Pre-Chamber Ignition for Direct Engine Starting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Direct starting of an engine is challenging due to the difficulty in igniting the air-fuel mixture in cylinders on expansion strokes, resulting in insufficient torque generation, especially when the engine is not rotating, due to trapped air amounts, spark plug location, lack of charge motion, and cool surfaces within the cylinder.
Innovation Solution
Injecting air and fuel into a pre-chamber, igniting the mixture via a spark plug, and exhausting the combusted air and fuel into the cylinder to improve combustion and torque generation during engine starting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If fuel is injected into a cylinder on expansion stroke for direct starting, then the engine can be started without external rotation assistance, but the combustion is insufficient due to small trapped air amount, spark plug location, lack of charge motion, and cool surfaces
Solution Approach 1:
The combustion chamber is segmented into a pre-chamber and a main chamber. The pre-chamber receives fuel injection and generates combustion independently, which then transfers to the main chamber. This segmentation allows reliable combustion to occur in the pre-chamber where conditions are more favorable, while still achieving direct starting of the entire engine.
Solution Approach 2:
The pre-chamber acts as an intermediary between the fuel injection system and the main cylinder chamber. It receives fuel, generates controlled combustion, and transfers the combusted gases to the main chamber, mediating the combustion process to overcome the unfavorable conditions in the main chamber during direct starting.
2Extent of automation
If fuel is injected into the cylinder on expansion stroke, then direct starting is enabled, but the torque generation is insufficient to reliably rotate the engine
Solution Approach 1:
The combustion process is segmented into two stages: first in the pre-chamber to generate high-pressure combustion gases, then transferring to the main chamber to produce torque. This segmentation allows the combustion to build pressure efficiently in the pre-chamber before applying force to the piston, improving torque generation for direct starting.
Solution Approach 2:
Combustion is initiated preliminarily in the pre-chamber before the main chamber combustion occurs. The pre-chamber combustion prepares the conditions (temperature, pressure, gas flow) necessary for subsequent main chamber combustion, ensuring sufficient torque is generated to start the engine.
3Device complexity
If traditional direct starting method is used with fuel injection into the cylinder, then the system remains simple, but the engine starting robustness is poor
Solution Approach 1:
The combustion chamber is divided into a pre-chamber and main chamber, with the pre-chamber serving as a dedicated combustion initiation zone. This segmentation improves starting robustness by providing a controlled environment for fuel combustion while adding minimal structural complexity compared to traditional single-chamber designs.
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 enhances combustion efficiency and torque production in non-rotating engines, improving direct starting robustness and reducing reliance on electric machines for engine rotation.
Implementation Method 1
igniting and combusting the air and fuel in the pre-chamber via a spark plug
Implementation Method 2
The combusted air and fuel mixture may expand to cause the piston in the cylinder to move
Data Source
AI summary
Systems and methods for starting and operating a direct injection engine are described. In one example, the air and fuel are injected into a pre-chamber of a cylinder of an engine while the engine is not rotating. The air and fuel are combusted in the pre-chamber to improve ignition of an air and fuel mixture in the cylinder.