Exhaust Gas Purifying Apparatus Dynamic Post-Injection Control
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Solution Overview
Problem
Existing exhaust gas purifying apparatuses face challenges in maintaining filter entrance temperature at target levels during changes in engine specifications or outside air temperature, leading to potential excessive temperature increases and THC release.
Innovation Solution
An exhaust gas purifying apparatus with a fuel injection device and control system that adjusts the post-injection quantity based on outside air temperature and exhaust path length, using sensors to detect temperatures and pressures to estimate path length and adjust the post-injection quantity accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the post-injection quantity is increased to reach the target filter temperature, then the filter regeneration is improved, but excessive temperature increase and THC release occur
Solution Approach 1:
The upper-limit value of post-injection quantity is made dynamically adjustable based on exhaust path length and outside air temperature. The control device modifies the upper-limit value according to detected path length (estimated from temperature difference) and temperature sensor readings, allowing the system to adapt the maximum post-injection quantity to current operating conditions, thereby preventing excessive temperature increase while ensuring sufficient heating for regeneration.
Solution Approach 2:
The system changes the parameter of post-injection quantity upper-limit value based on varying operating conditions (exhaust path length and outside air temperature). By adjusting this parameter according to environmental and structural variations, the system optimizes the balance between achieving target filter temperature and preventing harmful effects like excessive temperature rise and THC release.
2Temperature
If the exhaust path is extended or outside air temperature decreases, then the heat radiation increases, but the filter temperature cannot reach the target temperature with the existing upper-limit post-injection quantity
Solution Approach 1:
The upper-limit value of post-injection quantity transitions from a fixed value to a dynamic value that automatically adjusts to exhaust path length and outside air temperature. The control device detects these variations and modifies the upper-limit value accordingly, enabling the system to maintain effective filter regeneration across different operating conditions without manual intervention.
Solution Approach 2:
The system implements feedback control by using temperature sensors to detect the actual temperature conditions (filter entrance temperature and outside air temperature) and using this information to adjust the upper-limit value of post-injection quantity. This closed-loop approach ensures the system adapts to varying heat loss conditions caused by different path lengths and environmental temperatures.
3Object-generated harmful factors
If a fixed upper-limit value for post-injection quantity is set, then excessive temperature increase is suppressed, but the filter temperature cannot reach the target temperature under varying conditions
Solution Approach 1:
The fixed upper-limit value is replaced with a dynamic upper-limit value that varies according to exhaust path length and outside air temperature. This dynamic adjustment mechanism allows the system to maintain safety limits while adapting to different operating conditions, preventing both excessive temperature increase and insufficient heating for regeneration.
Solution Approach 2:
The system changes the upper-limit parameter of post-injection quantity based on detected operating conditions. By modifying this parameter in response to variations in exhaust path length and environmental temperature, the system maintains the balance between preventing harmful effects and ensuring effective filter regeneration across diverse operating scenarios.
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 apparatus effectively maintains filter entrance temperature at target levels while preventing excessive temperature increases and THC release, even with extended exhaust paths or decreased outside air temperatures.
Implementation Method 1
fuel is supplied into an exhaust path and oxidation catalyst brings about combustion of the fuel
Implementation Method 2
oxidation catalyst brings about combustion of the fuel
Implementation Method 3
diesel particulate filters having oxidation catalyst and filters
Implementation Method 4
the filter is regenerated by combustion of particulate matter trapped by the filter
Data Source
AI summary
Provided is an exhaust gas purifying apparatus capable of making a filter entrance temperature reach a target temperature while suppressing excessive temperature increases and release of THC even upon extension of the exhaust path or decreases in outside air temperature. The exhaust gas purifying apparatus includes an oxidation catalyst 18 and a filter 19 that are placed in an exhaust path 5 of an engine 1, a fuel injection device 13 for injecting fuel in accordance with a fuel injection pattern, and a control device 50 configured to be capable of setting the fuel injection pattern including post-injection, wherein an upper-limit value of post-injection quantity increases with decreasing outside air temperature and/or with elongating path length of the exhaust path 5.