Engine Control Device Ignition Timing Detection via Vibration Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control devices for internal combustion engines face challenges in accurately detecting ignition timing due to the interference of mechanical vibrations with combustion vibrations, leading to inaccurate fuel injection and potential engine performance issues.
Innovation Solution
A control device and method that utilize a vibration sensor to detect vibrations within a specific frequency bandwidth, separating combustion vibrations from mechanical vibrations, and adjusting injection amounts and timings based on the detected ignition timing to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a band-pass filter with frequency bandwidth of about 5 kHz to about 10 kHz is used to process knocking sensor output, then mechanical vibration influence is sufficiently excluded, but combustion vibration detection accuracy deteriorates
Solution Approach 1:
The patent changes the frequency bandwidth parameter of the band-pass filter from the conventional 5-10 kHz to a lower range of 0.5-5 kHz. This parameter change allows the filter to pass combustion vibrations while blocking mechanical vibrations, thereby simultaneously improving detection accuracy and excluding harmful vibrations.
Solution Approach 2:
The patent replaces the conventional mechanical vibration exclusion approach with an acoustic vibration detection approach. By using a band-pass filter tuned to acoustic combustion frequencies rather than mechanical vibration frequencies, the system substitutes the detection mechanism to achieve both goals.
2Measurement precision
If the frequency bandwidth is lowered to detect combustion vibration, then ignition timing detection accuracy improves, but mechanical vibration exclusion capability deteriorates
Solution Approach 1:
The patent optimizes the frequency bandwidth parameter to the specific range of 0.5-5 kHz, which is the overlapping frequency range where combustion vibrations are prominent while mechanical vibrations are suppressed. This precise parameter setting resolves the contradiction by finding the optimal frequency window.
Solution Approach 2:
The band-pass filter acts as an intermediary device that selectively transmits combustion vibrations while attenuating mechanical vibrations. By introducing this frequency-selective mediator, the system can detect combustion signals accurately while excluding mechanical vibration interference.
3Speed
If fuel injection timing is not accurately controlled, then engine response speed is faster, but fuel injection accuracy deteriorates leading to poor combustion efficiency
Solution Approach 1:
The patent implements a feedback control system where the detected ignition timing is compared with the target ignition timing, and the difference (deviation) is used to correct the fuel injection timing. This closed-loop feedback ensures accurate fuel injection timing while maintaining fast engine response.
Solution Approach 2:
The system uses the engine's own vibration signals to automatically detect and correct injection timing deviations without external intervention. The ECU self-adjusts the injection timing based on real-time vibration analysis, achieving both accuracy and responsiveness.
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 precise detection of ignition timing, enhancing fuel injection accuracy and engine performance by reducing mechanical vibration interference, thereby improving combustion efficiency and reducing engine noise.
Implementation Method 1
a vibration sensor configured to detect vibration of the engine body
Implementation Method 2
detect an ignition timing of fuel based on a vibration component of the engine body in a specific frequency bandwidth
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A control device for an internal combustion engine (100) includes an electronic control unit (200). The electronic control unit is configured to control an injection amount and an injection timing of fuel to a target injection amount and a target injection timing set based on an engine operation state, detect an ignition timing of fuel based on a vibration component of an engine body (1) in a specific frequency bandwidth, and correct at least one of the target injection amount and the target injection timing based on a deviation between the detected ignition timing and a target ignition timing according to the engine operation state. The specific frequency bandwidth is a bandwidth on a low frequency side of a frequency bandwidth where the engine body undergoes elastic vibration.