Fuel Injection Control Device with Crank Reference Position Switching
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Solution Overview
Problem
Existing fuel injection control devices for internal combustion engines face challenges in maintaining stable carburetion conditions among cylinders during engine startup, particularly due to variations in injection timing and the risk of double injection or injection failure during the transition from simultaneous to sequential injection.
Innovation Solution
A fuel injection control device with crank angle detecting means and stroke identifying means that switches from simultaneous to group injection after determining a crank reference position, followed by sequential injection, and includes an injection prohibition period to prevent double injection and ensure accurate fuel injection timing, using injection prohibition means to limit fuel injector operation based on stroke identification signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If simultaneous injection is performed after engine start until stroke identification completion, then fuel can be supplied to all cylinders, but injection timing varies among cylinders causing unstable carburetion conditions
Solution Approach 1:
The patent segments the injection process into three distinct phases: simultaneous injection (all cylinders at once), group injection (cylinders divided into groups with different timing), and sequential injection (individual cylinder timing). This segmentation allows the system to transition from a simple simultaneous injection mode to more precise timing modes as stroke identification progresses, resolving the contradiction between maintaining stable carburetion and achieving accurate injection timing.
Solution Approach 2:
The patent performs preliminary simultaneous injection to ensure all cylinders receive fuel during the initial startup phase before stroke identification is complete. This preliminary action guarantees fuel supply to all cylinders while acknowledging that precise timing cannot yet be achieved, thereby maintaining reliability without requiring premature precision that would worsen the contradiction.
2Measurement precision
If group injection is performed after crank reference position determination, then injection timing accuracy improves, but risk of double injection or injection failure increases during transition
Solution Approach 1:
The patent dynamically adjusts the injection control strategy based on the current engine state and stroke identification progress. The system transitions from static simultaneous injection to dynamic group injection with varying timing for different cylinder groups, optimizing timing accuracy while adapting to the evolving knowledge of crank position and stroke status to prevent injection errors.
Solution Approach 2:
The patent uses feedback from the crank angle sensor and stroke identification results to continuously refine injection timing. The ECU monitors crank position, determines stroke status for each cylinder, and adjusts injection timing accordingly, ensuring accurate timing while preventing double injection or injection failure through real-time feedback control.
3Reliability
If injection prohibition period is set to maximum required time for fuel to be sucked into all cylinders, then double injection is prevented, but injection response time increases
Solution Approach 1:
The patent applies local quality by setting different injection prohibition periods for different cylinder groups based on their specific injection timing requirements. Rather than using a uniform prohibition period for all cylinders, the system tailors the prohibition duration to the local needs of each cylinder group, preventing double injection where necessary while minimizing time loss for other cylinders that can proceed with injection.
Data Source
AI summary
A fuel injection control device for a more stable carburetion condition by setting an adequate fuel injection prohibition period at the start of an internal combustion engine. A fuel injection control device includes an injection switch which selectively switches among simultaneous injection which is performed after start of cranking in an engine until determination of a crank reference position, group injection which is performed after determination of a crank reference position until completion of stroke identification, and sequential injection which is performed after completion of stroke identification. The maximum period from simultaneous injection, after start of cranking, until simultaneously injected fuel is sucked into all cylinders #1 to #4 is set as an injection prohibition period t. The injection prohibition period t prevents “double injection,” if group injection is started just after determination of a crank reference position and “injection failure,” if the injection prohibition period is too long.