Port Injection Valve Controller Fuel Collection Reduction
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Solution Overview
Problem
Internal combustion engines with port injection valves face challenges in maintaining an optimal air-fuel ratio due to fuel collection in the intake passage, leading to increased particulate matter and deviations in air-fuel ratios, particularly when the engine is started or operates at varying conditions such as different temperatures and rotation speeds.
Innovation Solution
A controller that executes a base injection amount calculation and an increasing correction process, allowing for a multiple injection process and a single injection process, with the latter splitting fuel injection into synchronous and non-synchronous injections, and adjusts the correction ratio based on factors like engine start time, rotation speed, and temperature to minimize fuel collection in the intake passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the base injection amount is increased to compensate for fuel collection in the intake passage, then the air-fuel ratio deviation is reduced, but the amount of uncombusted fuel increases leading to more particulate matter
Solution Approach 1:
The fuel injection is divided into multiple sequences instead of a single injection. The controller executes a first fuel injection sequence followed by a second fuel injection sequence, with each sequence containing multiple injections. This segmentation allows the total fuel amount to be delivered in smaller portions, reducing the amount of fuel that collects in the intake passage while still achieving the required air-fuel ratio compensation.
Solution Approach 2:
The fuel injection is performed periodically in multiple sequences rather than continuously or in a single action. The controller alternates between the first fuel injection sequence and the second fuel injection sequence, creating a periodic injection pattern that distributes fuel delivery over time, thereby reducing instantaneous fuel collection in the intake passage.
2Device complexity
If a single fuel injection process is used, then the injection control is simple, but the fuel collection in the intake passage is significant causing air-fuel ratio deviation
Solution Approach 1:
The single fuel injection process is segmented into multiple injection sequences, each containing multiple individual injections. The controller manages the first fuel injection sequence with a plurality of injections, followed by the second fuel injection sequence with another plurality of injections. This segmentation improves air-fuel ratio accuracy by better controlling fuel delivery while maintaining relatively simple control logic through systematic sequencing.
3Reliability
If the fuel injection amount is increased after engine start, then the air-fuel ratio is maintained, but the particulate matter emission increases due to fuel collection
Solution Approach 1:
The increased fuel injection amount required for air-fuel ratio stability is segmented across multiple injection sequences and multiple injections within each sequence. Instead of delivering the entire increased amount in a single injection that would collect in the intake passage, the controller distributes it across the first fuel injection sequence and the second fuel injection sequence, reducing particulate matter formation while maintaining air-fuel ratio stability.
Solution Approach 2:
The fuel injection follows a periodic pattern with alternating first and second fuel injection sequences. This periodic multi-sequence injection approach allows the total fuel amount to be delivered over an extended period, reducing the instantaneous fuel load in the intake passage and thereby reducing particulate matter emissions while maintaining stable air-fuel ratio.
Data Source
Figure 1
Figure 2~3(b)
Figure 4~5
AI summary
A port injection valve (16) injects fuel into an intake passage (12). A controller (50) increases (S12-S24, S28) a base injection amount (Qb) over a predetermined period (S12: YES) after the internal combustion engine (10) is started and gradually decreases (S26) an increase correction ratio (efase1) of the base injection amount (Qb). One of two processes, a multiple injection process and a single injection process, is selected (S30-S34) in order to inject the increased base injection amount (Qd) of fuel. The increase correction ratio is set to be a smaller value in the multiple injection process than in the single injection process