Tank Ventilation Valve Heating to Prevent Icing

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Solution Overview

Problem

Conventional tank devices in hybrid motor vehicles face issues with icing and pressure imbalances due to condensation and temperature fluctuations, leading to valve seizure and inadequate ventilation, especially at low ambient temperatures.

Innovation Solution

Applying an excitation current greater than the threshold to the switching valve for heating purposes, even when not intended for ventilation, to prevent ice formation and ensure reliable operation across a wide temperature range, including the use of PWM control to manage valve opening and heating of pressure relief valves to prevent icing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the switching valve is heated by applying excitation current greater than the threshold, then ice formation is prevented and valve reliability is improved, but the valve may open unintentionally causing pressure loss

Engineering Contradiction:

Improvevalve operation reliabilityVSAvoidfluid loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies dynamic control of the excitation current by using PWM (pulse width modulation) to vary the duty cycle. This allows the heating effect to be maintained while controlling the average current to stay below the threshold that would cause valve opening, thus dynamically balancing heating needs with prevention of fluid loss

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical parameters of the excitation current (amplitude, duty cycle, frequency) to achieve different effects. By adjusting these parameters, the system can provide sufficient heating power without exceeding the current threshold that would trigger valve opening, resolving the contradiction between heating effectiveness and valve closure maintenance

Inventive Principle:

Principle #35Parameter changes

2Temperature

If the excitation current is increased to prevent ice formation, then the valve device is heated effectively, but the switching valve opens when it should remain closed

Engineering Contradiction:

Improvevalve device temperatureVSAvoidvalve state stability

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

The patent employs periodic excitation current application through PWM control, where the current is applied in pulses rather than continuously. This periodic action provides cumulative heating effect over time while the intermittent nature prevents sustained electromagnetic force that would cause valve opening, thus maintaining valve state stability while achieving temperature increase

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the excitation current parameters based on operating conditions, using pulse width modulation to optimize the balance between heating effectiveness and valve state maintenance, allowing the valve to remain closed while still receiving sufficient thermal energy

Inventive Principle:

Principle #15Dynamics

3Stress or pressure

If the tank is vented at low temperatures, then pressure management is achieved, but condensation forms and freezes causing valve seizure

Engineering Contradiction:

Improvetank pressureVSAvoidvalve operability

Core Design Contradiction:

Stress or pressureVSReliability

Solution Approach 1:

The patent applies preliminary heating to the valve device before venting operations at low temperatures. By pre-heating the valve area through controlled excitation current application, condensation is prevented from freezing on the valve components, ensuring valve operability is maintained during subsequent pressure management operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of cold temperatures (which cause freezing and seizure) into a beneficial heating effect by applying controlled excitation current. The same electrical system that controls valve opening is used to generate heat, transforming the cold environment's negative impact into a protective thermal effect that prevents valve seizure

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 method ensures reliable tank ventilation and pressure management by preventing valve seizure and maintaining operational integrity at low temperatures, allowing for safe aeration and venting without relying on the control unit's ventilation commands.

Implementation Method 1

an excitation current, which is greater than the excitation current threshold, is applied, at least temporarily, to the switching valve for heating purposes

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS9829894B2Method for operating a tank device, and corresponding tank device

Publication Date: 2017.11.28 AUDI AG

AI summary

In a method for operating a tank device of a motor vehicle, with the tank device having a tank and a tank ventilation device with at least one switching valve, an excitation current can be applied to the switching valve, and the switching valve opens only when the excitation current exceeds an excitation current threshold over a certain period of time. Provision is hereby made to apply an excitation current which is greater than the excitation current threshold, at least temporarily, in a first mode of operation to the switching valve for heating purposes, also when ventilation of the tank is not governed by a control unit of the tank device.