
A fuel supplier system that adjusts the low limit value of the duty ratio of the motor's voltage feedback control based on the accelerator open ratio, ensuring the fuel pressure remains at the target pressure by simultaneously increasing the number of revolutions of the fuel pump when the accelerator is pressed, and adjusting fuel supply according to throttle open ratio changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback control is used to maintain fuel pressure at target level by regulating motor duty ratio, then fuel pressure stability is improved, but response time increases causing delay in fuel pump revolution increase when accelerator is pressed
Solution Approach 1:
The control unit increases the low limit value of the duty ratio in advance based on accelerator open ratio detection, before fuel pressure deviation occurs. This preliminary adjustment ensures that when the accelerator is pressed, the fuel pump revolutions increase immediately without waiting for pressure deviation feedback, thus resolving the contradiction between pressure stability and response time.
2Use of energy by moving object
If the duty ratio is held at minimum value during idle condition, then energy consumption is reduced, but fuel pressure cannot be maintained when fuel consumption increases suddenly
Solution Approach 1:
The control system dynamically adjusts the low limit value of the duty ratio based on accelerator open ratio. During idle conditions, the low limit remains at minimum to reduce energy consumption. When accelerator open ratio increases, the low limit is increased proportionally, allowing the fuel pump to deliver more fuel and maintain pressure reliability. This dynamic adaptation resolves the contradiction between energy efficiency and pressure maintenance.
3Reliability
If fuel pump revolutions are increased to meet sudden fuel demand, then fuel pressure is maintained, but energy consumption increases
Solution Approach 1:
The control unit changes the duty ratio parameter dynamically based on accelerator open ratio. By increasing the low limit value of the duty ratio in proportion to accelerator open ratio, the system adjusts the motor's power delivery to match fuel demand, maintaining fuel pressure reliability while optimizing energy consumption according to actual driving conditions.
Data Source
AI summary
A fuel supplier for a motor vehicle, having a fuel tank and an internal combustion engine, includes a fuel pump pumping fuel from the fuel tank to the internal combustion engine, a motor driving the fuel pump, and a control unit carrying out feedback control of duty ratio of voltage applied to the motor such that the actual fuel pressure comes close to a target fuel pressure. The control unit increases a low limit value of the duty ratio in accordance with the change of an accelerator open ratio in an opening direction.