Active Pre-combustor Fuel Supply System for Lean Ignition
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Solution Overview
Problem
Conventional spark plugs struggle to ignite ultra-lean gas mixtures or gas mixtures with high EGR rates, requiring high-energy ignition devices, which complicates the implementation of efficient thermal management in gasoline engines while meeting emission regulations.
Innovation Solution
A fuel supply system for an active pre-combustor that includes a plunger air pump assembly to mix and deliver fuel and air to the pre-combustor, ensuring a consistent air-fuel ratio and reducing the risk of misfire, coking, and soot formation, by using a pre-mixing method and a high-temperature, high-pressure fuel mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional spark plugs are used to ignite ultra-lean gas mixtures or gas mixtures with high EGR rates, then the structure remains simple, but ignition reliability deteriorates and misfire occurs
Solution Approach 1:
The combustion chamber is divided into two parts: a pre-combustor and a main combustor. The pre-combustor serves as a separate ignition chamber where a rich fuel mixture is prepared and ignited first, then the resulting flame propagates to the main combustor. This segmentation allows the use of a simple spark plug in the pre-combustor while ensuring reliable ignition of the ultra-lean mixture in the main combustor.
Solution Approach 2:
A rich fuel mixture is prepared and ignited in the pre-combustor before the main combustion event. This preliminary action creates a high-temperature ignition source that reliably ignites the ultra-lean gas mixture in the main combustor, solving the ignition reliability problem without requiring a complex high-energy ignition device.
2Reliability
If high-energy ignition devices are used to ignite ultra-lean gas mixtures, then ignition reliability improves, but device complexity and cost increase
Solution Approach 1:
The combustion system is segmented into a pre-combustor and main combustor, allowing a simple spark plug to be used in the pre-combustor instead of a complex high-energy ignition device. The segmentation transforms the ignition function into a two-stage process that achieves reliable ignition with simpler components.
Solution Approach 2:
The pre-combustor acts as an intermediary between the simple spark plug and the ultra-lean gas mixture in the main combustor. It transforms the low-energy spark into a high-temperature flame that can reliably ignite the difficult-to-ignite ultra-lean mixture, serving as a mediator that bridges the gap between simple ignition source and demanding fuel mixture.
3Loss of energy
If lean combustion with excess air coefficient between 1 and 1.5 is adopted, then thermal efficiency improves, but emission regulations cannot be met without expensive after-treatment equipment
Solution Approach 1:
The system dynamically changes the air-fuel ratio parameter between different combustion modes. During normal operation, it uses ultra-lean combustion (excess air coefficient >1.5) to achieve high thermal efficiency and low NOx emissions. During cold starts or specific conditions, it switches to rich combustion mode, eliminating the need for expensive after-treatment equipment while maintaining emission compliance.
4Loss of energy
If ultra-lean combustion with excess air coefficient greater than 1.5 is adopted, then thermal efficiency improves and NOx emissions are reduced, but ignition difficulty increases
Solution Approach 1:
The combustion chamber is segmented into a pre-combustor for preparing a rich ignition mixture and a main combustor for ultra-lean combustion. This segmentation enables the main combustor to operate at ultra-lean conditions (excess air coefficient >1.5) for high thermal efficiency while the pre-combustor provides reliable ignition, resolving the ignition difficulty associated with ultra-lean mixtures.
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
The system enhances ignition stability, reduces the risk of misfire and coking, and lowers the difficulty of cold starts, while avoiding the need for expensive NOx after-treatment equipment and high-pressure gas storage, thereby improving thermal efficiency and compliance with emission regulations.
Implementation Method 1
the plunger air pump assembly is capable of mixing air and fuel into mixed fuel
Implementation Method 2
by using a pre-mixing method and a high-temperature, high-pressure fuel mixture
Implementation Method 3
by using a pre-mixing method and a high-temperature, high-pressure fuel mixture
Data Source
AI summary
A fuel supply system for an active pre-combustor, including a cylinder assembly. The cylinder assembly comprises a cylinder head, a cylinder body, and a piston. The cylinder head, the cylinder body and the piston form a main combustor. The fuel supply system for the active precombustor further includes a precombustion chamber assembly and a plunger air pump assembly. The pre-combustor assembly is communicated with the main combustor. The plunger air pump assembly is communicated with the pre-combustor assembly. The plunger air pump assembly can actively mix air with fuel into a mixed fuel and deliver it into the pre-combustor assembly (20). The fuel supply system for the active pre-combustor supplies the mixed fuel to the pre-combustor on the basis of a reciprocating stroke opposite to the piston by adding the plunger air pump assembly on the pre-combustor assembly, and is safe, reliable, and efficient.