Angled Pre-Chamber Design for Fuel Mixing
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Solution Overview
Problem
Pre-chamber ignition systems in internal combustion engines face challenges with air and fuel mixing due to the small size of the pre-chamber, leading to reduced control over fuel evaporation and charge motion, and complex injection control requirements.
Innovation Solution
The engine pre-combustion chamber is designed with a unique geometry, featuring a first chamber portion centered along a first axis and a second chamber portion joined at an angle, facilitating fuel evaporation and charge motion through a cylindrical upper portion with hemispherical lower openings, a curved joint, and a channel that directs air and fuel for enhanced mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single fuel injection is used in the pre-chamber, then fuel amount is reduced, but air and fuel mixing is insufficient
Solution Approach 1:
The pre-chamber is divided into multiple injection zones with separate fuel injectors and air injectors, allowing staged injection of fuel and air to improve mixing while maintaining controlled fuel quantity
Solution Approach 2:
Air is introduced as an intermediary substance to enhance fuel vaporization and mixing in the pre-chamber, facilitating better air-fuel composition without increasing fuel amount
2Device complexity
If fuel injection travels a short distance in the pre-chamber, then injection control is simplified, but surface wetting increases
Solution Approach 1:
Air injection is used as an intermediary to promote fuel vaporization and reduce liquid fuel contact with pre-chamber surfaces, decreasing surface wetting while maintaining injection control
Solution Approach 2:
Air flow dynamics are utilized to carry fuel vapor throughout the pre-chamber, reducing the need for long fuel travel distance while minimizing surface wetting through pneumatic mixing
3Reliability
If residual purging is increased, then pre-chamber misfire is reduced, but charge motion in the pre-chamber is reduced
Solution Approach 1:
Residual purging is applied periodically at specific engine cycles rather than continuously, allowing charge motion to be restored in subsequent cycles while still achieving misfire reduction through intermittent purging
Solution Approach 2:
Partial purging is applied to remove enough residuals to prevent misfire while maintaining sufficient charge motion, using only the necessary amount of purging rather than complete residual removal
4Stability of the object's composition
If air and fuel are pre-mixed before injection, then mixing control is improved, but injection control complexity increases
Solution Approach 1:
The injection system is segmented into separate fuel injectors and air injectors that operate independently, allowing separate control of fuel and air injection timing and quantity while achieving proper mixing through spatial distribution
Solution Approach 2:
Different regions of the pre-chamber are targeted with different injection strategies, with fuel injected in specific zones and air injected in complementary zones to achieve local mixing optimization without requiring complete pre-mixing
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 improves air and fuel mixing, reduces cylinder misfire, and provides robust pre-chamber ignition by generating swirl motion and increasing fuel evaporation, thus enhancing engine performance and efficiency.
Implementation Method 1
facilitate fuel evaporation and charge motion for increased air and fuel mixing
Implementation Method 2
generating swirl motion and increasing fuel evaporation
Implementation Method 3
a fuel injector directed to deliver a fuel spray diagonally across an upper portion of the pre-chamber
Implementation Method 4
an air injector directed to deliver an air flow into the pre-chamber
Implementation Method 5
a spark plug positioned in the upper chamber portion and directed to generate an electrical discharge
Implementation Method 6
igniting a first air-fuel mixture in the pre-chamber, the combustion of the first air-fuel mixture generating jets of hot gas that exit the pre-chamber
Data Source
AI summary
Systems and methods are provided for air and fuel delivery within a pre-chamber. In one example, an engine pre-combustion chamber comprises a first chamber portion centered along a first axis, and a second chamber portion joined to the first chamber portion and centered along a second axis arranged at an angle to the first axis. In this way, wall wetting may be decreased while favorable charge motion for robust ignition may be increased.