Fuel Pressure Switch for Low Pressure Fuel Subsystem Diagnosis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Direct injection internal combustion engines face issues with the high pressure fuel system due to insufficient fuel flow and pressure from the low pressure fuel sub-system, leading to potential degradation or damage, and existing fuel pressure sensors are expensive and limited in their response and range sensing characteristics.
Innovation Solution
An engine system that includes a fuel pressure switch and a control system to detect low fuel pressure conditions, limiting fuel pressure and flow rate, and notifying operators or service personnel when a clogging is inferred, thereby reducing the risk of damage to the high pressure pump and providing a more robust and cost-effective alternative to traditional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fuel pressure sensor is used to monitor the low pressure fuel sub-system, then the fuel pressure can be accurately measured, but the cost increases and the sensor may fail due to durability issues
Solution Approach 1:
The patent introduces a fuel pressure switch as an intermediary device that indirectly monitors fuel pressure conditions without requiring a direct fuel pressure sensor in the high pressure line. The switch detects pressure conditions through a diaphragm that responds to pressure changes, providing reliable monitoring without the durability issues of traditional fuel pressure sensors.
Solution Approach 2:
The fuel pressure switch uses a simple mechanical diaphragm-based mechanism that is more robust and less prone to failure compared to electronic fuel pressure sensors. The design accepts that the switch may need replacement but makes it more durable through simpler construction, reducing overall system cost and reliability concerns.
2Speed
If a fuel pressure sensor is used to monitor fuel pressure, then real-time pressure data can be obtained, but the response time and sensing range are limited
Solution Approach 1:
The fuel pressure switch acts as an intermediary that provides immediate mechanical response to pressure changes through the diaphragm mechanism, eliminating the electronic response delays inherent in fuel pressure sensors. The switch can detect a range of pressure conditions and provide immediate state changes based on pressure thresholds.
3Reliability
If the low pressure fuel sub-system provides insufficient fuel flow and pressure, then the high pressure pump may be damaged, but adding monitoring increases system complexity
Solution Approach 1:
The fuel pressure switch serves as a simple intermediary monitoring device that protects the high pressure pump from damage due to insufficient fuel pressure. The mechanical diaphragm-based switch provides reliable protection without the complexity of electronic sensors and control systems, directly indicating when pressure thresholds are exceeded.
4Measurement precision
If traditional fuel pressure sensors are used, then fuel pressure can be monitored, but the cost becomes prohibitively expensive
Solution Approach 1:
The fuel pressure switch uses a simple mechanical construction with a diaphragm, spring, and electrical contacts that is much cheaper to manufacture than electronic fuel pressure sensors. The design accepts that the switch may need periodic replacement but dramatically reduces the initial system cost and ongoing maintenance expenses.
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
The system effectively reduces the risk of degradation and damage to the fuel system by limiting fuel delivery during low pressure conditions and provides a more reliable and cost-effective solution for monitoring fuel pressure compared to traditional sensors.
Implementation Method 1
The fuel pressure switch is configured to switch to a high pressure state in response to a higher fuel pressure within the fuel passage downstream of the fuel filter and switch to a low pressure state in response to a lower fuel pressure within the fuel passage downstream of the fuel filter
Data Source
AI summary
An engine system for a vehicle and its method of operation are provided. In one embodiment, a control system is configured to indicate a clogging of a fuel filter based on a period of time that a fuel pressure switch remains in a low pressure state. In some embodiments, the control system may respond to an indicated clogging of the fuel system by limiting one or more of fuel pressure, fuel flow rate, and vehicle speed. By limiting the flow rate and/or the pressure at which fuel is delivered to the engine during conditions when the low pressure fuel sub-system is unable to provide sufficient fuel pressure and/or flow, degradation and/or damage to the fuel system, including the high pressure pump, may be reduced or eliminated.