Pressure Reducing Valve Control Apparatus for Fuel Rail
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Solution Overview
Problem
In internal combustion engines, pressure reducing valves fail to open reliably at low rail pressures due to insufficient electromagnetic force, leading to inefficiencies and increased costs when trying to maintain high rail pressures, especially when using large spring forces to counteract fuel-generated valve-opening forces.
Innovation Solution
A pressure reducing valve control apparatus that includes a hold control part and a hold value setting part, where the hold value is adjusted based on decreasing fuel pressure to ensure the valve opens effectively without requiring larger electromagnetic coils or increased material costs, by maintaining a predetermined current supply to the electromagnetic coil during a hold period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the spring force is increased to close the valve at high rail pressure, then the valve can remain closed at high pressure, but the electromagnetic force becomes insufficient to open the valve at low rail pressure
Solution Approach 1:
The patent applies dynamic control of the electromagnetic coil current through multiple operational modes (continuous conduction mode, discontinuous conduction mode, and idle mode) that adjust the current supply based on rail pressure conditions. This dynamic approach allows the system to provide sufficient electromagnetic force at low pressure while maintaining valve closure at high pressure, resolving the contradiction between spring force requirements and electromagnetic force availability.
Solution Approach 2:
The patent changes the electrical parameters (current magnitude, duty cycle, frequency) of the electromagnetic coil based on the rail pressure state. By adjusting these parameters dynamically, the system optimizes the electromagnetic force output to match the varying pressure conditions, ensuring reliable valve opening at low pressure without requiring excessive spring force that would prevent opening.
2Force
If the electromagnetic coil has more turns or uses high magnetic material to increase electromagnetic force, then the valve can open at low pressure, but the device size and material cost increase
Solution Approach 1:
Instead of increasing the physical size of the electromagnetic coil, the patent implements dynamic current control with multiple conduction modes. This allows the existing coil to generate sufficient electromagnetic force at low pressure by optimizing the electrical input parameters, avoiding the need for larger coils or expensive high magnetic materials while maintaining reliable valve opening.
Solution Approach 2:
The patent optimizes the electromagnetic force output by changing electrical parameters (current amplitude, duty cycle, frequency) rather than physical parameters (coil turns, magnetic material). This parameter-based optimization achieves the required force at low pressure without increasing device size or material cost.
3Reliability
If the current supply period is extended to increase electromagnetic force, then the valve opens more reliably, but the power consumption increases
Solution Approach 1:
The patent implements periodic action through discontinuous conduction mode, where the electromagnetic coil is activated in periodic pulses rather than continuously. This allows the valve to open reliably through repeated electromagnetic forcing while reducing overall power consumption compared to continuous current supply. The idle mode further reduces power consumption when valve opening is not required.
Solution Approach 2:
The patent dynamically adjusts the current supply duration and intensity based on real-time pressure conditions and valve state. This dynamic control ensures sufficient electromagnetic force for reliable opening while minimizing power consumption by avoiding unnecessary continuous current supply, especially during idle periods when the valve remains closed.
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
Ensures reliable valve opening across varying rail pressures without the need for larger valve sizes or more expensive materials, optimizing power consumption and maintaining efficient fuel injection operations.
Implementation Method 1
an electromagnetic coil for applying electromagnetic force to the valve body in a valve-opening direction
Implementation Method 2
a spring member for applying spring force to the valve body in a valve-closing direction
Implementation Method 3
the valve body is arranged to receive fuel pressure in the accumulation chamber in a valve-opening direction
Data Source
AI summary
A pressure reducing valve control apparatus is provided for a fuel supply system having a common rail and a pressure reducing valve to control rail pressure in the common rail by controlling a current supply state of the pressure reducing valve. The pressure reducing valve operates to open a valve body for discharging fuel from the common rail against a biasing force applied in a valve-closing direction by fuel-generated valve-opening force biasing the valve body in a valve-opening direction by the rail pressure and an electromagnetic force generated by current supply to an electromagnetic coil. The ECU starts to open the valve body during a period of holding a hold value by holding current supplied to the electromagnetic coil at a predetermined hold value after starting current supply to the electromagnetic coil. The ECU sets the hold value to increase as the rail pressure decreases.