In-Cylinder Injector Control for Partial Lift Injection
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Solution Overview
Problem
Partial lift injection in internal combustion engines results in irregular fuel injection amounts due to short needle valve open periods and varying valve-opening speeds, leading to significant injection amount irregularities, especially during multiple injections per combustion stroke.
Innovation Solution
A control device that optimizes the energizing time and number of maximum partial lift injections to ensure the injection amount equals or exceeds the target amount, using both in-cylinder and port injectors to achieve precise fuel injection by extending energizing time and adjusting the number of injections based on required fuel amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If partial lift injection is used to decrease minimum injection amount, then micro injection capability is improved, but injection amount irregularity increases due to short valve-open period and varying valve-opening speed
Solution Approach 1:
The patent changes the energizing time parameter to its maximum value for partial lift injection, which extends the valve-open period and stabilizes the valve-opening speed. This parameter optimization reduces injection amount irregularity while maintaining micro injection capability, resolving the contradiction between minimum injection amount and injection precision.
2Adaptability or versatility
If multiple partial lift injections are executed in a single combustion stroke, then total injection amount control flexibility is improved, but injection amount irregularity accumulates and becomes significant
Solution Approach 1:
The control device uses feedback by calculating the required injection amount and determining the appropriate number of maximum partial lift injections based on this requirement. This feedback mechanism ensures that while multiple injections provide control flexibility, the accumulated irregularity is minimized by optimizing the number of injections to meet the target amount precisely.
Solution Approach 2:
The patent dynamically adjusts the number of energizations for maximum partial lift injection based on the required injection amount. This dynamic control allows the system to maintain precision across multiple injections by adapting the injection count to the specific fuel demand, preventing irregularity accumulation.
3Manufacturing precision
If energizing time is extended for maximum partial lift injection, then injection amount precision is improved, but injection time increases which may affect engine speed performance
Solution Approach 1:
The patent applies partial lift injection where the needle valve does not reach the fully-open state, but optimizes the energizing time to maximum for this partial lift condition. This approach achieves high injection precision without requiring full valve opening, thereby minimizing injection time while maintaining accuracy, effectively resolving the time-precision trade-off.
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 minimizes injection amount irregularity, enabling high-accuracy micro injection and precise fuel control by executing maximum partial lift injections within the required range, even at high engine speeds, and supplements with full lift injections when necessary.
Implementation Method 1
a coil 35 arranged at an outer circumferential part of the fixed core 32. The movable core 33 is connected to the needle valve 36. When the coil 35 is not energized, the movable core 33 is separated from the fixed core 32 due to a biasing force of a spring 34
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A control device for an internal combustion engine is provided. The internal combustion engine includes an in-cylinder injector (30). The control device includes an electronic control unit (50). The electronic control unit (50) is configured to: (i) control energizing time for the in-cylinder injector (30) when a partial lift injection is performed such that the partial lift injection becomes maximum partial lift injection with a longest energizing time in the partial lift injection; and (ii) control the number of energizations for performing the maximum partial lift injection during a single injection stroke such that a total of injection amounts of the maximum partial lift injection by the number of the energizations is equal to or less than a required injection amount as a target amount for the injection amount of a single injection stroke.