Fuel Injector Needle Position Modeling for Injection Quantity
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Solution Overview
Problem
Existing methods for determining the injection quantity of fuel injectors with solenoid drives in internal combustion engines lack precision, especially during short injection times when the needle movement describes a ballistic trajectory, leading to variations in fuel delivery.
Innovation Solution
A method that calculates the injection quantity by determining the start and end times of the injection process and using a mathematical model to represent the nozzle needle's position as a function of time, combined with the through flow rate, to accurately determine the injected fuel quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant through flow rate is assumed for injection quantity calculation, then the calculation process is simple, but the precision of injection quantity determination deteriorates during short injection times
Solution Approach 1:
The patent applies dynamics by transitioning from a static assumption of constant through flow rate to a dynamic model where the needle position varies continuously with time during the injection process. The quadratic function y(t) = a*t^2 + b*t + c describes the time-dependent needle position, allowing the through flow rate to change dynamically throughout the injection, thereby achieving precise injection quantity determination even during short injection times.
2Device complexity
If the needle movement is not modeled precisely, then the calculation process is simple, but the uniformity of injection across multiple fuel injectors deteriorates
Solution Approach 1:
The patent applies parameter changes by using a quadratic function with three parameters (a, b, c) to describe the needle position as a function of time. These parameters are determined based on the start and end times of the injection process, allowing the model to adapt to different injection conditions and injector characteristics, thereby ensuring uniform injection across multiple fuel injectors.
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 allows for precise determination and correction of injection quantities, even during short injection times, ensuring consistent fuel delivery across multiple fuel injectors.
Implementation Method 1
A solenoid injector (also called a coil injector) of this kind has a coil which generates a magnetic field when current flows through the coil, as a result of which a magnetic force is exerted on an armature so that the armature moves
Implementation Method 2
The coil short-circuit causes a reversal of polarity of the voltage owing to the dissipation of the magnetic field which is stored in the coil
Data Source
AI summary
A method for determining an injection quantity of a fuel injector determines a first time at which an injection process of the fuel injector starts, a second time at which the injection process of the fuel injector ends, calculates a model on the basis of the first time and the second time, which model represents the position of a nozzle needle of the fuel injector as a function of the time, and calculates the quantity of fuel to inject.