NOx Sensor Heating for Accurate Cold Start Emission Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current NOx emission control during cold starts of vehicles is challenging due to the time required for NOx sensors to warm up, which often results in delayed or incomplete emission control and diagnostics, as these sensors are sensitive to humidity and take time to provide accurate readings.
Innovation Solution
A method and system that prevent the engine from starting until the NOx sensor reaches a sufficient temperature for accurate operation, involving a control unit that either forces the engine to remain off or instructs the driver to delay start, allowing controlled heating of the NOx sensor to vaporize water and reach operational temperature without damage, enabling efficient emission monitoring and diagnostics during cold starts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the vehicle starts immediately without warming up the NOx sensor, then the cold start sequence is completed quickly, but the NOx sensor cannot provide accurate readings and emission control is compromised
Solution Approach 1:
The system performs preliminary heating of the NOx sensor using a heating element before the engine is started. This preliminary action ensures the sensor reaches operational temperature in advance, enabling accurate measurements from the beginning of the cold start sequence without delaying the overall vehicle start process.
2Loss of time
If the NOx sensor is heated quickly to operational temperature, then accurate measurements are achieved faster, but water on the sensor may cause damage due to rapid vaporization
Solution Approach 1:
The system provides beforehand cushioning by controlling the heating rate to vaporize water on the sensor gradually before reaching high operating temperatures. This prevents sudden vaporization damage while still achieving operational temperature in a timely manner, balancing speed with sensor protection.
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
Ensures accurate NOx emission measurements and efficient emission control during cold starts by ensuring the NOx sensor is warm enough to provide reliable data, allowing for timely detection of faults and tracking of exhaust aftertreatment system performance over the vehicle's lifetime.
Implementation Method 1
initiating heating of the NOx sensor
Implementation Method 2
heating a ceramic sensor element at pre-heating... water on the sensor has vaporized
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method for NOx emission control during start of a vehicle (1) comprising an exhaust aftertreatment system (300), an engine (2), and a NOx sensor (308), the method comprising the steps of: determining (S102) a temperature of the NOx sensor; if the determined temperature of the NOx sensor is below a predetermined threshold, initiating (S104) heating of the NOx sensor, and performing (S106) a preventive action for delaying engine start until a determined temperature of the NOx sensor exceeds or is equal to the predetermined threshold. The invention also relates to an exhaust aftertreatment system, a vehicle comprising such a system, a computer program, a computer readable medium and a control unit configured to perform the method.