Burner Control Using Existing Lambda Sensors
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Solution Overview
Problem
Existing methods for controlling a burner in an exhaust system of an internal combustion engine are economically disadvantageous due to the need for additional lambda sensors to achieve optimal thermal power and air/fuel ratio.
Innovation Solution
A method that uses the signals from existing lambda sensors upstream and downstream of the burner to control the air flow rate and fuel fed to the burner, eliminating the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a further lambda sensor is housed along a duct to detect the air/fuel ratio of exhaust gases exiting the burner, then the control precision of the burner is improved, but the cost and device complexity increase
Solution Approach 1:
The patent makes the existing lambda sensors serve dual functions: the first lambda sensor detects both engine exhaust air/fuel ratio and burner exhaust air/fuel ratio at different times, and the second lambda sensor detects both engine exhaust oxygen concentration and burner exhaust oxygen concentration. This multi-functionality eliminates the need for dedicated sensors for burner control, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The system uses its own existing sensors to monitor and control the burner, rather than requiring external or additional sensors. The lambda sensors already present in the exhaust system are utilized to provide feedback for burner control, making the system self-sufficient and avoiding additional cost and complexity.
2Adaptability or versatility
If the burner is arranged to introduce exhaust gases between the first and second lambda sensors, then the control capability is improved, but the system complexity increases
Solution Approach 1:
The patent implements dynamic control by switching between different operational modes: during engine operation, the first lambda sensor controls fuel injection for optimal combustion; during burner operation (engine off), the same sensor controls the burner's air/fuel ratio. The system dynamically adapts its control strategy based on operational state, improving versatility without adding physical components.
Solution Approach 2:
The system establishes feedback loops using existing sensors: the first lambda sensor provides feedback for fuel injection control during engine operation and for burner control during burner operation; the second lambda sensor provides feedback for oxygen concentration control. This feedback mechanism enables precise control capability using the existing sensor infrastructure.
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 effective control of the burner, achieving optimal thermal power and desired air/fuel ratio without the economic burden of additional sensors, thereby simplifying and cost-reducing the control system.
Implementation Method 1
a first lambda sensor housed along the exhaust duct and arranged upstream of the precatalytic converter to detect the air/fuel ratio (or titer) of the exhaust gases entering the precatalytic converter; a second lambda sensor housed along the exhaust duct and interposed between the precatalytic converter and the assembly defined by the catalytic converter and by the particulate filter to detect the oxygen concentration inside the exhaust gases downstream of the precatalytic converter
Implementation Method 2
A combustion chamber is defined inside the burner, the chamber receives fresh air and receives fuel from an injector, which is designed to cyclically inject fuel inside the combustion chamber
Implementation Method 3
a spark plug is coupled to the burner to determine the ignition of the mixture present inside the combustion chamber
Implementation Method 4
a burner suited to introduce the exhaust gases (and consequently heat) into the exhaust duct so as to speed up heating of the catalytic converter and so as to facilitate the regeneration of the particulate filter
Data Source
Figure 1
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Figure 4~5
AI summary
A method to control an internal combustion engine (1) having an exhaust duct (10) and an exhaust gas after-treatment system (14) comprising at least one catalytic converter (15, 17) arranged along the exhaust duct (10); an oxygen sensor (18, 18*, 18**) housed along the exhaust duct (10) and arranged upstream of said at least one catalytic converter (15, 17); and a burner (21) suited to introduce the exhaust gases into the exhaust duct (10) upstream of the oxygen sensor (18, 18*, 18**) the method provides the steps of calculating the thermal power (POBJ) required to reach the nominal operating temperature of said at least one catalytic converter (15, 17) obtained with an objective value (λOBJ) of the air/fuel ratio value; and determining both the objective fuel flow rate (ṁF_OBJ) and the objective air flow rate (ṁA_OBJ) to be fed to the burner (21) to obtain the thermal power (POBJ) required to reach the nominal operating temperature of said at least one catalytic converter (15, 17).