Fuel Injection Control System Oxygen Sensor Feedback
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Solution Overview
Problem
Existing fuel injection control systems for internal combustion engines face challenges in maintaining a stable air-fuel ratio feedback control, particularly during engine warming-up and when using oxygen sensors, as they can lead to excessive enriching or leaning, and do not adequately account for environmental and vehicle-specific factors, and periodic trouble checking is limited.
Innovation Solution
A fuel injection control system that dynamically adjusts the air-fuel ratio feedback correction factor using a control unit to set varying limit ranges based on oxygen sensor output variations, considering factors like parts accuracy, temperature, altitude, and alcohol concentration, and continuously monitors the oxygen sensor state for trouble checking, allowing for adaptive feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a limit value for the air-fuel ratio feedback correction factor is set to prevent excessive enriching or leaning, then combustion stability is improved, but the system cannot adapt to environmental variations such as altitude, temperature, and parts accuracy
Solution Approach 1:
The patent applies dynamics by making the limit value of the air-fuel ratio feedback correction factor changeable based on engine operating conditions. The control unit dynamically adjusts the limit value according to parameters such as engine temperature, altitude, and warming-up status, allowing the system to adapt to environmental variations while maintaining combustion stability through condition-specific limit enforcement.
2Adaptability or versatility
If the limit value of the air-fuel ratio feedback correction factor is increased during warming-up operation, then the system adapts to warm-up conditions, but excessive enriching or leaning may still occur due to large correction amounts
Solution Approach 1:
The patent applies parameter changes by modifying the limit value parameter of the air-fuel ratio feedback correction factor based on engine operating conditions. During warming-up operation, the limit value is increased to accommodate larger correction amounts needed for warm-up adaptation, while the control unit continuously monitors and adjusts the correction factor to prevent excessive enriching or leaning, thus maintaining air-fuel ratio stability even with increased limits.
3Device complexity
If periodic trouble checking of the oxygen sensor is performed, then system complexity is reduced, but the system cannot continuously monitor sensor health and may use faulty sensor data for feedback control
Solution Approach 1:
The patent applies feedback by continuously monitoring the output signal of the oxygen sensor and using this information to adjust the air-fuel ratio feedback correction factor in real-time. The control unit processes the sensor output continuously rather than periodically, providing continuous feedback to the fuel injection system, which ensures reliable operation by preventing the use of faulty sensor data and maintaining accurate air-fuel ratio control throughout engine operation.
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 ensures stable air-fuel ratio feedback control by adjusting limit ranges according to changing conditions, preventing excessive rich or lean states and maintaining engine operability, while continuously monitoring the oxygen sensor to prevent combustion issues during trouble checking.
Implementation Method 1
an air-fuel ratio which is detected by an air-fuel ratio sensor (an oxygen sensor) provided at an exhaust pipe
Data Source
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Figure 3~4
AI summary
To provide a fuel injection control system which properly sets a limit value of an air-fuel ratio feedback correction value, thereby making a good air-fuel ratio feedback control possible. While a variation rate of an output value of an oxygen sensor (32) is changed from the positive to the negative or from the negative to the positive predetermined times after a power source of a vehicle is turned on, a control unit (C) sets a first limit range (L1) for an air-fuel ratio feedback correction factor (K02) as an upper/lower limit value which have a predetermined upper/lower width, in which the output value of the oxygen sensor (32) detected in a stoicshiometric air-fuel ratio state is a reference value (B1), and which is allowed to be used for calculating a correction injection quantity (T1). After a variation rate of the output value of the oxygen sensor (32) is changed from the positive to the negative or from the negative to the positive predetermined times, the air-fuel ratio feedback correction factor (K02) that is calculated when the variation rate is changed the predetermined times is regarded as a reference value (B2), and a second limit range (L2) which has a predetermined upper/lower width from the reference value (B2) and is narrower than the first limit range (L1) is set.