Internal Combustion Engine Pilot Injection for Low-Cetane Fuels
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Solution Overview
Problem
Internal combustion engines face challenges in efficiently combusting sustainable fuels, leading to incomplete combustion and increased environmental impact.
Innovation Solution
A method involving the injection of pilot fuel into the air intake system during the intake phase and primary fuel into the combustion chamber during the compression phase, utilizing fuels with different cetane levels to initiate diffusion combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sustainable fuels with low cetane levels are used in internal combustion engines, then environmental impact is reduced, but combustion efficiency deteriorates leading to incomplete combustion
Solution Approach 1:
The patent applies preliminary action by injecting pilot fuel into the air intake system before the main fuel injection during the compression phase. The pilot fuel is introduced early in the intake phase and mixed with air, creating a premixed charge that will ignite first during compression. This preliminary introduction of high-cetane pilot fuel prepares the combustion chamber for subsequent main fuel combustion, enabling complete combustion of low-cetane sustainable fuels.
Solution Approach 2:
The patent uses pilot fuel as an intermediary substance between the air and the main sustainable fuel. The pilot fuel, having higher ignitability, acts as a mediator that initiates combustion reactions and generates radicals that facilitate the combustion of the main low-cetane fuel. This intermediary approach allows the main sustainable fuel to burn more completely without requiring modification of the fuel itself.
2Reliability
If pilot fuel is injected directly into the combustion chamber, then combustion initiation is improved, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by using the air intake system to serve dual purposes: its primary function of providing air to the combustion chamber, and a secondary function as the injection point for pilot fuel. By utilizing the existing air intake infrastructure for pilot fuel introduction, the patent avoids adding separate dedicated injection systems into the combustion chamber, thereby maintaining system simplicity while achieving reliable combustion initiation.
Solution Approach 2:
The air intake system serves as an intermediary pathway that facilitates the introduction of pilot fuel without requiring direct modification of the combustion chamber structure. The pilot fuel is injected into the air stream, which then transports and distributes the fuel throughout the combustion chamber during the intake phase, eliminating the need for complex direct injection mechanisms into the combustion chamber.
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, reduces residuals, and lowers environmental impact by using sustainable fuels like methanol and hydrogen, while maintaining a robust engine operation.
Implementation Method 1
the elevated temperature and/or pressure in the combustion chamber during the compression phase will initiate chemical reactions of the pilot fuel which will generate radicals and heat which will initiate the combustion of the primary fuel
Implementation Method 2
the elevated temperature and/or pressure in the combustion chamber during the compression phase will initiate chemical reactions
Data Source
Figure 1~2
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AI summary
The present disclosure relates to a method for operating an internal combustion engine (1), the method comprising: during and/or prior to an intake phase when at least air is provided into a combustion chamber (7) from a air intake system (4) while a piston (3) is moving from a top dead center (TDC) to a bottom dead center (BDC), injecting (S1) a pilot fuel into the air intake system (4) by the pilot fuel injector (6), and during a compression phase following said intake phase when the piston (3) is moving from the bottom dead center (BDC) to the top dead center (TDC), injecting (S2) a primary fuel directly into the combustion chamber (7) by the main fuel injector (5). The disclosure also relates to an internal combustion engine system (10) and to a vehicle (100).