Urea Water Tank Inclined Surfaces Cooling Air Guide Passage

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Solution Overview

Problem

In hydraulic excavators, the installation of a urea water tank on the upstream side of the cooling air flow direction obstructs the cooling air passage to the heat exchanger, leading to reduced fluid cooling performance.

Innovation Solution

The urea water tank is designed with inclined surfaces and a cooling air guide passage between the heat exchanger and the tank's front inclined surface, allowing cooling air to flow efficiently around the tank and maintain effective heat exchanger performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the urea water tank is disposed in the heat exchanger upstream room, then the urea water storage capacity is sufficient and the tank is accessible for water supply work, but the cooling air passage to the heat exchanger is obstructed, reducing fluid cooling performance

Engineering Contradiction:
Improveurea water storage capacityVSAvoidfluid cooling performance
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The urea water tank is divided into multiple storage chambers (first storage chamber and second storage chamber) separated by a partition wall. This segmentation allows the tank to be positioned in the heat exchanger upstream room while maintaining adequate storage capacity and enabling selective access to different chambers for water supply operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A guide passage is introduced as an intermediary structure that directs cooling air from the heat exchanger upstream room around the urea water tank to reach the heat exchanger. This mediator element ensures that the presence of the tank does not completely block the cooling air flow, thereby maintaining fluid cooling performance despite the tank's obstructive position.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the urea water tank is positioned on the upstream side of the cooling air flow direction, then the tank is easily accessible for water supply work, but the cooling air passage is blocked, leading to reduced heat exchanger efficiency

Engineering Contradiction:
Improvewater supply accessibilityVSAvoidheat exchanger cooling efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The guide passage creates a three-dimensional flow path that routes cooling air around the urea water tank rather than allowing direct linear flow. This dimensional change in the air flow path enables the tank to be positioned in an accessible location while still permitting cooling air to reach the heat exchanger through an alternative route.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The guide passage acts as a mediator that reconciles the conflicting requirements of tank accessibility and cooling efficiency. It allows the tank to occupy the upstream position for ease of operation while simultaneously ensuring that cooling air can still reach the heat exchanger, thus maintaining productivity.

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 ensures efficient cooling of fluids by the heat exchanger even when the urea water tank is positioned on the upstream side of the cooling air flow direction, preventing a decrease in cooling performance.

Implementation Method 1

a cooling fan (8A) that is provided on one side in a left-right direction of the engine (8) and rotates using the engine (8) as a power source to thereby suck external air as cooling air

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

a heat exchanger (9) that is located closer to an upstream side in a flow direction of the cooling air than the cooling fan (8A) and is provided so as to face the cooling fan (8A) to thereby cool a fluid with the cooling air

Methodology Applied
Scientific EffectHeat Exchanger: Heat Exchanger

Data Source

PatentEP3361010B1Construction machine with exhaust gas treatment device
Publication Date: 2020.04.29 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3361010B1 patent drawingFigure 1
  • EP3361010B1 patent drawingFigure 2
  • EP3361010B1 patent drawingFigure 3

AI summary

A urea water tank (27) is formed as a box body that includes a rear inclined surface (28A) that inclines so as to be parallel with a left inclined surface (7C) of a counterweight (7), a front inclined surface (28B) that inclines with a space being left apart from the rear inclined surface (28A) and in substantially parallel with the rear inclined surface (28A) and a front surface (28C) that is formed on front ends of the rear inclined surface (28A) and the front inclined surface (28B) and is formed into a flat surface that is parallel with a left-right direction of an upper revolving body (4). The rear inclined surface (28A) of the urea water tank (27) is disposed along and facing the left inclined surface (7C) of the counterweight (7) and the front inclined surface (28B) is disposed with a gap being left apart from and facing the heat exchanger (9). A cooling air guide passage (33) through which cooling air flows is formed between the heat exchanger (9) and the front inclined surface (28B) of the urea water tank (27).