Solenoid Valve Current Control for Noise Reduction
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Solution Overview
Problem
The existing fuel injection systems in internal combustion engines produce an unpleasant audible sound due to the high impact velocity of the armature against the stroke limiting stops when the solenoid valve closes, which can lead to incomplete valve closure and insufficient pressure buildup, despite efforts to reduce actuation time and current levels.
Innovation Solution
The method involves reducing the coil current setpoint value from a first to a second value to slow down the activation response of the solenoid valve, ensuring full closure while minimizing the impact velocity and thus the audible sound, by determining a minimum current value based on actual pressure differences or setpoint pressure increases, and applying a safety offset to ensure reliable closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current in the coil is increased to ensure reliable closing of the solenoid valve, then the valve closure reliability is improved, but the impact velocity of the armature increases producing audible sound
Solution Approach 1:
The patent applies periodic action by dividing the current application into two distinct phases: an initial phase with a first current value to start armature movement, and a subsequent phase with a reduced second current value to maintain closure. This temporal separation allows the armature to accelerate initially then decelerate before impact, reducing audible sound while ensuring reliable valve closure
Solution Approach 2:
The patent changes the current parameter over time during the valve actuation process. The current is reduced from a first current value to a second current value that is lower by 10% to 50%, specifically adjusting the electrical parameter to control the magnetic force and thereby control the armature's impact velocity and reduce audible sound
2Object-generated harmful factors
If the current in the coil is reduced to decrease impact velocity, then the audible sound is reduced, but the actuation time increases and valve closure reliability decreases
Solution Approach 1:
The patent applies preliminary action by applying an initial higher current to the coil before the armature reaches its end position. This preliminary high current ensures the armature starts moving reliably and quickly, and only after this initial acceleration phase does the current get reduced, maintaining closure reliability while minimizing impact velocity
3Object-generated harmful factors
If the voltage applied to the coil is reduced before valve closure to decrease impact velocity, then the audible sound is reduced, but the actuation time increases
Solution Approach 1:
The patent uses periodic action by applying voltage in two distinct temporal phases: initially applying a higher voltage to quickly accelerate the armature, then reducing the voltage before the armature reaches the end position. This timing optimization ensures the armature has already gained sufficient momentum while the reduced voltage allows it to decelerate, minimizing both impact velocity and total actuation time
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 approach effectively reduces the audible noise during engine operation, ensuring a quieter and more pleasant experience while ensuring full solenoid valve closure and maintaining sufficient pressure buildup in the high-pressure pump.
Implementation Method 1
a solenoid valve electromagnetically operated by a coil
Data Source
AI summary
A method for regulating a fuel injection system of an internal combustion engine, wherein the fuel injection system includes a high-pressure pump which is associated with a quantity control valve having a solenoid valve electromagnetically operable by a coil for supplying fuel, the quantity control valve regulating the fuel quantity pumped by the high pressure pump and the coil of the solenoid valve being energized according to a setpoint current value in order to close the valve for supplying fuel to the high-pressure pump; when the solenoid valve closes, the setpoint current value is reduced from a first current setpoint value to a second current setpoint value so that an emission of audible noise generated when the solenoid valve closes during operation of the internal combustion engine is at least partially reduced.