Combustion Chamber Sensor Cooling via Expansion Channel
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Solution Overview
Problem
Conventional thermal engines lack precise and real-time measurement of combustion temperature due to the extreme conditions within the combustion chamber, limiting their control and efficiency.
Innovation Solution
A combustion chamber design with a measurement chamber and channel system that reduces temperature and increases sensor contact surface, allowing for direct and reliable temperature measurement of each explosion, enabling precise control of the fuel injector and engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is integrated directly into the combustion chamber to measure combustion temperature, then measurement precision is improved, but the sensor reliability deteriorates due to high temperatures (3000°C) and pressures (60-80 bar) causing rapid sensor deterioration
Solution Approach 1:
The combustion chamber is segmented into two distinct spaces: the explosion chamber where combustion occurs at 3000°C, and the measuring chamber where the temperature sensor operates at lower temperatures. The channel connecting these chambers has a smaller cross-sectional area than the measuring chamber, creating a geometric constraint that limits heat transfer to the sensor while allowing combustion gases to expand into the measuring chamber.
Solution Approach 2:
The measuring chamber acts as an intermediary space between the high-temperature combustion environment and the temperature sensor. This intermediate chamber allows combustion gases to expand and cool before contacting the sensor, protecting it from direct exposure to extreme temperatures while still enabling accurate temperature measurement of the combustion process.
2Reliability
If protective devices are used to protect temperature probes in the combustion chamber, then sensor reliability is improved, but measurement precision deteriorates because thermal resistance of protective materials prevents accurate temperature measurement
Solution Approach 1:
The temperature sensor is extracted from the direct combustion environment (explosion chamber) and placed in the measuring chamber, which is connected through a constrained channel. This extraction removes the sensor from the harmful high-temperature zone while maintaining its ability to measure combustion temperature through the channel, eliminating the need for thermal-resistant protective materials that would compromise measurement accuracy.
3Device complexity
If lambda sensors are used to measure oxygen level in exhaust gases to estimate combustion quality, then device complexity is reduced, but measurement precision and response time deteriorate because averaging over 1-2 seconds cannot provide real-time data for each explosion
Solution Approach 1:
The invention replaces the chemical-based lambda sensor measurement (which requires averaging over time) with a direct thermal measurement approach. The temperature sensor directly measures combustion temperature in real-time, providing immediate feedback for each explosion event without requiring temporal averaging or complex gas analysis, thus achieving both simplicity and real-time precision.
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 design allows for real-time temperature measurement of 1000°C despite explosion temperatures of 3000°C, improving engine performance and exceeding operating limits by correlating gas opening percentage directly with explosion temperature, resulting in increased power and reduced consumption.
Implementation Method 1
The geometric properties of the channel and the measuring chamber are designed to achieve a temperature drop between the explosion temperature and the temperature around a sensor located within the measuring chamber
Implementation Method 2
a temperature sensor of said combustion chamber... fixed so that a probe of said temperature sensor extends into said measuring chamber
Data Source
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AI summary
The invention relates to a combustion chamber (10) of a heat engine comprising a cylinder (11); a cylinder head (12); and a temperature sensor (14); said cylinder head comprising a measuring chamber (15) connected to an explosion chamber (13) by a channel (16) having a lower section having a dimension smaller than an upper section of said measuring chamber (15) so as to form a shoulder between said channel (16) and said measuring chamber; said measuring chamber comprising a bottom on which said temperature sensor is fixed so that a probe (19) of said temperature sensor (14) extends into said measuring chamber; said measuring chamber having an internal wall having a surface area between 1.3 and 2 times the surface area of said probe so as to form a free volume all around said probe in said measuring chamber.