Injector State Sensing via Differential Current Measurement
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Solution Overview
Problem
Existing injector condition recording systems face challenges with high cabling efforts, mechanical inertia delays, and low-resolution current detection, leading to uncertainties and noise interference, especially when detecting small changes in current flow.
Innovation Solution
A device using differential current measurements between the current flowing into the injector and the current flowing back, eliminating disruptive factors and allowing precise switch state detection without the need for high-resolution measurement or signal filtering, and enabling operation with only two cable lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a switch is used to detect injector state, then injector condition can be monitored, but mechanical inertia causes time delay between voltage application and switch triggering
Solution Approach 1:
The patent replaces the mechanical switch-based detection system with an electrical measurement system. Instead of using a mechanical switch that changes state when the valve needle moves, the invention measures electrical parameters (voltage, current, impedance) directly at the injector to detect the opening and closing states, thereby eliminating mechanical inertia delays
Solution Approach 2:
The patent performs preliminary electrical measurements during the voltage application process to detect injector state changes before the mechanical movement completes. By monitoring electrical parameters in real-time during the actuation process, the system can detect state changes earlier than waiting for mechanical switch triggering
2Measurement precision
If high-resolution current measurement is used to detect switch state, then detection precision improves, but system complexity and cost increase
Solution Approach 1:
The patent introduces an intermediary electrical parameter measurement approach. Instead of directly measuring small current changes through high-resolution ammeters, the system measures voltage, current, or impedance changes that occur when the switch state changes, using these electrical intermediaries to indirectly detect the switch state with simpler, lower-resolution measurement circuits
Solution Approach 2:
The patent detects switch state changes by monitoring changes in electrical parameters (voltage, current, impedance) rather than measuring absolute values with high precision. The measurement system detects the change in electrical characteristics when the switch opens or closes, allowing for accurate state detection using lower-resolution measurement circuits
3Reliability
If multiple wires are used for injector with switch, then state detection is enabled, but wiring complexity increases
Solution Approach 1:
The patent makes the electrical lines serve multiple functions. The same power supply lines used to energize the injector coil are also used to carry measurement signals for detecting the switch state and injector condition. This eliminates the need for separate dedicated measurement wires, reducing wiring complexity while maintaining detection capability
Solution Approach 2:
The patent merges the power supply function and measurement function into the same electrical lines. The electrical connections that deliver power to the injector are combined with the measurement circuitry to simultaneously perform both energization and state detection, thereby reducing the total number of wires required
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
Enables clear and reliable detection of the switch state even in noisy environments, reducing cabling requirements and eliminating interference, thus improving the accuracy and efficiency of injector condition recording.
Implementation Method 1
a first switch contact of the switch is connected to an electrical input line of the injector, and a second switch contact of the switch can be connected to ground
Data Source
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AI summary
The invention relates to a device for sensing the state of an injector, comprising an injector for injecting fuel into an engine combustion chamber, a switch, which is designed to change the switching state thereof in accordance with the state of the injector, and an evaluating unit for sensing the switching state of the switch, wherein a first switch contact of the switch is connected to an electrical input line of the injector, a second switch contact of the switch is connected to ground, and the evaluating unit is designed to carry out a first current measurement for a current flowing into the injector and into the switch and a second current measurement for the current flowing into the injector.