Fuel Injection Control Device Dynamic Pressure Detection Timing
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Solution Overview
Problem
Conventional fuel injection control devices for internal combustion engines face challenges in accurately learning fuel injection characteristics due to inappropriate detection of fuel pressure drops during divided injection, where the detection timing of fuel pressure coincides with the fuel injection period, leading to erroneous learning of injection characteristics.
Innovation Solution
A fuel injection control device that includes a fuel pressure sensor detecting pressure inside an accumulator and calculates fuel pressure drops based on a predetermined frequency, disallowing learning during fuel injection periods to ensure accurate detection and calculation of fuel injection characteristics, thereby correcting the fuel injection amount using learned injection characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If divided injection is performed with a time period longer than 180° CA, then fuel injection control flexibility is improved, but fuel pressure detection accuracy deteriorates because detection occurs during fuel injection
Solution Approach 1:
The patent dynamically adjusts the fuel pressure detection timing based on the injection timing of each cylinder. The ECU determines whether to perform fuel pressure detection in each cylinder cycle based on whether fuel injection is occurring at the scheduled detection timing. This dynamic adaptation allows the system to maintain measurement accuracy while supporting flexible divided injection strategies with variable timing durations.
Solution Approach 2:
The system changes the detection timing parameter conditionally - when divided injection is detected and the injection period overlaps with the scheduled detection time, the ECU skips detection in that cycle and performs it in the next cycle. This parameter adjustment ensures accurate fuel pressure measurement while accommodating the extended injection periods required for flexible divided injection control.
2Productivity
If fuel pressure is detected during fuel injection period, then detection frequency is maintained, but learning accuracy of injection characteristic deteriorates due to inappropriate fuel pressure drop amount
Solution Approach 1:
The ECU continuously monitors injection timing information and uses this feedback to determine appropriate fuel pressure detection timing. By checking whether fuel injection is occurring at the scheduled detection time, the system adapts its detection strategy to avoid corrupted measurements while maintaining overall detection frequency across multiple cycles.
Solution Approach 2:
The system performs preliminary checking of injection timing before executing fuel pressure detection. The ECU determines in advance whether detection should be performed in the current cycle by checking injection timing information, and if not appropriate, schedules detection for the next cycle, ensuring measurement validity before execution.
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 enables high-accuracy learning of fuel injection characteristics by excluding fuel pressure measurements during transient fluctuations, ensuring precise correction of fuel injection amounts and improving the overall fuel injection control.
Implementation Method 1
a fuel pressure sensor that detects fuel pressure inside of an accumulator that supplies accumulated fuel to each of the plurality of fuel injectors
Data Source
AI summary
An ECU has a fuel pressure sensor that detects fuel pressure inside of a common rail. The ECU detects the fuel pressure at a predetermined frequency and calculates a drop amount of the fuel pressure in accordance with fuel injection by fuel injectors based on the detected fuel pressure. The ECU acquires a fluctuation amount of a fuel injection amount of each of the fuel injectors based on the drop amount of the fuel pressure and learns an injection characteristic of each of the fuel injectors, the injection characteristic indicating a correlation between the fuel injection amount and the fluctuation amount of the fuel injection. In a case in which a detection timing of the fuel pressure is within a fuel injection period of a predetermined fuel injector, the ECU disallows the learning of the injection characteristic using the fuel pressure detected in the fuel injection period.