Engine Control System for Fuel-Air Mixing During Exhaust Gas Recirculation
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Solution Overview
Problem
The existing fuel injection timing control systems for gasoline engines experience reduced fuel spray penetration due to increased exhaust gas recirculation, leading to worsened ignition and combustion fluctuations, which decreases engine efficiency and worsens exhaust emissions.
Innovation Solution
The engine control system advances the fuel injection timing, increases fuel pressure, reduces the frequency of divided multi-stage injection, or shortens the injection interval from intake to compression top dead center, to enhance fuel distribution and mixing within the combustion chamber, particularly when exhaust gas recirculation amounts and temperatures increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the fuel injection timing is retarded upon exhaust gas recirculation, then the combustion temperature is reduced, but the fuel spray penetration is shortened and mixing of fuel and air is reduced
Solution Approach 1:
The system performs preliminary action by advancing the fuel injection timing before the exhaust gas recirculation effect fully develops. This ensures that fuel is injected earlier when chamber pressure is lower and temperature conditions are more favorable for achieving adequate spray penetration and atomization, thereby preventing the mixing problems that would occur with retarded injection timing.
Solution Approach 2:
The system dynamically changes the fuel injection timing parameter based on exhaust gas recirculation conditions. When exhaust gas recirculation is detected, the control system adjusts the injection timing parameter to an advanced position, compensating for the adverse effects of high temperature and pressure on spray penetration, thus maintaining optimal fuel-air mixing conditions.
2Stability of the object's composition
If the fuel injection timing is retarded, then the abnormal combustion suppression effect is achieved, but the ignition becomes difficult and combustion fluctuation worsens
Solution Approach 1:
The system performs preliminary action by advancing the fuel injection timing to ensure proper fuel atomization and distribution before ignition. This preliminary positioning of fuel droplets in optimal locations ensures reliable ignition and stable combustion, preventing the combustion fluctuations that would result from retarded injection timing.
Solution Approach 2:
The system uses feedback from combustion sensors to monitor combustion quality and adjust injection timing accordingly. When combustion fluctuations are detected, the control system modifies the injection timing parameter to maintain stable combustion, ensuring that ignition reliability is preserved while achieving abnormal combustion suppression.
3Object-generated harmful factors
If the exhaust gas recirculation amount is increased, then the exhaust gas purification is improved, but the fuel spray penetration is reduced and mixing is worsened
Solution Approach 1:
The system dynamically changes the fuel injection timing parameter in response to varying exhaust gas recirculation amounts. When EGR amount increases, the injection timing is advanced to compensate for the reduced spray penetration caused by higher chamber pressure and temperature, thereby maintaining adequate fuel-air mixing while allowing high EGR rates for emission control.
Solution Approach 2:
The system performs preliminary action by advancing fuel injection timing before the adverse effects of high EGR rates fully manifest. This ensures that fuel is injected at optimal timing to achieve proper atomization and penetration even when large amounts of exhaust gas are recirculated, maintaining mixing quality while achieving emission reduction goals.
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 extends fuel spray penetration, promotes fuel and air mixing, thereby suppressing combustion fluctuations and achieving compatibility between engine efficiency and exhaust gas purification.
Implementation Method 1
The cylinder direct injection fuel supply device uses a fuel injection valve (hereinafter referred to as the injector) to inject fuel directly into a combustion chamber
Implementation Method 2
The exhaust gas recirculation device recirculates exhaust gas emitted from the gasoline engine into an intake pipe, and flows it back into the combustion chamber for combustion
Implementation Method 3
The specific heat of gas in the combustion chamber is increased to reduce the temperature of the gas
Implementation Method 4
the fuel is injected into the gas at a higher temperature to promote atomization and vaporization
Implementation Method 5
an internal combustion engine which combusts fuel in a combustion chamber and removes power
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The purpose of the present invention is to provide an engine control system that is capable of promoting mixing of fuel and air during exhaust gas recirculation, thereby suppressing combustion fluctuation of a gasoline engine, such that efficiency and exhaust gas purification can be simultaneously achieved. The engine control system controls an engine and is equipped with an injection device for injecting fuel directly into a cylinder and a recirculation device for recirculating exhaust gas to the intake side. When the temperature of the recirculating exhaust gas recirculated by the recirculation device is high as opposed to when the temperature is low, or when the amount of the recirculating exhaust gas recirculated by the recirculation device is large as opposed to when the amount is small, at least one of the following is executed: advancing of the fuel injection timing (IT_SP (n-2) of the injection device; increasing of the fuel pressure (FP) to be supplied to the injection device; reducing the frequency (n) of divided multi-stage injection to be performed by the injection device during the period between intake top dead center and compression top dead center; and reducing of the interval of divided multi-stage injection (IT_RE (n-2)).