Exhaust Pipe Heating With Spark Plug Ionization Sensing
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Solution Overview
Problem
Existing solutions for heating an exhaust pipe in a motor vehicle require significant sensor equipment to monitor temperature and combustion air mixture balance, which is complex and costly.
Innovation Solution
A method and device that inject a preset quantity of fuel and comburent into the exhaust pipe and perform multiple spark cycles to initiate combustion, using the spark plug as a sensor to detect ionization current and determine combustion presence without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors and combustion air mixture sensors are installed in the exhaust pipe to monitor combustion, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The spark plug is made to serve dual functions: its traditional ignition function and its function as a combustion monitoring sensor. By detecting ionization current through the spark plug electrodes, the system obtains combustion information without requiring separate temperature or combustion air mixture sensors, thus reducing device complexity while maintaining measurement capability
Solution Approach 2:
The spark plug monitors its own operation by detecting ionization current between its electrodes. This self-diagnostic capability allows the system to determine combustion presence and quality using the spark plug's inherent structure, eliminating the need for additional external sensing equipment
2Reliability
If multiple sensors are installed to monitor temperature and combustion air mixture, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The spark plug performs multiple functions including ignition and combustion monitoring, eliminating the need for separate temperature sensors and combustion air mixture sensors. This reduction in component count directly lowers manufacturing costs while maintaining reliable combustion detection through ionization current measurement
Solution Approach 2:
The monitoring function is merged into the existing spark plug structure rather than being implemented as a separate system. By combining ignition and monitoring capabilities in a single component, the system reduces overall component count and manufacturing complexity while ensuring reliable operation
3Temperature
If a burner is installed upstream of the catalytic converter to heat the exhaust pipe, then heating effectiveness is improved, but device complexity increases
Solution Approach 1:
The heating function is merged with the existing spark plug and injector system rather than installing a separate burner assembly. By utilizing the spark plug for both ignition and combustion monitoring, and the injector for fuel delivery, the system achieves effective exhaust heating without the complexity of a dedicated burner system with its own sensors and control mechanisms
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 efficient heating of the exhaust pipe while reducing the need for additional sensors, simplifying the system and improving reliability by utilizing the spark plug to monitor combustion.
Implementation Method 1
performing a plurality of spark cycles in succession. Each spark cycle proceeds to generate at least one spark between the ends of a pair of electrodes located in proximity to the injection area in order to start combustion
Implementation Method 2
the value of a representative quantity of an ionization current flowing between said ends of the pair of electrodes following the extinction of said spark is detected
Data Source
Figure 1~2
Figure 3~5
AI summary
A method for heating an exhaust pipe in a motor vehicle, comprising a plurality of spark cycles performed in succession at a preset frequency, wherein each spark cycle comprises injecting a preset fuel quantity into an injection area (A) inside of an exhaust pipe (100) in a motor vehicle and generating at least one spark between the ends of a pair of electrodes (7, 8) located in proximity to the injection area (A) in order to start combustion. Thus, a value of an ionization current flowing between the ends of the pair of electrodes (7, 8) is detected following the extinction of the spark and this ionization current value is compared with a preset reference value. Therefore, the presence of combustion in the spark cycle is determined, if the ionization current value is greater than the preset reference value, or the absence of combustion in the spark cycle, if the ionization current value is lower than the preset reference value.