Combustion Timing Detection via Engine Block Vibration Analysis
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Solution Overview
Problem
Directly measuring combustion timing in high-temperature, high-pressure combustion chambers is challenging due to sensor durability issues and high costs, making it impractical for mass-produced vehicles.
Innovation Solution
Measuring engine block vibration signals using an acceleration sensor and performing continuous wavelet transformations to extract and analyze frequency differences, determining combustion timing by comparing calculated values with predetermined thresholds and averaging crank angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are directly exposed to combustion fire to accurately measure combustion timing, then measurement precision is improved, but sensor durability deteriorates due to high temperature and high pressure conditions
Solution Approach 1:
The patent uses engine block vibration signals as an intermediary to indirectly measure combustion timing. Instead of placing sensors directly in the combustion chamber, the system attaches acceleration sensors to the engine block which transmit vibration signals caused by combustion. This intermediary approach allows accurate combustion timing measurement while protecting sensors from high temperature and pressure damage.
Solution Approach 2:
The patent replaces direct mechanical/thermal measurement methods with vibration-based measurement. By substituting pressure sensors or thermal sensors with acceleration sensors that detect mechanical vibrations transmitted through the engine block, the system achieves combustion timing measurement without exposing sensors to harsh combustion conditions.
2Measurement precision
If sensors are directly exposed to combustion fire to accurately measure combustion timing, then measurement precision is improved, but device cost increases due to expensive high-durability sensors
Solution Approach 1:
The patent employs inexpensive acceleration sensors mounted on the engine block instead of expensive high-temperature resistant sensors. These standard acceleration sensors can be mass-produced at low cost and do not require the expensive materials and manufacturing processes needed for sensors that can withstand direct combustion exposure, making the system economically viable for mass-produced vehicles.
Solution Approach 2:
By using engine block vibrations as an intermediary measurement medium, the system avoids the need for expensive sensors capable of withstanding combustion conditions. The vibration signals serve as a low-cost proxy for direct combustion measurement, enabling accurate timing detection without high sensor costs.
3Measurement precision
If vibration signals are analyzed using wavelet transformation to determine combustion timing, then measurement precision is improved, but device complexity increases due to signal processing requirements
Solution Approach 1:
The patent replaces complex direct combustion measurement systems with a vibration analysis system using wavelet transformation. While wavelet transformation adds signal processing steps, it eliminates the need for complex high-temperature sensor systems and their associated protection mechanisms, overall simplifying the hardware while maintaining measurement precision through advanced signal processing.
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
Accurately determines combustion timing using vibration signals, enabling effective control of direct injection compression ignition engines without the need for expensive, durable sensors, thus improving durability and reducing costs.
Implementation Method 1
measuring a vibration signal of an engine block that is generated in a combustion process of an engine
Data Source
AI summary
An accelerator sensor that is mounted on an engine block may be used to detect vibration of a compression ignition engine, and the detected vibration signal is analyzed to determine the combustion timing of the engine. A method for detecting combustion timing may include measuring a block vibration signal generated in a combustion process of an engine, setting up a frequency area that is to be analyzed in the block vibration to divide the frequency area into wavelet scales, executing continuous wavelet transformations of the divided wavelet scales to extract respective result values thereof and to calculate differences between former result values and latter result values, comparing the calculated difference value with a predetermined value to store crank angles of pertinent timing if the calculated difference values exceed the predetermined value, and averaging the stored crank angles to determine combustion timing in a case that all wavelet scales are processed.