Fuel Cell Vehicle Pressure Sensor Calibration

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Solution Overview

Problem

Calibration of pressure sensors in fuel cell vehicles often generates noticeable sounds during stoppages, which can be disruptive.

Innovation Solution

The fuel cell vehicle calibrates pressure sensors while traveling using electric power from a secondary battery, ensuring that the hydrogen pressure upstream and downstream of the pressure reducing valve become equal, thereby minimizing noise during the calibration process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure sensor calibration is performed while the fuel cell vehicle is stopped, then calibration accuracy can be ensured, but noticeable noise is generated during the calibration process

Engineering Contradiction:

Improvepressure sensor calibration accuracyVSAvoidnoise during calibration

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent transitions the calibration process from a static state (vehicle stopped) to a dynamic state (vehicle traveling). By performing calibration during vehicle travel, the system eliminates noticeable noise while maintaining calibration accuracy through continuous monitoring and adjustment of pressure differential values throughout the driving cycle.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The calibration process is extended from a discrete stopped-state operation to a continuous process during vehicle travel. The control device continuously acquires pressure differential values and updates calibration data throughout the driving cycle, ensuring both noise elimination and sustained calibration accuracy.

Inventive Principle:

Principle #20Continuity of useful action

2Measurement precision

If the shut-off valve closes and hydrogen gas is exhausted for calibration, then pressure sensor calibration can be performed, but the calibration process takes time and disrupts vehicle operation

Engineering Contradiction:

Improvepressure sensor calibrationVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs pressure sensor calibration in advance during vehicle travel before the vehicle needs to be stopped. By completing calibration during the driving cycle, the system eliminates the need for subsequent calibration stoppages, thereby reducing overall time loss and ensuring readiness for operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The calibration process is integrated into the continuous vehicle operation rather than being a separate stopped-state procedure. This allows calibration to occur during normal driving, eliminating downtime and ensuring the vehicle remains operational throughout the calibration process.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If calibration is performed with pressure differential between upstream and downstream of the pressure reducing valve, then calibration can be completed faster, but measurement accuracy decreases

Engineering Contradiction:

Improvecalibration speedVSAvoidpressure measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts the pressure differential during calibration by continuously monitoring the difference between upstream and downstream pressures. By maintaining an appropriate pressure differential throughout the driving cycle and updating calibration data in real-time, the system achieves both fast calibration and high measurement accuracy.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control device continuously monitors pressure differential values during calibration and uses this feedback to update the calibration curve. This real-time feedback mechanism ensures that even with pressure differential present during travel, the calibration maintains high accuracy by continuously adjusting based on actual measured values.

Inventive Principle:

Principle #23Feedback

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 allows for silent calibration of pressure sensors, preventing the generation of noticeable sounds during the process, ensuring quieter operations and maintaining vehicle functionality.

Implementation Method 1

a fuel cell that generates power by using an electrochemical reaction between hydrogen gas and oxidation gas

Methodology Applied

Scientific EffectElectrochemical reaction: Fuel Cell

Implementation Method 2

a pressure reducing valve that reduces hydrogen pressure in the hydrogen gas flow channel

Methodology Applied

Scientific EffectPressure reduction: Pressure Drop

Data Source

PatentUS10107705B2Fuel cell vehicle

Publication Date: 2018.10.23 TOYOTA JIDOSHA KK

AI summary

When a calibration starting condition of a pressure sensor is satisfied while a fuel cell vehicle is traveling, the fuel cell vehicle starts to travel by using electric power supplied from a secondary battery. In the fuel cell vehicle, a pressure sensor is calibrated based on hydrogen pressure in a hydrogen gas flow channel downstream of a pressure reducing valve after a shut-off valve of a hydrogen tank is closed, and the hydrogen in a hydrogen gas flow channel is exhausted until hydrogen pressure upstream of the pressure reducing valve and hydrogen pressure downstream of the pressure reducing valve become substantially equal to each other. The fuel cell vehicle travels by using electric power supplied from the secondary battery while the pressure sensor is being calibrated, so that calibration processing of the pressure sensor can be performed without causing a noise.