Ship Engine Auxiliary Air Supply for Uniform Fuel Mixing
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Solution Overview
Problem
Conventional ship engines face issues with non-uniform fuel and air mixing, leading to reduced power output, increased nitrogen oxide emissions, and elevated operational costs due to high-pressure fuel supply requirements.
Innovation Solution
The engine design incorporates a dual air supply system with a main and auxiliary air supply member, controlled by a controller that synchronizes air and fuel injection with the piston's movement, ensuring uniform mixing and optimized combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gas is supplied at low pressure with air compression for premixed combustion, then fuel and air can be mixed before ignition, but the mixing is not uniform leading to power loss and increased NOx emissions
Solution Approach 1:
The invention divides the air supply into two separate paths: main air supplied through the air supply valve and auxiliary air supplied through the auxiliary air supply member. This segmentation allows different air streams to serve different functions - main air for combustion support and auxiliary air for uniform fuel-air mixing - thereby resolving the contradiction between premixed combustion capability and power output.
Solution Approach 2:
The auxiliary air supply member acts as an intermediary device that introduces additional air between the fuel injection point and the combustion chamber. This intermediary air stream facilitates more uniform fuel-air mixing without requiring high pressure, thus maintaining power output while enabling effective premixed combustion.
2Reliability
If compression ratio is decreased to prevent knocking in gas mode, then knocking is prevented, but engine efficiency is deteriorated in diesel mode
Solution Approach 1:
The invention dynamically adjusts the air-fuel mixing process by controlling the auxiliary air supply timing and quantity based on operating conditions. This dynamic control allows the engine to achieve uniform mixing at lower compression ratios in gas mode (preventing knocking) while maintaining adequate compression for efficient diesel mode operation, thus resolving the efficiency-loss contradiction.
3Power
If gas is sprayed at high pressure for diffusion combustion, then high power is produced, but a separate high pressure fuel supply device is required increasing installation cost and operational expense
Solution Approach 1:
The invention merges the auxiliary air supply function with the existing air supply system by utilizing the air supply valve and air supply passage already present in the engine. This integration eliminates the need for a separate high-pressure fuel supply device, reducing system complexity while maintaining the capability to produce high power through controlled diffusion combustion.
Solution Approach 2:
The air supply valve and air supply passage are designed to serve multiple functions: supplying main air for combustion, providing auxiliary air for fuel-air mixing, and potentially controlling both premixed and diffusion combustion modes. This multi-functionality eliminates the need for dedicated high-pressure fuel supply equipment, reducing overall system complexity.
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 prevents power loss, reduces nitrogen oxide emissions, and lowers operational costs by ensuring uniform fuel and air mixing and improving combustion efficiency.
Implementation Method 1
the piston is being moved from the bottom dead point to the top dead point
Implementation Method 2
a cylinder providing a space for combusting fuel
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to an engine for a ship, which includes: a cylinder providing a space for combusting fuel; a piston reciprocating between a top dead point and a bottom dead point in the cylinder; and a supplier coupled to the cylinder, the supplier supplying the fuel and air to the cylinder. The supplier includes: a fuel supply apparatus supplying the fuel to the cylinder; and an air supply apparatus supplying the air to the cylinder. The air supply apparatus includes an auxiliary air supply member supplying the air to the cylinder between a lower side and an upper side of the cylinder. The auxiliary air supply member supplies the air together with the fuel when the fuel is supplied by the fuel supply apparatus while the piston is being moved from the dead point to the top dead point.