Hydraulic Pump Pressure Control for Exhaust Gas Heating

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Solution Overview

Problem

Conventional hydraulic drive systems for hydraulic working machines fail to control engine load minimally to raise exhaust gas temperature for effective combustion of particulate matter, leading to inefficiencies in energy saving and particulate matter elimination.

Innovation Solution

A hydraulic drive system with a pressure detection and control mechanism, including a variable restrictor, that adjusts delivery pressure to a preset value to minimize engine load and ensure sufficient exhaust gas temperature for particulate matter combustion, using a control system that manages the actuator control valve, displacement, and delivery pressure to optimize engine output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the delivery pressure of the variable displacement hydraulic pump is increased to raise exhaust gas temperature for particulate matter combustion, then the temperature of exhaust gas is improved, but the engine output is wasted due to manufacturing errors causing actual delivery pressure to exceed preset values

Engineering Contradiction:
Improveexhaust gas temperatureVSAvoidengine output waste
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent implements a feedback control mechanism where a pressure detection means continuously monitors the actual delivery pressure of the hydraulic pump, and a control means adjusts the delivery pressure based on the detected value to maintain it at the preset minimum level required for particulate matter combustion, preventing energy waste from excessive pressure

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the delivery pressure parameter of the hydraulic pump based on detected actual pressure values, changing it to match the preset minimum required value, thereby optimizing the balance between achieving sufficient exhaust gas temperature and minimizing engine output waste

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the delivery pressure is set to a preset value to minimize engine load, then energy saving is improved, but the actual delivery pressure may become insufficient due to manufacturing errors leading to inadequate particulate matter elimination

Engineering Contradiction:
Improveengine outputVSAvoidparticulate matter elimination performance
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The pressure detection means provides continuous feedback on actual delivery pressure, enabling the control means to detect when pressure falls below the preset minimum value and automatically adjust it upward, ensuring reliable particulate matter combustion while maintaining energy efficiency

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the delivery pressure parameter upward from the preset minimum value when detection indicates insufficiency, ensuring the pressure remains at the optimal level for both energy saving and reliable particulate matter elimination

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If the engine output is reduced to the minimum level for cooling and lubrication in non-operation state, then energy saving is improved, but the exhaust gas temperature drops making particulate matter combustion difficult

Engineering Contradiction:
Improveengine outputVSAvoidexhaust gas temperature
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The patent applies hydraulic load to the engine through the variable displacement hydraulic pump operating in non-feed state, using the hydraulic system to generate the necessary load that raises exhaust gas temperature to the level required for particulate matter combustion while maintaining relatively low engine output

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 solution allows precise control of delivery pressure to achieve the necessary exhaust gas temperature for particulate matter combustion, reducing fuel consumption and contributing to energy saving by minimizing engine load while preventing filter clogging.

Implementation Method 1

a variable restrictor (19) arranged on an upstream side of the actuator control valve (7) in a direction of a flow of pressure oil delivered from the variable displacement hydraulic pump (4), and adapted to restrict the flow of pressure oil delivered from the variable displacement hydraulic pump (4)

Methodology Applied
Scientific EffectHydraulic pressure control: Hydraulic Press

Implementation Method 2

an exhaust gas purification system for trapping in a filter particulate matter in exhaust gas as produced by incomplete combustion in the engine

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

an engine output is increased to provide the exhaust gas with heat needed for combustion of the particulate matter so that the particulate matter in the filter of the exhaust gas purification system is combusted and eliminated

Methodology Applied
Scientific EffectThermal energy: Heating

Implementation Method 4

a variable displacement hydraulic pump drivable by power transmitted from the engine

Methodology Applied
Scientific EffectHydraulic pump mechanism: Pump

Data Source

PatentEP2474739B1Hydraulic drive device of hydraulic operating machine
Publication Date: 2018.08.29 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP2474739B1 patent drawingFigure 1
  • EP2474739B1 patent drawingFigure 2
  • EP2474739B1 patent drawingFigure 3

AI summary

Provided is a hydraulic drive system for a hydraulic working machine, which can surely set a delivery pressure at a preset value upon raising a temperature of exhaust gas to a temperature needed for combustion of particulate matter by increasing a load to be applied to an engine. In a non-operation state of the hydraulic working machine, a variable restrictor (19) is controlled by a controller (14) and a delivery pressure control valve (20) to increase a delivery pressure of a variable displacement hydraulic pump (4), so that the load to be applied to the engine is increased to raise the temperature of exhaust gas to the temperature needed for the combustion of the particulate matter. At this time, a controller (14) controls the delivery pressure control valve (20) such that a delivery pressure to be detected by a delivery pressure sensor (21) will conform with a preset reference delivery pressure. The reference delivery pressure has been set as a minimum pressure that can provide the exhaust gas with heat needed for the combustion of the particulate mater.