Electric Heating Catalytic Converter Cold Start Control
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Solution Overview
Problem
Internal combustion engines face challenges in quickly and efficiently heating catalytic converters to operating temperature, especially during cold starts, which affects pollutant conversion efficiency and increases fuel consumption.
Innovation Solution
A method involving an electric heating device for catalytic converters, where a secondary air mass flow is strategically supplied upstream of the catalytic converter, with controlled heating power and flow rates to rapidly reach and maintain the light-off temperature, ensuring efficient heating and preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If combustion measures are implemented to heat the catalytic converter using waste heat from the internal combustion engine, then the heating speed is improved, but fuel consumption increases and the cold-start emission period cannot be eliminated
Solution Approach 1:
The catalytic converter is heated to operating temperature before the internal combustion engine is started, using an external heating device. This preliminary heating action ensures that the catalyst is already active when the engine starts, eliminating the cold-start emission period without requiring combustion measures that would increase fuel consumption.
2Reliability
If the entire catalyst substrate volume is heated to operating temperature using an electric heating device, then pollutant conversion efficiency is improved, but the heating time and energy consumption increase
Solution Approach 1:
The catalyst substrate is divided into two functional zones: a heated zone near the electric heating device where the catalyst is rapidly brought to operating temperature, and a non-heated zone that remains at lower temperature. This segmentation allows the critical pollutant conversion function to be activated quickly without the time and energy penalty of heating the entire substrate volume.
Solution Approach 2:
Different regions of the catalyst substrate are maintained at different temperatures according to their functional requirements. The region adjacent to the electric heating device is heated to operating temperature for effective catalysis, while other regions remain at lower temperatures, optimizing both conversion efficiency and energy consumption.
3Speed
If high heating power is applied to rapidly heat the catalytic converter before engine start, then the light-off temperature is reached faster, but thermal damage to the heating device may occur
Solution Approach 1:
The heating power of the electric heating device is dynamically adjusted based on real-time temperature feedback from the catalyst substrate. The control system continuously monitors the temperature and modulates the heating power to maintain optimal heating rates while preventing overheating and thermal damage to the heating device, enabling rapid heating without compromising durability.
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 allows for rapid and efficient heating of the catalytic converter before engine start, ensuring high pollutant conversion rates and reducing energy consumption, while preventing thermal damage to the heating device.
Implementation Method 1
electric heating device, which convert electrical power into heating power
Implementation Method 2
catalytic converters are used for this purpose, among other things, in which a chemical conversion of combustion pollutants is carried out by oxidation or reduction of the pollutant in question
Implementation Method 3
chemical conversion of combustion pollutants is carried out by oxidation or reduction of the pollutant in question
Data Source
AI summary
Various embodiments of the teachings herein include a method for heating a catalytic converter arranged in an exhaust-gas tract of an internal combustion engine and comprising an electric heating device. An example method may include: activating the electric heating device with a specified heating power at a time before the internal combustion engine is started; monitoring the catalyst temperature in a region of the catalytic converter adjacent the heating device; before the catalyst temperature has reached a predetermined first threshold value, supplying a secondary air mass flow with a first flow rate is supplied into the exhaust-gas tract upstream of the catalytic converter; and after the catalyst temperature has reached the predetermined first threshold value, increasing the secondary air mass flow to a second flow rate greater than the first flow rate.