Tank Ventilation Valve Control for Engine-On Leak Detection
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Solution Overview
Problem
Existing methods for checking tank ventilation devices in internal combustion engines are limited by requiring the engine to be turned off, are sensitive to ambient temperature, and prone to errors due to insufficient cooling and small pressure drops, making them inefficient and requiring extensive calibration.
Innovation Solution
A method that involves detecting the position of a pressure switch and using a controllable tank ventilation valve to pneumatically connect or disconnect the fuel vapor storage system and intake pipe, allowing for frequent checks of the tank ventilation device's operation while the engine is running, regardless of ambient temperature, by creating a strong vacuum in the intake pipe to achieve a sharp pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine is turned off to perform the check, then the tank ventilation device can cool sufficiently to form natural vacuum, but the check can only be performed during prolonged engine-off intervals, reducing productivity
Solution Approach 1:
The patent applies preliminary action by creating vacuum conditions in advance through engine operation before the actual check is performed. The engine is run to generate vacuum in the intake pipe, which is then used immediately for the tank ventilation device check, eliminating the need to wait for natural cooling and vacuum formation.
Solution Approach 2:
The patent enables continuous useful action by performing the check during engine operation rather than requiring engine shutdown. The vacuum generation and check process occur continuously during normal engine running, maximizing productivity while maintaining check reliability.
2Reliability
If ambient temperature is high, then the tank ventilation device cannot cool sufficiently for natural vacuum to form, but the check requires sufficient cooling, reducing adaptability
Solution Approach 1:
The patent maintains continuous useful action by generating vacuum actively during engine operation through the intake pipe, rather than relying on passive cooling of the tank ventilation device. This active vacuum generation works reliably across all ambient temperatures, making the check feasible and adaptable to any environmental conditions.
3Loss of time
If the pressure drop amount is small, then the method is prone to errors and requires extensive calibration, worsening measurement precision
Solution Approach 1:
The patent applies parameter changes by utilizing the large vacuum pressure already present in the intake pipe during engine operation, rather than relying on small natural pressure drops from cooling. This significant pressure differential creates clear, easily detectable signals that improve measurement precision and eliminate the need for extensive calibration.
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 robust and frequent checks of the tank ventilation device, reducing error sensitivity and calibration efforts, as the method can be performed during almost the entire engine runtime and accurately identifies faults and leak sizes without additional components beyond standard engine sensors.
Implementation Method 1
detecting the position of a pressure switch of the tank ventilation device, wherein the pressure switch being in a low-pressure position if the pressure in the tank ventilation device is less than a specified threshold pressure, and otherwise being in a high-pressure position
Implementation Method 2
opening at least partially a controllable tank ventilation valve of the tank ventilation device, which is arranged in a connecting pipe between a fuel-vapor storage system and an intake pipe of the internal combustion engine, and pneumatically connects the fuel vapor storage system and the intake pipe when in an open state
Data Source
AI summary
A robust method, an accordingly designed control device, and an internal combustion engine, enables the proper performance of a tank ventilation device during the operation of the internal combustion engine. For this purpose, the position of a pressure switch of the tank ventilation device is detected, which indicates the pressure present in the tank ventilation device, a controllable tank ventilation valve, which is disposed in a connecting line between a fuel vapor accumulator and an intake pipe of the internal combustion engine, is opened at least partially during the operation of the internal combustion engine, the position of the pressure switch is again detected after opening of the tank ventilation valve, the proper performance of the tank ventilation device; is analyzed based on a comparison of the position of the pressure switch before opening the tank ventilation valve to the position of the pressure switch after opening the tank ventilation valve.