Engine Control System Using In-Cylinder Oxygen and Compression Temperature
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Solution Overview
Problem
Conventional control systems for internal combustion engines with exhaust gas recirculation struggle to maintain stable combustion, reduce combustion noise, prevent torque shock, and improve acceleration performance, especially in transient operating conditions and high load scenarios.
Innovation Solution
A control system that calculates the in-cylinder oxygen amount and compression end temperature to determine fuel injection parameters, incorporating an oxygen concentration calculator and injection timing corrector, and adjusts air handling parameters to stabilize combustion and control torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fuel injection control is based only on intake air temperature, then the control system is simple, but stable combustion cannot be maintained particularly in low temperature combustion mode or premix combustion mode
Solution Approach 1:
The patent changes the control parameter from intake air temperature to in-cylinder oxygen amount. By calculating the actual oxygen concentration in the cylinder considering both intake air and recirculated exhaust gases, the system achieves accurate fuel injection control that maintains stable combustion across different operating modes including low temperature and premix combustion modes.
2Device complexity
If conventional fuel injection control is used, then the control system is simple, but combustion noise becomes large immediately after fuel cut operation due to high oxygen concentration in recirculated exhaust gases
Solution Approach 1:
The patent implements feedback control by continuously calculating the in-cylinder oxygen amount based on detected intake air amount and recirculated exhaust gas amount. This feedback mechanism allows the system to detect high oxygen concentrations after fuel cut operation and adjust fuel injection accordingly, suppressing combustion noise while maintaining simple control architecture.
3Quantity of substance
If boost pressure is increased to increase in-cylinder oxygen amount in high load condition, then oxygen availability improves, but the rate of increase in boost pressure becomes low since it is near maximum boost pressure
Solution Approach 1:
The patent changes the approach from controlling boost pressure to controlling fuel injection amount based on calculated in-cylinder oxygen amount. In high load conditions where boost pressure is near maximum, the system calculates the actual oxygen concentration and adjusts fuel injection accordingly, enabling rapid response without being constrained by boost pressure limitations.
4Object-generated harmful factors
If exhaust gas recirculation is used to reduce combustion noise, then combustion noise is suppressed, but in-cylinder oxygen amount becomes insufficient during transient state causing unstable combustion
Solution Approach 1:
The patent uses feedback control to monitor the actual in-cylinder oxygen amount resulting from exhaust gas recirculation. By continuously calculating oxygen concentration and adjusting fuel injection based on this feedback, the system maintains stable combustion during transient states while still benefiting from noise suppression through controlled recirculation.
Data Source
AI summary
A control system for an internal combustion engine, wherein in the control system, an in-cylinder oxygen amount is calculated and a compression end temperature, which is a temperature of the pressurized air-fuel mixture, is calculated according to an intake air temperature. A fuel injection parameter is determined according to the compression end temperature, the in-cylinder oxygen amount, and an engine rotational speed. The fuel injector is controlled based on the determined fuel injection parameter. By determining the fuel injection parameter according to the compression end temperature in addition to the in-cylinder oxygen amount, the combustion state is adjusted when the compression end temperature is low, thereby maintaining a stable combustion state.