Outboard Motor Fuel Supply System Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fuel supply systems for outboard motors experience temperature increases due to heat radiation from booster pumps, leading to fuel bubble formation and excessive fuel return, which is not effectively mitigated by existing methods.
Innovation Solution
A fuel supply system with a returnless structure, incorporating a fuel pressure sensor and controller for feedback control of the booster pump to maintain fuel pressure above a threshold, ensuring all fuel is injected into the engine without returning excess fuel to the sub tank, thereby preventing temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the booster pump operates continuously to supply fuel to the engine, then the fuel pressure is maintained, but the fuel temperature increases due to heat radiation from the electric motor
Solution Approach 1:
The electric motor driving the booster pump is controlled to operate intermittently rather than continuously. The control unit stops the motor when a small amount of fuel is required to be injected, reducing heat radiation to the fuel while maintaining fuel supply capability when needed.
2Temperature
If the duty cycle of the booster pump is reduced to decrease excess fuel return, then the fuel temperature increase is reduced, but the fuel pressure stability deteriorates
Solution Approach 1:
A control unit monitors the operating conditions and adjusts the duty cycle of the booster pump based on the required fuel injection amount. When small amounts of fuel are required, the control unit reduces the motor's duty cycle to minimize heat generation while maintaining adequate fuel pressure through precise control.
3Stress or pressure
If excess fuel is returned to the sub fuel tank through the return pipe, then the fuel pressure is regulated, but the fuel temperature increases due to continuous circulation through the heated system
Solution Approach 1:
The booster pump operates intermittently based on actual fuel demand. When small amounts of fuel are required, the pump reduces operation, thereby reducing the volume of fuel circulated through the heated system and minimizing temperature increase while still maintaining pressure regulation when needed.
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 solution effectively prevents fuel temperature increases, reduces energy consumption by eliminating the need for fuel cooling mechanisms, and minimizes energy loss by avoiding excess fuel return, ensuring efficient fuel injection and operation.
Implementation Method 1
the temperature of the fuel is increased due to radiation of heat from an electric motor that drives the booster pump
Implementation Method 2
a booster pump disposed inside the sub fuel tank... The booster pump is disposed inside the sub fuel tank. The fuel pipe with the returnless structure supplies the fuel with a pressure increased by the booster pump
Data Source
AI summary
A fuel supply system includes a sub fuel tank, a booster pump, a fuel pipe, a fuel pressure sensor and a controller. The sub fuel tank stores a fuel supplied thereto from a main fuel tank. The booster pump is disposed inside the sub fuel tank. The fuel pipe has a returnless structure and supplies the fuel with a pressure increased by the booster pump to a fuel injection device of an engine. The fuel pressure sensor detects the pressure of the fuel inside the fuel pipe. The controller is configured or programmed to perform a feedback control of the booster pump based on a value of the pressure of the fuel detected by the fuel pressure sensor such that the pressure of the fuel inside the fuel pipe becomes greater than or equal to a first threshold.