Fuel Injector Leakage Detection via Pressure Differential
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Solution Overview
Problem
In direct injecting internal combustion engines, fuel leakage between the fuel supply tube and the combustion chamber leads to pollutant emissions, uncontrollable fuel increase during combustion, soot particle formation, and adverse effects on the fuel injection spray image, especially after prolonged parking phases or at low fuel pressure.
Innovation Solution
A method involving a pressure sensor to measure pressure changes in the fuel injector's volume, determining a baseline state with closed inlets and outlets, and evaluating pressure changes over time to detect leakage, considering temperature effects and physical properties of the fuel, with the ability to store leakage data for diagnostic purposes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the injection device is used in direct-injection internal combustion engines, then fuel can be injected into the combustion chamber with specified spray pattern, but fuel leakage occurs between the fuel supply line and combustion chamber leading to pollutant emissions and soot particle formation
Solution Approach 1:
The patent applies preliminary action by conducting a leakage test before the engine operates normally. The test is performed with the injection device in a specific state (inlet and outlet closed) to detect leakage conditions prior to actual combustion operations, preventing harmful effects before they occur.
Solution Approach 2:
The patent replaces mechanical sealing verification with a pressure-based detection method. Instead of relying solely on mechanical seals to prevent leakage, the system uses pressure sensors and pressure differential measurements to detect and quantify leakage, substituting mechanical trust with sensor-based monitoring.
2Productivity
If the engine is restarted after extended periods of inactivity, then the engine can resume operation, but fuel hammer occurs due to significant leaks and high pressure differential
Solution Approach 1:
The leakage test is performed as a preliminary action before engine restart or during operational monitoring. By detecting leakage conditions in advance, the system can prevent fuel hammer from occurring during engine restart or high-pressure differential conditions.
Solution Approach 2:
The patent implements feedback by continuously monitoring pressure changes in the fuel supply line and using this information to detect leakage conditions. The control unit receives pressure signals, evaluates pressure changes over time, and provides feedback about leakage status, enabling preventive action before fuel hammer occurs.
3Stress or pressure
If the pressure differential between combustion chamber and supply pipe reverses, then the injector may open due to high pressure, but this leads to fouling of the injector and negatively affects spray pattern
Solution Approach 1:
The patent replaces mechanical pressure differential control with sensor-based pressure monitoring. Pressure sensors continuously measure the pressure in the fuel supply line, and the control unit evaluates pressure changes to detect conditions that could cause injector fouling, substituting passive mechanical response with active sensor-based monitoring and control.
4Reliability
If a leakage test is performed by evaluating pressure drop in the fuel system, then fuel leakage can be detected, but the method requires the engine to be switched off and does not provide continuous monitoring
Solution Approach 1:
The patent applies dynamics by transitioning from a static leakage test (engine off) to a dynamic monitoring approach. The system continuously monitors pressure changes in the fuel supply line during engine operation, allowing leakage detection without stopping the engine. The control unit evaluates pressure signals in real-time, making the system adaptable to dynamic operational conditions.
Solution Approach 2:
The patent ensures continuity of useful action by enabling continuous leakage monitoring during engine operation. Instead of requiring the engine to be switched off for testing, the system maintains continuous pressure monitoring throughout operation, ensuring that leakage detection is always available without interrupting productive engine use.
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
Accurately detects fuel leakage, preventing pollutant emissions and maintaining optimal fuel injection by identifying and quantifying leakage, thus ensuring efficient engine operation and reducing soot particle formation.
Implementation Method 1
The injection device has a first pressure sensor for measuring a pressure in the volume
Implementation Method 2
evaluating a pressure change from the first pressure to the second pressure
Data Source
Figure 1
AI summary
Method for diagnosing an injection device (1) for an internal combustion engine (2), wherein the injection device (1) has a volume (3) with at least one inlet (4) through which the volume (3) can be fluidically connected to a pressure line (5), and at least one outlet (6) through which the volume (3) can be connected to at least one combustion chamber (7) of the internal combustion engine (2); wherein the injection device (1) further has a first pressure sensor (8) for measuring a pressure (9, 10) in the volume (3); wherein the method comprises at least the following steps: a) determining a first state (11) of the injection device (1) in which the at least one inlet (4) and the at least one outlet (6) are closed and the volume (3) has a constant volume (3); b) measuring a first pressure (9) at a first time (13); c) measuring a second pressure (10) at a later second time (14);d) Evaluation of a pressure change from the first pressure (9) to the second pressure (10).;