Burner Control via Pressure Pulsation for Catalyst Light-Off
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Solution Overview
Problem
Internal combustion engines face challenges in achieving quick light-off temperatures for three-way catalysts during cold starts, leading to inefficient emissions control, especially without the aid of lambda probes which are not yet operational.
Innovation Solution
A method to estimate the lambda value in exhaust gases by determining pressure pulsation values, allowing for adjustment of combustion air and fuel quantities without a lambda probe, using pressure sensors to maintain optimal fuel-air ratios and accelerate catalyst light-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lambda probe is used to monitor exhaust gas composition, then accurate fuel-air ratio control is achieved, but the system requires a warm-up phase and additional complexity
Solution Approach 1:
The patent replaces the chemical/electrical sensing mechanism of a lambda probe with a mechanical pressure sensing approach. By using pressure sensors to detect pressure pulsations in the exhaust gas, the system determines the fuel-air ratio without requiring the thermal processing and electrical signal generation of a lambda probe, thereby eliminating the warm-up phase requirement.
Solution Approach 2:
The patent introduces pressure pulsations as an intermediary parameter to indirectly measure the fuel-air ratio. Instead of directly measuring exhaust gas composition with a lambda probe, the system uses pressure sensors to detect pulsations caused by combustion processes, which correlate with the fuel-air ratio, providing a faster and more direct measurement approach.
2Device complexity
If pressure sensors are used to monitor combustion, then fuel-air ratio can be determined without lambda probe, but pressure sensors must be positioned strategically
Solution Approach 1:
The patent makes the pressure sensor system multi-functional by using the same pressure sensors that monitor combustion for the dual purpose of determining fuel-air ratio. This eliminates the need for separate lambda probes and reduces overall system complexity, as the pressure sensors serve both combustion monitoring and exhaust gas composition analysis functions.
3Reliability
If catalyst heating measures are applied to accelerate light-off, then emissions control is improved, but engine efficiency deteriorates
Solution Approach 1:
The patent implements a feedback control system that continuously monitors pressure pulsations and adjusts the burner operation accordingly. By using the pressure sensor data to determine fuel-air ratio and controlling the burner to maintain optimal conditions, the system achieves efficient catalyst heating without excessive energy consumption, balancing emissions control with engine efficiency.
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
Enables rapid catalyst light-off and efficient emissions control during cold starts by adjusting fuel-air mixtures based on pressure pulsation amplitudes, reducing emissions and eliminating the need for a warm-up phase or lambda probe, thus improving combustion stability and emissions reduction.
Implementation Method 1
determining a pressure pulsation value in the exhaust gas downstream of the burner and/or in an air path upstream of the burner
Implementation Method 2
igniting the air-fuel mixture in the burner
Implementation Method 3
Three-way catalysts (TWC) can be used to achieve legally prescribed emission limits by converting the relevant gaseous pollutants NOx, HC, and CO into harmless products such as N2, H2O and CO2
Data Source
AI summary
A method for operating a burner, comprising supplying a controlled quantity of combustion air to the burner, supplying a controlled quantity of fuel to the burner, igniting the air-fuel mixture in the burner, determining a pressure pulsation value in the exhaust gas downstream of the burner and/or in an air path upstream of the burner, and adjusting the quantity of combustion air and/or the fuel depending on the pressure pulsation value. Further proposed are a computing unit and a computer program product for performing such a method.