Dynamic Catalyst Temperature Control for DPF Regeneration
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Solution Overview
Problem
Conventional exhaust gas purification systems face challenges in oxidizing unburned fuel at low exhaust gas temperatures, leading to white smoke emission and inefficient DPF regeneration due to fixed catalyst activation temperatures that do not account for varying engine speeds and exhaust gas flow velocities.
Innovation Solution
The system dynamically adjusts the predetermined determining temperature for oxidizing unburned fuel based on engine speed, ensuring that the unburned fuel is oxidized by the oxidation catalyst, thereby preventing white smoke and efficiently raising the DPF temperature during forced regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed predetermined determining temperature is used for oxidizing unburned fuel, then the system structure is simple, but white smoke is emitted and oxidation is incomplete at varying engine speeds
Solution Approach 1:
The patent applies dynamics by making the predetermined determining temperature variable rather than fixed. The temperature threshold for oxidizing unburned fuel is dynamically adjusted based on engine speed feedback, allowing the system to adapt to varying operating conditions and prevent white smoke emission across different engine speeds
Solution Approach 2:
The patent implements feedback control by monitoring engine speed and using this information to adjust the predetermined determining temperature. The system continuously compares actual engine speed with reference values and modifies the temperature threshold accordingly, ensuring complete oxidation of unburned fuel under varying conditions
2Loss of energy
If the exhaust gas temperature is low, then fuel consumption is reduced, but the catalyst temperature is lowered and oxidation reaction is not promoted
Solution Approach 1:
The patent applies parameter changes by adjusting the predetermined determining temperature based on engine speed rather than using a fixed threshold. This dynamic parameter adjustment ensures that the oxidation catalyst operates effectively across varying temperature conditions without requiring excessive fuel consumption for heating
Solution Approach 2:
The patent applies preliminary anti-action by proactively adjusting the temperature threshold before oxidation becomes ineffective. By monitoring engine speed and preemptively modifying the determining temperature, the system prevents catalyst deactivation rather than reacting after oxidation efficiency has already declined
3Temperature
If multiple injection or post injection is conducted to raise exhaust gas temperature, then the catalyst activation temperature is achieved, but the system complexity and fuel injection control complexity increase
Solution Approach 1:
The patent applies dynamics by implementing dynamic adjustment of the predetermined determining temperature based on real-time engine speed feedback. This eliminates the need for complex multi-stage injection control while maintaining effective catalyst activation across varying operating conditions
Solution Approach 2:
The patent applies parameter changes by modifying the temperature threshold parameter according to engine speed rather than changing the injection strategy. This simpler parameter adjustment approach achieves the same temperature control objective without increasing injection system complexity
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 that unburned fuel is consistently oxidized, preventing white smoke and efficiently regenerating the DPF, even at varying engine speeds, by adjusting the catalyst activation temperature in real-time according to engine speed, ensuring effective exhaust gas purification.
Implementation Method 1
HC (hydrocarbon), which is an unburned fuel, is increased in the exhaust gas exhausted from the cylinder and the HC is oxidized by the oxidation catalyst, by which the temperature of the exhaust gas on the downstream of the oxidation catalyst can be raised
Implementation Method 2
the HC is oxidized by the oxidation catalyst
Implementation Method 3
the PM accumulated in the filter is burned and removed
Data Source
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AI summary
In an exhaust gas purification system (1) comprising an exhaust gas purification device (12) having an oxidation catalyst device (12a) carrying an oxidation catalyst and a DPF (12b) arranged in order from an upstream side or a DPF carrying an oxidation catalyst in an exhaust passage (11) of an internal combustion engine (10), in which at regeneration of the DPF (12b), when a catalyst temperature index temperature (Tg2) indicating a temperature of the oxidation catalyst becomes equal to a predetermined determining temperature (Tc1) or above, control of raising a temperature of the DPF (12b) is conducted by supplying an unburned fuel to the upstream side of the oxidation catalyst to thereby oxidize the unburned fuel by the oxidation catalyst, wherein the predetermined determining temperature (Tc1) is changed according to an engine speed Ne of the internal combustion engine (10). By this arrangement, at the regeneration of the DPF (12b), in the regeneration control of raising the temperature of the DPF (12b) by oxidizing the unburned fuel supplied into an exhaust gas by the oxidation catalyst (12a), the unburned fuel supplied into the exhaust gas is surely oxidized and outflow of white smoke is prevented regardless of an operation state of the internal combustion engine (10).