Combustion Engine Injector Damping Element Design
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Solution Overview
Problem
Injectors for combustion engines face challenges in achieving precise and reliable fluid dosage, particularly at low volumes and high pressures, leading to unpredictable fluid quantity dispensing due to kinetic energy transfer and potential sticking issues during operation.
Innovation Solution
Incorporation of a damping element, such as a viscoelastic material or O-ring, between the valve needle and the pole piece to provide controlled damping during movement, ensuring accurate fluid injection by compensating for tolerances and inaccuracies, and preventing unintended mass flow variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a damping element is added to the injector, then manufacturing precision and reliability of fluid dosage improve, but device complexity increases
Solution Approach 1:
A damping element is introduced as an intermediary component between the valve needle and pole piece. This mediator absorbs kinetic energy during valve needle movement, compensating for manufacturing tolerances and preventing sticking issues, thereby improving fluid dosage precision without requiring higher manufacturing tolerances on existing components.
Solution Approach 2:
The damping element changes the dynamic parameters of the valve needle movement by providing controlled resistance during its travel. This modifies the kinetic energy transfer characteristics, allowing the system to maintain precise fluid dosage across varying operating conditions including temperature changes and different injection rates.
2Productivity
If the valve needle is made axially movable for opening the valve, then fluid injection capability improves, but reliability deteriorates due to kinetic energy transfer and sticking issues
Solution Approach 1:
The damping element is positioned to interact with the valve needle before it reaches the end of its travel or potentially sticks. By providing continuous damping force throughout the movement, it prevents excessive kinetic energy accumulation that could cause sticking or unpredictable behavior, thereby maintaining reliability while preserving injection capability.
Solution Approach 2:
The damping element converts the potentially harmful kinetic energy transfer into a beneficial controlled damping force. Instead of allowing uncontrolled energy transfer that causes sticking and reliability issues, the damping element dissipates this energy in a controlled manner, turning a source of problems into a mechanism for improving operational reliability.
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 damping element allows for precise and controllable fluid dosing, maintaining accuracy even in ballistic operation modes and across varying temperatures, ensuring reliable and consistent fluid delivery.
Implementation Method 1
The injector further comprises a damping element which is arranged and configured to mechanically interact with the valve needle and the pole piece during movement of the valve needle with respect to the pole piece
Implementation Method 2
Incorporation of a damping element, such as a viscoelastic material or O-ring, between the valve needle and the pole piece to provide controlled damping during movement
Implementation Method 3
The electromagnetic actuator assembly comprises a pole piece being fixedly coupled with respect to the injection valve housing and an armature being axially movable within the injection valve cavity for actuating the valve needle
Data Source
AI summary
An injector for a combustion engine may include a valve housing, a valve needle, an electromagnetic actuator, and a damping element. The valve needle may be axially movable within a valve cavity of the housing. The electromagnetic actuator may comprise a pole piece coupled with the valve housing and an armature axially movable within the valve cavity. The pole piece may have a central recess extending axially there through. The central recess may include a step defining a first portion and a second portion, the first having a larger cross-sectional area than the second, and a stop surface defined by a radially extending surface of the step. The valve needle may include an armature retainer in the first portion of the central recess. The armature may be axially displaceable with respect to the valve needle and interact with the valve needle by means of the retainer for actuating the valve needle. The damping element may be arranged between the stop surface and the armature retainer to interact with the valve needle and the pole piece during movement.