Aftertreatment Temperature Estimation Using Upstream Sensor Data
Solution Overview
Problem
Existing diesel aftertreatment systems are complex and require numerous sensors for thermal and chemical management, leading to high costs, complex diagnostics, and difficulties in achieving an optimal fuel-urea consumption balance for NOx conversion between Lean NOx Trap (LNT) and Selective Catalytic Reduction (SCR) systems.
Innovation Solution
An apparatus and method that use a processing means to calculate an approximated temperature of exhaust gases downstream of an exhaust system component by combining temperature and flow rate signals, reducing the number of sensors needed and improving response time, while also calculating heat loss and chemical reaction rates to enhance temperature accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple temperature sensors are used to monitor exhaust gas temperature at different locations, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a single temperature sensor upstream of the exhaust system component and calculates the downstream temperature as a copy/derivation of this measurement. The processing means computes the downstream temperature by accounting for heat loss and chemical reactions, avoiding the need for physical duplicate sensors while maintaining measurement capability.
Solution Approach 2:
The processing means acts as an intermediary that transforms the single upstream temperature measurement into an estimated downstream temperature value. It mediates between the limited sensor input and the control system's need for downstream temperature information by performing calculations based on heat loss models and reaction rates.
2Measurement precision
If multiple temperature sensors are installed downstream of exhaust system components, then temperature monitoring accuracy is improved, but response time to temperature changes decreases due to sensor location and thermal inertia
Solution Approach 1:
The system performs preliminary calculation of downstream temperature based on upstream measurements before actual downstream temperature changes occur. By computing the downstream temperature estimate in advance using heat loss models and flow rate data, the system anticipates temperature changes and provides timely control signals without waiting for downstream sensors to detect them.
Solution Approach 2:
The patent replaces the mechanical/physical temperature sensing approach with a computational model. Instead of relying on physical sensors downstream that suffer from thermal inertia and slow response, the system uses mathematical calculations based on upstream sensor data, heat transfer equations, and reaction kinetics to determine downstream temperature in real-time.
3Device complexity
If independent operation of LNT and SCR systems is maintained, then system simplicity is preserved, but optimal fuel-urea consumption balance for NOx conversion cannot be achieved
Solution Approach 1:
The patent merges the control of LNT and SCR systems into a unified control strategy. The processing means coordinates both systems based on the calculated downstream temperature and exhaust gas composition, allowing them to work together as an integrated aftertreatment system rather than independently. This enables optimized fuel injection timing and urea dosing to achieve better overall NOx conversion efficiency.
Solution Approach 2:
The system dynamically adjusts operational parameters of both LNT and SCR based on real-time temperature estimates and exhaust conditions. By changing parameters such as fuel injection rate, injection timing, and urea dosing in coordination between the two systems, the patent achieves optimal energy efficiency for NOx conversion that independent operation cannot accomplish.
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 reduces the number of sensors required, enhances response time to temperature changes, and improves the accuracy of temperature calculations, thereby optimizing the aftertreatment process and balancing fuel-urea consumption for efficient NOx conversion.
Implementation Method 1
calculate a rate of heat loss from the exhaust gases during the passage of the exhaust gases through the first exhaust system component
Implementation Method 2
calculate a rate of heat loss from the exhaust gases to a substrate of the first exhaust system component during the passage of the exhaust gases through the first exhaust system component
Implementation Method 3
calculate a rate of heat generated by chemical reactions during the passage of the exhaust gases through the first exhaust system component
Data Source
AI summary
Apparatus (100) for controlling an aftertreatment system of an internal combustion engine (101), a system comprising an apparatus, a vehicle comprising a system and a method (1000) of controlling injection in an internal combustion engine (101) are disclosed. The apparatus comprises a processing means (102) configured to receive a first signal from a first temperature sensing means (103) indicative of a first temperature of exhaust gases outputted from an internal combustion engine (101) at a first location upstream of a first exhaust system component (104) configured to provide a passage for exhaust gases. The processing means is also configured to receive a second signal from a flow rate sensing means (105) indicative of a flow rate of the exhaust gases outputted from the engine (101) and calculate an approximated value at least from the first signal and the second signal. The approximated value is indicative of a second temperature of exhaust gases at a location downstream of the first exhaust system component (104). The processing means is further configured to provide an output signal to control the after treatment system, in dependence of the calculated approximated value.