Two-Stage Cavity Piston Fuel Distribution Control
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Solution Overview
Problem
In compression-ignition engines with a two-stage cavity, the distribution ratio of fuel between the upper and lower cavities changes with engine speed and load, making it difficult to maintain rapid multi-stage combustion across varying operational states.
Innovation Solution
A control system that adjusts the distribution ratio of fuel between the upper and lower cavities through pilot and main injections, using a controller to output signals that compensate for changes in engine load by modifying the injection timing and quantity, ensuring a predetermined ratio is maintained regardless of engine state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel spray is distributed to the upper cavity and lower cavity by a lip portion in a two-stage cavity engine, then rapid multi-stage combustion is realized, but the distribution ratio of fuel between cavities changes with engine speed and load, limiting the combustion mode to extremely limited operational states
Solution Approach 1:
The patent applies dynamics by making the fuel injection system adjustable based on operating conditions. The control unit dynamically modifies injection parameters (timing, quantity, pressure) in response to changes in engine speed and load, allowing the system to adapt to various operational states while maintaining stable rapid multi-stage combustion. This transforms a static geometric distribution system into a dynamic controlled system.
Solution Approach 2:
The patent changes physical parameters of the fuel injection process to compensate for variations caused by different engine speeds and loads. By adjusting injection timing, injection quantity, and injection pressure as control parameters, the system maintains the predetermined fuel distribution ratio between upper and lower cavities across different operational states, enabling rapid multi-stage combustion to occur reliably throughout the entire operating range.
2Adaptability or versatility
If the total fuel amount injected and injection pressure change with engine speed and load, then the fuel spray property and combustion chamber environment change, but the distribution ratio of fuel between cavities becomes unstable
Solution Approach 1:
The patent implements feedback control where the control unit continuously monitors engine operating conditions (speed, load) and adjusts the fuel injection parameters accordingly. Based on detected changes in operational state, the control unit modifies injection timing and quantity to compensate for changes in spray properties and combustion chamber environment, thereby maintaining stable fuel distribution ratio between the upper and lower cavities across the entire operational range.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and adjusting injection parameters before fuel injection occurs. The control unit determines the appropriate injection timing and quantity based on anticipated operating conditions, ensuring that the fuel spray properties and distribution ratio are optimized in advance for the specific engine speed and load, thereby maintaining stability despite changing operational states.
3Use of energy by moving object
If pilot injection and main injection are performed to achieve rapid multi-stage combustion, then thermal efficiency and emission performance improve, but the combustion mode cannot be maintained across varying engine speeds and loads
Solution Approach 1:
The patent makes the multi-stage injection system dynamic by allowing the control unit to adjust the timing and quantity of both pilot injection and main injection based on real-time engine operating conditions. This dynamic adjustment ensures that the rapid multi-stage combustion mode, which improves thermal efficiency and emission performance, can be maintained reliably across the entire range of engine speeds and loads, transforming it from a limited-operational feature to a universally applicable combustion mode.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the injection timing and quantity parameters of both pilot and main injections in response to changes in engine speed and load. The control unit modifies these parameters to compensate for changes in combustion chamber environment and fuel spray properties, ensuring that rapid multi-stage combustion with improved thermal efficiency and emission performance is maintained across all operational states.
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 allows for consistent rapid multi-stage combustion, improving thermal efficiency, reducing fuel consumption, and enhancing exhaust gas cleaning while maintaining high thermal efficiency and low noise levels.
Implementation Method 1
a fuel injection valve (18) for injecting a fuel spray (180) into the combustion chamber (6)
Implementation Method 2
a piston (5) to be moved up and down in the cylinder (11a)
Implementation Method 3
The combustion chamber (6) has a two-stage cavity (50)... performs at least one pilot injection and the main injection
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 outputs a control signal to a fuel injection valve so that a distribution ratio of the fuel spray of the pilot injection for the upper cavity is higher when the engine operates in the second state than when the engine operates in the first state.