Work Machine Powertrain Thermal Coupling for Cold-Start Transmission
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Solution Overview
Problem
Electrically driven work machines require complex and powerful stepped transmissions due to low waste heat from internal combustion engines and high efficiency of electric drives, leading to delayed usability at low ambient temperatures.
Innovation Solution
A powertrain comprising at least one electric motor, an electric energy store, a multi-stage manual transmission, a heating circuit, and a cooling circuit, where the heating and cooling circuits are thermally coupled via a heat exchanger, allowing for efficient heating of the energy store and lubrication of the transmission, reducing the need for a separate cooling device and enabling immediate operation in cold conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electrically driven work machines use high efficiency electric drives with low waste heat, then energy efficiency is improved, but the transmission fluid cannot reach required operating temperature in cold conditions
Solution Approach 1:
The patent combines the heating circuit for the battery and the cooling circuit for the transmission into a single integrated thermal management system. The heat exchanger enables thermal coupling between the two circuits, allowing heat generated during battery charging to be transferred to the transmission fluid, thus solving both heating requirements simultaneously while maintaining high energy efficiency.
Solution Approach 2:
The patent converts the heat generated during battery charging (which would otherwise be wasted energy) into a beneficial resource by transferring it to the transmission fluid through the heat exchanger. This resolves the contradiction by utilizing what would be considered waste heat to solve the transmission fluid temperature problem in cold conditions.
2Adaptability or versatility
If electrically driven work machines use complex and powerful stepped transmissions, then work requirements are met, but the system complexity increases
Solution Approach 1:
The patent implements a multi-functional thermal management system where the heat exchanger serves dual purposes: cooling the battery during charging and heating the transmission fluid during cold operation. This integrated approach reduces overall system complexity by combining multiple thermal control functions into a single device, while still meeting all operational requirements.
3Temperature
If separate cooling devices are used for heating and cooling circuits, then temperature control is improved, but device complexity increases
Solution Approach 1:
The patent merges the heating and cooling circuits into a single integrated system with one common cooling device. The heat exchanger enables thermal coupling between the battery heating circuit and the transmission cooling circuit, allowing a single cooling device to serve both functions by redirecting heat flow based on operational requirements, thus reducing device complexity while maintaining precise temperature control.
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 solution allows for immediate and reliable operation of work machines by heating the energy store and transmission fluid, reducing viscosity and ensuring functional clutches, thereby overcoming the limitations of delayed usability due to cold temperatures and high efficiency of electric drives.
Implementation Method 1
The heating circuit and the cooling circuit are coupled via a heat exchanger
Data Source
AI summary
A powertrain for a work machine, including at least one electric motor, an electric energy store, a multi-stage manual transmission, a heating circuit, and a cooling circuit. The at least one electric motor is configured to provide a mechanical input power. The manual transmission is configured to convert the mechanical input power and provide it as mechanical output power. The energy store is configured to supply the at least one electric motor and the heating circuit with electric power. The heating circuit is configured to provide a heating fluid for heating the energy store. The cooling circuit is configured to provide a cooling fluid for cooling and lubricating the manual transmission. The heating circuit and the cooling circuit are coupled via a heat exchanger and have only a single joint cooling device.