Pre-chamber Auto-ignition for Methane Engine Operation
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Solution Overview
Problem
Existing methods for operating internal combustion engines with gas fuel, such as the HPDI process, require diesel fuel, increasing system complexity and limiting CO2 savings potential.
Innovation Solution
A method involving a pre-combustion chamber where a pilot quantity of gaseous fuel is self-ignited, increasing temperature and pressure to ignite a main quantity of gas fuel, eliminating the need for diesel and allowing for efficient combustion similar to a diesel process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the HPDI process is used to operate a gas-fueled internal combustion engine, then combustion efficiency is improved, but system complexity increases due to the continued need for diesel fuel
Solution Approach 1:
The invention extracts and eliminates the diesel fuel component from the HPDI process, retaining only the gas fuel injection and combustion functions. This is achieved by using a pre-chamber to auto-ignite the gas fuel without requiring diesel pilot injection, thereby reducing system complexity while maintaining combustion efficiency.
Solution Approach 2:
The pre-chamber enables self-ignition of the gas fuel through auto-ignition of a pilot quantity, eliminating the need for external diesel ignition. The system serves itself by using compressed gas fuel to ignite subsequent main injections without requiring a second fuel type or additional ignition system.
2Productivity
If the HPDI process is used to operate a gas-fueled internal combustion engine, then combustion efficiency is improved, but CO2 savings potential is limited due to the continued need for diesel fuel
Solution Approach 1:
The invention removes diesel fuel from the combustion process, extracting only the beneficial compression-ignition combustion characteristics. This allows the engine to operate exclusively on gas fuel (such as methane), realizing full CO2 savings potential while maintaining the efficient combustion properties of the HPDI process.
Solution Approach 2:
The invention changes the fuel parameter from a dual-fuel system (diesel + gas) to a single-gas-fuel system by modifying the ignition mechanism. The pre-chamber auto-ignition process enables gas fuel to undergo compression-ignition combustion without diesel, changing the fundamental fuel parameter and enabling complete decarbonization of the fuel system.
3Reliability
If compression ratio is increased to enable auto-ignition of gaseous fuel in the pre-chamber, then ignition reliability is improved, but mechanical stress on the engine increases
Solution Approach 1:
The invention segments the combustion chamber into a pre-chamber and a main chamber, allowing the pre-chamber to handle the high compression ratio required for auto-ignition while the main chamber operates at lower stress. This segmentation isolates the high-stress ignition process to a small volume, protecting the overall engine structure from excessive mechanical stress.
Solution Approach 2:
The pre-chamber acts as an intermediary that facilitates auto-ignition of the gas fuel under controlled high-compression conditions. It serves as a buffer zone where the pilot quantity can be reliably ignited, and then transfers the ignition to the main chamber, mediating between the high compression requirements and the engine's mechanical stress limitations.
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
Enables the operation of internal combustion engines purely with methane or other gaseous fuels, reducing system complexity and achieving CO2 savings by eliminating the need for diesel fuel, while maintaining combustion efficiency similar to diesel processes.
Implementation Method 1
compressing supplied air in a main combustion chamber and a pre-combustion chamber by moving a piston in the main combustion chamber to a top dead center
Implementation Method 2
auto-igniting the pilot quantity of gaseous fuel in the pre-chamber
Implementation Method 3
igniting the main quantity of gaseous fuel through the conditions in the pre-chamber caused by the auto-ignited pilot quantity
Data Source
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AI summary
The invention relates inter alia to a method for operating an internal combustion engine (10). The method comprises feeding a pilot quantity of gaseous fuel, preferably methane, into a prechamber (22) before a piston (18) reaches a top dead centre. The method comprises an auto-ignition of the pilot quantity of gaseous fuel in the prechamber (22), a feed of a main quantity of gaseous fuel into the prechamber (22) after the auto-ignition, and an ignition of the main quantity of gaseous fuel by the conditions in the prechamber (22) that are effected by the auto-ignited pilot quantity. The invention makes it possible to operate an internal combustion engine purely with methane or some other gaseous fuel, specifically by means of compression auto-ignition of the pilot quantity.