Engine Purge Valve Control Using Tank Pressure Correction
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Solution Overview
Problem
Existing engine control systems face challenges in maintaining an appropriate flow rate of purge gas during high-pressure purge operations, leading to potential rich air-fuel mixtures and complex control requirements, which increase costs and reduce efficiency.
Innovation Solution
A controlling apparatus for an engine that includes a purge path connected to a sealing-type fuel tank and an intake system, featuring a purge valve with a calculation unit that adjusts the valve's opening degree based on a target introduction ratio using correction coefficients for tank pressure, flow velocity, and pipe resistance, ensuring a suitable flow rate without complex calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the degree of opening of the purge valve is controlled similarly as upon normal purge in high-pressure purge, then the control method is simple, but the flow rate of purge gas increases from the intended introduction ratio
Solution Approach 1:
The patent applies parameter changes by introducing a correction coefficient that adjusts the purge valve opening degree based on tank pressure conditions. During high-pressure purge, the correction coefficient is set to a value less than 1 to reduce the opening degree compared to normal purge, thereby compensating for the increased flow rate tendency and maintaining accurate purge gas introduction ratio despite the simplified control approach.
2Manufacturing precision
If accurate purge gas flow rate control is achieved in high-pressure purge, then the air-fuel mixture precision is improved, but the control becomes complicated requiring separate fuel injection adjustment
Solution Approach 1:
The patent extracts the flow rate control function from the complex multi-parameter control system and concentrates it into a single correction coefficient applied to the purge valve opening degree. This allows accurate air-fuel mixture control to be achieved through simple purge valve control alone, eliminating the need for separate fuel injection adjustment mechanisms.
3Productivity
If a vacuum control valve is used for high-pressure purge, then the purge function is achieved, but the upstream pressure becomes higher than atmospheric pressure causing increased purge gas flow rate
Solution Approach 1:
The patent implements feedback control by using a pressure sensor to detect tank pressure and a correction coefficient map that provides appropriate correction values based on the detected pressure. This feedback mechanism allows the system to automatically adjust the purge valve opening degree to compensate for the high upstream pressure condition, maintaining accurate flow rate control throughout the purge process.
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 solution simplifies the configuration to secure an appropriate purge gas flow rate during high-pressure purge operations, reducing the need for complex calculations and ROM capacity, while maintaining efficient fuel introduction and improving engine control accuracy.
Implementation Method 1
purge gas containing evaporated fuel from the fuel tank to flow therethrough
Implementation Method 2
the degree of opening is corrected at least using a tank pressure flow velocity correction coefficient corresponding to an upstream pressure of the purge valve
Data Source
AI summary
A controlling apparatus for an engine includes a purge path connected to a sealing-type fuel tank and an intake system of an engine and is configured to allow purge gas containing evaporated fuel from the fuel tank to flow therethrough. A purge valve placed in the purge path is configured to adjust a flow rate of the purge gas. A calculation unit calculates a degree of opening of the purge valve based on a target introduction ratio of the purge gas, and a controlling unit controls the purge valve so as to establish the degree of opening calculated by the calculation unit. The calculation unit corrects, in high-pressure purge performed when a pressure in the fuel tank increases exceeding a predetermined pressure, the degree of opening using a tank pressure flow velocity correction coefficient K2 corresponding to an upstream pressure of the purge valve.