Multi-Pulse Fuel Injection Control for Combustion Noise
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Solution Overview
Problem
Current internal combustion engines face challenges in managing combustion noise and stability, particularly during transient operations and when dealing with varying cylinder charge temperatures, which can lead to inefficient fuel delivery and increased emissions.
Innovation Solution
A multi-pulse fuel delivery control system that adjusts the timing and volume of fuel injections in real-time based on engine and vehicle operating conditions, using sensors like O2 and Wide Range Air Fuel sensors, to modulate the second fuel pulse and stabilize combustion, reducing noise and improving engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pulse of fuel is injected into the combustion chamber, then the fuel delivery system is simple, but combustion noise increases and stability decreases during transient operations
Solution Approach 1:
The fuel injection is divided into multiple pulses (typically two pulses per combustion cycle) instead of a single pulse. The first pulse is injected during the intake stroke and the second pulse is injected near top dead center. This segmentation allows better control of combustion timing and reduces combustion noise during transient operations while maintaining system simplicity.
2Device complexity
If fuel injection timing is fixed, then the control system is simple, but combustion stability deteriorates during transient operations and varying cylinder charge temperatures
Solution Approach 1:
The fuel injection timing and duration are made dynamic rather than fixed. The control system adjusts the timing and amount of each fuel pulse based on real-time engine operating conditions including transient operations and cylinder charge temperature. This dynamic adjustment maintains optimal combustion stability across varying conditions.
Solution Approach 2:
The control system uses feedback from sensors monitoring engine operating conditions to adjust fuel injection parameters. Based on detected conditions such as transient operations or abnormal cylinder temperatures, the system modifies the second pulse timing and amount to stabilize combustion, creating a closed-loop control system.
3Stability of the object's composition
If the second fuel pulse amount is increased to stabilize combustion, then combustion stability improves, but combustion noise increases
Solution Approach 1:
The system changes multiple parameters of the second fuel pulse including timing, duration, and amount. By optimizing the timing to occur near top dead center and carefully controlling the pulse duration and amount, the system achieves combustion stability while minimizing noise. The parameter adjustments are coordinated rather than isolated.
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 effectively decreases burst combustion noise, stabilizes combustion during transient operations, and minimizes noise due to exhaust gas recirculation delays, providing silent load transient operation without significant performance degradation.
Implementation Method 1
a fuel injector operable, when activated, to deliver multiple pulses of fuel per combustion cycle into a combustion chamber
Implementation Method 2
a spark plug operable to ignite a fuel-air mixture in the combustion chamber
Implementation Method 3
During a subsequent (second) stage, known as the 'compression stroke,' the intake and exhaust valves are closed as the piston travels from bottom-to-top and compresses the fuel-air mixture
Implementation Method 4
The exhaust manifold, in turn, collects and combines the exhaust gases for recirculation into the intake manifold
Data Source
AI summary
Disclosed are multi-pulse fuel delivery control systems, methods for using such systems, and motor vehicles with engines employing multi-pulse fuel injection schemes. A fuel delivery control system is disclosed with fuel injectors that selectively inject multiple pulses of fuel per working cycle into cylinders of an engine. An engine sensor detects an operating condition of the engine, and an exhaust gas recirculation (EGR) sensor detects a state of an EGR system coupled to the engine. An engine control unit is programmed to: determine, from the detected EGR state, a current intake burned gas fraction; determine, from the detected engine operating condition, a desired intake burned gas fraction; determine a secondary fuel mass injection adjustment based on the desired and current intake burned gas fractions; and command the fuel injectors to inject two fuel pulses into each cylinder per working cycle, with the second pulse modified based on the determined adjustment.