Electric Compressor Cooling Circuit for Internal Combustion Engine
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Solution Overview
Problem
Existing air supercharging systems for internal combustion engines, particularly those using electric compressors, face challenges in efficiently cooling the electric machine at low engine speeds, leading to potential overheating and irreversible damage due to the inefficiency of existing cooling circuits that rely on engine speed-dependent pressure gradients.
Innovation Solution
A cooling circuit with an air recirculation duct and a solenoid valve control system that regulates the flow of cooled compressed air to effectively cool the electric compressor and control the air flow independently of engine speed, using the pressure gradient between the heat exchanger outlet and the intake manifold to ensure adequate air circulation and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an electric compressor is used to provide majority of air supply for supercharging, then torque production at low speeds is improved, but the electric machine overheats due to prolonged operation
Solution Approach 1:
A cooling circuit is introduced as an intermediary system between the electric compressor and the environment. This cooling circuit includes a cooling device that actively removes heat from the electric machine, allowing the compressor to operate continuously at high power without overheating. The cooling circuit acts as a mediator that enables sustained high-performance operation by managing thermal effects.
2Temperature
If a cooling circuit relying on pressure gradient is used, then cooling function is provided, but the cooling effectiveness is insufficient at low engine speeds
Solution Approach 1:
The cooling system transitions from a static pressure-gradient-dependent design to a dynamic active cooling design. The cooling device can actively adjust its operation based on real-time temperature and speed conditions, ensuring adequate cooling effectiveness across the entire operating range including low engine speeds where passive pressure gradients are insufficient.
Solution Approach 2:
The passive mechanical cooling system relying on engine-speed-dependent pressure gradients is replaced with an active cooling device that can independently control cooling flow and effectiveness. This substitution allows the cooling function to be decoupled from engine speed, providing reliable cooling at all operating conditions.
3Duration of action of moving object
If the electric compressor operates uninterruptedly for long periods, then continuous power supply is achieved, but significant overheating and potential irreversible damage occurs
Solution Approach 1:
The cooling circuit provides beforehand cushioning by continuously removing heat from the electric machine during operation. This preventive cooling approach prevents temperature accumulation that would lead to overheating and irreversible damage, allowing the system to maintain reliable continuous operation for extended periods without thermal degradation.
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 solution allows for effective cooling of the electric compressor and power electronics, reducing the risk of damage and optimizing engine performance by maintaining efficient air circulation and temperature control, even at low engine speeds, thereby enhancing the reliability and longevity of the electric compressor.
Implementation Method 1
an exchanger heat to cool the compressed air from the compressor
Implementation Method 2
the stator circuits of the machine heat up by the Joule effect
Implementation Method 3
By the effect of the pressure gradient between the air inlet of the compressor and the outlet of the heat exchanger, a flow of fresh compressed air is drawn into the first bypass duct
Data Source
Figure 1~2
AI summary
The invention relates to an air supercharging device (1) of an internal combustion engine (2), comprising a cooling circuit (41, 42) of the electrical compressor (8), the cooling circuit (41, 42) comprising an air intake conduit (41) to the electrical compressor (6), extending between the outlet (47) of the heat exchanger (14) and the electrical compressor (6), in such a way as to be able to capture a fraction of the cooled compressed air, characterised in that it further comprises an air recirculation conduit (42) extending between the electrical compressor (6) and the vicinity of the inlet (45) of the intake manifold (3).