Implement Pump Pressure Control for DPF Regeneration Load

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Solution Overview

Problem

Earthmoving machines face difficulties in particulate filter regeneration due to low exhaust temperatures and low engine load conditions, which hinder the oxidation of accumulated particulate matter, leading to increased back pressure and reduced emissions efficiency.

Innovation Solution

A hydraulic system with an electrohydraulic proportional relief valve and solenoid that adjusts hydraulic fluid pressure to the implement pump, increasing the power demand on the engine during regeneration cycles by delivering current through the solenoid, ensuring sufficient exhaust temperature for particulate filter oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the engine operates at low load conditions, then fuel consumption is reduced, but exhaust temperature becomes insufficient for particulate filter regeneration

Engineering Contradiction:

Improvefuel consumptionVSAvoidexhaust temperature

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The hydraulic system acts as an intermediary mechanism to transfer power from the engine to the implement pump, which then converts hydraulic energy back to mechanical energy at the auger. This intermediate hydraulic conversion allows the engine to operate at lower loads while still providing sufficient power to the working implement, and the heat from this controlled operation maintains exhaust temperature for regeneration.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the operating parameters by using hydraulic pressure multiplication. The implement pump receives pressurized hydraulic fluid from the engine-driven hydraulic pump, and this high-pressure hydraulic system allows the engine to operate at lower RPM and load conditions while still delivering adequate mechanical power to the implement, thereby maintaining exhaust temperature for DPF regeneration.

Inventive Principle:

Principle #35Parameter changes

2Power

If hydraulic fluid pressure to the implement pump is increased, then power demand on the engine increases, but this may cause excessive load under normal operating conditions

Engineering Contradiction:

Improvepower demand on engineVSAvoidoperational flexibility

Core Design Contradiction:

PowerVSEase of operation

Solution Approach 1:

The system dynamically adjusts hydraulic pressure based on operational needs. The electrohydraulic valve controls the amount of hydraulic fluid delivered to the implement pump, allowing the system to increase power demand only when regeneration is needed, while maintaining normal operational flexibility during standard working conditions. This dynamic control prevents excessive load during normal operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The hydraulic system provides a means to control and modulate power delivery. By using hydraulic pressure control through the electrohydraulic valve, the system can precisely regulate the power demand on the engine, increasing it only when particulate filter regeneration is required, while maintaining ease of operation during normal implement functions.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Power

If an electrohydraulic proportional relief valve is used to control hydraulic pressure, then precise power control is achieved, but device complexity increases

Engineering Contradiction:

Improvepower control precisionVSAvoidhydraulic system complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical power control mechanisms with an electrohydraulic control system. The electrohydraulic proportional relief valve uses electrical signals to control hydraulic pressure, providing precise power control without the complexity of mechanical variable displacement mechanisms or multiple control valves. This substitution simplifies the overall control architecture while maintaining precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The system effectively enhances particulate filter regeneration by increasing engine load and exhaust temperature, even under low ambient or engine load conditions, thereby improving emissions control and reducing back pressure.

Implementation Method 1

a solenoid configured to adjust the pressure of hydraulic fluid delivered to the implement pump proportionally to a current delivered through the solenoid

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

The regeneration may promote oxidation (e.g., burning off) of the particulate matter on the filter with heat from engine exhaust

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11649609B2Hydraulic system and methods for an earthmoving machine

Publication Date: 2023.05.16 CATERPILLAR INC

AI summary

A hydraulic system for a machine includes an implement pump, a valve, and an implement valve subsystem. The implement pump includes a load sensing control, and the valve controls the flow of hydraulic fluid to the implement pump. The implement valve subsystem includes one or more implement control subsystems to control movement of an implement. The valve is an electrohydraulic proportional relief valve and includes a solenoid configured to adjust the pressure of hydraulic fluid delivered to the implement pump proportionally to a current delivered through the solenoid.