Retrofit Drive Module for Hybrid Tandem Roller Operation
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Solution Overview
Problem
Construction machines face challenges in operating with either an internal combustion engine or an electric motor as primary drive sources, with hybrid machines being expensive and conventional electric machines having limited range, while fully electrified machines require new purchases and are costly.
Innovation Solution
A construction machine comprising a main machine with a primary drive unit and an add-on drive module, allowing for hybrid operation by integrating a secondary drive unit, such as an electric motor, through a hybrid hydraulic circuit that connects to the main machine's hydraulic system, enabling flexible operation between combustion and electric power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a construction machine uses an internal combustion engine as the primary drive source, then it can operate independently without external power supply, but it generates harmful emissions that conflict with legal requirements and tender stipulations
Solution Approach 1:
The drive system is segmented into two independent parts: the existing internal combustion engine and an add-on electric drive module. This allows the machine to operate in different drive modes (combustion-only, electric-only, or hybrid) depending on emission requirements and availability of external power, thereby reducing emissions while maintaining operational versatility
Solution Approach 2:
A hydraulic coupling device acts as an intermediary between the electric motor and the machine's existing hydraulic system. This mediator enables the electric drive module to integrate with the combustion engine system without requiring complete system redesign, allowing emission reduction while preserving the machine's existing functionality
2Object-generated harmful factors
If a construction machine is fully electrified with an electric motor as the primary drive source, then emissions are reduced, but the machine requires a battery power supply which limits the operating range
Solution Approach 1:
The system merges two power sources: the add-on electric motor and the existing internal combustion engine. The electric motor provides emission-free operation when external power is available, while the combustion engine serves as a backup or supplementary power source, thereby extending the operating range beyond what a battery-only system could achieve
Solution Approach 2:
The drive system is made dynamic by allowing switching between different power sources based on operational needs. The machine can operate in electric mode near power supplies to reduce emissions, and switch to combustion mode or hybrid mode when longer range is needed, optimizing both emission reduction and operating range
3Adaptability or versatility
If a construction machine is designed as a hybrid machine with both internal combustion engine and electric motor as primary drive sources, then it can operate in both combustion and electric modes, but the machine becomes comparatively expensive to purchase and maintain
Solution Approach 1:
The add-on electric drive module is designed to be universally applicable to various combustion-engine construction machines through standardized hydraulic coupling. This multi-functionality allows a single electric module design to work with different machine types, reducing development and manufacturing costs compared to dedicated hybrid systems
Solution Approach 2:
The electric drive capability is extracted as a separate, removable module that can be added to existing machines without redesigning the core combustion engine system. This extraction approach allows the expensive hybrid functionality to be implemented as an optional add-on rather than requiring complete system redesign, thereby reducing overall cost
4Adaptability or versatility
If a conventional construction machine is retrofitted with an add-on drive module, then it can operate with electric motor temporarily, but the machine requires minimal intervention in the hydraulic architecture
Solution Approach 1:
The machine's existing hydraulic system serves itself by providing the coupling mechanism for the add-on electric module. The hydraulic pump and coupling device, which are already part of the combustion engine system, are utilized to integrate the electric motor without requiring additional complex hydraulic infrastructure, thereby minimizing conversion effort
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
Enables cost-effective operation of conventional machines with temporary electric motor use, reducing emissions and eliminating the need for a complete hybrid fleet by retrofitting existing machines with a single add-on module, minimizing conversion effort.
Implementation Method 1
the hydraulic pump of the add-on module is driven by a secondary drive unit encompassed by the add-on drive module, thereby pumping hydraulic fluid in the hybrid hydraulic circuit to drive the first hydraulic pump and/or the first hydraulic motor
Data Source
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AI summary
The invention relates to a construction machine, in particular a tandem roller, comprising a main machine and an attachment drive module connectable to the main machine. The invention further relates to a method for converting a construction machine with a primary drive unit into a construction machine with a primary drive unit and a secondary drive unit by means of an attachment drive module.