Combined HCCI and DCI Ignition Control for Low-Octane Gasoline
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Solution Overview
Problem
Conventional internal combustion engines face challenges with low thermal power conversion efficiency due to slow flame spreading in gasoline engines and excessive soot in diesel engines, and homogeneous charge compression ignition engines have a narrow operational range and low power output.
Innovation Solution
A combined ignition control method using both homogeneous charge compression ignition and diffusion compression ignition for low-octane gasoline, with multi-stage fuel injection and exhaust gas recycling, along with an insulation method for the internal combustion engine exhaust system using vacuum jacket assemblies to maintain high exhaust gas temperature and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If homogeneous charge compression ignition mode is used, then thermal power conversion efficiency is improved, but flame spreading speed is slow leading to knocks
Solution Approach 1:
The fuel injection process is divided into multiple stages: pre-injection stage (intake stroke) and primary injection stage (compression stroke). This segmentation allows different portions of fuel to be injected at different times, creating both homogeneous premixed charge and controlling combustion timing to prevent knocks while maintaining efficiency.
Solution Approach 2:
Fuel is injected during the intake stroke before compression (pre-injection stage), allowing the fuel to be premixed with air in advance. This preliminary mixing creates a homogeneous charge that combusts efficiently after ignition, improving thermal power conversion efficiency while the controlled injection timing prevents knocking.
2Reliability
If diffusion compression ignition mode is used, then combustion is achieved, but excessive soot is produced in exhaust gases
Solution Approach 1:
Different regions of the combustion chamber have different fuel concentrations. The pre-injected fuel creates a homogeneous premixed region that combusts cleanly, while the primary injection creates a localized diffusion combustion region. This local quality differentiation reduces overall soot emissions while maintaining reliable combustion.
Solution Approach 2:
The air-fuel ratio and fuel concentration distribution are changed by using multi-stage injection. The pre-injection creates a homogeneous mixture with controlled equivalence ratio, while the primary injection provides additional fuel for diffusion combustion. This parameter control reduces soot formation while ensuring complete combustion.
3Loss of energy
If homogeneous charge compression ignition with multi-point ignition is used, then compression ratio and lean burning are improved, but operational range is narrowed
Solution Approach 1:
The fuel injection timing and amount are dynamically controlled based on operating conditions. The control system adjusts the pre-injection and primary injection timing, duration, and quantity to optimize combustion for different load and speed conditions, thereby expanding the operational range while maintaining high efficiency.
Solution Approach 2:
Multiple combustion control parameters are changed and optimized: pre-injection timing and amount, primary injection timing and amount, air-fuel ratio, compression ratio. This multi-parameter optimization allows the engine to adapt to various operating conditions while maintaining high thermal power conversion efficiency.
4Loss of energy
If compression ratio is increased to improve efficiency, then thermal power conversion efficiency is improved, but knocks occur more easily
Solution Approach 1:
Fuel is pre-injected during the intake stroke to create a homogeneous premixed charge that is ready for controlled combustion. This preliminary preparation allows the use of higher compression ratios for improved efficiency while the controlled timing prevents knocking by ensuring fuel is available at the optimal moment for combustion.
Solution Approach 2:
The control system monitors combustion conditions and adjusts injection timing and amount to prevent knocks. This feedback control allows the engine to operate at high compression ratios for improved efficiency while dynamically preventing knocking through real-time adjustment of combustion parameters.
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 engine efficiency, reduces soot emissions, and allows for a broader operational range without knocks, achieving higher power output and lower specific fuel consumption compared to traditional engines.
Implementation Method 1
an insulation method for the internal combustion engine exhaust system using vacuum jacket assemblies to maintain high exhaust gas temperature and pressure
Implementation Method 2
a combined ignition control method using both homogeneous charge compression ignition and diffusion compression ignition for low-octane gasoline
Implementation Method 3
a combined ignition control method using both homogeneous charge compression ignition and diffusion compression ignition for low-octane gasoline
Implementation Method 4
with multi-stage fuel injection and exhaust gas recycling
Data Source
AI summary
Disclosed is a homogeneous charge compression ignition and diffusion compression ignition combined ignition control method for low-octane gasoline, using a diffusion compression ignition control mode as a forced ignition measure, to ignite a premixed homogeneous lean oil and gas mixture, and meanwhile to achieve homogeneous charge compression ignition of the oil and gas mixture. During an intake stroke, a fuel is partially injected into the cylinder or an intake manifold, to form a low-concentrated, homogeneous, premixed oil and gas mixture. Before the piston reaches a top dead center during the compression stroke, the remaining part of fuel is injected into the cylinder, diffuses in the air, and spontaneously ignites, thus achieving diffusion compression ignition. A flame is generated in the diffusion compression ignition, and ignites the premixed oil and gas mixture in the cylinder, to achieve ignition and combustion of the homogeneous lean fuel. As the temperature and the pressure rise in the cylinder, multi-point spontaneous ignition occurs within the homogeneous lean oil and gas mixture, thus achieving homogeneous charge compression ignition. Such a combined ignition control method achieves a high compression ratio, lean combustion, stratified combustion, and fast combustion, without causing any knocks. Also disclosed are an insulation method of an internal combustion engine exhaust system, and a product thereof.