Diesel Engine Injection Timing Control via Pressure-Dependent Interval
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Solution Overview
Problem
Existing diesel engine systems struggle to optimize the timing of after-injection to balance soot reduction and fuel efficiency, as the interval between main and after-injections is typically fixed, leading to suboptimal air utilization and energy conversion.
Innovation Solution
The diesel engine system adjusts the injection interval period based on injection pressure, ensuring the after-injection timing aligns with the oxygen arrival timing, enhancing air utilization and allowing earlier start of the after-injection to improve fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the interval from the main injection to the after-injection is shortened to improve fuel efficiency, then the energy conversion improves, but soot generation increases due to insufficient oxygen
Solution Approach 1:
The patent applies dynamics by making the injection interval variable rather than fixed. The control device dynamically adjusts the injection interval based on detected combustion properties from the main injection, allowing the system to adapt to changing combustion conditions and optimize both fuel efficiency and soot reduction in real-time
Solution Approach 2:
The patent changes the parameter of injection timing by adjusting the injection interval based on detected combustion properties. The control device modifies the timing parameters of the after-injection relative to the main injection, optimizing the balance between energy conversion and oxygen availability to reduce soot while maintaining fuel efficiency
2Object-generated harmful factors
If the interval from the main injection to the after-injection is lengthened to reduce soot generation, then oxygen availability improves, but fuel efficiency deteriorates due to reduced energy conversion
Solution Approach 1:
The system dynamically adjusts the injection interval based on real-time combustion properties rather than using a fixed long interval. This allows the system to maintain sufficient oxygen availability for soot reduction while optimizing the timing to preserve energy conversion efficiency
Solution Approach 2:
The control device uses feedback from detected combustion properties (such as pressure pulsation) to adjust the after-injection timing. This feedback mechanism enables the system to determine the optimal injection interval that balances oxygen availability and energy conversion, preventing both soot generation and fuel efficiency deterioration
3Object-generated harmful factors
If the after-injection timing is set to match oxygen arrival timing to improve air utilization, then soot reduction improves, but the system complexity increases due to real-time detection and adjustment requirements
Solution Approach 1:
The control device uses the combustion properties detected from the main injection itself to determine the optimal after-injection timing. The system serves itself by using its own combustion data as the basis for adjustment, eliminating the need for external complex sensing systems while achieving precise oxygen arrival timing alignment
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 approach effectively reduces soot generation and enhances fuel efficiency by optimizing the air utilization factor and energy conversion during combustion, particularly under varying engine conditions.
Implementation Method 1
an injector which injects fuel containing diesel fuel into a combustion chamber
Implementation Method 2
a combustion chamber which is a space above the piston
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A diesel engine system has a piston in which a cavity is formed in a crown surface. The cavity has a bottom part, a peripheral part dented so as to be convex radially outward in a cross-sectional view, and a lip part formed above the peripheral part and protruding so as to be convex radially inward in the cross-sectional view. An injection controller causes an injector to perform, during operation in a given operating range, a main injection in which injected fuel is directed to the lip part, and an after-injection in which a smaller amount of fuel than the main injection is injected at a given period later than the main injection in an expansion stroke. An injection interval period that is a period of time from an end of the main injection to a start of the after-injection is shorter as an injection pressure of fuel increases.