Variable Area Fuel Injection Valve for Pent Roof Combustion Chamber
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Solution Overview
Problem
In high compression ratio engines, the non-uniform fuel injection regions due to a pent roof-shaped combustion chamber lead to inhomogeneous fuel-air mixtures, resulting in inefficient combustion, after-burning, and increased emissions during spark ignition.
Innovation Solution
The engine design includes a fuel injection valve with multiple injection openings arranged circumferentially, each with varying opening areas to match the volume of corresponding fuel injection regions, ensuring proportional fuel injection and homogeneous mixtures at ignition timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pent roof-shaped combustion chamber is used, then the filling efficiency is improved, but the homogeneity of the fuel-air mixture deteriorates
Solution Approach 1:
The fuel injection valve employs injection openings with different opening areas arranged in different radial directions to match the non-uniform volumes of fuel injection regions created by the pent roof-shaped combustion chamber. This local variation in injection opening areas ensures uniform fuel distribution across regions with different volumes, resolving the contradiction between maintaining filling efficiency and achieving fuel-air mixture homogeneity.
2Loss of time
If fuel is injected from a plurality of injection openings in a short period, then the combustion timing is improved, but the homogeneity of the fuel-air mixture deteriorates
Solution Approach 1:
The injection openings are designed with different opening areas corresponding to the volumes of fuel injection regions in different directions. This allows the fuel injection valve to maintain homogeneous fuel-air mixture formation even during rapid injection in a short time period, as each region receives the appropriate amount of fuel proportional to its volume.
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 design secures the homogeneity of the fuel-air mixture at ignition, enhancing fuel efficiency and reducing emissions by ensuring uniform fuel distribution across the combustion chamber.
Implementation Method 1
a fuel injection valve arranged at the cylinder head so as to be located at a position corresponding to a middle portion of the piston, the fuel injection valve being configured to inject the fuel into the cavity of the piston
Implementation Method 2
perform ignition after a compression top dead center
Implementation Method 3
complete combustion in a short period of time
Data Source
AI summary
An engine includes: a piston including a cavity; a cylinder head configured to form a combustion chamber having a pent roof shape; a fuel injection valve configured to inject fuel from a second half of a compression stroke until a first half of an expansion stroke; and a spark plug arranged at a position corresponding to an upper side of the cavity. Injection openings are arranged in a circumferential direction surrounding a longitudinal axis of the valve. The combustion chamber at a compression top dead center is divided into a plurality of fuel injection regions, located in respective injection directions of the injection openings, by vertical surfaces extending radially from the longitudinal axis through a middle between adjacent injection openings. When a volume of the fuel injection region located in the injection direction of the injection opening is large, an opening area of the injection opening is large.