Electric Exhaust Heating Control for Catalyst Light-Off
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Solution Overview
Problem
Existing methods for heating exhaust systems downstream of internal combustion engines are inefficient, particularly in quickly reaching the required operating temperature for catalysts, and they consume excessive electrical energy.
Innovation Solution
A method using an electric heating device that calculates and controls the precise amount of heat required to reach the target temperature in the exhaust system, taking into account the current temperatures, fluid mass flow rates, and energy efficiency, with a model-based feedforward control system to optimize heating power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If internal engine catalyst heating measures are applied to quickly heat the catalyst, then the catalyst reaches operating temperature faster, but the engine efficiency is worsened due to late ignition angles
Solution Approach 1:
An electric heating device is introduced as an intermediary element between the engine exhaust system and the catalyst. This heating device directly heats the exhaust gas or catalyst without requiring changes to engine combustion parameters, thus achieving fast catalyst light-off while maintaining optimal engine ignition timing and efficiency
Solution Approach 2:
The mechanical/thermal heating approach through engine optimization (changing ignition angles) is replaced with an electrical heating system. This substitution allows independent control of catalyst temperature from engine operation parameters, eliminating the trade-off between heating speed and engine efficiency
2Speed
If external catalyst heating measures are used to quickly heat remote exhaust components, then the heating speed is improved, but the electrical energy consumption increases
Solution Approach 1:
The system performs preliminary heating of the exhaust gas or catalyst using electric heating devices before the catalyst requires full operating temperature. By pre-heating the exhaust stream, less electrical energy is required to reach the target catalyst temperature, reducing overall energy consumption while maintaining fast heating capability
Solution Approach 2:
The system dynamically adjusts heating parameters (power, duration, distribution) based on real-time temperature measurements and catalyst state. By optimizing these parameters, the system achieves the minimum necessary electrical energy input for the required heating speed, avoiding excessive energy consumption
3Reliability
If electric heating devices are used to heat the exhaust system, then the heating effectiveness is improved, but the load on the vehicle electrical system and battery increases
Solution Approach 1:
The electrical heating system operates dynamically, adjusting power output based on real-time catalyst temperature, exhaust flow conditions, and vehicle operating state. This dynamic control ensures heating effectiveness is maintained while electrical power demand is optimized, preventing excessive and unnecessary load on the vehicle electrical system and battery
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 minimizes energy consumption by providing only the required amount of heat, reduces electrical load on the vehicle's system, and ensures precise temperature control, thereby efficiently heating the exhaust system and catalysts.
Implementation Method 1
heating an exhaust system downstream of an internal combustion engine by means of an electric heating device
Implementation Method 2
heat is transported by means of the engine exhaust gas mass flow or using externally supplied transport air into the components of the exhaust system arranged downstream of the heating disk(s)
Data Source
AI summary
A method for heating an exhaust system downstream from an internal combustion engine using an electrical heating device. The method includes an ascertainment of a current temperature in the exhaust system, an ascertainment of a current temperature of the electrical heating device and a fluid mass flow flowing through the electrical heating device, an ascertainment of a heating requirement based on the ascertained current temperature and a target temperature, a calculation of a required amount of heat depending on the heating requirement and an amount of energy required to heat up the electrical heating device, taking into account a heat input into the fluid mass flow to be expected at the ascertained current temperature of the electrical heating device, and a control of the electrical heating device to generate the calculated amount of heat. A computing unit and a computer program are also described.