Hybrid Drive Unit Thermal Layout Using Shared Oil-Coolant Paths
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Solution Overview
Problem
Hybrid vehicles face challenges in improving vehicle motion performance due to the limited mounting space for the drive unit containing an engine and a motor, necessitating downsizing while maintaining effective cooling systems.
Innovation Solution
The solution involves sharing a coolant circulation path and engine oil circulation path within the engine cooling system to cool the motor, utilizing multiple heat exchangers and refrigerant paths to manage temperature thresholds, and incorporating an ebullient cooler to maintain motor temperature, allowing for downsizing of the drive unit and improved vehicle maneuverability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate cooling systems are provided for the engine and motor, then cooling effectiveness is ensured, but the drive unit size increases
Solution Approach 1:
The patent combines the engine cooling system and motor cooling system into a single integrated cooling system. The coolant circulation path serves both the engine and motor, allowing heat removal from both components through shared radiators and circulation pumps, thereby reducing overall system volume while maintaining cooling effectiveness for both the engine and motor.
Solution Approach 2:
The cooling system is designed with multi-functionality where the same coolant circulation path, radiators, and pumps serve dual purposes: cooling the engine during engine operation and cooling the motor during motor operation. The system can adaptively switch between engine cooling mode and motor cooling mode based on operational requirements.
2Ease of operation
If the drive unit is arranged near the vehicle center to improve motion performance, then vehicle maneuverability improves, but mounting space becomes limited
Solution Approach 1:
By merging the engine cooling system and motor cooling system into a single integrated unit, the overall volume of the drive unit is reduced. This consolidation allows the drive unit to be compact enough to be mounted near the vehicle center, thereby improving vehicle maneuverability while still providing adequate cooling capacity for both engine and motor.
3Area of stationary object
If the drive unit is downsized to fit in limited mounting space, then mounting flexibility improves, but cooling system integration becomes complex
Solution Approach 1:
The patent integrates the engine cooling system and motor cooling system into a unified structure with shared components including coolant circulation paths, radiators, and pumps. This merging approach reduces the number of separate systems needed, thereby simplifying the overall integration complexity while achieving the required downsizing for limited mounting space.
Solution Approach 2:
The cooling system employs multi-functional components that can serve both engine cooling and motor cooling purposes. The same radiators and circulation pumps can adaptively cool either the engine or the motor based on operational mode, reducing the number of dedicated components needed and simplifying system integration.
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 enables the drive unit to be positioned closer to the vehicle's center, enhancing motion performance by reducing size while ensuring effective cooling of both the engine and motor, maintaining appropriate temperatures, and improving engine efficiency during mode transitions.
Implementation Method 1
a first heat exchanger that allows the engine coolant and the motor coolant to exchange heat with each other
Implementation Method 2
an ebullient cooler having: a refrigerant circulation path in which an ebullient cooling refrigerant, a boiling point of which is lower than that of the motor coolant, circulates; an ebullient section that is disposed in the middle of the refrigerant circulation path to allow heat exchange between the motor coolant and the ebullient cooling refrigerant
Implementation Method 3
a second engine cooling path that is a path of second engine coolant for cooling the engine, is different from the first engine cooling path, and has a fan
Data Source
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AI summary
In a cooling path of a motor 14, an oil control valve 45 is provided between a path LN21 and a path LN11, a heat exchanger 42 is provided between a path LN11 and a path LN31, and a heat exchanger 43 is provided between a path LN12 and a path LN32. In a motor-drive mode, a valve control section 52 switches a valve 45 to the path LN11 side when an engine temperature T is lower than a first threshold TTH1, and switches the valve 45 to the path LN12 side when the engine temperature T is equal to or higher than the first threshold TTH1. In the heat exchanger 42, motor cooling oil and engine oil exchange heat. In the heat exchanger 43, the motor cooling oil and a coolant for the engine exchange the heat.