Engine Control Device Multistage Post Injection Smoke Suppression
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Solution Overview
Problem
Existing internal combustion engine control systems face challenges in suppressing smoke and oil dilution during post injection, particularly due to the limitations of multistaged post injection, where early-stage post injection can lead to excessive heat generation and smoke production, and delayed boost pressure increase can result in oil dilution.
Innovation Solution
A control device that performs multistaged post injections with the earliest-stage injection having a smaller amount than subsequent stages, and adjusts injection amounts and timing based on acceleration or deceleration requests, engine load, speed, and operating conditions to optimize fuel injection and reduce smoke and oil dilution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the post injection is multistaged with equal injection amounts per stage, then the fuel vaporization is promoted and oil dilution is reduced, but the smoke generation increases due to heat generation in the cylinder
Solution Approach 1:
The post injection is divided into multiple stages (first-stage, second-stage, third-stage) with different injection amounts. The first-stage post injection uses a smaller injection amount to suppress heat generation and smoke, while subsequent stages use larger amounts to ensure complete combustion and reduce oil dilution.
Solution Approach 2:
Different injection amounts are assigned to different stages of post injection based on the local combustion conditions at each stage. The earliest stage uses a reduced injection amount where cylinder temperature and pressure are highest, while later stages use increased amounts as conditions change.
2Power
If the earliest-stage post injection amount is increased to meet acceleration demand, then the power output is improved, but the smoke generation and heat generation increase significantly
Solution Approach 1:
The post injection control is segmented into multiple stages with progressively increasing injection amounts. During acceleration, the total post injection amount is increased by prioritizing later stages (second-stage and third-stage) while keeping the first-stage amount relatively small, thus maintaining power output while suppressing smoke.
Solution Approach 2:
The injection amounts for each post injection stage are dynamically adjusted based on acceleration requests and engine operating conditions. The control device increases the injection amounts of later stages before or after the middle-stage to meet power demands without excessive smoke from the earliest stage.
3Object-generated harmful factors
If the post injection is delayed to reduce heat generation, then the smoke generation is suppressed, but the fuel vaporization is insufficient and oil dilution occurs
Solution Approach 1:
The post injection is divided into multiple stages occurring at different times on the expansion stroke. The first-stage occurs earlier with smaller amount to limit heat generation, while second-stage and third-stage occur later with larger amounts to ensure complete vaporization and combustion, preventing oil dilution.
Solution Approach 2:
The injection parameters (amount, timing) are changed across different stages. The first-stage uses smaller amount at earlier timing to suppress smoke, while subsequent stages use larger amounts at later timings to ensure complete combustion and prevent fuel deposition on cylinder walls.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses smoke and oil dilution by managing injection amounts and timing, ensuring efficient heat management and minimizing fuel deposition on cylinder walls, thereby improving engine performance and reducing emissions.
Implementation Method 1
a fuel injection device that injects fuel into a cylinder
Implementation Method 2
vaporization of the fuel is promoted
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A control device of an internal combustion engine is provided. The internal combustion engine includes a fuel injection device (12) that injects fuel into a cylinder. The control device includes an electronic control unit (30). The electronic control unit (30) is configured to control the fuel injection device (12) so as to perform post injection comprising multistage post injections, on an expansion stroke of the internal combustion engine after combustion caused by main injection, and control the fuel injection device such that an injection amount of an earliest-stage post injection as one of the multistage post injections is smaller than the injection amount of each of subsequent-stage post injections that follow the earliest-stage post injection.