Diesel Fuel Injection Control Dynamic Calculation Timing
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Solution Overview
Problem
In diesel engines with a large number of cylinders, the limited crank angle available for calculating fuel injection amounts leads to incomplete calculations at high engine speeds, resulting in potential fuel injection misses or inefficiencies, especially when transitioning between low and high rotation speeds.
Innovation Solution
A fuel injection control apparatus that dynamically adjusts the calculation start timing based on engine rotation speed, using an engine control unit (ECU) with storage areas for each cylinder to store and switch calculation results, ensuring timely fuel injection by advancing calculations for higher-speed conditions and prioritizing results for subsequent cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the calculation start timing is aligned with high rotation speed side, then the control precision at high speed is improved, but the actual time for calculation increases on low rotation speed side leading to reduced precision
Solution Approach 1:
The calculation start timing is made dynamic by adjusting it based on detected engine rotation speed. The ECU switches between different calculation start timings (first timing for high speed, second timing for low speed) to optimize the balance between calculation precision and time availability under varying operating conditions
2Loss of time
If the calculation start timing is aligned with low rotation speed side, then the actual time for calculation is reduced, but the calculation is not completed in time on high rotation speed side
Solution Approach 1:
The system dynamically adjusts calculation start timing based on real-time rotation speed detection. When high rotation speed is detected, the first calculation start timing is used to ensure completion before the limit angle. When low rotation speed is detected, the second calculation start timing is used to allow sufficient calculation time
3Quantity of substance
If the number of cylinders increases, then the engine capacity is improved, but the crank angle available for calculation narrows leading to incomplete calculations at high speeds
Solution Approach 1:
The calculation start timing is dynamically adjusted based on rotation speed to compensate for the reduced crank angle availability in multi-cylinder engines. The ECU detects rotation speed and switches between different timing strategies to ensure calculation completion before the calculation completion limit angle regardless of engine configuration
Data Source
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AI summary
Fuel injection control apparatus for a diesel engine having a plurality of cylinders, the fuel injection control apparatus comprising a calculation unit that calculates a fuel injection amount for each cylinder, and a storage unit (16) that has a storage area corresponding to each cylinder and stores in a corresponding storage area a calculation result generated by the calculation unit. When a low rotation speed switches to a high rotation speed, a calculation result Q#2, which was used to inject fuel into a cylinder #2 prior to the switch, is used to inject fuel into a cylinder #3, which is subjected to fuel injection following the cylinder #2. A calculation result Q#1 can be used by an ECU (8) to inject fuel into the cylinder #2 immediately after the aforesaid switch.