Internal-Combustion Engine Pre-Chamber Control for Torque Conversion
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Solution Overview
Problem
In general spark-ignition internal combustion engines, the in-cylinder pressure peak occurs at a timing that is not optimal for converting pressure into torque, limiting the improvement of thermal efficiency despite advanced ignition timing.
Innovation Solution
An engine system with an auxiliary combustion chamber and controlled ignition and fuel injection, where the ignition timing is set to align the in-cylinder pressure peak with the maximum mechanical efficiency timing, and the auxiliary chamber pipe is used to form a pre-chamber with a lower compression ratio to delay the pressure peak.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If ignition timing is advanced to increase in-cylinder pressure peak value, then power output is improved, but thermal efficiency cannot be improved because pressure peak occurs at suboptimal timing for torque conversion
Solution Approach 1:
The combustion chamber is segmented into a main chamber and an auxiliary chamber. The auxiliary chamber serves as a pre-combustion chamber where fuel is ignited first, and the resulting pressure wave propagates to the main chamber to drive the piston. This segmentation allows optimization of combustion timing and pressure distribution to improve both power output and thermal efficiency.
Solution Approach 2:
Fuel is injected and ignited in the auxiliary chamber before the main combustion event in the main chamber. This preliminary action creates a pressure wave that propagates to the main chamber, ensuring that the main combustion occurs at the optimal timing for torque conversion, thereby improving thermal efficiency while maintaining power output.
2Ease of operation
If in-cylinder pressure peak occurs immediately after compression top dead center, then ignition timing can be simplified, but mechanical efficiency of torque conversion is not optimized
Solution Approach 1:
By dividing the combustion chamber into auxiliary and main chambers, the system can independently control the timing of pressure generation in each chamber. The auxiliary chamber generates pressure earlier to prepare the main chamber for optimal combustion timing, resolving the conflict between simple ignition control and torque conversion efficiency.
3Loss of energy
If auxiliary chamber pipe is inserted into auxiliary chamber hole, then a pre-chamber is formed to delay pressure peak timing, but device complexity increases
Solution Approach 1:
The auxiliary chamber pipe is designed to be movable relative to the auxiliary chamber hole. The pipe can be inserted to form a pre-chamber when delayed combustion is needed, and retracted when standard combustion is required. This dynamic configuration allows the system to adapt combustion timing without permanently increasing structural complexity.
Solution Approach 2:
The auxiliary chamber pipe is positioned in advance to create the pre-chamber configuration before combustion occurs. This preliminary setup allows the system to control pressure peak timing without requiring complex real-time adjustments during the combustion process.
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 the thermal efficiency of the engine by optimizing the in-cylinder pressure peak timing and reducing knocking, thereby improving torque conversion efficiency.
Implementation Method 1
a spark plug attached to the cylinder head; ignite the spark plug when the auxiliary chamber pipe is inserted into the auxiliary chamber hole
Implementation Method 2
an injector configured to inject a fuel to be supplied into the main chamber
Implementation Method 3
a main chamber defined by a piston, a cylinder and a cylinder head
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An engine system S includes an internal combustion engine 1 and a control unit 100. The internal combustion engine includes a main chamber 5 which is defined by a piston 2, a cylinder 3, and a cylinder head 4; a spark plug 10 which is attached to the cylinder head, an auxiliary chamber pipe 11 which surrounds the spark plug and protrudes downward from the cylinder head, an auxiliary chamber hole 17 which is formed in the piston and into which the auxiliary chamber pipe is insertable, and an injector 9 configured to inject a fuel to be supplied into the main chamber. The control unit ignites the spark plug when the auxiliary chamber pipe is inserted into the auxiliary chamber hole, and injects the fuel from the injector at a timing before the spark plug is ignited and before the auxiliary chamber pipe is inserted into the auxiliary chamber hole.