High-Speed Coolant Pump With Small Impeller and Integrated Cooling
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Solution Overview
Problem
Existing fluid pumps for coolant in fuel cell systems face challenges in effectively cooling high-powered electric motors and electronics while minimizing installation space, weight, and costs.
Innovation Solution
A fluid pump design with a reduced impeller diameter and increased rotational rate, utilizing a permanent magnet synchronous motor with a laminated stator core and bearings, and a cooling concept that transfers heat losses to easily cooled components, achieving a characteristic index value greater than 350 kW/m².
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the impeller diameter is reduced to decrease installation space and weight, then the pump can generate the required volumetric flow and pressure difference only by increasing rotational rate, which increases torque requirements and complicates motor design
Solution Approach 1:
The patent changes the operating parameters of the pump by reducing impeller diameter from conventional sizes to 40-90mm range and increasing rotational rate to 6900-7900 rpm, achieving a characteristic index value K > 350 kW/m². This parameter transformation allows the pump to maintain required hydraulic performance (volumetric flow 450-550 l/min, pressure difference 3-4 bar) while reducing installation space and weight, despite increased torque requirements at higher speeds
Solution Approach 2:
The patent employs a permanent magnet synchronous motor with dynamic control capability that can operate at high rotational rates (6900-7900 rpm) with precise torque control. The motor's dynamic performance allows it to meet the increased torque requirements at high speed while maintaining high efficiency (90-92%), enabling the reduced impeller diameter design to function effectively
2Productivity
If high rotational rates are used to compensate for reduced impeller diameter, then volumetric flow is maintained, but torque losses increase and cooling requirements become more stringent
Solution Approach 1:
The patent implements a self-cooling concept where the pump coolant serves dual purposes: it cools the fuel cell stack and simultaneously cools the motor and electronics through integrated cooling channels. The coolant flow path is designed to remove heat from motor losses and electronic components, allowing the system to handle the increased torque losses at high rotational rates without additional cooling systems
Solution Approach 2:
The patent operates the pump at high rotational rates (6900-7900 rpm) to maintain volumetric flow (450-550 l/min) with the reduced impeller diameter, accepting increased torque losses as a trade-off. The characteristic index value K > 350 kW/m² reflects this parameter optimization, where higher speed compensates for smaller size while the integrated cooling system manages the resulting energy losses
3Weight of stationary object
If the impeller diameter is reduced to less than 90 mm, then weight and installation space are decreased, but the motor and electronics require more effective cooling due to concentrated heat losses
Solution Approach 1:
The patent merges the cooling functions for the fuel cell stack, motor, and electronics into a single integrated cooling system. The motor and electronics are positioned within the coolant flow path, and cooling channels are designed to conduct heat from these components to the coolant. This combination allows the reduced impeller diameter design (40-90mm) to be effectively cooled using the same coolant that cools the fuel cell stack, eliminating the need for separate cooling systems and reducing overall weight
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
Enhances cooling efficiency, reduces torque losses, and increases overall cooling effectiveness by transferring heat losses to easily cooled components, while maintaining high volumetric flow and pressure difference.
Implementation Method 1
An alternating electromagnetic field can be generated in the stator coils. A voltage can be applied to the stator coils by an inverter in the motor. The alternating electromagnetic field can then interact with the magnetic field of the permanent magnets such that the rotor is rotated with the shaft, thus driving the impeller.
Implementation Method 2
The electric motor and the electronics require an effective cooling because of the high-powered hydraulics or electronics.
Data Source
AI summary
The invention relates to a fluid pump that has an electric motor with a shaft and an impeller with an outer diameter, that is connected to the shaft for conjoint rotation. A maximum volumetric flow and a maximum pressure difference (dp) can be generated in the fluid pump by the rotating impeller. A characteristic index number (K) for the fluid pump is greater than 350 kW/m2. The index number (K) corresponds to the product of the maximum volumetric flow and the maximum pressure difference in the fluid pump divided by the square of the outer diameter of the impeller.