Fuel Pump Inlet Valve Latching Mechanism
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Solution Overview
Problem
Existing pump units for fuel injection systems cannot readily vary the volume of fuel delivered during each pump cycle, often requiring additional metering systems for certain applications.
Innovation Solution
A pump unit with a latching mechanism for the inlet valve member that allows for controlled metering of fuel by latching the valve in the open position during the pumping stroke, using a combination of magnetic fields and a spring bias to manage the valve's operation, enabling precise control of fuel volume delivered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a spring-biased inlet valve member is used to control fuel supply, then the pump unit can deliver fuel to the high pressure manifold, but the volume of fuel delivered during each pump cycle cannot be readily varied
Solution Approach 1:
The inlet valve member is transformed from a static spring-biased valve to a dynamic latched valve that can be actively controlled to remain open during the pumping stroke. The latching mechanism allows the valve to maintain its open position dynamically throughout the stroke, enabling variable fuel volume delivery by controlling when the valve closes, thereby providing metering capability without additional complex metering systems.
Solution Approach 2:
The conventional spring-biased mechanical valve control system is replaced with a latching mechanism that uses magnetic fields (electromagnet and permanent magnet) to control the inlet valve member position. This substitution of mechanical spring bias with magnetic latching enables precise control of valve timing and fuel volume delivery, resolving the contradiction between productivity control and device complexity.
2Measurement precision
If the inlet valve member is held open during the pumping stroke, then precise metering of fuel volume is achieved, but additional latching control mechanisms are required
Solution Approach 1:
The latching mechanism merges multiple functions into a single integrated system: the electromagnet provides active latching control, the permanent magnet provides passive holding force, and the spring provides reset bias. This combination allows precise metering control through coordinated interaction of these elements, achieving high measurement precision while managing device complexity through functional integration rather than separate independent systems.
Solution Approach 2:
The latching mechanism acts as an intermediary between the control system and the inlet valve member. The electromagnet and permanent magnet together create a magnetic field intermediary that translates electrical control signals into mechanical valve positioning, enabling precise fuel volume metering control without direct mechanical linkage complexity.
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 precise metering of fuel volume during each pump cycle, reducing the need for additional metering systems and improving the efficiency of fuel delivery to the high-pressure manifold.
Implementation Method 1
a permanent magnet for establishing a magnetic field to latch the inlet valve member in its open position
Implementation Method 2
an electromagnet to establish a magnetic field at least partially to counter the magnetic field established by the permanent magnet and unlatch the inlet valve member
Implementation Method 3
a spring member operable to establish a force to bias the inlet valve member towards its closed position
Data Source
AI summary
The present application relates to a pump unit for a fuel injection system. The pump unit has a low pressure fuel supply line and a high pressure fuel outlet. A pumping chamber having a plunger is operable to perform a pumping cycle comprising a pumping stroke and a filling stroke. The pump unit also includes an inlet valve having an inlet valve member movable between an open position for permitting the supply of fuel to the pumping chamber from the low pressure fuel supply line and a closed position for inhibiting the supply of fuel from the pumping chamber to the low pressure supply line. An outlet valve is provided in the high pressure fuel outlet. The pump unit also includes a means for latching the inlet valve member in its open position. The present application also relates to a method of operating a pump unit.