Fuel Supply System with Return Flow Sensor for Stopped-State Detection
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Solution Overview
Problem
Internal combustion engines face challenges in detecting fuel property changes, especially in hybrid vehicles where the engine is infrequently started, leading to potential long-term undetection of fuel degradation or abnormal fuel introduction due to the placement of fuel property sensors in the fuel flow path between the pump and injector.
Innovation Solution
A fuel supply system with a pressure adjustment device, return flow path, and fuel property sensor allows for fuel property determination during engine operation and at stopped states by actuating the fuel pump at programmed timings, enabling early detection of fuel changes in the tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel property sensor is placed in the fuel flow path between the fuel pump and the injector, then the fuel property can be determined during engine operation, but the fuel property cannot be detected during engine stopped state
Solution Approach 1:
The system performs preliminary fuel property measurement by directing fuel through the return flow path and sensor before the engine actually operates. The fuel pump is activated in advance during stopped state to circulate fuel through the sensor, enabling detection before combustion begins, thus ensuring reliable detection regardless of engine state
Solution Approach 2:
A return flow path is introduced as an intermediary channel that allows fuel to be redirected from the main fuel supply line back to the fuel tank through the sensor. This intermediary path enables fuel circulation and measurement without requiring the engine to be in operation, bypassing the limitation of the original direct fuel flow path
2Reliability
If the fuel pump is continuously actuated to enable fuel property detection during stopped state, then early detection of fuel degradation is possible, but energy consumption increases
Solution Approach 1:
Instead of continuous operation, the fuel pump is activated periodically at predetermined intervals during stopped state. The control unit determines fuel property at specific timing points, allowing sufficient detection capability while minimizing unnecessary energy consumption from continuous pump operation
Solution Approach 2:
The system utilizes the existing fuel circulation mechanism and return flow path to enable self-diagnosis and self-monitoring of fuel quality. The fuel system serves its own monitoring function by redirecting a portion of its own flow through the sensor, eliminating the need for separate continuous pumping systems
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 continuous monitoring of fuel properties during engine operation and periodic checks during stopped states, preventing undetected fuel degradation or abnormal fuel introduction, while minimizing unnecessary fuel pump actuation to conserve energy.
Implementation Method 1
a fuel property sensor that detects a fuel property of a fuel in the return flow path
Data Source
AI summary
A fuel supply system of an internal combustion engine includes: a pressure adjustment device provided on a fuel flow path that connects a fuel pump and an injector; a return flow path for returning a fuel discharged from the pressure adjustment device to a fuel tank; a fuel property sensor disposed in the return flow path; a fuel pump control portion that actuates the fuel pump at a predetermined programmed timing, when the internal combustion engine is in a stopped state; and a fuel property determination portion that determines a fuel property of the fuel in the fuel tank by using an output value of the fuel property sensor, when the fuel pump is actuated during the stopped state of the internal combustion engine.