Fuel Injector Current Shift Detection via Peak Arrival Time
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Solution Overview
Problem
Existing control devices for internal combustion engines with electromagnetically-driven fuel injectors cannot accurately determine shifts in detected current, leading to reduced control accuracy due to variations in drive current profiles, particularly peak current values, and are unable to early detect shifts in detected current.
Innovation Solution
A control device that includes a current detection section, a current control section, an arrival time calculation section, a difference time calculation section, a storage section, and a determination section, which calculates and compares peak-current arrival times to determine shifts in detected current, using predefined relationships and adjustments for variations in load resistance and drive voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current detection section is used to detect drive current, then control accuracy can be improved, but the system cannot determine shifts in detected current, leading to reduced reliability
Solution Approach 1:
The system uses feedback by comparing the detected current waveform characteristics (peak current value and time to peak) against pre-stored reference values. The determination section continuously monitors whether the detected characteristics fall within predetermined ranges, providing ongoing verification of current detection accuracy and enabling shift detection through this closed-loop comparison mechanism.
Solution Approach 2:
The invention introduces an intermediary current detection section that specifically detects the drive current waveform characteristics. This intermediary detection mechanism acts as a mediator between the fuel injector drive system and the control section, enabling indirect determination of current shifts by analyzing waveform parameters rather than directly measuring absolute current values.
2Device complexity
If the detected current shifts are not determined, then control simplicity is maintained, but control accuracy deteriorates due to uncorrected drive current variations
Solution Approach 1:
The invention replaces complex mechanical current calibration systems with an electronic waveform analysis approach. Instead of using mechanical adjustment mechanisms or complex calibration hardware, the system substitutes electronic detection of current waveform characteristics (peak value and timing) and uses software-based comparison with reference values to determine shifts, thereby maintaining simplicity while improving accuracy.
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 accurate and early detection of shifts in detected current, maintaining control accuracy by using predefined peak-current arrival times adjusted for actual current slopes and drive voltage variations, thereby ensuring precise fuel injection.
Implementation Method 1
An electromagnetically-driven fuel injector in general drives a needle to be opened by electromagnetic force generated when a drive coil is energized
Data Source
AI summary
An ECU calculates peak-current arrival time (time elapsed before a detected current arrives at a target peak current), and calculates predetermined-current arrival difference time (time elapsed before the detected current becomes lower than a predetermined current after exceeding the predetermined current). The ECU uses a beforehand stored relationship between the predetermined-current arrival difference time and defined peak-current arrival time to calculate the defined peak-current arrival time corresponding to the latest predetermined-current arrival difference time. The ECU uses such defined peak-current arrival time to compare the latest peak-current arrival time with the defined peak-current arrival time (for example, calculates a difference between the peak-current arrival time and the defined peak-current arrival time), and thus determines a shift in detected current of a current detection circuit.