Reducing Agent Injection Control for Exhaust Purification
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Solution Overview
Problem
Existing exhaust purification control systems face complexity in adjusting reducing agent injection due to varying engine conditions, and catalyst efficiency methods lack clear parameter utilization for quick engine state transitions.
Innovation Solution
A control device and method that calculate a pre-correction injection amount of reducing agent based on engine operating state, then adjust it using the rates of change in engine rotation speed and fuel injection to increase or decrease the injection amount accordingly, ensuring a simple and effective correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the correction amount is calculated to increase as the increase amount of the accelerator opening degree increases and to decrease as the increase amount of the engine rotation speed increases, then the injection amount adjustment can respond to engine transitions, but the adjustment of the correction amount becomes complicated when both the accelerator opening degree and engine rotation speed increase simultaneously
Solution Approach 1:
The correction amount calculation is segmented into two independent parts: a basic reactant supply amount based on engine operating conditions, and a correction amount based on the rate of change of engine speed. This segmentation allows each part to be calculated independently using different parameters, avoiding the complexity of simultaneously considering multiple conflicting parameters in a single calculation.
Solution Approach 2:
The patent introduces an intermediary parameter - the rate of change of engine speed - that mediates between the accelerator opening degree and the engine rotation speed. Instead of directly correlating correction amount with both accelerator opening and engine speed (which creates conflict), the correction amount is correlated with their rate of change, providing a unified measure that resolves the contradiction.
2Productivity
If multiple parameters are used to quickly display engine transition state for adjusting reducing agent injection, then the catalyst efficiency can be improved, but the method does not show how to utilize these parameters clearly
Solution Approach 1:
The patent extracts the essential characteristic from multiple possible parameters and focuses on a single key parameter - the rate of change of engine speed. Instead of attempting to utilize multiple parameters simultaneously (which would create complexity), the invention identifies and extracts the most critical parameter that best represents engine transition state, making the control method clear and implementable.
Solution Approach 2:
The patent changes the parameter used for control from static parameters (accelerator opening degree, engine speed) to a dynamic parameter (rate of change of engine speed). This parameter change allows the system to quickly respond to engine transitions by detecting changes over time, improving catalyst efficiency while maintaining clear and simple parameter utilization.
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 allows for a straightforward correction of reducing agent injection, optimizing its amount based on real-time engine conditions, thereby enhancing the efficiency and simplicity of exhaust purification.
Implementation Method 1
a selective reduction catalyst 61 which purifies the exhaust gas by a selective catalytic reduction
Implementation Method 2
a catalyst that is provided in an exhaust passage of an internal combustion engine to purify an exhaust gas
Data Source
AI summary
There is provided a control device that controls an injection amount of a reducing agent to be supplied to a selective reduction catalyst provided in an exhaust passage of an internal combustion engine. The control device includes a pre-correction injection amount calculation unit configured to calculate a pre-correction injection amount of the reducing agent based on an operating state of the engine, and an injection amount correction unit configured to calculate a corrected injection amount obtained by correcting the pre-correction injection amount, based on a rate of change over time of a rotation speed of the engine and a rate of change over time of a fuel injection amount of the engine, such that the injection amount of the reducing agent increases when at least both the rate of change over time of the rotation speed and the rate of change over time of the fuel injection amount are positive.