Coordinated Electric Heater and Engine Exhaust Temperature Control
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Solution Overview
Problem
Existing engine systems face challenges in maintaining the optimal temperature of Selective Catalytic Reduction (SCR) catalysts, which is crucial for efficient conversion of NOx emissions into less harmful components, especially during cold-start conditions when the catalyst efficiency is hindered by low exhaust gas temperatures.
Innovation Solution
A system that coordinates the operation of an electric heater and engine-based temperature control levers, including close and far post injections, to maintain the SCR catalyst at a predefined threshold temperature, utilizing a controller to modulate heater power and injection commands based on real-time temperature readings from sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an electric heater is used to heat the exhaust gas to maintain catalyst temperature, then the catalyst temperature is maintained, but the energy consumption increases
Solution Approach 1:
The system performs preliminary heating of the exhaust gas using the electric heater before the exhaust reaches the catalyst, ensuring the catalyst reaches its light-off temperature quickly during cold start conditions. This preliminary action prevents the need for prolonged heater operation once the catalyst is active, reducing overall energy consumption.
Solution Approach 2:
The control system dynamically adjusts the heater power output based on real-time feedback from temperature sensors monitoring the exhaust gas temperature and catalyst temperature. By continuously changing the heating parameter according to actual conditions, the system maintains catalyst temperature while minimizing energy consumption.
2Speed
If the heater power is increased to rapidly heat the exhaust gas, then the catalyst reaches operating temperature faster, but the energy consumption and potential overheating risk increase
Solution Approach 1:
The heater control system operates dynamically by continuously adjusting the heater power based on real-time temperature feedback from sensors. The control algorithm modulates the heater output to achieve the desired heating rate while preventing overheating, ensuring both rapid catalyst activation and temperature control stability.
Solution Approach 2:
The system employs feedback control where temperature sensors monitor the exhaust gas temperature and catalyst temperature, and the controller adjusts the heater power accordingly. This closed-loop feedback mechanism ensures the heater provides sufficient heating rate to reach operating temperature quickly while preventing excessive temperature increases that could damage the catalyst.
3Temperature
If post injection is used to increase exhaust gas temperature, then the catalyst temperature is maintained, but the fuel consumption increases
Solution Approach 1:
The system applies partial post injection only when and where needed to supplement heating, rather than continuous full post injection. The control algorithm determines the minimal amount of post injection required to maintain catalyst temperature, reducing unnecessary fuel consumption while still achieving the temperature maintenance goal.
4Stability of the object's composition
If the heater is operated continuously to maintain catalyst temperature, then the catalyst remains at optimal temperature, but the energy consumption and potential catalyst damage from overheating increase
Solution Approach 1:
The system uses feedback control with temperature sensors monitoring the catalyst temperature and exhaust gas temperature. The controller adjusts the heater operation based on this feedback, turning the heater on only when the catalyst temperature drops below the optimal range and turning it off when the temperature is sufficient, thereby maintaining temperature stability while avoiding continuous operation and energy waste.
Solution Approach 2:
The exhaust gas itself serves as the heating medium, utilizing its own thermal energy to maintain catalyst temperature. The system leverages the heat from the exhaust gas flow to keep the catalyst warm during operation, reducing the need for continuous external heating and minimizing energy consumption.
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 coordination ensures the SCR catalyst operates efficiently by maintaining the required temperature, enhancing NOx conversion rates even in cold-start situations, thereby improving the overall emissions treatment efficiency.
Implementation Method 1
A system and method combine and coordinate exhaust temperature control with an electric heater of an engine
Implementation Method 2
a reductant may be injected into the exhaust stream to chemically bind to particles in the exhaust gas. This mixture interacts with a Selective Catalytic Reduction (SCR) catalyst that, at a certain temperature, causes a reaction in the mixture that converts the harmful NOx particles into pure nitrogen and water
Implementation Method 3
provide a second command for close post injection based on the exhaust gas temperature
Data Source
AI summary
A system includes an aftertreatment system coupled to an engine, a heater, at least one sensor configured to determine an exhaust gas temperature, and a processing circuit. The processing circuit is structured to determine whether the exhaust gas temperature is at or below a predefined threshold temperature; provide a first command to control the heater in response to the exhaust gas temperature being at or below the predefined threshold temperature; selectively provide a second command to increase the exhaust gas temperature; and coordinate the first and second commands, where the first command is provided followed by the second command only if the predefined threshold temperature is not attained by the first command.