Engine Control Device for Piston Cavity Fuel Injection
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Solution Overview
Problem
Current engine combustion systems with a piston crown surface featuring upper and lower 2-step cavities lack an effective fuel injection control method to utilize the oxygen inside the combustion chamber efficiently, leading to incomplete combustion and soot generation.
Innovation Solution
A control device with a processor-controlled fuel injection system that performs three distinct injections: a first injection targeting the connecting part of the cavities, a second injection aimed at the first cavity part, and a middle injection with a shorter duration between the first and second injections, optimizing fuel distribution and air utilization within the combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel is injected toward the cavity using a single injection mode, then the fuel can be supplied to the combustion chamber, but the oxygen inside the combustion chamber cannot be effectively utilized leading to incomplete combustion and soot generation
Solution Approach 1:
The fuel injection is divided into three distinct injection modes (first injection toward connecting part, second injection toward first cavity part, middle injection at radial center) to different regions of the combustion chamber. This segmentation allows each injection to target specific oxygen-rich zones, ensuring complete combustion and preventing soot formation by avoiding localized fuel accumulation.
Solution Approach 2:
Each injection mode is designed with specific local characteristics: the first injection targets the connecting part with a specific injection axis, the second injection targets the first cavity part, and the middle injection is limited to the radial center area with a shorter injection period. This local quality approach ensures that fuel is distributed according to oxygen availability in different regions, optimizing combustion efficiency and reducing soot.
2Quantity of substance
If the middle injection has a longer injection period, then more fuel can be supplied to the combustion chamber, but the fuel would reach the cavity parts and interfere with the first and second injections reducing combustion efficiency
Solution Approach 1:
The middle injection uses a shorter injection period compared to the first and second injections, providing a partial fuel supply that is sufficient for the radial center region but intentionally limited to prevent excessive fuel from reaching the cavity parts. This partial action approach ensures that the middle injection complements rather than interferes with the other injections.
Solution Approach 2:
The injection process is segmented into three distinct temporal and spatial phases, with the middle injection occupying a specific time window between the first and second injections and a specific spatial zone (radial center). This segmentation prevents fuel from the middle injection from interfering with the cavity-targeted injections while still contributing to overall combustion efficiency.
3Ease of operation
If fuel is injected without precise timing control, then the injection system is simpler to operate, but the oxygen utilization is poor and soot is generated
Solution Approach 1:
The fuel injection is executed as a periodic sequence of three distinct injection modes with specific timing relationships: the first injection occurs at a specific crank angle position, the middle injection occurs between the first and second injections, and the second injection occurs at a retarded timing. This periodic action pattern ensures optimal oxygen utilization and prevents soot formation through precise temporal control.
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
This configuration effectively utilizes oxygen inside the combustion chamber, reduces soot generation, and enhances engine torque by ensuring efficient combustion through precise timing and distribution of fuel injections, while also canceling out pressure waves to minimize noise.
Implementation Method 1
fuel is injected from the fuel injection valve toward the cavity... fuel is injected at a timing when the piston is located at an advancing side of a compression top dead center... fuel is mixed with air (oxygen) in the cavity parts to form a mixture gas
Implementation Method 2
fuel is mixed with air (oxygen) in the cavity parts to form a mixture gas, thereby resulting in combustion... combustion by the middle injection contributes to engine torque
Data Source
AI summary
A control device for an engine is provided. A cavity formed in a crown surface of a piston of the engine includes a first cavity part disposed in a radially center area, a second cavity part disposed radially outward of the first cavity part, and a connecting part connecting these two parts. The control device causes a fuel injection valve to perform a first injection in which fuel is injected at a timing when the piston is located at an advancing side of CTDC and an injection axis thereof intersects with the connecting part, a second injection in which fuel is injected toward the first cavity part at a retarding side of the first injection, and a middle injection in which fuel is injected at a timing between the first and second injections, for a period shorter than each of the first and second injections.