Two-Stage Diesel Piston Cavity Injection Control at Varying Speed
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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 is not maintained consistently when engine speed or load changes, affecting the realization of rapid multi-stage combustion and resulting in suboptimal fuel efficiency and emission performance.
Innovation Solution
A control system that adjusts the injection timing and amount of pilot and main fuel injections using sensors and a controller to maintain a predetermined distribution ratio between the upper and lower cavities, regardless of engine speed or load changes, by increasing the pilot injection amount and maintaining the main injection amount when engine speed increases, and adjusting the pilot injection timing and increasing the main injection pressure when engine load increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the fuel injection amount and pressure are increased to meet higher engine load demands, then the engine power output is improved, but the distribution ratio of fuel between the upper cavity and lower cavity changes, causing deviation from the predetermined distribution ratio and affecting rapid multi-stage combustion
Solution Approach 1:
The patent applies dynamics by making the fuel injection system adjustable based on operating conditions. The control unit dynamically adjusts injection parameters (amount, pressure, timing) according to engine speed and load, allowing the system to adapt to varying demands while maintaining optimal fuel distribution ratio through real-time control rather than fixed parameters
Solution Approach 2:
The patent changes physical parameters of fuel injection (injection amount, injection pressure, injection timing) based on engine operating conditions. By adjusting these parameters dynamically, the system maintains the predetermined fuel distribution ratio between upper and lower cavities across different load and speed conditions, resolving the contradiction between power output and distribution precision
2Productivity
If the engine speed is increased to improve productivity, then the output per unit time is improved, but the fuel spray penetration and distribution characteristics change due to changes in injection pressure and combustion chamber pressure, causing the distribution ratio to deviate from the predetermined ratio
Solution Approach 1:
The system dynamically adjusts fuel injection parameters in response to engine speed changes. The control unit modifies injection amount, pressure, and timing based on real-time speed signals, ensuring that the fuel distribution ratio between upper and lower cavities remains at the predetermined ratio regardless of speed variations, thus maintaining combustion optimization across the operating range
Solution Approach 2:
The patent implements feedback control by using sensors to detect engine speed and load conditions, then feeding this information back to the control unit which adjusts injection parameters accordingly. This closed-loop control ensures the fuel distribution ratio is maintained at the optimal predetermined value across different operating conditions
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 a high degree of quietness and cleaner exhaust gas production.
Implementation Method 1
a fuel injection valve that is disposed on a top surface of a combustion chamber formed by the cylinder and the piston, and injects fuel spray along an injection axis
Implementation Method 2
a turbocharger that is mounted on the engine and boosts intake air by exhaust energy of the engine
Implementation Method 3
a fuel pressure regulator that increases an injection pressure of the fuel when a total injection amount of the fuel injected to the combustion chamber during one combustion cycle increases
Data Source
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 of the engine includes a lower cavity, an upper cavity, and a lip portion between the lower cavity and the upper cavity. A controller causes a main injection and at least one pilot injection to be executed when an engine operates in a first state and a second state in which the speed is higher than the speed in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller maintains an injection amount of the main injection and increases an injection amount of the pilot injection(s) when the engine operates in the second state as compared to when the engine operates in the first state.