Exhaust Heater Cyclic Control for Deposit Management
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Solution Overview
Problem
Exhaust-gas treatment devices with heaters often become contaminated or blocked, leading to increased flow resistance and reduced heating performance due to deposit formation, which existing technologies fail to effectively address.
Innovation Solution
A method involving an electric heater with a feed point for additives, where the operating state is monitored for deposit formation, and the heater is cyclically activated and deactivated at a set frequency to prevent and remove deposits, using a cycle frequency calculated based on operating parameters like temperature and mass flow, to maintain efficient heating with minimal energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater is continuously operated to maintain heating performance, then heating effectiveness is improved, but energy consumption increases and deposit formation accelerates
Solution Approach 1:
The heater is operated cyclically with defined active and inactive phases rather than continuously. During active phases, the heater raises exhaust gas temperature to prevent deposits; during inactive phases, energy consumption is reduced. This periodic operation maintains heating performance when needed while minimizing overall energy usage.
Solution Approach 2:
The control unit monitors exhaust gas temperature and operating parameters to determine when heater activation is necessary. Based on this feedback, the heater is activated only when the temperature falls below a threshold or deposits are detected, optimizing the balance between heating performance and energy consumption.
2Reliability
If the heater is operated continuously to prevent deposits, then heating performance is maintained, but energy consumption increases
Solution Approach 1:
The heater operates in periodic cycles with active heating phases followed by inactive phases. During active phases, deposits are prevented or removed; during inactive phases, energy is conserved. This maintains reliability of heating function while reducing overall energy consumption compared to continuous operation.
Solution Approach 2:
The system uses the natural exhaust gas flow and temperature fluctuations to determine when heater activation is necessary. The control unit automatically adjusts heater operation based on monitored parameters, allowing the system to self-regulate and maintain performance without continuous energy input.
3Reliability
If the heater operates at high power to remove deposits quickly, then cleaning effectiveness is improved, but energy consumption increases
Solution Approach 1:
The heater uses high power during brief active phases to effectively remove deposits, then switches to inactive phases to conserve energy. This periodic high-power operation achieves effective deposit removal while minimizing overall energy consumption compared to sustained high-power operation.
Solution Approach 2:
The heater power parameter is dynamically adjusted based on operating conditions. During deposit removal phases, high power is applied; during normal operation, power is reduced or shut off. This parameter change optimizes the balance between cleaning effectiveness and 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 method effectively prevents and removes deposits on the heater while minimizing energy input, ensuring consistent heating performance and reducing energy consumption, particularly by operating the heater for less than 20% of the time when in a predefined operating state range.
Implementation Method 1
providing an electric heater for heating at least one exhaust-gas stream or a surface in the exhaust-gas treatment device
Implementation Method 2
the additive impinges on the electric heater... cyclically activating and deactivating the electric heater... to prevent and remove deposits
Data Source
AI summary
A method for operating an exhaust gas treatment device including an electric heater for heating an exhaust gas flow in the exhaust gas treatment device and/or a surface in the exhaust gas treatment device and a feed point for feeding an additive into the exhaust gas treatment device to impinge upon the electric heater, includes supplying additives to the feed point, determining an operational state of the exhaust gas treatment device, in which deposits can impinge upon the electric heater, using at least one state variable, determining a cycle frequency in dependence on the operating state when the operating state lies in a predetermined operating state range, and cyclically activating and deactivating the electric heater using the determined cycle frequency when the determined operating state lies in the predetermined operating state range. A motor vehicle having the exhaust-gas treatment device is also provided.