Seal Valve Function Diagnosis in Evaporated Fuel Processing
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Solution Overview
Problem
Existing evaporated fuel processing devices lack a method for properly diagnosing the function of the seal valve, which is crucial for maintaining the integrity of the evaporated fuel sealing system and preventing atmospheric contamination.
Innovation Solution
Incorporating a diagnosis unit that uses a pressure generating unit and internal pressure detecting units to perform leak and function diagnostics of the seal valve, including a predetermined wait time for stability and power management to ensure accurate and efficient diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leak diagnosis is performed using existing methods, then the evaporated fuel sealing system can be monitored, but the seal valve function cannot be properly diagnosed
Solution Approach 1:
The patent implements feedback by detecting tank internal pressure and comparing it against expected pressure ranges to determine seal valve status. The control unit receives pressure sensor data, processes it through diagnostic logic, and generates diagnostic results that feed back into system monitoring and alert mechanisms, enabling continuous verification of seal valve functionality.
Solution Approach 2:
The patent replaces direct mechanical inspection or complex diagnostic mechanisms with a pressure-based sensing system. By using pressure sensors and electronic control units to detect and analyze tank internal pressure, the system substitutes mechanical diagnosis methods with electronic sensing and computational analysis, enabling remote and automated seal valve function verification.
2Reliability
If continuous monitoring is performed to ensure system integrity, then atmospheric contamination is prevented, but power consumption increases
Solution Approach 1:
The patent implements periodic monitoring instead of continuous operation. The control unit performs diagnostic checks at predetermined intervals or under specific conditions (such as engine start/stop cycles), allowing the pressure sensor and processing systems to remain in low-power states between measurements while still maintaining system integrity through regular verification.
Solution Approach 2:
The patent changes operational parameters by adjusting monitoring frequency based on system state. The control unit can modify the timing and frequency of pressure measurements and diagnostic routines according to operating conditions, reducing power consumption during normal operation while intensifying monitoring when anomalies are detected or during critical operational phases.
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
Enables proper function diagnosis of the seal valve, reducing power consumption and ensuring the evaporated fuel sealing system operates effectively, thereby preventing fuel escape and maintaining atmospheric cleanliness.
Implementation Method 1
a canister internal pressure detecting unit disposed in a canister side section of the communication passage, where the canister side section is one of two sections of the communication passage divided at a position of the seal valve and including the canister, and configured to detect a canister internal pressure of the canister
Implementation Method 2
a tank internal pressure detecting unit configured to detect a tank internal pressure of the fuel tank
Implementation Method 3
a pressure generating unit configured to generate pressure in the evaporated fuel sealing system
Data Source
AI summary
A evaporated fuel processing device includes a seal valve that seals off the fuel tank from the atmosphere, a canister, a changeover valve that allows or inhibits communication of the canister with the atmosphere, the canister internal pressure sensor, a controller that sends an open/close command to the seal valve and the changeover valve, a diagnosis unit that performs leak diagnosis of an evaporated fuel sealing system, and a negative pressure pump that generates pressure in the evaporated fuel sealing system. The diagnosis unit performs leak diagnosis of the entirety of the evaporated fuel sealing system before performing leak diagnosis of a canister side section. The diagnosis unit performs function diagnosis of the seal valve with the seal valve closed and the changeover valve at a shut-off position based on whether the detection value of the tank internal pressure sensor varies beyond a predetermined range of the generated pressure.