Engine Controller Injection Timing Advancement
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Solution Overview
Problem
Internal combustion engines face challenges in fuel atomization and particulate matter (PM) reduction, particularly at low temperatures, where excessive fuel in the intake passage increases PM and particle number (PN), and existing control methods struggle to maintain optimal air-fuel ratio controllability during transition between single and multiple injection processes.
Innovation Solution
A controller for internal combustion engines that executes a fuel injection process, switching between single and multiple injection processes, with the multiple injection process splitting the required fuel amount into synchronous and non-synchronous injections, and advancing the non-synchronous injection timing to reduce fuel accumulation in the intake passage, thereby reducing PN and promoting atomization while maintaining air-fuel ratio controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the single injection process is used with a large injection amount, then the fuel injection coverage is improved, but the amount of fuel collecting in the intake passage increases which leads to increased particle number (PN)
Solution Approach 1:
The patent divides the single large fuel injection into multiple smaller injections (intake air synchronous injection and intake air non-synchronous injection). This segmentation reduces the amount of fuel collecting in the intake passage at any one time, thereby reducing particle number (PN) while still delivering the total required fuel amount to the combustion chamber.
2Manufacturing precision
If the injection timing is advanced to promote atomization, then fuel atomization is improved, but the amount of fuel collecting in the intake passage increases which may prevent atomization
Solution Approach 1:
The patent performs preliminary fuel injection (intake air non-synchronous injection) before the intake valve opens, allowing fuel to be injected at an advanced timing when the intake passage is still relatively empty. This preliminary action promotes atomization while minimizing fuel accumulation issues by delivering fuel before the valve opens and using the valve opening to clear the passage.
3Object-generated harmful factors
If the injection timing is retarded to reduce fuel accumulation in the intake passage, then particle number (PN) is reduced, but the time interval to combustion stroke is shortened which may affect atomization
Solution Approach 1:
The patent uses segmented injection timing where the first injection (intake air non-synchronous injection) occurs at an advanced timing before the intake valve opens to promote atomization, and the second injection (intake air synchronous injection) occurs at a retarded timing synchronized with intake valve opening to reduce particle number (PN) by clearing the intake passage.
4Object-generated harmful factors
If the fuel injection process is switched from single to multiple injection, then particle number (PN) is reduced, but the control complexity increases
Solution Approach 1:
The patent makes the port injection valve perform multiple functions by enabling it to execute different injection patterns (single injection, multiple injection with synchronous injection, multiple injection with non-synchronous injection) based on operating conditions. This multi-functionality allows the system to reduce particle number (PN) through multiple injection while using the same hardware component, thereby limiting the increase in control complexity.
Data Source
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AI summary
A port injection valve (16) injects fuel into an intake passage (12). An intake synchronous injection is to inject fuel in synchronization with an opening period of an intake valve (18). A single injection process is to execute only an intake air non-synchronous injection. A majority of a fuel injection period of the single injection process is prior to the opening timing of the intake valve (18). A controller causes, when switching a fuel injection process from the single injection process to a multiple injection process, an injection start timing (Ins) of the intake air non-synchronous injection to be more advanced than an injection start timing (11) of the single injection process prior to the switching (S18-S32, S36, S38 in Fig.4).