Construction Machine Sensor Fault Handling for Exhaust Filter

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Solution Overview

Problem

Conventional construction machines face issues with excessive engine output restriction due to faulty regeneration-related device sensors, leading to potential inability to move from work sites to maintenance locations, and the risk of continuous engine operation despite filter clogging.

Innovation Solution

A construction machine equipped with differential pressure detectors, a trouble determining unit, an excessive accumulation determining unit, and an operation restricting unit to assess and manage sensor troubles and particulate matter accumulation, allowing for controlled engine operation and movement to maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If engine output is restricted when any regeneration-related device sensor shows abnormality, then engine reliability is improved, but construction machine mobility deteriorates

Engineering Contradiction:

Improveengine reliabilityVSAvoidconstruction machine mobility

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent segments sensor abnormalities into two categories: differential pressure sensor abnormalities and other sensor abnormalities. For differential pressure sensor abnormalities, the system determines excessive particulate matter accumulation and restricts engine output accordingly. For other sensor abnormalities without excessive accumulation, the system maintains normal engine operation. This segmentation resolves the contradiction by applying targeted responses rather than blanket restrictions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the control parameter based on the type of sensor abnormality detected. When differential pressure sensor failure occurs, the system switches to using differential pressure detector data to determine particulate matter accumulation level, and adjusts engine output restriction accordingly. This parameter change allows the system to maintain mobility while ensuring reliability through appropriate restrictions.

Inventive Principle:

Principle #35Parameter changes

2Speed

If engine output is not restricted when sensor abnormality occurs, then construction machine mobility is maintained, but engine safety deteriorates

Engineering Contradiction:

Improveconstruction machine mobilityVSAvoidengine safety

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system continuously monitors sensor status and differential pressure data, providing feedback to the control unit. When excessive particulate matter accumulation is detected through differential pressure detector readings, the system provides feedback to restrict engine output, preventing filter damage while maintaining mobility when safe to operate.

Inventive Principle:

Principle #23Feedback

3Duration of action of stationary object

If regeneration treatment is executed based on trapping amount estimation, then filter durability is improved, but measurement precision deteriorates due to sensor abnormalities

Engineering Contradiction:

Improvefilter durabilityVSAvoidtrapping amount measurement precision

Core Design Contradiction:

Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The differential pressure detector serves as an intermediary measurement tool when primary sensors fail. The system uses differential pressure readings across the filter to estimate particulate matter accumulation level, providing an alternative measurement method that maintains filter durability monitoring precision even when other sensors are abnormal.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration enables necessary failsafe measures, preventing excessive engine output restriction and ensuring the machine can be moved for repair while preventing continuous operation that could damage the engine or filter.

Implementation Method 1

differential pressure detectors for detecting a differential pressure that is a difference between a pressure in an inlet side and a pressure in an outlet side of the filter

Methodology Applied

Scientific EffectDifferential pressure detection: Pressure Drop

Implementation Method 2

a regeneration device that burns the particulate matter trapped in the filter to execute regeneration treatment of the filter

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentEP2803832B1Construction machine

Publication Date: 2017.01.04 HITACHI CONSTRUCTION MACHINERY TIERRA CO LTD

AI summary

In an engine (10), an exhaust gas purifying device (20) and a regeneration device (24), there are provided detectors for detecting working states thereof, such as a rotational sensor (28), a cooling water temperature sensor (29), an intake temperature sensor (30), exhaust gas temperature sensors (31, 32, 33, 34), pressure sensors (35, 36), and opening degree sensors (37, 38, 39). When a trouble occurs in any of the sensors (28 to 34 and 37 to 39) other than the pressure sensors (35, 36) among them, a light degree of operation restrictions is performed for restricting a rotational speed of the engine (10) while it can be determined that particulate matter is not excessively accumulated in a particulate matter removing filter (23) from a detection value of the pressure sensors (35, 36). On the other hand, when the particulate matter is excessively accumulated in the particulate matter removing filter (23) or when any of the pressure sensors (35, 36) has a trouble, a heavy degree of the operation restrictions accompanied by a fuel injection quantity restriction of the engine (10) is performed.