Hybrid Drive Cooling Circuit Segmentation for Heat Recovery
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Solution Overview
Problem
Existing hybrid drive devices for motor vehicles face inefficiencies due to heat management, where heat generated by the electric machine is not effectively utilized to preheat the internal combustion engine or optimize transmission efficiency, leading to suboptimal performance and energy loss.
Innovation Solution
A drive device with a common cooling circuit and a circulation line that can be fluidically decoupled using a switching valve, allowing for independent temperature control of the electric machine and transmission heat exchanger, with heat from the electric machine being used to preheat the internal combustion engine and temper the transmission for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common cooling circuit is used for both the internal combustion engine and electric machine, then temperature control is simplified, but heat from the electric machine cannot be effectively utilized to preheat the engine or optimize transmission efficiency
Solution Approach 1:
The cooling circuit is segmented into a common cooling circuit and a separate circulation line with a switching valve. This allows the system to selectively isolate the electric machine's heat from the common cooling circuit and redirect it through the circulation line to the transmission heat exchanger, enabling targeted heat utilization without complicating the overall cooling system architecture
Solution Approach 2:
A circulation line with a switching valve acts as an intermediary between the common cooling circuit and the transmission heat exchanger. This intermediary component enables controlled heat transfer from the electric machine to the transmission, allowing efficient heat utilization while maintaining the simplicity of the common cooling circuit structure
2Productivity
If heat from the electric machine is used to preheat the internal combustion engine, then engine start-up efficiency is improved, but transmission temperature optimization is compromised when the engine is not active
Solution Approach 1:
The switching valve dynamically redirects heat flow based on system conditions. When the internal combustion engine requires preheating, the valve directs heat to the engine. When the engine is inactive, the valve redirects heat to the transmission heat exchanger, ensuring optimal transmission temperature. This dynamic adaptability resolves the contradiction between engine preheating and transmission temperature optimization
Solution Approach 2:
The system changes the destination parameter (heat recipient) based on operational conditions. By switching between directing heat to the internal combustion engine or to the transmission heat exchanger, the system optimizes either engine start-up efficiency or transmission temperature control depending on current needs, resolving the temperature management contradiction
3Productivity
If the transmission operates at optimal temperature independently, then transmission efficiency is improved, but additional temperature control components increase device complexity
Solution Approach 1:
The circulation line and switching valve serve multiple functions: they enable heat redirection to the transmission heat exchanger for transmission temperature optimization, and can also redirect heat to the internal combustion engine for preheating. This multi-functionality achieves independent transmission temperature control without adding significant complexity to the temperature control system
Solution Approach 2:
The transmission heat exchanger utilizes waste heat from the electric machine through the circulation line, allowing the transmission to self-regulate its temperature using otherwise wasted thermal energy. This self-service approach improves transmission efficiency without requiring additional energy input or complex active cooling systems
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 configuration enhances the overall efficiency of the drive device by ensuring the transmission operates at optimal temperature, even when the internal combustion engine is not active, and allows for efficient energy use by preheating the engine and optimizing transmission efficiency.
Implementation Method 1
the cooling fluid in the drive unit absorbs the heat present and transports it away from the drive unit
Implementation Method 2
A cooling fluid, for example a coolant or a refrigerant, is circulated at least temporarily in the cooling circuit
Implementation Method 3
by means of which the heat now present in the cooling fluid is given off to the outside of the drive device
Implementation Method 4
a cooler is assigned to the cooling circuit, by means of which the heat now present in the cooling fluid is given off
Implementation Method 5
the transmission has a transmission heat exchanger for temperature control, which is fluidically connected or can be connected to the cooling circuit via a circulation line
Implementation Method 6
heat from the electric machine being used to preheat the internal combustion engine and temper the transmission
Implementation Method 7
the circulation line can be fluidically decoupled from the cooling circuit by means of a switching valve
Data Source
Figure 1
AI summary
The invention relates to a drive unit (4) comprising a first drive unit (5) designed as an internal combustion engine, a second drive unit (6) designed as an electric machine, and a transmission (7) via which the first drive unit (5) and/or the second drive unit (6) is coupled or can be coupled to an output shaft (8) of the drive unit (4), wherein the first drive unit (5) and the second drive unit (6) are connected to a common cooling circuit (9) for temperature control. The transmission (7) is provided with a transmission heat exchanger (12) for temperature control, which is fluidically connected or can be connected to the cooling circuit (9) via a circulation line (13). The invention further relates to a method for operating a drive unit (4).