Two-Stage Cavity Piston Fuel Distribution Control
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Solution Overview
Problem
Compression-ignition engines with two-stage cavities face challenges in maintaining the distribution ratio of fuel between upper and lower cavities when engine speed or load changes, leading to suboptimal rapid multi-stage combustion, reduced fuel efficiency, and increased emissions.
Innovation Solution
A control system that adjusts the timing and amount of pilot and main fuel injections to maintain a predetermined distribution ratio between the upper and lower cavities by varying injection pressure and timing, utilizing a turbosupercharger to optimize fuel spray distribution across different engine states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the engine speed or load changes, then the total fuel amount injected and injection pressure change, but the distribution ratio of fuel between upper and lower cavities becomes unstable
Solution Approach 1:
The patent applies dynamics by making the injection timing variable rather than fixed. The control device adjusts the injection timing based on engine speed and load conditions to maintain optimal fuel distribution ratio between upper and lower cavities across different operational states. This dynamic adjustment compensates for changes in injection pressure and fuel spray penetration that occur with varying engine conditions.
Solution Approach 2:
The patent changes the timing parameter of fuel injection to maintain consistent fuel distribution. By varying the injection timing parameter in response to changes in engine speed and load, the system compensates for changes in injection pressure and spray characteristics, thereby maintaining a stable fuel distribution ratio between the two cavities.
2Power
If the injection pressure increases to handle high load, then the fuel spray penetration increases, but the fuel spray reaches the lip portion before the piston separates, causing improper fuel distribution
Solution Approach 1:
The patent makes the injection timing dynamic rather than fixed. Under high load conditions with increased injection pressure, the control device adjusts the injection timing to occur later in the compression stroke, ensuring that the fuel spray reaches the lip portion at the appropriate moment when the piston has separated sufficiently. This prevents premature fuel arrival and maintains proper fuel distribution despite high injection pressure.
Solution Approach 2:
The control system performs preliminary adjustment of injection timing based on predicted engine conditions. By advancing or retarding the injection timing in anticipation of piston position and injection pressure conditions, the system ensures optimal fuel spray distribution to the cavities under varying load conditions.
3Productivity
If the injection timing is advanced to improve combustion efficiency, then the fuel spray distributes differently to cavities, but rapid multi-stage combustion cannot be maintained across all operational states
Solution Approach 1:
The patent applies dynamics by making injection timing variable across different operational states. The control device adjusts the injection timing to maintain rapid multi-stage combustion in both the first and second operational states. By dynamically optimizing the timing parameter for each state, the system maintains consistent combustion efficiency and proper fuel distribution ratio despite different engine speeds and loads.
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
Ensures consistent rapid multi-stage combustion across varying engine conditions, improving fuel efficiency, reducing emissions, and maintaining high thermal efficiency and quiet operation.
Implementation Method 1
a fuel injection valve that injects fuel spray into the combustion chamber
Implementation Method 2
utilizing a turbosupercharger to optimize fuel spray distribution across different engine states
Implementation Method 3
the penetration of the fuel spray injected from the fuel injection valve is high
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In a compression-ignition engine having a two-stage cavity, the distribution ratio between fuel for an upper cavity and fuel for a lower cavity is maintained even when the operational state of the engine changes. A piston 5 of the compression-ignition engine includes a lower cavity (lower cavity portion 51), an upper cavity (upper cavity portion 52), and a lip portion 53 between the lower cavity and the upper cavity. A controller (ECU 10) causes a main injection and at least one pilot injection to be executed when the engine 1 operates in a first state and a second state in which the load is lower than the load in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller sets the timing of the pilot injection so that the distribution ratio of the fuel spray of the pilot injection for the lower cavity is higher when the engine operates in the first state than when the engine operates in the second state.