Auxiliary Charge Air Compression Using Recuperated Hydraulic Energy

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Solution Overview

Problem

Existing working machines face challenges in providing additional charge air to internal combustion engines during highly dynamic power demands due to turbo lag, which is not efficiently addressed by current energy recuperation systems.

Innovation Solution

Incorporating a secondary pneumatic or hydraulic working circuit with an auxiliary compressor driven by energy stored in a pressure accumulator to supply additional charge air to the internal combustion engine during power surges, using hydraulic displacement units to store and retrieve energy as needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If energy recuperation systems are implemented in working machines, then energy efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoiddevice complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines the energy recuperation system with the existing hydraulic working circuit of the working machine. The hydraulic circuit serves dual purposes: performing work operations and recuperating energy during lowering maneuvers. This integration merges two functions into one system, improving energy efficiency without proportionally increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hydraulic circuit is designed to perform multiple functions: it acts as both the working circuit for operating the machine's equipment and as an energy recuperation system. The same hydraulic fluid and components are utilized for both work performance and energy recovery, making the system universal and reducing the need for separate dedicated recuperation components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Speed

If additional charge air is provided during highly dynamic power demands, then engine power response is improved, but turbo lag is worsened

Engineering Contradiction:
Improveengine power responseVSAvoidturbo lag
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The system pre-compresses air in the pressure accumulator during phases when the engine does not require maximum power. This preliminary compression of air allows the auxiliary compressor to immediately supply additional charge air when the engine suddenly demands high power, eliminating the delay normally associated with turbocharger response.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pressure accumulator acts as an intermediary energy storage device between the engine and the auxiliary compressor. It stores compressed air that can be rapidly delivered to the engine's charge air system, mediating the delay between power demand and charge air supply that causes turbo lag.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If engine size is reduced for downsizing, then fuel consumption is improved, but power availability is worsened

Engineering Contradiction:
Improvefuel consumptionVSAvoidpower availability
Core Design Contradiction:
Loss of energyVSPower

Solution Approach 1:

The patent replaces part of the mechanical engine power output requirement with a hydraulic-energy-stored-compressed-air system. The auxiliary compressor, driven by hydraulic energy from the pressure accumulator, substitutes for engine power that would otherwise be needed to drive a larger turbocharger or engine, enabling downsizing while maintaining power availability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the parameter of charge air supply by introducing an auxiliary compression source that operates independently of engine speed and load. This allows the engine to be downsized while the charge air parameters (pressure and flow) are maintained or enhanced through the auxiliary compressor during high-demand phases.

Inventive Principle:
Principle #35Parameter changes

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

Enhances engine dynamics and efficiency by providing immediate additional charge air during power increases, allowing for engine downsizing and reduced fuel consumption, while maintaining performance and reducing turbo lag.

Implementation Method 1

energy from the secondary working circuit can be recuperated and fed to a pressure accumulator (13) of the work machine for storage in the form of compression energy

Methodology Applied
Scientific EffectCompression energy storage: Compression

Implementation Method 2

at least one auxiliary compressor (15) which can be driven by the energy stored in the pressure accumulator (13) to generate compressed additional charge air

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP4606959A1Work machine with energy recuperation and method for operating a work machine
Publication Date: 2025.08.27 LIEBHERR MACHINES BULLE
  • EP4606959A1 patent drawingFigure 1
  • EP4606959A1 patent drawingFigure 2a
  • EP4606959A1 patent drawingFigure 2b

AI summary

The invention relates to a work machine comprising an internal combustion engine and at least one secondary pneumatic or hydraulic working circuit, wherein during operation of the secondary working circuit energy is recuperated and can be fed to a pressure accumulator of the work machine for energy storage, characterized in that at least one auxiliary compressor is provided which can be driven by the energy stored in the pressure accumulator, and an engine control is provided and configured to detect a highly dynamic increase in the power requirement of the internal combustion engine and, if necessary, to generate additional charge air by means of the auxiliary compressor, which is fed to the charge air path of the internal combustion engine in addition to the regular charge air flow of the internal combustion engine.