Fuel Control Device Stabilizing Boost Voltage via Off-State Detection
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Solution Overview
Problem
The existing fuel control devices for internal combustion engines inaccurately detect boost voltage due to extra voltage generated by the ESR component of the boosting capacitor at low temperatures, leading to premature stopping of the boosting operation and unstable fuel injection, which affects fuel consumption.
Innovation Solution
The solution involves detecting the boost voltage only when current is not flowing in the boosting capacitor during the boosting operation, ensuring that the legitimate boost voltage value is compared to the prescribed value for accurate control, thereby stabilizing the boost voltage and ensuring accurate fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the boost voltage is detected using the existing method, then the boost voltage detection is simple, but the detection precision deteriorates due to extra voltage from ESR component at low temperatures
Solution Approach 1:
The control unit determines the state of the switching element before detecting the boost voltage. By checking whether the switching element is in the on-state or off-state in advance, the system selects the appropriate detection method, thereby improving detection precision while managing complexity through structured decision-making
Solution Approach 2:
The detection method dynamically changes based on the switching element state. When the switching element is in the off-state, the existing detection method is used; when in the on-state, a different detection approach is applied. This dynamic adaptation resolves the contradiction by adjusting the detection strategy to environmental conditions
2Reliability
If the boosting operation is stopped when the observed voltage reaches the prescribed value, then the control is simple, but the reliability deteriorates due to erroneous detection at low temperatures
Solution Approach 1:
The control unit determines the switching element state before stopping the boosting operation. This preliminary check ensures that the stop decision is based on accurate information about whether the observed voltage is legitimate or erroneous, thereby improving reliability
Solution Approach 2:
The system uses feedback from the switching element state detection to adjust the boosting operation control. By continuously monitoring the switching element state and using this information to决定是否 stop boosting, the system achieves reliable control while maintaining a manageable control process through structured feedback loops
3Measurement precision
If the boost voltage detection is performed at any timing, then the productivity is high, but the measurement precision deteriorates due to extra voltage generation during switching
Solution Approach 1:
The boost voltage is detected periodically at specific timings determined by the switching element state. By establishing a periodic detection schedule that aligns with the switching element's on/off cycles, the system achieves both high productivity through regular detection and high precision by detecting only when conditions are appropriate
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 stabilizes the boost voltage at the legitimate value regardless of temperature conditions, ensuring accurate fuel injection and improved fuel consumption.
Implementation Method 1
a boosting capacitor 204, and a boost voltage detection unit 206
Implementation Method 2
an ESR (equivalent series resistance) component of the boosting capacitor, configured using an electrolytic capacitor forming the boost circuit, increases
Data Source
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Figure 3(a)~3(g)
AI summary
Provided is a fuel control device for an internal combustion engine that is able to detect the correct boost voltage regardless of the temperature condition, and stabilize the boost voltage value, and is able to inject an accurate amount of fuel from a fuel injection valve. The boost voltage value detected when current is not flowing in a boosting capacitor at least during a boosting operation is taken as a legitimate boost voltage value, and this legitimate boost voltage value is compared with a prescribed boost voltage value to control the boosting operation. Thus, it is possible to stabilize the boost voltage at a legitimate boost voltage value regardless of the temperature condition, and it is possible to inject an accurate amount of fuel from a fuel injection valve, thereby improving fuel consumption.