Fuel Injection Control Apparatus for Three Cylinder Engine
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Solution Overview
Problem
Existing fuel injection control systems for three cylinder engines do not effectively compute fuel quantities for strokes other than the compression and intake strokes, and they fail to reduce computation load, particularly in four stroke cycle engines.
Innovation Solution
A fuel injection control apparatus with computation devices aligned at specific timings (240 degrees apart) computes fuel quantities for each stroke by calculating differences in intake air amounts, reducing errors in actual injection volumes and optimizing fuel distribution between first and second fuel injection valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fuel injection control is exercised based on intake air amount for each cylinder in a three cylinder engine, then fuel injection accuracy is improved, but computation load increases due to the need to compute fuel quantities for all strokes of all cylinders
Solution Approach 1:
The patent divides the fuel injection control system into three separate computation devices, each responsible for computing fuel quantities for specific strokes of specific cylinders. This segmentation allows parallel computation and reduces the burden on any single computation unit, thereby managing complexity while maintaining accuracy.
Solution Approach 2:
The patent performs fuel quantity computations at predetermined timings before the actual injection occurs. By computing fuel quantities in advance based on intake air amounts measured at specific crank angle positions, the system prepares injection data beforehand, reducing real-time computation load during critical injection moments.
2Manufacturing precision
If fuel quantity computation is performed for each stroke of each cylinder, then injection control precision is improved, but the number of computation interruptions increases
Solution Approach 1:
The patent establishes periodic computation timings for each computation device, where computations are performed at regular intervals corresponding to specific crank angle positions (e.g., every 240 degrees). This periodic approach ensures precise fuel quantity determination while reducing the frequency and number of computation interruptions compared to continuous or event-driven computation for every stroke.
3Adaptability or versatility
If computation timings are not synchronized across cylinders, then control flexibility is improved, but fuel injection accuracy deteriorates due to mismatched computation timing with intake air measurement
Solution Approach 1:
The patent assigns asymmetric computation timings to different computation devices based on their specific functions and the crank angle positions of the cylinders they serve. Each computation device operates at optimized timings relative to its target cylinder's intake stroke, rather than using a uniform timing for all cylinders. This asymmetric timing arrangement maintains precision for each specific computation while allowing overall system flexibility.
Data Source
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AI summary
A fuel injection control apparatus of a four cycle engine having three cylinders comprises: a crank angle detection device for detecting the crank angle of the four cycle engine; a first computation device for computing the quantity of fuel, which is injected in a predetermined stroke of a four stroke cycle, at a first computation timing; a second computation device for computing the quantity of fuel, which is injected one stroke before the predetermined stroke, at a second computation timing 240 degrees ahead of the crank angle of the first computation timing; and a third computation device for computing the quantity of fuel, which is injected two strokes before the predetermined stroke, at a third computation timing 240 degrees ahead of the crank angle of the second computation timing. The fuel injection control apparatus is adapted to decrease interruptions by computations for fuel injection control in the three cylinder engine, and reduce control load.